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MIC38HC42/3/4/5
Micrel
MIC38HC42/3/4/5
BiCMOS 1A Current-Mode PWM Controllers
General Description
The MIC38HC4x family are fixed frequency current-mode PWM controllers with 1A drive current capability. Micrel's BiCMOS devices are pin-compatible with 384x bipolar devices. Their high output drive, with fast rise and fall times, combined with low startup current make it an ideal PWM controller where high efficiency is required. Undervoltage lockout circuitry allows the '42 and '44 versions to start up at 14.5V and operate down to 9V, and the '43 and '45 versions start at 8.4V with operation down to 7.6V. All versions operate up to 20V. When compared to bipolar UC384x devices operating from a 15V supply, start-up current has been reduced to 50A typical and operating current has been reduced to 4.0 mA typical. Decreased output rise and fall times drive larger MOSFETs, and rail-to-rail output capability increases efficiency, especially at lower supply voltages. The MIC38HC4x also features a trimmed oscillator discharge current and bandgap reference. MIC38HC4x-1 is available in 14-pin plastic DIP and SOIC packages. 8-pin devices feature small size, while 14-pin devices separate the analog and power connections for improved performance and power dissipation.
Features
* Fast 20ns output rise and 15ns output fall times * -40C to +85C temperature range exceeds UC284x specifications * High-performance, low-power BiCMOS Process * Ultralow start-up current (50A typical) * Low operating current (4mA typical) * High output drive (1A peak current, HC version) * CMOS outputs with rail-to-rail swing * Current-mode operation up to 500kHz * Trimmed 5V bandgap reference * Pin-for-pin compatible with UC3842/3843/3844/3845(A) * Trimmed oscillator discharge current * UVLO with hysteresis * Low cross-conduction currents
Applications
* * * * * * * Current-mode, off-line, switched-mode power supplies Current-mode, dc-to-dc converters. Step-down "buck" regulators Step-up "boost" regulators Flyback, isolated regulators Forward converters Synchronous FET converters
Functional Diagram
VDD
7 (12)
* 35V 5V Reference UVLO
VREF
8 (14)
(VD)
(11)
RT/CT
4 (7)
Oscillator T Q
OUT
6 (10)
FB
2 (3)
2R 2.5V R S R Q
(PGND)
(8)
* COMP
1 (1)
GND*(AGND)
5 (9)
ISNS
3 (5)
( ) pins are on MIC38HC4x-1 (14-lead) versions only * MIC38HC4x (8-lead) versions only MIC38HC42, MIC38HC43 (96% max. duty cycle) versions only MIC38HC44, MIC38HC45 (50% max. duty cycle) versions only
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
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MIC38HC42/3/4/5
MIC38HC42/3/4/5
Micrel
Ordering Information
Part Number MIC38HC42BN MIC38HC43BN MIC38HC44BN MIC38HC45BN MIC38HC42-1BN MIC38HC43-1BN MIC38HC44-1BN MIC38HC45-1BN MIC38HC42BM MIC38HC43BM MIC38HC44BM MIC38HC45BM MIC38HC42-1BM MIC38HC43-1BM MIC38HC44-1BM MIC38HC45-1BM Temperature Range -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C Package 8-pin Plastic DIP 8-pin Plastic DIP 8-pin Plastic DIP 8-pin Plastic DIP 14-pin Plastic DIP 14-pin Plastic DIP 14-pin Plastic DIP 14-pin Plastic DIP 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 14-pin SOIC 14-pin SOIC 14-pin SOIC 14-pin SOIC
Selection Guide
UVLO Thresholds Duty Cycle 0% to 96% 0% to 50% Startup 8.4V Minimum Operating 7.6V MIC38HC43 MIC38HC45 Startup 14.5V Minimum Operating 9V MIC38HC42 MIC38HC44
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Micrel
Pin Configuration
MIC38HC4x-1
COMP 1 NC 2 FB 3 14 VREF 13 NC 12 VDD 11 VD 10 OUT 9 AGND 8 PGND
MIC38HC4x
COMP 1 FB 2 ISNS 3 RT/CT 4 8 7 6 5 VREF VDD OUT GND
NC 4 ISNS 5 NC 6 RT/CT 7
8-Pin DIP (N) 8-Lead SOIC (M)
14-Pin DIP (-1BN) 14-Lead SOIC (-1BM)
Pin Description
Pin Number N, M, MM 1 Pin Number -1BN, -1BM 1 2 2 3 4 3 5 6 4 5 8 9 6 10 11 7 12 13 8 14 7 Pin Name COMP NC FB NC ISNS NC RT/CT GND PGND AGND OUT VD VDD NC VREF Pin Function Compensation: Connect external compensation network to modify the error amplifier output. Not internally connected. Feedback (Input): Error amplifier input. Feedback is 2.5V at desired output voltage. Not internally connected. Current Sense (Input): Current sense comparator input. Connect to current sensing resistor or current transformer. Not internally connected. Timing Resistor/Timing Capacitor: Connect external RC network to select switching frequency. Ground: Combined analog and power ground. Power Ground: N-channel driver transistor ground. Analog Ground: Controller circuitry ground. Power Output: Totem-pole output. Power Supply (Input): P-channel driver transistor supply input. Return to power ground (PGND). Analog Supply (Input): Controller circuitry supply input. Return to analog ground (AGND). Not internally connected. 5V Reference (Output): Connect external RC network.
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Micrel
Absolute Maximum Ratings
Zener Current (VDD) ................................................... 30mA Operation at 18V may require special precautions (Note 6). Supply Voltage (VDD), Note 6 ....................................... 20V Switch Supply Voltage (VD) .......................................... 20V Current Sense Voltage (VISNS) ..................... -0.3V to 5.5V Feedback Voltage (VFB) ................................ -0.3V to 5.5V Output Current, 38HC42/3/4/5 (IOUT) .............................. 1A Operating Junction Temperature (TJ) ....................... 150C Package Thermal Resistance 8-Pin Plastic DIP (JA) ....................................... 125C/W 8-Pin MM8TM (JA) ............................................. 250C/W 8-Pin SOIC (JA) ...............................................170C/W 14-Pin Plastic DIP (JA) ....................................... 90C/W 14-Pin SOIC (JA) ............................................. 145C/W Storage Temperature (TA) ....................... -65C to +150C
Electrical Characteristics
VDD = 15V, Note 4; RT = 9.09k; CT = 3.3nF; -40C TA 85C; unless noted Parameter Reference Section Output Voltage Line Regulation Load Regulation Temp. Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Oscillator Section Initial Accuracy Voltage Stability Temp. Stability Clock Ramp Reset Current Amplitude Error Amp Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth PSRR Output Sink Current Output Source Current VOUT High VOUT Low VCOMP = 2.5V VFB = 5.0V 2 VO 4V Note 1 12 VDD 18V VFB = 2.7V, VCOMP = 1.1V VFB = 2.3V, VCOMP = 5V VFB = 2.3V, RL = 15k to ground VFB = 2.7V, RL = 15k to VREF 65 0.7 60 2 -0.5 5 14 -1 6.8 0.1 1.1 2.42 2.50 -0.1 90 1.0 2.58 -2 V A dB MHz dB mA mA V V TA = 25C, Note 5 12 VDD 18V, Note 6 TMIN TA TMAX, Note 1 TA = 25C, VRT/CT = 2V TA = TMIN to TMAX VRT/CT peak to peak 7.7 7.2 49 52 0.2 0.04 8.4 8.4 1.9 9.0 9.5 55 1.0 kHz % %/C mA mA Vp-p TA = 25C, IO = 1mA 12V VDD 18V, IO = 5A, Note 6 1 IO 20mA Note 1 Line, Load, Temp., Note 1 10Hz f 10kHz, TA = 25C, Note 1 TA = 125C, 1000 hrs., Note 1 -30 4.82 50 5 -80 25 -180 4.90 5.00 2 1 0.2 5.18 5.10 20 25 V mV mV mV/C V V mV mA Test Conditions Min Typ Max Units
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MIC38HC42/3/4/5
Parameter Current Sense Gain MaximumThreshold PSRR Input Bias Current Delay to Output Output RDS(ON) `HC' High RDS(ON) `HC' Low Rise Time Fall Time Undervoltage Lockout Start Threshold MIC38HC42/4 MIC38HC43/5 Minimum Operating Voltage MIC38HC42/4 MIC38HC43/5 Pulse Width Modulator Maximum Duty Cycle MIC38HC42/3 MIC38HC44/5 Minimum Duty Cycle Total Standby Current Start-Up Current VDD = 13V, 38HC42/44 VDD = 7.5V, 38HC43/45 Operating Supply Current Zener Voltage (VDD) VFB = VISNS = 0V IDD = 25mA, Note 6 30 4.0 37 6.0 50 200 94 46 96 50 0 13.5 7.8 8 7.0 14.5 8.4 9 7.6 15.5 9.0 10 8.2 ISOURCE = 200mA ISINK = 200mA TA = 25C, CL = 1nF TA = 25C, CL = 1nF 10 5.5 20 15 50 40 Notes 2, 3 VCOMP = 5V, Note 2 12 VDD 18V, Note 2 2.85 0.9 3.0 1 70 -0.1 120 -2 250 3.15 1.1 Test Conditions Min Typ Max
Micrel
Units
V/V V dB A ns
ns ns
V V V V
% % %
A mA V
Note 1: These parameters, although guaranteed, are not 100% tested in production. Note 2: Parameter measured at trip point of latch with VEA = 0. Note 3: Gain defined as:
A=
VPIN1 ; 0 VTH (ISNS ) 0.8V VTH (ISNS )
Note 4: Adjust VDD above the start threshold before setting at 15V. Note 5: Output frequency equals oscillator frequency for the MIC38HC42 and MIC38HC43. Output frequency for the MIC38HC44, and MIC38HC45 equals one half the oscillator frequency. Note 6: On 8-pin version, 20V is maximum input on pin 7, as this is also the supply pin for the output stage. On 14-pin version, 40V is maximum for pin 12 and 20V maximum for pin 11.
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MIC38HC42/3/4/5
Micrel
Typical Characteristics
Oscillator Frequency Configuration
100
OSC. DISCHARGE CURRENT (mA)
MIC38C/HC42/43 Output Dead Time vs. Oscillator Frequency
100
Oscillator Discharge Current vs. Temperature
9.0 8.8 8.6 8.4 8.2 8.0 7.8 7.6 7.4 7.2 VDD = 15V VOSC = 2V
1nF 1.8nF 10 4.7nF 10nF VDD = 15V
OUTPUT DEAD TIME (%)
RT RESISTANCE (k)
200pF 470pF
VDD = 15V
4.7nF 10 10nF 200pF 470pF 1nF 18nF 1 1x104 1x105 FREQUENCY (Hz) 1x106
1 1x105 1x106 1x104 OSCILLATOR FREQUENCY (Hz)
7.0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
CURRENT SENSE AMP THRESHOLD (V)
1.2 1.0 125C 0.8 0.6 25C 0.4 0.2 0.0 -50C
VREF SHORT CURCUIT CURRENT (mA)
Current Sense Amplifier vs. Error Amplifier Output
Short-Circuit Reference Current vs. Temperature
120 25
MIC38C4x Output Waveform
OUTPUT VOLTAGE (V)
20 15 10 5 0 -5 -10 -15 0.0 VD = 15V CL = 1nF 0.2 0.4 0.6 TIME (s) 0.8 1.0
100 80 60 40 20 VDD = 15V
0 2 4 6 8 ERROR AMPLIFIER OUTPUT (V)
0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
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MIC38HC42/3/4/5
Micrel
Package Information
PIN 1 DIMENSIONS: INCH (MM)
0.380 (9.65) 0.370 (9.40)
0.135 (3.43) 0.125 (3.18)
0.255 (6.48) 0.245 (6.22) 0.300 (7.62)
0.013 (0.330) 0.010 (0.254) 0.018 (0.57) 0.100 (2.54) 0.130 (3.30) 0.0375 (0.952) 0.380 (9.65) 0.320 (8.13)
8-Pin Plastic DIP (N)
.770 (19.558) MAX PIN 1
.235 (5.969) .215 (5.461)
.060 (1.524) .045 (1.143) .160 MAX (4.064) .310 (7.874) .280 (7.112) .080 (1.524) .015 (0.381)
.015 (0.381) .008 (0.2032) .160 (4.064) .100 (2.540) .110 (2.794) .090 (2.296) .060 (1.524) .045 (1.143) .023 (.5842) .015 (.3810) .400 (10.180) .330 (8.362)
14-Pin Plastic DIP (N)
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MIC38HC42/3/4/5
MIC38HC42/3/4/5
Micrel
0.026 (0.65) MAX)
PIN 1
0.157 (3.99) 0.150 (3.81)
DIMENSIONS: INCHES (MM)
0.050 (1.27) TYP
0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102) 0-8 SEATING PLANE 45 0.010 (0.25) 0.007 (0.18)
0.064 (1.63) 0.045 (1.14)
0.197 (5.0) 0.189 (4.8)
0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79)
8-Pin SOIC (M)
PIN 1
0.154 (3.90)
DIMENSIONS: INCHES (MM)
0.026 (0.65) MAX)
0.050 (1.27) 0.016 (0.40) TYP TYP 0.006 (0.15)
0.193 (4.90) 45 3-6 0.244 (6.20) 0.228 (5.80)
0.057 (1.45) 0.049 (1.25)
0.344 (8.75) 0.337 (8.55)
SEATING PLANE
14-Pin SOIC (M)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 2000 Micrel Incorporated
MIC38HC42/3/4/5
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