MIC37502WU-TR - MICROCHIP TECHNOLOGY

MIC37501/37502

5A, Low Voltage μCap LDO Regulator

Super eta is a registered trademark of Micrel Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

General Description

The MIC37501 and MIC37502 are 5A, low dropout

linear voltage regulator that provide low voltage, high

current outputs with a minimum of external components.

They offer high precision, ultra-low dropout (500mV),

and low ground current.

The MIC37501and MIC37502 operate from an input of

2.3V to 6.0V. They are designed to drive digital circuits

requiring low voltage at high currents (i.e., PLDs, DSPs,

microcontrollers, etc.). They are available in fixed and

adjustable output voltages. Fixed voltages include 1.5V,

1.65V, 1.8V, 2.5V, and 3.3V. The adjustable version is

capable of 1.24V to 5.5V.

MIC37501 and MIC37502 LDOs feature thermal and

currentlimit protection and reverse current protection.

Logic enable and error flag pins are available.

Junction temperature range of the MIC37501/02 is from

–40°C to 125°C.

For applications requiring input voltage greater than

6.0V, see MIC3910x, MIC3915x, MIC3930x, and

MIC3950x LDOs.

All support documentation can be found on Micrel’s web

site at www.micrel.com.

Features

• 5A minimum guaranteed output current

• 500mV maximum dropout voltage

– Ideal for 3.0V to 2.5V conversion

– Ideal for 2.5V to 1.8V, 1.65V, or 1.5V

conversion

• Stable with ceramic or tantalum capacitor

• Wide input voltage range:

- V

IN: 2.3V to 6.0V

• ±1.0% initial output tolerance

• Fixed and adjustable output voltages:

– MIC37501—7 terminal fixed voltage

– MIC37502—5 (TO-263) and 7 (SPAK) terminal

adjustable voltage

• Excellent line and load regulation specifications

• Logic controlled shutdown

• Thermal shutdown and current-limit protection

• Reverse-leakage protection

• Low profile S-Pak and TO-263 packages

Applications

• LDO linear regulator for low-voltage digital IC

• PC add-in cards

• High efficiency linear power supplies

• SMPS post regulator

• Battery charger

Typical Applications

VOUTVIN

FLG

GND

VEN

COUT

100F, Ceramic

100k

MIC37501

VIN = 3.0V VOUT = 2.5V

CIN

Fixed 2.5V Regulator with Error Flag

VOUTVIN

ADJ

GND

VEN

COUT

100F, Ceramic

1.3V

MIC37502

CIN

Adjustable Regulator

100

150

200

250

300

350

400

450

012345

DROPOUT (mV)

OUTPUT CURRENT (A)

Dropout

vs. Output Current

2.5VOUT

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Ordering Information

Part Number

Standard RoHS Compliant(1)

Output

Current Voltage(2) Junction Temp. Range Package

MIC37501-1.5BR MIC37501-1.5WR 5A 1.5V –40°C to +125°C S-Pak-7

MIC37501-1.65BR MIC37501-1.65WR 5A 1.65V –40°C to +125°C S-Pak-7

MIC37501-1.8BR MIC37501-1.8WR 5A 1.8V –40°C to +125°C S-Pak-7

MIC37501-2.5BR MIC37501-2.5WR 5A 2.5V –40°C to +125°C S-Pak-7

MIC37501-3.3BR MIC37501-3.3WR 5A 3.3V –40°C to +125°C S-Pak-7

MIC37502BR MIC37502WR 5A Adj. –40°C to +125°C S-Pak-7

MIC37502BU MIC37502WU 5A Adj. –40°C to +125°C To-263-5

Notes:

1. RoHS compliant with “high-melting solder” exemption.

2. Other Voltage available. Contact Micrel for detail.

Pin Configuration

TAB

5 ADJ

4 VOU

3 GND

2 VIN

1EN

TO-263-5

TAB

7 FLG/ADJ

6 VOUT

5 VOUT

4 GND

3 VIN

2 VIN

1EN

S-PAK-7

Pin Description

Pin Number

TO-263-5

Pin Number

S-PAK-7

Pin Name Pin Name

1 1 EN

Enable (input): CMOS-compatible input. Logic high = enable, logic

low = shutdown.

2 2, 3 VIN

Input voltage which supplies current to the output power device.

Connect pins 2 and 3 together externally.

3 4 GND Ground (TAB is connected to ground).

4 5, 6 VOUT Regulator Output: Connect pins 5 and 6 together externally.

— 7 FLG

Error Flag (output): Open collector output. Active low indicates an

output fault condition.

5 7 ADJ

Adjustable regulator feedback input. Connect to resistor voltage

divider.

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Absolute Maximum Ratings(1)

Supply Voltage (VIN) ................................................. 6.5V

Enable Input Voltage (VEN) ....................................... 6.5V

Power Dissipation(PD) .......................... Internally Limited

Junction Temperature(TJ) ............... –40°C  TJ  +125°C

Storage Temperature(TS) ............... –65°C  TJ  +150°C

Lead Temperature (soldering, 5 sec.) ....................260°C

ESD Rating(3)...............................................................2kV

Operating Ratings(2)

Supply Voltage (VIN) .........................................2.3V to 6.0V

Enable Input Voltage (VEN) .................................. 0V to 6.0V

Junction Temperature Range(TJ) ....... –40°C  TJ  +125°C

Maximum Power Dissipation .....................................Note 4

Package Thermal Resistance

S-Pak(JA) ......................................................... 38°C/W

S-Pak(JC) ........................................................... 2°C/W

TO-263(JA).................................................... 26.2°C/W

TO-263(JC)......................................................... 2°C/W

Electrical Characteristics(5)

TA = 25°C with VIN = VOUT + 1V; VEN = VIN; bold values indicate –40°C < TJ < +125°C; unless otherwise noted.

Parameter Condition Min Typ Max Units

IL = 10mA –1 +1 % Output Voltage Accuracy

10mA < IOUT < IL(max), VOUT + 1  VIN  6V –2 +2

Output Voltage Line Regulation VIN = VOUT +1.0V to 6.0V 0.06 0.5 %

Output Voltage Load Regulation IL = 10mA to 5A 0.2 1 %

IL = 2.5A 350 mV

VIN – VOUT, Dropout Voltage(6)

IL = 5A 330 500 mV

Ground Pin Current(7) IL = 5A 57 100 mA

Ground Pin Current in Shutdown VIL < 0.5V, VIN = VOUT + 1V 1.0 µA

Current Limit VOUT = 0 5 7.5 11 A

Start-up Time VEN = VIN, IOUT = 10mA, COUT = 100µF 170 500 µs

Enable Input

Regulator enable 2.25 V Enable Input Threshold

Regulator shutdown 0.8 V

VIL < 0.8V (Regulator shutdown) 2

µA

Enable Pin Input Current

VIH > 2.25V (Regulator enabled) 1 15 30

µA

Flag Output

IFLG(LEAK) VOH = 6V 1

µA

VFLG(LO) VIN = 2.25V, IOL = 250µA(8) 210

400

500

Low threshold, % of VOUT below nominal 93 %

Hysteresis 2 %

VFLG

High threshold, % of VOUT below nominal 99.2 %

MIC37502 Only

Reference Voltage 1.228

1.215

1.240 1.252

1.265

Adjust Pin Bias Current 40 80

120

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Notes:

1. Exceeding the ratings in the “Absolute Maximum Ratings” section may damage the device.

2. The device is not guaranteed to function outside its operating rating.

3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

4. PD(max) = (TJ(max) – TA) / θJC, where θJC depends upon the printed circuit layout. See “Applications Information” section.

5. Specification for packaged product only

6. VDO = VIN – VOUT when VOUT decreased to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 1.75V,

dropout voltage specification does not apply dut to a minimum input operating voltage of 2.3V.

7. IGND is the quiescent current. IIN = IGND + IOUT.

8. For a 2.5V device, VIN = 2.3V (device is in dropout).

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Typical Characteristics

100

150

200

250

300

350

400

450

012345

DROPOUT (mV)

OUTPUT CURRENT (A)

Dropout

vs. Output Current

2.5VOUT

250

300

350

400

450

500

-40 -20 02 04 06 08 0 100 120

DROPOUT (mV)

TEMPERATURE (°C)

Dropout

vs. Temperature

2.5VOUT

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.5 1.7 1.9 2.1 2.3 2.5

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(1.5V)

10mA load

5A load

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.8

1.5 1.7 1.9 2.1 2.3 2.5 2.7

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(1.8V)

5A load

10mA load

0.5

1.0

1.5

2.0

2.5

3.0

1.5 2.0 2.5 3.0 3.5

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(2.5V)

5A load

10mA load

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1.5

1.8

2.0

2.3

2.5

2.8

3.0

3.3

3.5

3.8

4.0

4.3

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(3.3V)

10mA load

5A load

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

GROUND CURRENT (mA)

OUTPUT CURRENT (A)

Ground Current

vs. Output Current

2.5VOUT

0.1

0.2

0.3

0.4

0.5

0.6

0.7

012345

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Suppl (1.5V)

10mA

100mA

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Suppl (1.5V)

2.5A

0.1

0.2

0.3

0.4

0.5

0.6

0.7

012345

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Suppl (1.8V)

10mA

100mA

012345

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Suppl (1.8V)

2.5A

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

012345

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Suppl (2.5V)

10mA

100mA

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0.02

0.04

0.06

0.08

0.10

0.12

01234 5

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Supply (2.5V)

2.5A

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

01234 5

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Supply (3.3V)

100mA

10mA

100

120

01234 5

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Supply (3.3V)

2.5A

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

-40 -20 02 04 06 08 0 100 120

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

100m A

10m A

-40 -20 02 04 06 08 0 100 120

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

2.5A

2.40

2.42

2.44

2.46

2.48

2.50

2.52

2.54

2.56

2.58

2.60

-40 -20 02 04 06 08 0 100 120

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Output Voltage

vs. Temperature

2.25 3 3.75 4.5 5.25 6

SHORT CIRCUIT CURRENT (A)

SUPPLY VOLTAGE (V)

Short Circuit Current

vs. Suppl Voltage

-40 -20 02 04 06 08 0 100 120

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Short Circuit Current

vs. Temperature

ERROR FLAG (V)

)

VIN =5V

Flag High (OK)

Flag Low (FAULT)

0.01 0.1 110 1k

100 10k

Error Flag Pull-Up Resistor

-40 -20 02 04 06 08 0 100 120

ENABLE CURRENT(μA)

TEMPERATURE (°C)

Enable Current

vs. Temperature

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Functional Characteristics

VIN = 3.3V

VOUT = 2.5V

COUT = 100µF Ceramic

IOUT = 5A

Enable Transient Response

VIN = 3.3V

VOUT = 2.5V

COUT = 100µF Ceramic

Line Transient Response

3.3V

VIN = 3.3V

VOUT = 2.5V

COUT = 100µF Ceramic

Load Transient Response

VIN = 3.3V

VOUT = 2.5V

COUT = 100µF Ceramic

Load Transient Response

100mA

Micrel, Inc. MIC37501/37502

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Application Information

The MIC37501/02 is a high-performance, low dropout

voltage regulator suitable for moderate to high-current

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 based-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 PNP®

process reduces this drive requirement to only 2% to

5% of the load current.

The MIC37501/02 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.

The output structure of these regulators allows

voltages in excess of the desired output voltage to be

applied without reverse current flow.

Thermal Design

Linear regulators are simple to use. The most

complicated design parameters to consider are

thermal characteristics. Thermal design requires the

following application-specific parameters:

• Maximum ambient temperature (TA)

• Output current (IOUT)

• Output voltage (VOUT)

• Input voltage (VIN)

• Ground current (IGND)

First, calculate the power dissipation of the regulator

from these numbers and the device parameters from

this data sheet.

PD = (VIN – VOUT) IOUT + VIN IGND

where the ground current is approximated by using

numbers from the “Electrical Characteristics” or

“Typical Characteristics” sections. The heat sink

thermal resistance is then determined with this

formula:

SA = ((TJ(max) – TA)/ PD) – (JC + CS)

Where TJ(max) 125°C and CS is between 0°C and

2°C/W. 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 1.0µF 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

applications.

Output Capacitor

The MIC37501/02 requires an output capacitor for

stable operation. As a µCap LDO, the MIC37501/02

can operate with ceramic output capacitors as long as

the amount of capacitance is 100µF or greater. For

values of output capacitance lower than 100µF, the

recommended ESR range is 200m to 2. The

minimum value of output capacitance recommended

for the MIC37501/02 is 47µF.

For 100µF or greater, the ESR range recommended is

less than 1. Ultra-low ESR ceramic capacitors are

recommended for output capacitance of 100µF or

greater to help improve transient response and noise

reduction at high frequency. X7R/X5R dielectric-type

ceramic capacitors are recommended because of

their temperature performance. X7Rtype capacitors

change capacitance by 15% over their operating

temperature range and are the most stable type of

ceramic capacitors. Z5U and Y5V dielectric capacitors

change value by as much as 50% and 60%,

respectively, over their operating temperature ranges.

To use a ceramic chip capacitor with Y5V dielectric,

the value must be much higher than an X7R ceramic

capacitor to ensure the same minimum capacitance

over the equivalent operating temperature range.

Input Capacitor

An input capacitor of 1.0µF or greater is recom-

mended when the device is more than 4 inches away

from the bulk supply capacitance, or when the supply

is a battery. Small, surfacemount chip capacitors can

be used for the bypassing. The capacitor should be

placed within 1" of the device for optimal performance.

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, 2.5V to 1.8V

or 1.65V, or 2.5V to 1.5V Conversions

The MIC37501/02 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 47µF output capacitor is all

Micrel, Inc. MIC37501/37502

May 2011 9 M9999-050511-B

that is required. Larger values help to improve

performance even further.

Enable Input

The MIC37501/02 also 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 up to VIN. When

enabled, it draws approximately 15µA.

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,

2.5V to 1.8V or 1.65V, or 2.5V to 1.5V, 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 at

least 3.7V. The MIC37501/02 regulator will provide

excellent performance with an input as low as 3.0V or

2.25V, respectively. This gives the PNP-based

regulators a distinct advantage over older, NPN-based

linear regulators.

Adjustable Regulator Design

VOUT

VIN

COUT

OUT

ADJ

GND

MIC37502

ENABLE

SHUTDOWN

V 1.240V 1 R1

OUT =+

⎛

⎝

⎜⎞

⎠

⎟

Minimum Load Current

The MIC37501/02 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

operation.

Figure 2. Adjustable Regulator with Resistors

Error Flag The MIC37502 allows programming the output voltage

anywhere between 1.24V and the 5.5V maximum

operating rating of the family. Two resistors are used.

Resistors can be quite large, up to 1M, because of

the very high input impedance and low bias current of

the sense comparator.

The MIC37501 features an error flag circuit that

monitors the output voltage and signals an error

condition when the voltage drops 5% below the

nominal output voltage. The error flag is an open-

collector output that can sink 10mA during a fault

condition. The resistor values are calculated by:

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.

⎟

⎠

⎞

⎜

⎝

⎛−= 1

1.240

R2R1 OUT

Where VOUT is the desired output voltage. Figure 2

shows component definition. Applications with widely

varying load currents may scale the resistors to draw

the minimum load current required for proper

operation (see above).

Micrel, Inc. MIC37501/37502

May 2011 10 M9999-050511-B

Package Information

7-Pin S-PAK (R)

1θ

θ1

3θ

4θ

1θ

2θ

3θ4θ

2θ1θ

5-Pin TO-263 (U)

Micrel, Inc. MIC37501/37502

May 2011 11 M9999-050511-B

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com

Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This

information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,

specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual

property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability

whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties

relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.

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.