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MIC39500/39501
Micrel
MIC39500/39501
5A Low-Voltage Low-Dropout Regulator Advance Information
General Description
The MIC39500 and MIC39501 is a 5A low-dropout linear voltage regulator that provides a low-voltage, high-current output with a minimum of external components. Utilizing Micrel's proprietary Super eta PNPTM pass element, the MIC39500 offers extremely low dropout (typically 400mV at 5A) and low ground current (typically 70mA at 5A). The MIC39500 is ideal for PC Add-In cards that need to convert from standard 5V or 3.3V, down to new, lower core voltages. A guaranteed maximum dropout voltage of 500mV over all operating conditions allows the MIC39500 to provide 2.5V from a supply as low as 3V. The MIC39500 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 is fully protected with overcurrent limiting, thermal shutdown, reversed-battery and reversed-lead insertion protection. The MIC39501 offers a TTL-logic-compatible enable pin and an error flag that indicates undervoltage and overcurrent conditions. The MIC39500 comes in the TO220 and TO-263 packages and is an ideal upgrade to older, NPN-based linear voltage regulators.
Features
* * * * * * * * * * 5A minimum guaranteed output current 500mV maximum dropout voltage over temperature 1% initial accuracy Low ground current Current limiting and thermal shutdown Reversed-battery and reversed-lead insertion protection Fast transient response TO-263 and TO-220 packages TTL/CMOS compatible enable pin (MIC39501 only) Error flag output (MIC39501 only)
Applications
* * * * * * * LDO linear regulator for PC add-in cards PowerPCTM power supplies High-efficiency linear power supplies SMPS post regulator Multimedia and PC processor supplies Low-voltage microcontrollers StrongARMTM processor supply
For applications requiring input voltage greater than 16V, see the MIC29500/1/2/3 family.
Ordering Information
Part Number MIC39500-2.5BT MIC39500-2.5BU MIC39501-2.5BT MIC39501-2.5BU Voltage 2.5V 2.5V 2.5V 2.5V Junction Temp. Range -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
Typical Application
MIC39500-2.5 VIN 3.3V 1.0F IN OUT GND 47F VOUT 2.5V
Enable Shutdown
100K
MIC39501-2.5 EN IN FLG OUT GND 47F
ERROR FLAG OUTPUT
VIN 3.3V 1.0F
VOUT 2.5V
MIC39500
StrongARM is a trademark of Advanced RISC Machines, Ltd.
MIC39501
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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Micrel
Pin Configuration
3
TAB
OUT
TAB
3 2 1
OUT GND IN
2 1
GND IN
MIC39500-x.xBT TO-220 (T)
MIC39500-x.xBU TO-263 (U)
5 4 3 2 1
FLG OUT GND IN EN
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 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 VEN IIN Ground Current, Note 7 IOUT = 2.5A, VIN = VOUT + 1V IOUT = 5A, VIN = VOUT + 1V Dropout Ground Pin Current Current Limit Output Noise Voltage VIN VOUT(nominal) - 0.5V, IOUT = 10mA VOUT = 0V, VIN = VOUT + 1V COUT = 47F, IOUT = 100mA, 10Hz to 100kHz logic low (off) logic high (on) Enable Input Current VEN = VIN VEN = 0.8V IOUT(shdn) IFLG(leak) VFLG(do)
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Note 7. Note 8. Note 9.
Condition 10mA IOUT 5A, VOUT + 1V VIN 16V IOUT = 10mA, VOUT + 1V VIN 16V VIN = VOUT + 1V, 10mA IOUT 5A
Min -1 -2
Typ
Max 1 2
Units % % % % ppm/C mV mV
0.06 0.2 20 125 320 400 15 70 2.1 7.5 260
0.5 1 100 250
500 50
mV mA mA mA A V(rms)
Enable Input (MIC39501) Enable Input Voltage 0.8 2.4 30 35 75 2 4 10 20 V V A A A A A A A mV mV
Shutdown Output Current
Note 8
Flag Output (MIC39501) Output Leakage Current Output Low Voltage VOH = 16V VIN = 2.250V, IOL, = 250A, Note 9 0.01 125 1 2 150 200
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 0C. VDO = VIN - VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. 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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Functional Diagram
IN O.V. ILIMIT 1.180V FLAG* 1.240V 18V
OUT
Ref.
EN* Thermal Shutdown
GND * MIC39501 only
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The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large compared 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. A low-ESR 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 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. 3.3V to 2.5V Conversion 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, 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 with
Applications Information
The MIC39500/1 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regulator applications. Its 500mV 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 CIN OUT GND COUT VOUT
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: SA = TJ(max) - TA PD - JC + CS
(
)
where: TJ (max) 125C and CS is between 0 and 2C/W.
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an input as low as 3.0V. This gives PNP-based regulators a distinct advantage over older, NPN-based 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. 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
0.151 D 0.005 (3.84 D 0.13) 0.410 0.010 (10.41 0.25) 0.108 0.005 (2.74 0.13) 0.176 0.005 (4.47 0.13)
0.050 0.005 (1.27 0.13)
0.590 0.005 (14.99 0.13)
7
0.818 0.005 (20.78 0.13)
0.356 0.005 (9.04 0.13)
7
3
1.140 0.010 (28.96 0.25)
0.050 0.003 (1.27 .08) 0.100 0.005 (2.54 0.13)
0.030 0.003 (0.76 0.08)
0.018 0.008 (0.46 0.020)
0.100 0.020 (2.54 0.51) DIMENSIONS: INCH (MM)
TO-220 (T)
0.150 D 0.005 (3.81 D 0.13) 0.400 0.015 (10.16 0.38) 0.108 0.005 (2.74 0.13) 0.241 0.017 (6.12 0.43)
0.177 0.008 (4.50 0.20) 0.050 0.005 (1.27 0.13)
0.578 0.018 (14.68 0.46)
SEATING PLANE
7 Typ. 0.550 0.010 (13.97 0.25)
0.067 0.005 (1.70 0.127) 0.268 REF (6.81 REF)
0.032 0.005 (0.81 0.13)
0.018 0.008 (0.46 0.20)
0.103 0.013 (2.620.33)
Dimensions: inch (mm)
TO-220-5 (T)
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0.4050.005 0.065 0.010 202 0.0500.005
0.176 0.005 0.050 0.005
0.3600.005 0.6000.025 SEATING PLANE 0.004 +0.004 -0.008
0.100 BSC DIM. = INCH
0.050
8 MAX 0.015 0.002
0.100 0.01
TO-263 (U)
0.4050.005 0.065 0.010 202 0.0500.005
0.176 0.005 0.060 0.005
0.3600.005 0.6000.025 SEATING PLANE 0.004 +0.004 -0.008
0.0670.005 DIM. = INCH
0.032 0.003
8 MAX 0.015 0.002
0.100 0.01
TO-263-5 (U)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 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) 1999 Micrel Incorporated
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