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MIC39500/39501
5A Cap Low-Voltage Low-Dropout Regulator
General Description
The MIC39500 and MIC39501 are 5A low-dropout linear voltage regulators that provide a low-voltage, high-current output with a minimum of external components. Utilizing Micrel's proprietary Super eta PNPTM pass element, the MIC39500/1 offers extremely low dropout (typically 400mV at 5A) and low ground current (typically 70mA at 5A). The MIC39500/1 is ideal for PC Add-In cards that need to convert from standard 2.5V or 3.3V, down to new, lower core voltages. A guaranteed maximum dropout voltage of 500mV over all operating conditions allows the MIC39500/1 to provide 2.5V from a supply as low as 3V or 1.8V from 2.5V. The MIC39500/1 also has fast transient response, for heavy switching applications. The device requires only 47F of output capacitance to maintain stability and achieve fast transient response The MIC39500/1 is fully protected with overcurrent limiting, thermal shutdown, reversed-battery protection, reversedlead insertion protection, and reversed-leakage protection. The MIC39501 offers a TTL-logic-compatible enable pin and an error flag that indicates undervoltage and overcurrent conditions. Offered in a fixed voltages, 1.8V and 2.5V, the MIC39500/1 comes in the TO-220 and TO-263 packages and an ideal upgrade to older, NPN-based linear voltage regulators. For applications requiring input voltage greater than 16V, see the MIC29500/1/2/3 family. For applications with input voltage 6V or below, see MIC3750x LDOs.
Features
* 5A minimum guaranteed output current * 400mV dropout voltage Ideal for 3.0V to 2.5V conversion Ideal for 2.5V to 1.8V conversion * 1% initial accuracy * Low ground current * Current limiting and thermal shutdown * Reversed-battery and reversed-lead insertion protection * Reversed-leakage protection * Fast transient response * TO-263 and TO-220 packages * TTL/CMOS compatible enable pin (MIC39501 only) * Error flag output (MIC39501 only) * Ceramic capacitor stable (See Application Information)
Applications
* * * * * * * Low Voltage Digital ICs LDO linear regulator for PC add-in cards High-efficiency linear power supplies SMPS post regulator Multimedia and PC processor supplies Low-voltage microcontrollers StrongARMTM processor supply
Typical Application
MIC39500-2.5 IN OUT GND 47F
Enable Shutdown
100K
MIC39501-2.5 VIN 3.3V 1.0F VOUT 2.5V EN IN FLG OUT GND
ERROR FLAG OUTPUT
VIN 3.3V 1.0F
VOUT 2.5V 47F
MIC39500
MIC39501
StrongARM is a trademark of Advanced RISC Machines, Ltd. Micrel, Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
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MIC39500/39501
Micrel Voltage 2.5V 2.5V 2.5V 2.5V 1.8V 1.8V 1.8V 1.8V Junction Temp. Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package 3-Lead TO-220 3-Lead TO-263 5-Lead TO-220 5-Lead TO-263 3-Lead TO-220 3-Lead TO-263 5-Lead TO-220 5-Lead TO-263
Ordering Information
Part Number Standard MIC39500-2.5BT MIC39500-2.5BU MIC39501-2.5BT MIC39501-2.5BU MIC39500-1.8BT MIC39500-1.8BU MIC39501-1.8BT MIC39501-1.8BU RoHS Compliant* MIC39500-2.5WT* MIC39500-2.5WU* MIC39501-2.5WT* MIC39501-2.5WU* MIC39500-1.8WT* MIC39500-1.8WU* MIC39501-1.8WT* MIC39501-1.8WU*
* RoHS compliant with high-melting solder exemption.
Pin Configuration
3 OUT 2 GND 1 IN
TAB
3 2 1
TAB
OUT GND IN
MIC39500-x.xBT TO-220-3 (T)
5 4 3 2 1 FLG OUT GND IN EN
MIC39500-x.xBU TO-263-3 (U)
5 4 3 2 1 FLG OUT GND IN EN
TAB
TAB
MIC39501-x.xBT TO-220-5 (T)
MIC39501-x.xBU TO-263-5 (U)
Pin Description
Pin Number MIC39500 Pin Number MIC39501 1 1 2, TAB 3 2 3, TAB 4 5 Pin Name EN IN GND OUT FLG Pin Function Enable (Input): TTL/CMOS compatible input. Logic high = enable; logic low or open = shutdown Unregulated Input: +16V maximum supply. Ground: Ground pin and TAB are internally connected. Regulator Output Error Flag (Ouput): Open collector output. Active low indicates an output fault condition.
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Absolute Maximum Ratings (Note 1)
Supply Voltage (VIN) .......................................-20V to +20V Enable Voltage (VEN) .................................................. +20V Storage Temperature (TS) ........................ -65C to +150C Lead Temperature (soldering, 5 sec.) ........................ 260C ESD, Note 3
Operating Ratings (Note 2)
Supply Voltage (VIN) ................................... +2.25V to +16V Enable Voltage (VEN) .................................................. +16V Maximum Power Dissipation (PD(max)) ..................... Note 4 Junction Temperature (TJ) ........................ -40C to +125C Package Thermal Resistance TO-263 (JC) ......................................................... 2C/W TO-220 (JC) ......................................................... 2C/W
Electrical Characteristics
TJ = 25C, bold values indicate -40C TJ +125C; unless noted Symbol VOUT Parameter Output Voltage Line Regulation Load Regulation VOUT/T ppm/C VDO Output Voltage Temp. Coefficient, Note 5 Dropout Voltage, Note 6 IOUT = 250mA, VOUT = -2% IOUT = 2.5A, VOUT = -2% IOUT = 5A, VOUT = -2% IGND IGND(do) IOUT(lim) en V(rms) VEN IIN Ground Current, Note 7 Dropout Ground Pin Current Current Limit Output Noise Voltage IOUT = 2.5A, VIN = VOUT + 1V IOUT = 5A, VIN = VOUT + 1V VIN VOUT(nominal) - 0.5V, IOUT = 10mA VOUT = 0V, VIN = VOUT + 1V COUT = 47F, IOUT = 100mA, 10Hz to 100kHz 125 320 400 15 70 2.1 7.5 260 575 50 250 mV mV mV mA mA mA A Condition 10mA 10mA IOUT 5A, VOUT + 1V VIN 16V IOUT = 10mA, VOUT + 1V VIN 16V VIN = VOUT + 1V, 10mA IOUT 5A Min -1 1 -2 0.06 0.2 20 Typ Max 1 2 0.5 1 100 Units % % % %
Enable Input (MIC39501) Enable Input Voltage Enable Input Current logic low (off) logic high (on) VEN = VIN VEN = 0.8V IOUT(shdn) IFLG(leak) VFLG(do) Shutdown Output Current Output Leakage Current Output Low Voltage Low Threshold VFLG
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Note 7. Note 8. Note 9.
0.8 2.25 30 35 75 2 4 10 0.01 180 93 99.2 1 20 1 2 300 400
V V A A A A A A A mV mV % % %
Note 8 VOH = 16V VIN = 2.250V, IOL, = 250A, Note 9 1% of VOUT 1% of VOUT
Flag Output (MIC39501)
High Threshold Hysteresis
Exceeding the absolute maximum ratings may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. PD(max) = (TJ(max) - TA) / JA, where JA depends upon the printed circuit layout. See "Applications Information." Output voltage temperature coefficient is VOUT(worst case) / (TJ(max) - TJ(min)) where TJ(max) is +125C and TJ(min) is -40C. VDO = VIN - VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. For voltages below 2.25V, Dropout voltage is the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V. IGND is the quiescent current. IIN = IGND + IOUT. VEN 0.8V, VIN 8V, and VOUT = 0V For a 2.5V device, VIN = 2.250V (device is in dropout).
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Typical Characteristics
P ower S upply R ejection R atio
V IN = 3.3V V OUT = 2.5V I LOAD = 5A
PSRR (dB)
35 30 25
PSRR (dB)
35 30
P ower S upply R ejection R atio
450 400
DROPOUT VOLTAGE (mV)
Dropout V oltage vs . Output C urrent
V OUT = 1.8V
20 15 10 5 C IN = 0 C OUT = 47F T ant 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
V IN = 3.3V V OUT = 2.5V 20 I LOAD = 5A 25 15 10 5 C IN = 0 C OUT = 100F C eramic 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
350 300 250 200 150 100 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
V OUT = 2.5V
0
OUTPUT CURRENT (mA)
600 500
DROPOUT VOLTAGE (mV)
Dropout V oltage vs . T emperature
2.8
V OUT = 1.8V
OUTPUT VOLTAGE (V)
Dropout C harac teris tic s
80
G round C urrent vs . Output C urrent
V IN = V OUT +1V
2.6 2.4 2.2 2 1.8 1.6 I LOAD = 2.5A
I LOAD = 100mA
GROUND CURRENT (mA)
70 60 50 40 30 20 10
400 300 200 100
0 20 40 60 -40 -20 80 100 120 140
V OUT = 2.5V
I LOAD = 5A
V OUT = 2.5V
V OUT = 1.8V
0
500 1000 1500 2000 2500
TEMPERATURE (C)
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
12.0 10.0
GROUND CURRENT (mA)
G round C urrent vs . S upply V oltage
180 160
GROUND CURRENT (mA)
G round C urrent vs . S upply V oltage
10 9 8 7 6 5 4 3
G round C urrent vs . Temperature
GROUND CURRENT (mA)
140 120 100 80 60 40 20 0 0 I LOAD = 5.0A I LOAD = 2.5A I LOAD = 2.0A 2 4 6 8 SUPPLY VOLTAGE (V) 10
8.0 6.0 4.0 2.0 0.0
I LOAD = 10mA
V OUT = 2.5V
I LOAD = 100mA
V OUT = 1.8V
0 1 2 3 4 5 6 7 8 9 10 SUPPLY VOLTAGE (V)
2I LOAD = 10mA 1 V =V + 1V IN OUT 0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
30 25
GROUND CURRENT (mA)
G round C urrent vs . T emperature
V OUT = 2.5V
80.0 70.0
G round C urrent vs . T emperature
V OUT = 2.5V
10.0 9.0
S hort C irc uit C urrent vs . T emperature
T ypical 2.5V Device
GROUND CURRENT (mA)
60.0 50.0 V OUT = 1.8V 40.0 30.0 20.0 10.0 I LOAD = 5A V IN = V OUT = 1V
SHORT CIRCUIT CURRENT (A)
8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 V IN = V OUT + 1V 0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C) T ypical 1.8V Device
20 15 10
V OUT = 1.8V
5 I LOAD = 2.5A V IN = V OUT + 1V 0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
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3000 3500 4000 4500 5000
0
I LOAD = 5A
1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
1.4
0
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Micrel
6 5
E rror F lag P ull-up R es is tor
F lag_HIG H (OK )
7 6
ENABLE CURRENT (A)
E nable C urrent vs . Temperature
350 300
FLAG VOLTAGE (V)
F lag L ow V oltage vs . Temperature
FLAG VOLTAGE (V)
4 3 2 1 0 F lag_LOW (F AULT )
5 4 3 2 1 V E N = 2.25V V IN = V OUT + 1V 0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
250 200 150 100 50 V IN = 2.8V R P ULL-UP = 22k 0 -40 -20 0 20 40 60 80 100 120 140 TEMPERATURE (C)
1
10
100
0.1
1000
0.01
10000
0.001
RESISTANCE (k)
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100000
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Functional Diagram
IN O.V. ILIMIT 1.180V Ref. 1.240V 18V
OUT
FLAG*
EN* Thermal Shutdown
GND * MIC39501 only
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Micrel pared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. The low-dropout properties of Micrel Super eta PNP regulators allow significant reductions in regulator power dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least 1F is needed directly between the input and regulator ground. Refer to Application Note 9 for further details and examples on thermal design and heat sink specification. Output capacitor The MIC39500/1 requires an output capacitor to maintain stability and improve transient response. Proper capacitor selection is important to ensure proper operation. The MIC39500/1 output capacitor selection is dependent upon the ESR (equivalent series resistance) of the output capacitor to maintain stability. When the output capacitor is 47F or greater, the output capacitor should have less than 1 of ESR. This will improve transient response as well as promote stability. Ultra-low-ESR capacitors, such as ceramic chip capacitors may promote instability. These very low ESR levels may cause an oscillation and/or underdamped transient response. When larger capacitors are used, the ESR requirement approaches zero. A 100F ceramic capacitor can be used on the output while maintaining stability. A low-ESR 47F solid tantalum capacitor works extremely well and provides good transient response and stability over temperature. Aluminum electrolytics can also be used, as long as the ESR of the capacitor is < 1. The value of the output capacitor can be increased without limit. Higher capacitance values help to improve transient response and ripple rejection and reduce output noise. Input capacitor An input capacitor of 1F or greater is recommended when the device is more than 4 inches away from the bulk ac supply capacitance, or when the supply is a battery. Small surfacemount ceramic chip capacitors can be used for bypassing. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage. Transient Response and 3.3V to 2.5V or 2.5V to 1.8V Conversion The MIC39500/1 has excellent transient response to variations in input voltage and load current. The device has been designed to respond quickly to load current variations and input voltage variations. Large output capacitors are not required to obtain this performance. A standard 47F output capacitor, preferably tantalum, is all that is required. Larger values improve performance even further. By virtue of its low-dropout voltage, this device does not saturate into dropout as readily as similar NPN-based designs. When converting from 3.3V to 2.5V, or 2.5V to 1.8V, the NPN-based regulators are already operating in dropout, with typical dropout requirements of 1.2V or greater. To convert down to 2.5V without operating in dropout, NPN-based regulators require an input voltage of 3.7V at the very least. The MIC39500/1 regulator provides excellent performance 7
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Applications Information
The MIC39500/1 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regulator applications. Its 400mV dropout voltage at full load makes it especially valuable in battery-powered systems and as a high-efficiency noise filter in post-regulator applications. Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the base-to-emitter voltage drop and collector-to-emitter saturation voltage, dropout performance of the PNP output of these devices is limited only by the low VCE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. Micrel's Super eta PNPTM process reduces this drive requirement to only 2% to 5% of the load current. The MIC39500/1 regulator is fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current during overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spikes above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow.
VIN MIC39500-x.x IN OUT GND VOUT
CIN
COUT
Figure 1. Capacitor Requirements Thermal Design Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires four application-specific parameters: * Maximum ambient temperature (TA) * Output Current (IOUT) * Output Voltage (VOUT) * Input Voltage (VIN) * Ground Current (IGND) Calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet, where the ground current is taken from data sheet. PD = (VIN - VOUT) x IOUT + VIN x IGND The heat sink thermal resistance is determined by:
where: TJ (max) 125C and CS is between 0 and 2C/W. The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large comAugust 2005
MIC39500/39501 with an input as low as 3.0V or 2.5V respectively. This gives PNP-based regulators a distinct advantage over older, NPNbased linear regulators. A typical NPN regulator does not have the headroom to do this conversion. Minimum Load Current The MIC39500/1 regulator is specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. A 10mA minimum load current is necessary for proper regulation.
Micrel Error Flag The MIC39501 version features an error flag circuit which monitors the output voltage and signals an error condition when the voltage 5% below the nominal output voltage. The error flag is an open-collector output that can sink 10mA during a fault condition. Low output voltage can be caused by a number of problems, including an overcurrent fault (device in current limit) or low input voltage. The flag is inoperative during overtemperature shutdown. When the error flag is not used, it is best to leave it open. The flag pin can be tied directly to pin 4, the output pin. Enable Input The MIC39501 version features an enable input for on/off control of the device. Its shutdown state draws "zero" current (only microamperes of leakage). The enable input is TTL/CMOS compatible for simple logic interface, but can be connected to up to 20V.
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Package Information
3-Lead TO-263 (U)
3-Lead TO-220 (T)
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Micrel
4
1
2 1 3
5-Lead TO-263-5 (U)
MICREL INC.
TEL
+ 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
2180 FORTUNE DRIVE
1
5-Lead TO-220 (T) SAN JOSE, CA 95131 USA
This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2005 Micrel Incorporated
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