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19-3875; Rev 1; 8/06
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
General Description
The MAX6791-MAX6796 ultra-low-quiescent-current, single-/dual-output linear regulators are ideal for automotive applications. The devices offer a wide 5V to 72V operating input range, allowing them to withstand automotive load-dump conditions while consuming only 68A. The MAX6791-MAX6794 are dual-output regulators capable of supplying up to 150mA per output. The MAX6795/MAX6796 offer a single output capable of delivering up to 300mA. These devices offer standard output-voltage options (5V, 3.3V, 2.5V, or 1.8V) and can be adjusted to any voltage from 1.8V to 11V. The MAX6791-MAX6794 also offer a fixed 5V output. All devices feature a push-pull or open-drain, active-low RESET output with a fixed output reset threshold that is 92.5%/87.5% of the regulator output OUT/OUT1. The reset output asserts low when OUT/OUT1 drops below the reset threshold and remains low for the fixed or capacitor-adjustable reset timeout period after OUT/OUT1 exceeds the reset threshold. The MAX6791-MAX6796 provide a watchdog input that monitors a pulse train from the microprocessor (P) and generates reset pulses if the watchdog input remains high or low for a duration longer than the watchdog timeout period. All devices are available with either a fixed watchdog timeout period of 280ms (min) or a period adjustable with an external capacitor. The MAX6791/MAX6792 feature a windowed watchdog timeout period with selectable window ratio. The watchdog feature can be disabled. The MAX6791-MAX6794 provide dual enable inputs (ENABLE1 and ENABLE2) that control each regulator independently. The single-output MAX6795/MAX6796 feature one enable input (ENABLE). All devices include a hold input (HOLD) that aids the implementation of a self-holding circuit without requiring external components. Once the regulator is enabled, setting HOLD low forces the regulator to remain on even if ENABLE/ENABLE1 is subsequently set low. Releasing HOLD shuts down the regulator. The MAX6791-MAX6796 are available in a small, thermally enhanced TQFN package. The 5mm x 5mm package dissipates up to 2.7W, supporting continuous regulator operation during high ambient temperatures, high battery voltage, and high load-current conditions. The MAX6791-MAX6796 are specified for a -40C to +125C operating temperature range.
KIT ATION EVALU BLE AVAILA
Features
Low 68A Quiescent Current Wide 5V to 72V Supply Voltage Range Output Current Single Output Up to 300mA Dual Outputs Up to 150mA per Output Low Dropout Voltage 420mV (typ) at 100mA (Single) 840mV (typ) at 100mA (Dual) Fixed Output-Voltage Options: 5V, 3.3V, 2.5V, 1.8V, or Adjustable Output (from 1.8V to 11V) ENABLE and HOLD Functionality RESET Output: Open Drain or Push-Pull Internally Fixed (35s, 3.125ms, 12.5ms, 50ms, or 200ms) or Capacitor-Adjustable Reset Timeout Periods Internally Fixed or Capacitor-Adjustable Watchdog Timeout Periods Windowed (Minimum/Maximum) Watchdog Timer Options (MAX6791/MAX6792) Watchdog Disable Feature Thermal, Short-Circuit, and Output Overvoltage Protection Fully Specified from -40C to +125C Small, Thermally Enhanced, 5mm x 5mm TQFN
MAX6791-MAX6796
Ordering Information
PART MAX6791TP_D _+ MAX6792TP_D _+ MAX6793TP_ D_+ MAX6794TP_ D_+ MAX6795TP_ D_+ MAX6796TP_D _+ TEMP RANGE -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C PINPACKAGE 20 TQFN 20 TQFN 20 TQFN 20 TQFN 20 TQFN 20 TQFN PKG CODE T2055-4 T2055-4 T2055-4 T2055-4 T2055-4 T2055-4
Applications
Automotive
+Denotes lead-free package. For tape-and-reel, add a T after the "+." Tape-and-reel are offered in 2.5k increments. The first placeholder "_" designates preset output-voltage option and preset reset threshold level; see Table 1. The second placeholder "_ " designates the reset timeout period; see Table 2. For example, the MAX6791TPSD3+ indicates a 3.3V output voltage with a reset threshold of 87.5% at nominal voltage and a 50ms reset timeout period. Samples are generally held in stock. Nonstandard versions require a 2.5k minimum order quantity. Typical Application Circuit, Pin Configurations, and Selector Guide appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
ABSOLUTE MAXIMUM RATINGS
(All pins referenced to GND, unless otherwise noted.) IN to GND ...............................................................-0.3V to +80V ENABLE, ENABLE1, ENABLE2, PFI, GATEP to GND ...........................................-0.3V to (IN + 0.3V) GATEP to IN ...........................................................-12V to +0.3V OUT, OUT1, OUT2, PFO, RESET (open-drain versions), CSRT, CSWT .......................................................-0.3V to +12V HOLD, RESET (push-pull versions), WDI, WDS0, WDS1, WD-DIS, SET, SET1......................-0.3V to (OUT/OUT1 + 0.3V) OUT, OUT1, OUT2 Short Circuit to GND....................................................................Continuous Maximum Current (all pins except IN and OUT_)...............50mA Continuous Power Dissipation (TA = +70C) 20-Pin TQFN (derate 33.3mW/C above +70C) .....2666.7mW Operating Temperature Range (TA) ..................-40C to +125C Junction Temperature (TJ) .................................................150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = 14V, CIN = 1F, COUT = 10F, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER Supply Voltage Range SYMBOL VIN Regulators on (ILOAD = 0mA), VIN = 8V VIN = 8V, ILOAD = 300mA (MAX6795/MAX6796) VIN = 14V, ILOAD = 100mA (MAX6795/MAX6796) Regulators on, OUT/OUT1 = OUT2 = 5V VIN = 8V, ILOAD1 = ILOAD2 = 150mA (MAX6791-MAX6794) VIN = 14V, ILOAD1 = ILOAD2 = 50mA (MAX6791-MAX6794) Regulators on (ILOAD = 0mA), VIN = 42V Regulators on (ILOAD = 20mA, total) OUT1/OUT2/OUT = 5V, VIN = 42V Shutdown Supply Current ISHDN Regulators off, VIN = 14V CONDITIONS MIN 5 68 130 100 TYP MAX 72 85 220 160 UNITS V
Supply Current
IIN
130
220
A
100 74 100 27
160 95 170 45 A
2
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 14V, CIN = 1F, COUT = 10F, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER SYMBOL CONDITIONS L/M, ILOAD = ILOAD1 = 1mA L/M, ILOAD = 150mA (MAX6791-MAX6794), VIN = 8V L/M, ILOAD = 300mA (MAX6795/MAX6796), VIN = 8V T/S, ILOAD = ILOAD1 = 1mA T/S, ILOAD = 150mA (MAX6791-MAX6794), VIN = 6V VOUT/ VOUT1 T/S, ILOAD = 300mA (MAX6795/MAX6796), VIN = 6V Z/Y, ILOAD = ILOAD1 = 1mA Z/Y, ILOAD = 150mA (MAX6791-MAX6794), VIN = 5.5V Z/Y, ILOAD = 300mA (MAX6795/MAX6796), VIN = 5.5V W/V, ILOAD = ILOAD1 = 1mA W/V, ILOAD = 150mA (MAX6791-MAX6794), VIN = 5V W/V, ILOAD = 300mA (MAX6795/MAX6796), VIN = 5V Output Voltage (MAX6791-MAX6794) SET/SET1 Threshold Voltage Adjustable Output Voltage Dual-ModeTM SET Threshold SET/SET1 Input Current VOUT2 VSET VOUT SET/SET1 rising SET/SET1 falling SET/SET1 = 1V, VIN = 11V L/M, ILOAD = 20mA (Note 2) (MAX6795/ L/M, ILOAD = 300mA (Note 2) MAX6796) T/S, ILOAD = 300mA (Note 3) (MAX6791- L/M, ILOAD = 10mA (Note 2) MAX6794) T/S, ILOAD = 150mA (Note 3) Guaranteed Output Current (Note 4) MAX6791-MAX6794, inferred from dropout test L/M, ILOAD = 150mA (Note 2) -100 84 1200 1700 1000 84 1700 300 150 ILOAD2 = 1mA ILOAD2 = 150mA ILOAD = ILOAD1 = 1mA, OUT/OUT1 = 5V MIN 4.858 4.811 4.850 3.206 3.175 3.201 2.429 2.405 2.425 1.748 1.731 1.746 4.858 4.811 1.207 1.8 124 62 +100 130 1800 2400 1800 130 2400 mA mV TYP 4.974 4.945 5 3.282 3.263 3.3 2.487 2.472 2.5 1.791 1.780 1.8 4.974 4.945 1.2315 MAX 5.090 5.078 5.150 3.360 3.351 3.399 2.546 2.539 2.575 1.832 1.828 1.854 5.090 5.079 1.256 11.0 V V V mV nA V UNITS
MAX6791-MAX6796
Output Voltage
Dropout Voltage
VDO
MAX6795/MAX6796, inferred from dropout test
Dual Mode is a trademark of Maxim Integrated Products, Inc.
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 14V, CIN = 1F, COUT = 10F, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER Short-Circuit Output Current Limit (Note 4) Thermal-Shutdown Temperature Thermal-Shutdown Hysteresis Line Regulation 8V VIN 72V, ILOAD = 1mA 8V VIN 72V, ILOAD = 10mA IOUT = 1mA to 300mA (MAX6795/MAX6796) Load Regulation (Note 5) IOUT = 1mA to 150mA (MAX6791-MAX6794) Power-Supply Rejection Ratio PSRR ILOAD = 10mA, f = 100Hz, VIN = 500mVP-P ILOAD = 300mA, VOUT = 5V, OUT = 90% of its nominal value Startup Response Time tSTART ILOAD = 150mA, VOUT = 5V, OUT1/OUT2 = 90% of its nominal value ISINK = 1mA from OUT/OUT1/OUT2 VOUT = VOUT (nominal) x 1.15 IGATEP = -100A, VIN = 20V IGATEP = 0, VIN = 20V VIL VIH Enable is internally pulled down to GND HOLD is internally pulled to OUT/OUT1 1.4 0.5 2 5 13.8 8 69 180 s 360 1.05 x VOUT 10 16.3 10 18.8 12 0.4 1.1 x VOUT V mA V V V V A A 1.5 dB SYMBOL CONDITIONS MAX6795/MAX6796, output shorted, VIN = 6V MAX6791-MAX6794, output shorted, VIN = 6V MIN 400 200 TYP 480 mA 240 +165 20 1 1 2 % C C % of VOUT MAX UNITS
Output Overvoltage Protection Threshold Output Overvoltage Protection Sink Current IN to GATEP Clamp Voltage IN to GATEP Drive Voltage ENABLE/ENABLE1/ENABLE2/ HOLD Input-Voltage Low ENABLE/ENABLE1/ENABLE2/ HOLD Input-Voltage High ENABLE/ENABLE1/ENABLE2 Input Pulldown Current HOLD Input Pullup Current
OVTH
4
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 14V, CIN = 1F, COUT = 10F, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER RESET OUTPUT L M T Reset Threshold (Preset Output Voltage) SET/SET1 = GND S Z Y W V L/T/Z/W Reset Threshold (Adjustable Output Voltage) M/S/Y/V OUT to Reset Delay VOUT1/VOUT falling D0 D1 Reset Timeout Period (CSRT = OUT/OUT1) tRP VOUT1/VOUT rising D2 D3 D4 CSRT Ramp Current CSRT Ramp Threshold WATCHDOG INPUT Normal Watchdog Timeout Period Fast Watchdog Timeout Period SET Ratio = 8 Fast Watchdog Timeout Period SET Ratio = 16 Fast Watchdog Timeout Period SET Ratio = 64 Fast Watchdog Minimum Period CSWT Ramp Current CSWT Ramp Threshold Undercurrent Threshold for Watchdog Enable Undercurrent Threshold for Watchdog Disable tWD2 tWD1 tWD1 tWD1 tWD0 Adjustable timeout Adjustable timeout CSWT = OUT/OUT1 (fixed) CSWT = 1500pF (adjustable) CSWT = OUT/OUT1 (fixed) CSWT = 1500pF (adjustable) CSWT = OUT/OUT1 (fixed) CSWT = 1500pF (adjustable) CSWT = OUT/OUT1 (fixed) CSWT = 1500pF (adjustable) 280.0 170 37.5 21.95 18.75 10.80 4.68 2.52 2000 800 1.185 7.0 3 1000 1.218 10 5 1250 1.255 13.8 7 400.0 236.2 50.0 29.52 25.0 14.76 6.25 3.69 520.0 290 62.5 36.90 31.25 18.45 7.81 4.62 ms ms ms ms ns nA V mA mA 2.187 8.75 35 140 800 1.185 4.500 4.250 2.970 2.805 2.250 2.125 1.620 1.530 0.90 x VOUT 0.85 x VOUT 4.625 4.375 3.053 2.888 2.313 2.188 1.665 1.575 0.925 x VOUT 0.875 x VOUT 35 35 3.125 12.5 50 200 1000 1.218 4.063 16.25 65 260 1250 1.255 nA V ms 4.750 4.500 3.135 2.970 2.375 2.250 1.710 1.620 0.95 x VOUT 0.90 x VOUT s s V SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX6791-MAX6796
V
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 14V, CIN = 1F, COUT = 10F, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER Input-Voltage Low Input-Voltage High Input Current POWER-FAIL COMPARATOR PFI Threshold PFI Hysteresis PFI Input Current PFI to PFO Delay LOGIC OUTPUT (RESET, PFO) Output-Voltage Low (Open Drain or Push-Pull) VOL ISINK = 50A (output asserted) ISINK = 3.2mA (output asserted) VOUT 1.0V, ISOURCE = 10A (output not asserted) Output-Voltage High (Push-Pull) VOH VOUT 1.5V, ISOURCE = 100A (output not asserted) VOUT 2.2V, ISOURCE = 500A (output not asserted) Open-Drain Leakage V RESET = V PFO = 12V (output not asserted) 0.8 x VOUT 0.8 x VOUT 0.8 x VOUT 100 nA V 0.3 0.4 V VPFI = 14V (VPFI + 50mV) to (VPFI - 50mV) -100 35 VPFI 1.199 1.231 0.5 +100 1.263 V % nA s SYMBOL VIL VIH Inputs connected to OUT/OUT1 or GND 1.4 -100 +100 CONDITIONS MIN TYP MAX 0.4 UNITS V V nA LOGIC INPUT (WDS0, WDS1, WD-DIS, WDI)
Note 1: Note 2: Note 3: Note 4: Note 5:
All devices are 100% production tested at TJ = +25C and +125C. Limits at -40C are guaranteed by design. Dropout voltage is defined as (VIN - VOUT) when VOUT is 98% of VOUT for VIN = 8V. Dropout voltage is defined as (VIN - VOUT) when VOUT is 98% of VOUT for VIN = 6V. Operation beyond the absolute maximum power dissipation is not guaranteed and may damage the part. Test at VIN = 8V (L/M), VIN = 6V (T/S), VIN = 5V (Z/Y/W/V).
6
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Typical Operating Characteristics
(VIN = VEN = 14V, CIN = 0.1F, COUT = 10F, TJ = TA = +25C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX6791-96 toc01
SUPPLY CURRENT vs. TEMPERATURE
MAX6791 toc02
SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX6793/MAX6794 35 SUPPLY CURRENT (A) 30 25 20 15
MAX6791-96toc03
80 75 SUPPLY CURRENT (A) 70 65 60 55 50 45 40 5 15 25 35 45 55 65 MAX6791 NO LOAD
120 110 SUPPLY CURRENT (A) 100 90 80 70 60 MAX6791 50 ILOAD = 1mA ILOAD = 0
40
ILOAD = 100mA ILOAD = 50mA
10 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) 5 15 25 35 45 55 65 75 SUPPLY VOLTAGE (V)
75
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE
MAX6791toc04
NORMALIZED RESET THRESHOLD vs. TEMPERATURE
MAX6791toc05
DROPOUT VOLTAGE vs. TEMPERATURE
1400 DROPOUT VOLTAGE (mV) 1200 1000 800 600 400 200 ILOAD = 10mA -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) ILOAD = 100mA MAX6792 VOUT = 5V ILOAD = 150mA
MAX6791toc06
40 SHUTDOWN SUPPLY CURRENT (A) MAX6795 VIN = 14V 35
1.020 MAX6796 NORMALIZED RESET THRESHOLD 1.010
1600
30
1.000
25
0.990
20 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
0.980 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
0
DROPOUT VOLTAGE vs. TEMPERATURE
MAX6791toc07
OUTPUT VOLTAGE vs. INPUT VOLTAGE
4.989 4.988 OUTPUT VOLTAGE (V) 4.987 VOUT (V) 4.986 4.985 4.984 4.983 4.982 4.5 4.0 3.5 3.0 2.5 2.0 5 15 25 35 45 55 65 75 MAX6795 PRESET VOLTAGE, NO LOAD
MAX6791-96toc08
OUTPUT VOLTAGE vs. LOAD CURRENT
5.5 5.0 MAX6796 VIN = 14V VOUT = 5V
MAX6791-96 toc09
2000 1800 1600 DROPOUT VOLTAGE (mV) 1400 1200 1000 800 600 400 200 0 ILOAD = 10mA ILOAD = 100mA ILOAD = 150mA MAX6796 ILOAD = 300mA
4.990
6.0
VOUT = 3.3V
4.981 4.980
SET EXTERNALLY 0 50 100 150 200 250 300 LOAD CURRENT (mA)
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
INPUT VOLTAGE (V)
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Typical Operating Characteristics (continued)
(VIN = VEN = 14V, CIN = 0.1F, COUT = 10F, TJ = TA = +25C, unless otherwise noted.)
NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE
MAX6791toc10
PSRR vs. FREQUENCY
-45 -50 PSRR (dB) -55 -60 -65 -70 -75 VIN = 6V VOUT = 1.8V ILOAD = 10mA
MAX6791toc11
1.03 NORMALIZED RESET TIMEOUT PERIOD MAX6796 1.02
-40
1.01
1.00
0.99
0.98 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
-80 10 100 1k FREQUENCY (Hz) 10k 100k
NORMALIZED WATCHDOG TIMEOUT PERIOD vs. TEMPERATURE
NORMALIZED WATCHDOG TIMEOUT PERIOD
MAX6791toc12
NORMALIZED PFI THRESHOLD vs. TEMPERATURE
MAX6796 NORMALIZED PFI THRESHOLD 1.000 0.999 0.998 0.997 0.996 0.995
MAX6791toc13
1.020 1.015 1.010 1.005 1.000 0.995 0.990 0.985 0.980 MAX6796
1.001
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
RESET OUTPUT vs. SOURCE CURRENT
MAX6791-96toc14
RESET OUTPUT VOLTAGE vs. SINK CURRENT
0.9 RESET OUTPUT VOLTAGE (V) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 MAX6796
MAX6791-96toc15
5.0 4.5 4.0 RESET OUTPUT (V) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 2 4 6 8 10 12 MAX6796
1.0
14
0
1
2
3
4
5
6
7
8
9
10
SOURCE CURRENT (mA)
SINK CURRENT (mA)
8
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Typical Operating Characteristics (continued)
(VIN = VEN = 14V, CIN = 0.1F, COUT = 10F, TJ = TA = +25C, unless otherwise noted.)
RESET TIMEOUT PERIOD vs. CCSRT
MAX6791-96toc16
WATCHDOG TIMEOUT PERIOD vs. CCSWT
MAX6791-96toc17
10,000
100,000
RESET TIMEOUT PERIOD (ms)
1000
WATCHDOG TIMEOUT PERIOD
10,000
100
1000
10
100
1 0.1 0.0001 0.001 0.01 CCSRT (F) 0.1 1
10
1 0.0001
0.001 CCSWT (F)
0.01
0.1
LOAD-TRANSIENT RESPONSE
MAX6791-96toc18
LOAD-TRANSIENT RESPONSE
MAX6796 VIN = 14V VOUT = 5V
MAX6791-96toc19
IOUT1
MAX6796 COUT = 10F VOUT = 5V VIN = 14V
IOUT 100mA/div 1mA
100mA/div 1mA
OUT1 VOUT ACCOUPLED 400s/div
1V/div
OUT OUT ACCOUPLED 400s/div
500mV/div
LINE-TRANSIENT RESPONSE
MAX6791-96toc20
MAX6796 ILOAD = 10mA VIN 10V/div (AC-COUPLED)
OUT OUT ACCOUPLED 1ms/div
20mV/div
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Typical Operating Characteristics (continued)
(VIN = VEN = 14V, CIN = 0.1F, COUT = 10F, TJ = TA = +25C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
MAX6791-96toc21
LOAD-TRANSIENT RESPONSE
MAX6791-96toc22
100mA/div IOUT1 1mA
IOUT1
100mA/div 20mA
OUT1 AC-COUPLED MAX6792 OUT1 = 5V COUT = 10F 1ms/div
500mV/div
OUT1 AC-COUPLED MAX6792 OUT1 = 5V COUT = 10F 1ms/div
500mV/div
Pin Description
PIN MAX6791/ MAX6793/ MAX6792 MAX6794 1, 2 1, 2 MAX6795/ MAX6796 -- NAME FUNCTION Regulator 1 Output. Fixed (+1.8V, +2.5V, +3.3V, or +5V) or adjustable (+1.8V to +11V). OUT1 = 150mA (max). Connect a 10F (min) capacitor from OUT1 to GND. Feedback Input for Setting the OUT1 Voltage. Connect SET1 to GND to select the preset output voltage. Connect to an external resistive divider for adjustable output operation. Active-Low, Open-Drain, Power-Fail Comparator Output. PFO asserts low when PFI is below the internal 1.231V threshold. PFO deasserts when PFI is above the internal 1.231V threshold. Watchdog Timeout Period Adjust Input. Connect CSWT to OUT1/OUT for the internally fixed watchdog timeout period. For adjustable watchdog timeout period, connect a capacitor from CSWT to GND. See the Selecting Watchdog Timeout Period section for more details. Reset Timeout Period Adjust Input. Connect CSRT to OUT1/OUT for the internally fixed timeout period. For adjustable timeout, connect a capacitor from CSRT to GND. See the Reset Output section for more details. Ground Active-Low Reset Output. RESET remains low while OUT1/OUT is below the reset threshold. RESET remains low for the duration of the reset timeout period after the reset conditions end. RESET is available in push-pull and open-drain options.
OUT1
3
3
--
SET1
4
4
4
PFO
5
5
5
CSWT
6 7 8
6 7 8
6 7 8
CSRT GND RESET
10
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Pin Description (continued)
PIN MAX6791/ MAX6793/ MAX6792 MAX6794 9 10 -- -- MAX6795/ MAX6796 -- -- NAME FUNCTION
MAX6791-MAX6796
WDS1 WDS0
Min/Max Watchdog Logic-Select Input. WDS0 and WDS1 select the watchdog window ratio or disable the watchdog timer. Drive WDS0 and WDS1 high or low to select the desired ratio, see Table 4. Watchdog Input. MAX6793-MAX6796: A falling or rising transition must occur on WDI within the selected watchdog timeout period or a reset pulse occurs. The watchdog timer clears when a transition occurs on WDI or whenever RESET is asserted. MAX6791/MAX6792: WDI falling and rising transitions within periods shorter than tWD1 or longer than tWD2 force RESET to assert low for the reset timeout period. The watchdog timer begins to count after RESET is deasserted. The watchdog timer clears when a valid transition occurs on WDI or whenever RESET is asserted. Connect WDS0 high and WDS1 low to disable the watchdog timer function. See the Watchdog Timer section. Active-Low Regulator Hold Input. When HOLD is forced low, OUT1/OUT remains ON even if ENABLE1/ENABLE is pulled low. To shut down the output of the regulator (OUT/OUT1), release HOLD after ENABLE1/ENABLE is pulled low. Connect HOLD to OUT1/OUT or leave unconnected if unused. HOLD is internally connected to OUT/OUT1 through a 2A current source. Regulator 2 Output. OUT2 is a fixed +5V output. Connect a 10F (min) capacitor from OUT2 to GND. Active-High Enable Input 2. Drive ENABLE2 high to turn on OUT2. ENABLE2 is internally connected to ground through a 0.5A current sink. Adjustable Power-Fail Comparator Input. Connect PFI to a resistive-divider to set the desired PFI threshold. The PFI input is referenced to an accurate 1.231V threshold. Regulator Inputs. Bypass IN with a 1F capacitor to GND. pFET Gate Drive. Connect GATEP to the gate of a p-channel MOSFET to provide low drop reverse-battery voltage protection. Active-High Enable Input 1. Drive ENABLE1 high to turn on OUT1. ENABLE1 is internally connected to ground through a 0.5A current sink. Watchdog Disable Input. Drive WD-DIS low to disable the watchdog timer. Drive WD-DIS high or connect to OUT/OUT1 to enable the watchdog timer. The watchdog timer clears when reset asserts.
11
11
11
WDI
12
12
12
HOLD
13, 14 15
13, 14 15
-- --
OUT2 ENABLE2
16 17, 18 19 20
16 17, 18 19 20
16 17, 18 19 --
PFI IN GATEP ENABLE1
--
9
9
WD-DIS
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11
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Pin Description (continued)
PIN MAX6791/ MAX6793/ MAX6792 MAX6794 -- -- 10 -- MAX6795/ MAX6796 10, 13, 14, 15 1, 2 NAME FUNCTION
N.C. OUT
Not Internally Connected Regulator Output. Fixed +5V, +3.3V, +2.5V, +1.8V, or adjustable output (+1.8V to +11V). Connect a 10F (min) capacitor from OUT to GND. Feedback Input for Setting the OUT Voltage. Connect SET to GND to select the preset output voltage. Connect to an external resistive-divider for adjustable output operation. Active-High Enable Input. Drive ENABLE high to turn on the regulator. ENABLE is internally connected to ground through a 0.5A current sink. Exposed Pad. EP is internally connected to GND. Connect EP to the ground plane to provide a low thermal-resistance path from the IC junction to the PC board. Do not use as the electrical connection to GND.
--
--
3
SET
--
--
20
ENABLE
--
--
--
EP
Detailed Description
The MAX6791-MAX6796 ultra-low-quiescent-current, single-/dual-output, high-input-voltage linear regulators operate from 5V to 72V. The MAX6791-MAX6794 feature dual regulators that deliver up to 150mA of load current per output. One output is available with preset output-voltage options (+1.8V, +2.5V, +3.3V, and +5.0V) and can be adjusted to any voltage between +1.8V to +11V using an external resistive-divider at SET1. The other output provides a fixed 5V output voltage. The MAX6795/MAX6796 feature a single regulator that delivers up to 300mA of current with preset outputvoltage options (+1.8V, +2.5V, +3.3V, and +5.0V) or can be adjusted to any voltage between +1.8V to +11V. All devices include an integrated P reset circuit with a fixed/adjustable reset and watchdog timeout period. The MAX6791-MAX6796 monitor OUT/OUT1 and assert a reset output when the output falls below the reset threshold.
+5V, or an adjustable output voltage of +1.8V to +11V, selected using an external resistive-divider network connected between OUT1/OUT, SET1/SET, and GND (see Figure 1). In addition to an adjustable output, the MAX6791-MAX6794 feature a fixed 5V output voltage.
Reset Output
The reset output is typically connected to the reset input of a P. A P's reset input starts or restarts the P in a known state. The MAX6791-MAX6796 supervisory circuits provide the reset logic output to prevent codeexecution errors during power-up, power-down, and brownout conditions (see the Typical Application Circuit). RESET changes from high to low whenever the monitored output voltage drops below the reset threshold voltage or the watchdog timeout expires. Once the monitored voltage exceeds its respective reset threshold voltage, RESET remains low for the reset timeout period, then goes high.
Regulators
The single and dual regulators accept an input voltage from 5V to 72V. The MAX6791-MAX6796 offer fixed preset output voltages of +1.8V, +2.5V, +3.3V, and
12
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Functional Diagrams
MAX6791-MAX6796
ENABLE2 MAX6791/MAX6792
OUT2 THERMAL PROTECTION IN GATEP OVERCURRENT PROTECTION OUT1
ENABLE1 HOLD
CONTROL LOGIC
1.23V 124mV RESET TIMEOUT RESET WATCHDOG TIMEOUT
SET1
1.138V OR 1.076V
RESET CSRT WDI CSWT WDS0 WDS1 PFO
GND
PFI
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13
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Functional Diagrams (continued)
ENABLE2 MAX6793/MAX6794
OUT2 THERMAL PROTECTION IN GATEP OVERCURRENT PROTECTION OUT1
ENABLE1 HOLD
CONTROL LOGIC
1.23V 124mV RESET TIMEOUT RESET WATCHDOG TIMEOUT
SET1
1.138V OR 1.076V
RESET CSRT WDI CSWT WD-DIS PFO
GND
PFI
14
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Functional Diagrams (continued)
MAX6791-MAX6796
THERMAL PROTECTION IN GATEP OVERCURRENT PROTECTION
MAX6795/MAX6796 OUT
ENABLE HOLD
CONTROL LOGIC
1.23V 124mV RESET TIMEOUT RESET WATCHDOG TIMEOUT
SET
1.138V OR 1.076V
RESET CSRT WDI CSWT WD-DIS PFO
GND
PFI
______________________________________________________________________________________
15
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Watchdog Timer
The MAX6791-MAX6796 include a watchdog timer that asserts RESET if the watchdog input (WDI) does not toggle high to low or low to high within the watchdog timeout period t WD (280ms min or externally adjustable). RESET remains low for the fixed or useradjustable reset timeout period, tRP. If the watchdog is not updated for lengthy periods of time, the reset output appears as a pulse train, asserted for t RP , deasserted for tWD, until WDI is toggled again. Once RESET asserts, it stays low for the entire reset timeout period ignoring any WDI transitions that may occur. To prevent the watchdog from asserting RESET, toggle WDI with a valid rising or falling edge before tWD from the last edge. The watchdog counter clears when WDI toggles prior to tWD from the last edge or when RESET asserts. The watchdog resumes counting after RESET deasserts. The MAX6791/MAX6792 have a windowed watchdog timer that asserts RESET for the adjusted reset timeout period when the watchdog recognizes a fast watchdog fault (tWDI < tWD1), or a slow watchdog fault (tWDI > tWD2). The reset timeout period is adjusted independently of the watchdog timeout period. preregulated input of the power supply (such as a battery) or providing an early power-fail warning so software can conduct an orderly system shutdown. Set the power-fail threshold with a resistive-divider, as shown in Figure 5. The typical comparator delay is 35s from PFI to PFO. Connect PFI to GND or IN if unused.
Reverse-Battery Protection Circuitry
The MAX6791-MAX6796 include an overvoltage protection circuit that is capable of driving a p-channel MOSFET to protect against reverse-battery conditions. This MOSFET eliminates the need for external diodes, thus minimizing the input voltage drop. See the Typical Application Circuit. The low p-channel MOSFET onresistance of 30m or less yields a forward-voltage drop of only a few millivolts versus hundreds of millivolts for a diode, thus improving efficiency in batteryoperated devices. Connecting a positive battery voltage to the drain of Q1 (see the Typical Application Circuit) forward biases its body diode. When the source voltage exceeds Q1's threshold voltage, Q1 turns on. Once the FET is on, the battery is fully connected to the system and can deliver power to the device and the load. An incorrectly inserted battery reverse-biases the FET's body diode. The gate remains at the ground potential. The FET remains off and disconnects the reversed battery from the system. The internal zener diode and resistor combination at GATEP prevent damage to the p-channel MOSFET during an overvoltage condition. See the Functional Diagrams.
Enable and Hold Inputs
The MAX6791-MAX6796 support two logic inputs, ENABLE1/ENABLE and HOLD, making these devices suitable for automotive applications. For example, when the ignition key signal drives ENABLE1/ENABLE high, the regulator turns on and remains on even if ENABLE1/ENABLE goes low, as long as HOLD is forced low and stays low after initial regulator power-up. In this state, releasing HOLD turns the regulator output (OUT/OUT1) off. This feature makes it possible to implement a self-holding circuit without external components. Forcing ENABLE1/ENABLE low and HOLD high or unconnected places the MAX6791-MAX6796 into shutdown mode in which the MAX6791-MAX6796 draw less than 27A of supply current. Table 3 shows the state of the regulator output with respect to the voltage level at ENABLE1/ENABLE and HOLD. Connect HOLD to OUT1/OUT or leave it unconnected to allow the ENABLE1/ENABLE input to act as a standard ON/OFF switch for the regulator output (OUT/OUT1).
Thermal Protection
When the junction temperature exceeds TJ = +165C, the internal protection circuit turns off the internal pass transistor and allows the IC to cool. The thermal sensor turns the pass transistor on again after the junction temperature drops to +145C, resulting in a cycled output during continuous thermal-overload conditions. Thermal protection protects the MAX6791-MAX6796 in the event of fault conditions. For continuous operation, do not exceed the absolute maximum junction temperature rating of +150C.
Proper Soldering of Package Heatsink
The MAX6791-MAX6796 package features an exposed thermal pad on its underside that should be used as a heatsink. This pad lowers the package's thermal resistance by providing a direct heat-conduction path from the die to the PC board. Connect the exposed pad and GND to the system ground using a large pad or ground plane, or multiple vias to the ground plane layer.
Power-Fail Comparator
PFI is the noninverting input to a comparator. If PFI is less than VPFI (1.231V), PFO goes low. Common uses for the power-fail comparator include monitoring the
16
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Applications Information
Output Voltage Selection
The MAX6791-MAX6796 feature dual-mode operation: these devices operate in either a preset voltage mode or an adjustable mode. In preset voltage mode, internal trimmed feedback resistors set the internal linear regulator to +1.8V, +2.5V, +3.3V, or +5V (see the Selector Guide). Select preset voltage mode by connecting SET1 (MAX6791-MAX6794)/SET(MAX6795/MAX6796) to GND. In adjustable mode, select an output voltage between +1.8V and +11V using two external resistors connected as a voltage-divider to SET1/SET (see Figure 1). Set the output voltage using the following equation: R1 VOUT = VSET 1 + R2 where VSET = 1.2315V and R1, R2 200k.
Selecting Reset Timeout Period
The reset timeout period is adjustable to accommodate a variety of P applications. Adjust the reset timeout period by connecting a capacitor between CSRT and GND. Use the following formula to set the reset timeout period: V tRP = CCSRT 1.218 x 106 A where tRP is in seconds and CCSRT is in Farads. Connect CSRT to OUT1 (MAX6791-MAX6794) or to OUT (MAX6795/MAX6796) to select an internally fixed timeout period. Connect CSRT to GND to force RESET low. C CSRT must be a low-leakage (< 10nA) type capacitor. Ceramic capacitors are recommended; do not use capacitors lower than 100pF to avoid the influence of parasitic capacitances.
MAX6791-MAX6796
Available Output-Current Calculation
The MAX6791-MAX6794 provide up to 150mA per output, and the MAX6795/MAX6796 provide up to 300mA of load current. Since the input voltage can be as high as +72V, package power dissipation limits the amount of output current available for a given input/output voltage and ambient temperature. Figure 2 shows the maximum power-dissipation curve for the MAX6791- MAX6796. The graph assumes that the exposed metal pad of the device package is soldered to a solid 1in2 section of PC board copper. Use Figure 2 to determine the allowable package dissipation for a given ambient temperature. Alternately, use the following formula to calculate the allowable package dissipation: PDMAX = Maximum Power Dissipation PDMAX = 2.666W, for TA +70C PDMAX = [2.666W - 0.0333W x (TA - 70C)], for +70C < TA +125C where 0.0333W is the MAX6791-MAX6796 package thermal derating in W/C and TA is the ambient temperature in C. After determining the allowable package dissipation, calculate the maximum output current using the following formula: PD = Power Dissipation PD < PDMAX where PD = [(IN - OUT1) x IOUT1] + [(IN OUT2) x IOUT2], for MAX6791-MAX6794. Also, IOUT1 should be 150mA and IOUT2 should be 150mA in any case. PD < PD MAX where PD = [(IN - OUT) x I OUT ], for MAX6795/MAX6796. Also, IOUT should be 300mA in any case.
VIN
IN OUT1/OUT MAX6791-MAX6796 SET1/SET R2 GND R1
Figure 1. Setting the Output Voltage Using a Resistive-Divider
IOUT vs. (VIN - VOUT)
350 300 250 IOUT (mA) 200 150 100 50 0 0 10 20 30 40 50 60 70 75 (VIN - VOUT) (V) VOUT = 1.8V +70C SAFE OPERATION REGION FOR EACH TEMPERATURE POINT IS UNDER THE CURVE +85C +125C
Figure 2. Maximum Power Dissipation for MAX6791-MAX6796 17
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Selecting Watchdog Timeout Period
The watchdog timeout period is adjustable to accommodate a variety of P applications. With this feature, the watchdog timeout can be optimized for software execution. The programmer can determine how often the watchdog timer should be serviced. Adjust the watchdog timeout period (tWD) by connecting a capacitor between CSWT and GND. For normal-mode operation, calculate the watchdog timeout capacitor as follows: V t WD2 = CCSWT 155 x 106 A where tWD is in seconds and CCSWT is in Farads. To select the internally fixed watchdog timeout period for the MAX6791-MAX6794, connect CSWT to OUT1. To select the internally fixed watchdog timeout period for the MAX6795/MAX6796, connect CSWT to OUT. CCSWT must be a low-leakage (< 10nA) type capacitor. Ceramic capacitors are recommended; do not use capacitors lower than 100pF to avoid the influence of parasitic capacitances. The MAX6791/MAX6792 have a windowed watchdog timer that asserts RESET for tRP when the watchdog recognizes a fast watchdog fault (time between transitions < tWD1), or a slow watchdog fault (time between transitions > tWD2). The reset timeout period is adjusted independently of the watchdog timeout period. The slow watchdog period, tWD2, is calculated as follows:
V t WD2 = CCSWT 155 x 106 A
where tWD2 is in seconds and CCSWT is in Farads.
The fast watchdog period, tWD1, is selectable as a ratio from the slow watchdog fault period (tWD2). Select the fast watchdog period by connecting WDS0 and WDS1 to OUT/OUT1 or GND according to Table 4, which illustrates the settings for the 8, 16, and 64 window ratios (t WD2/t WD1). For example, if C CSWT is 2000pF, and WDS0 and WDS1 are low, then tWD2 is 318ms (typ) and tWD1 is 40ms (typ). RESET asserts if the watchdog input has two edges too close to each other (faster than tWD1); or has edges that are too far apart (slower than tWD2). All WDI inputs are ignored while RESET is asserted. The watchdog timer begins to count after RESET is deasserted. If the time difference between two transitions on WDI is shorter than tWD1 or longer than tWD2, RESET is forced to assert low for the reset timeout period. If the time difference between two transitions on WDI is between tWD1 (min) and tWD1 (max) or tWD2 (min) and tWD2 (max), RESET is not guaranteed to assert or deassert; see Figure 3. To guarantee that the window watchdog does not assert RESET, strobe WDI between t WD1 (max) and t WD2 (min). The watchdog timer is cleared when RESET is asserted. Disable the watchdog timer by connecting WDS0 high and WDS1 low. There are several options available to disable the watchdog timer (for system development or test purposes or when the P is in a low-power sleep mode). One way to disable the watchdog timer is to drive WD-DIS low for the MAX6793-MAX6796 and drive WDS0 high and WDS1 low for the MAX6791/MAX6792. This prevents the capacitor from ramping up. Finally, reducing the OUT/OUT1 regulator current below the specified regulator current watchdog-disable threshold (3mA min) also disables the watchdog timer. The
tWD0
MIN
tWD1
MAX
MIN
tWD2
MAX
RESET: WDI INPUT:
GUARANTEED TO ASSERT UNDETERMINED
GUARANTEED TO NOT ASSERT UNDETERMINED
GUARANTEED TO ASSERT
FAST FAULT
NORMAL OPERATION
SLOW FAULT
Figure 3. Windowed Watchdog Timing Diagram 18 ______________________________________________________________________________________
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
watchdog re-enables immediately when any of these conditions are removed (as long as the RESET is not asserted). Note that the output current threshold limit includes hysteresis so that output current must exceed 13.8mA (max) to reenable the watchdog timer.
MAX6791-MAX6796
VIN
IN
Capacitor Selection and Regulator Stability
For stable operation over the full temperature range and with load currents up to 150mA, use a 10F (min) output capacitor with an ESR < 0.5. To reduce noise and improve load-transient response and power-supply rejection, use larger output-capacitor values. Some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. For these types of capacitors (such as Z5U and Y5V), much higher-value capacitors are required to maintain stability over the temperaure range. With X7R dielectrics, a 10F capacitor should be sufficient at all operating temperatures. To improve power-supply rejection and transient response, increase the capacitor between IN and GND.
MAX6792 MAX6794 MAX6796 RESET
GND
Figure 4. Ensuring RESET Valid to VIN = 0V
VIN
VTERM
When VIN falls below 1V, RESET current-sinking capabilities decline drastically. High-impedance CMOSlogic inputs connected to RESET can drift to undetermined voltages. This presents no problems in most applications, since most Ps and other circuitry do not operate with a supply voltage below 1V. In those applications where RESET must be valid down to 0, adding a pulldown resistor between RESET and GND sinks any stray leakage currents, holding RESET low (Figure 4). The value of the pulldown resistor is not critical; 100k is large enough not to load RESET and small enough to pull RESET to ground. Open-drain RESET versions are not recommended for applications requiring valid logic for VIN down to 0. Adding Hysteresis to PFI The power-fail comparator has a typical input hysteresis of 0.5% (of VTH). This is sufficient for most applications where a power-supply line is being monitored through an external resistive-divider (Figure 5). Figure 6 shows how to add hysteresis to the power-fail comparator. Select the ratio of R5 and R6 so PFI sees 1.23V when VIN falls to the desired trip point (VTRIP). Since PFO is an open-drain output, resistors R7 and R8 add hysteresis. R7 typically is an order of magnitude greater than R5 or R6. The current through R5 and R6 should be at least 10A to ensure that the 100nA (max) PFI input current does not shift the trip point. R7 should be larger than 50k to prevent it from loading down the PFO.
Ensuring a Valid RESET Output Down to VIN = 0
IN R5 PFI R6 GND MAX6791 PFO
Figure 5. Setting Power-Fail Comparator to Monitor VIN
VIN
R7
VTERM
IN R8 R5 PFI R6 GND MAX6791 PFO
Figure 6. Adding Hysteresis Power-Fail Comparator ______________________________________________________________________________________ 19
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Table 1. Preset Output Voltage and Reset Threshold
PART SUFFIX (_) L M T S Z Y W V OUTPUT VOLTAGE (V) 5.0 5.0 3.3 3.3 2.5 2.5 1.8 1.8 RESET THRESHOLD (NOMINAL) 4.625 4.375 3.053 2.888 2.313 2.188 1.665 1.575
Use the following formulas to determine the high/low threshold levels and the hysteresis: VL-H = VPFI x (1 + R5 / R6 +R5 / R7) VH-L = VPFI x (1 + R5 / R6 ) + (VPFI - VTERM) [R5 / (R7 + R8)] VHYS = VPFI x (R5 / R7 ) - (VPFI - VTERM) [R5 / (R7 + R8)] where VL-H is the threshold level for the monitored voltage rising and VH-L is the threshold level for the monitored voltage falling.
Chip Information
PROCESS: BiCMOS
Table 2. Preset Timeout Period
PART SUFFIX (_) D0 D1 D2 D3 D4 RESET TIMEOUT PERIOD (NOMINAL) 35s 3.125ms 12.5ms 50ms 200ms
Table 3. ENABLE/ENABLE1 and HOLD Truth Table/State Table
OPERATING STATE Initial state Turn-on state Hold setup state ENABLE1/ ENABLE Low High High HOLD Don't care Don't care Low REGULATOR 1 OUTPUT Off On On COMMENT ENABLE/ENABLE1 is pulled to GND through internal pulldown. OUT/OUT1 is disabled. ENABLE/ENABLE1 is externally driven high turning OUT/OUT1 on. HOLD is pulled up to OUT/OUT1. HOLD is externally pulled low while ENABLE/ENABLE1 remains high, and the regulator latches on. ENABLE/ENABLE1 is driven low (or allowed to float low by an internal pulldown). HOLD remains externally pulled low keeping OUT/OUT1 on. HOLD is driven high (or allowed to float high by the internal pullup) while ENABLE/ENABLE1 is low. OUT/OUT1 is turned off and ENABLE/ENABLE1 and HOLD logic returns to the initial state.
Hold state
Low
Low
On
Off state
Low
High (floats high)
Off
20
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Table 4. MIN/MAX Watchdog Setting
WDS0 0 0 1 1 WDS1 0 1 0 1 RATIO 8 16 Watchdog disabled 64
Table 5. Standard Version Part Number
PART NUMBER MAX6791TPLD2+ MAX6791TPSD2+ MAX6792TPLD2+ MAX6792TPSD2+ MAX6793TPLD2+ MAX6793TPSD2+ MAX6794TPLD2+ MAX6794TPSD2+ MAX6795TPLD2+ MAX6795TPSD2+ MAX6796TPLD2+ MAX6796TPSD2+ +Denotes lead-free package. OUTPUT VOLTAGE (V) 5.0 3.3 5.0 3.3 5.0 3.3 5.0 3.3 5.0 3.3 5.0 3.3 RESET TIMEOUT PERIOD (ms) (NOMINAL) 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 RESET THRESHOLD (V) (NOMINAL) 4.625 2.888 4.625 2.888 4.625 2.888 4.625 2.888 4.625 2.888 4.625 2.888
Selector Guide
PART MAX6791TP_D_ MAX6792TP_D_ MAX6793TP_D_ MAX6794TP_D_ MAX6795TP_D_ MAX6796TP_D_ RESET OUTPUT Open drain Push-pull Open drain Push-pull Open drain Push-pull NUMBER OF OUTPUTS 2 2 2 2 1 1 WINDOWED WATCHDOG TIMEOUT -- -- -- -- ENABLE INPUTS Dual Dual Dual Dual Single Single WATCHDOG DISABLE INPUT
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21
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Typical Application Circuit
12V BATT
TO OTHER CIRCUITRY
GATEP OUT1
IN
IN
ENABLE1
PFI ENABLE2
SET1
OUT2
MAX6791/MAX6792
CSWT PFO CSRT GND RESET HOLD WDS1 WDS0 WDI
RESET VCC INT
I/O C
I/O
TXD
VCC INH XCVR
BATT
CANH
RXD
CANL
22
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High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Pin Configurations
MAX6791-MAX6796
ENABLE2
HOLD
OUT2
HOLD 12
OUT2
OUT2
OUT2
WDI
15
14
13
12
11
15
14
13
PFI 16 IN 17 IN 18 GATEP 19 ENABLE1 20 +
10 9
WDS0 WDS1 RESET GND CSRT
WDI 11
TOP VIEW
TOP VIEW
ENABLE2
PFI 16 IN 17 IN 18 GATEP 19 ENABLE1 20 +
10 9
N.C. WD-DIS RESET GND CSRT
MAX6791/MAX6792
8 7 6
MAX6793/MAX6794
8 7 6
1 OUT1
2 OUT1
3 SET1
4 PFO
5 CSWT
1 OUT1
2 OUT1
3 SET1
4 PFO
5 CSWT
THIN QFN 5mm x 5mm TOP VIEW
THIN QFN 5mm x 5mm
HOLD 12
N.C.
N.C.
N.C.
15
14
13
WDI 11
PFI 16 IN 17 IN 18 GATEP 19 ENABLE 20 +
10 9
N.C. WD-DIS RESET GND CSRT
MAX6795/MAX6796
8 7 6
1 OUT
2 OUT
3 SET
4 PFO
5 CSWT
THIN QFN 5mm x 5mm
______________________________________________________________________________________
23
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions MAX6791-MAX6796
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
24
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QFN THIN.EPS
High-Voltage, Micropower, Single/Dual Linear Regulators with Supervisory Functions
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)
MAX6791-MAX6796
Revision History
Pages changed at Rev 1: 1, 10, 11, 18, 19, 24, 25
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 25 (c) 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

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