Micrel, Inc.

MIC1344

April 24, 2015

3

Revision 1.0

Pin Description (Continued)

Pin Number

Pin Name

Pin Function

7

ENA

The ENA and ENB digital inputs control which voltage input (INA or INB) is connected to the

voltage out (OUT) pin. There is an internal 570k

Ω pull-down on this pin to ensure that automatic

select mode is active when the logic that is driving the MIC1344 is being powered-up. Table 1

shows how to control the power routing with the ENA and ENB inputs.

8

ILIMA

A resistor from this pin to ground sets the current limit for INA. The current flowing into INA can be

monitored by the voltage on this pin.

9

ASEL\

Open Drain Output. Low if Input A (INA) is providing power to the OUT pin.

10

STAOK

Open drain output, digital status monitor for supply voltage Input A (INA). Voltage will be low if

any of the following conditions occur:

•

INA is below the UVLO limit.

•

The output current from INA is at its set current limit.

•

The die temperature exceeds the overtemperature limit.

•

•

Prolonged high hysteresis mode engaged.

11

INA

Supply Voltage Input A. This input may be bypassed to GND with >0.1µF, X7R or similar, ceramic

type capacitor. This input is hot swappable.

12

OUT

Voltage Output. This is the power output. Bypass this pin to ground with a capacitor suitable to

provide adequate power during the switchover time of the MIC1344. This capacitor should be a

minimum of 10µF, X7R or similar temperature stability, ceramic capacitor.

EP

ePad

Internally connected to electrical ground (GND) pin. Connect to as large a PCB area as practical

to dissipate heat from the MIC1344.