MICREL MIC29371-3.3BT, MIC29371-12BT, MIC2937A-12BU, MIC2937A-3.3BT, MIC2937A-3.3BU Datasheet

MIC2937A/29371/29372 Micrel

MIC2937A/29371/29372

750mA Low-Dropout Voltage Regulator

General Description

The MIC2937A family are “bulletproof” efficient voltage
regulators with very low dropout voltage (typically 40mV at
light loads and 300mV at 500mA), and very low quiescent
current (160µA typical). The quiescent current of the MIC2937A
increases only slightly in dropout, thus prolonging battery life.
Key MIC2937A features include protection against reversed
battery, fold-back current limiting, and automotive “load dump”
protection (60V positive transient).

The MIC2937 is available in several configurations. The
MIC2937A-xx devices are three pin fixed voltage regulators
with 3.3V, 5V, and 12V outputs available. The MIC29371 is a
fixed regulator offering logic compatible ON/OFF switching
input and an error flag output. This flag may also be used as
a power-on reset signal. A logic-compatible shutdown input is
provided on the adjustable MIC29372, which enables the
regulator to be switched on and off.

Features

• High output voltage accuracy

• Guaranteed 750mA output

• Low quiescent current

• Low dropout voltage

• Extremely tight load and line regulation

• Very low temperature coefficient

• Current and thermal limiting

• Input can withstand –20V reverse battery and +60V
positive transients

• Error flag warns of output dropout

• Logic-controlled electronic shutdown

• Output programmable from 1.24V to 26V(MIC29372)

• Available in TO-220, TO-263, TO-220-5, and TO-263-5
packages.

Applications

• Battery Powered Equipment

• Cellular Telephones

• Laptop, Notebook, and Palmtop Computers

• PCMCIA VCC and V

• Bar Code Scanners

• Automotive Electronics

• SMPS Post-Regulator/ DC to DC Modules

• High Efficiency Linear Power Supplies

Regulation/Switching

PP

Pin Configuration

GROUND

TO-263 Package

(MIC2937A-xxBU)

Five Lead Package Pin Functions:

MIC29371 MIC29372

1) Error Adjust

2) Input Shutdown

3) Ground Ground

4) Output Input

5) Shutdown Output

OUTPUTINPUT

The TAB is Ground on the TO-220 and TO-263 packages.

12345

TO-263-5 Package

(MIC29371/29372BU)

12 3
Front View

GROUND OUTPUTINPUT

TO-220 Package

(MIC2937A-xxBT)

12345

TO-220-5 Package

(MIC29371/29372BT)

3-18 October 1999

MIC2937A/29371/29372 Micrel

Ordering Information

Part Number Voltage Temperature Range* Package

MIC2937A-3.3BU 3.3 –40°C to +125°C TO-263-3
MIC2937A-3.3BT 3.3 –40°C to +125°C TO-220
MIC2937A-5.0BU 5.0 –40°C to +125°C TO-263-3
MIC2937A-5.0BT 5.0 –40°C to +125°C TO-220
MIC2937A-12BU 12 –40°C to +125°C TO-263-3
MIC2937A-12BT 12 –40°C to +125°C TO-220
MIC29371-3.3BT 3.3 –40°C to +125°C TO-220-5
MIC29371-3.3BU 3.3 –40°C to +125°C TO-263-5
MIC29371-5.0BT 5.0 –40°C to +125°C TO-220-5
MIC29371-5.0BU 5.0 –40°C to +125°C TO-263-5
MIC29371-12BT 12 –40°C to +125°C TO-220-5
MIC29371-12BU 12 –40°C to +125°C TO-263-5
MIC29372BT Adj –40°C to +125°C TO-220-5
MIC29372BU Adj –40°C to +125°C TO-263-5

Absolute Maximum Ratings

If Military/Aerospace specified devices
are required, contact your local Micrel
representative/distributor for availability
and specifications.

Power Dissipation (Note 1) .............. Internally Limited

Lead Temperature (Soldering, 5 seconds) ........ 260°C

Storage Temperature Range ............ –65°C to +150°C

Operating Junction Temperature Range

................................................. –40°C to +125°C

TO-220 θJC...................................................... 2.5°C/W

TO-263 θJC...................................................... 2.5°C/W

Input Supply Voltage ...............................–20V to +60V

Operating Input Supply Voltage ...................2V† to 26V

Adjust Input Voltage (Notes 9 and 10)

......................................................–1.5V to +26V

Shutdown Input Voltage .........................–0.3V to +30V

Error Comparator Output Voltage .......... –0.3V to +30V

†

Across the full operating temperature, the minimum
input voltage range for full output current is 4.3V to 26V.
Output will remain in-regulation at lower output voltages
and low current loads down to an input of 2V at 25°C.

* Junction temperatures

October 1999 19 MIC2937A/29371/29372

MIC2937A/29371/29372 Micrel

Electrical Characteristics

Limits in standard typeface are for TJ = 25°C and limits in boldface apply over the full operating temperature range.
Unless otherwise specified, VIN = V
and V

SHUTDOWN

≤ 0.6V (MIC29371-xx and MIC29372 only).

Symbol Parameter Conditions Min Typical Max Units

V

O

Output Voltage Variation from factory trimmed V
Accuracy –2 2

∆V

O

Output Voltage (Note 2) 20 100 ppm/°C

∆T Temperature Coef. Output voltage > 10V 80 350
∆V

V
∆V
V

O

O

O

O

Line Regulation VIN = V

Load Regulation IL = 5 to 500mA 0.04 0.16 %

+ 1V, IL = 5mA, CL = 10µF. The MIC29372 are programmed for a 5V output voltage,

OUT

OUT

–1 1 %

5mA ≤ IL ≤ 500mA –2.5 2.5
MIC2937A-12 and 29371-12 only: –1.5 1.5

–3 3

5mA ≤ IL ≤ 500mA –4 4

+ 1V to 26V 0.03 0.10 %

OUT

0.40

(Note 3) 0.30

VIN – V

I

GND

I

GNDDO

I

LIMIT

∆V

O

∆P

D

e

n

O

Dropout Voltage IL = 5mA 80 150 mV
(Note 4) 180

IL = 100mA 200

Output voltage > 10V 240

IL = 500mA 300

Output voltage > 10V 420

IL = 750mA 370 600

750

Ground Pin Current IL = 5mA 160 250 µA
(Note 5) 300

IL = 100mA 1 2.5 mA

3

IL = 500mA 8 13

16

IL = 750mA 15 25

Ground Pin VIN = 0.5V less than designed V
Current at Dropout (V

≥ 3.3V)

OUT

OUT

200 500 µA

(Note 5) IO = 5mA
Current Limit V

= 0V 1.1 1.5 A

OUT

(Note 6) 2

Thermal Regulation (Note 7) 0.05 0.2 %/W

Output Noise CL = 10µF 400 µV RMS
Voltage
(10Hz to 100kHz) CL = 100µF 260
IL = 100mA

MIC2937A/29371/29372 20 October 1999