August 2005

1

MIC5156/5157/5158

MIC5156/5157/5158

Micrel, Inc.

MIC5156/5157/5158

Super LDO™ Regulator Controller

either 3.3V, 5.0V, or 12V. The MIC5158 can be configured

as a fixed 5V controller or programmed to any voltage from

1.3V to 36V using two external resistors.

The MIC5156 is available in an 8-pin DIP or SOIC. The

MIC5157 and MIC5158 are available in a 14-pin DIP or SOIC

which operate from –40°C to +85°C.

Features

• 4.5mA typical operating current

• <1µA typical standby current

• Low external parts count

• Optional current limit (35mV typical threshold)

• 1% initial output voltage tolerance in most configurations

• 2% output voltage tolerance over temperature

• Fixed output voltages of 3.3V, 5.0V (MIC5156)

• Fixed output voltages of 3.3V, 5.0V, 12V (MIC5157)

• Programmable (1.3 to 36V) with 2 resistors (MIC5156/8)

• Internal charge pump voltage tripler (MIC5157/8)

• Enable pin to activate or shutdown the regulator

• Internal gate-to-source protective clamp

• All versions available in DIP and SOIC

Applications

• Ultrahigh current ultralow dropout voltage regulator

• Constant high-current source

• Low parts count 5.0V to 3.3V computer supply

• Low noise/low-dropout SMPS post regulator

• High-current, current-limited switch

10A 5V to 3.3V Desktop Computer Regulator

General Description

The MIC5156, MIC5157, and MIC5158 Super Low-Dropout

(LDO) Regulator Controllers are single IC solutions for high-

current low-dropout linear voltage regulation. Super LDO™

Regulators have the advantages of an external N-channel

power MOSFET as the linear pass element.

The MIC5156/7/8 family features a dropout voltage as low

the output current. The output current can be as high as the

largest MOSFETs can provide.

The MIC5156/7/8 family operates from 3V to 36V. The

MIC5156 requires an external gate drive supply to provide

the higher voltage needed to drive the gate of the external

MOSFET. The MIC5157 and MIC5158 each have an inter-

nal charge pump tripler to produce the gate drive voltage.

The tripler is capable of providing enough voltage to drive a

logic-level MOSFET to 3.3V output from a 3.5V supply and

is clamped to 17.5V above the supply voltage. The tripler

requires three external capacitors.

The regulator output is constant-current limited when the

controller detects 35mV across an optional external sense

resistor. An active-low open-collector flag indicates a low

voltage of 8% or more below nominal output. A shutdown

(low) signal to the TTL-compatible enable control reduces

controller supply current to less than 1µA while forcing the

output voltage to ground.

The MIC5156-3.3 and MIC5156-5.0 controllers have inter-

nally fixed output voltages. The MIC5156 [adjustable] output

is configured using two external resistors. The MIC5157 is a

fixed output controller which is externally configured to select

1

2

3

4

14

13

12

11

5

6

7

10

9

8

MIC5157

3.3V, 10A

(3.61Vmin.)

0.1µF

1.0µF

0.1µF

3mΩ

IRLZ44 (Logic Level MOSFET)

47µF

*Improves transient

response to load changes

Enable

Shutdown

47µF

10A Low-Dropout Voltage Regulator

1

2

3

8

7

6

4

5

MIC5156-3.3

3.3V, 10A

5V

0.1µF

3mΩ

SMP60N03-10L

47µF

*Improves transient

response to load changes

+12V

Enable

Shutdown

47µF

Typical Applications

Super LDO is a 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