Micrel

MIC2589/MIC2595

December 2005

4

M9999-120505

(408) 955-1690

Pin Description

Pin Number

Pin Name

Pin Function

1

PWRGD1

(MIC25XX-1)

Active High

/PWRGD1

(MIC25XX-2)

Active Low

2

PGTIMER

A capacitor connected from this pin to VEE sets the time interval between assertions

of PWRGD2 (or /PWRGD2) and PWRGD3 (or /PWRGD3) relative to PWRGD1 (or

/PWRGD1). See the “Functional Description” for further detail.

3

UV

(MIC2589

and

MIC2589R)

threshold, the GATE pin is immediately pulled low by an internal 100µA current pull-

down. The UV pin is also used to cycle the device off and on to reset the circuit

breaker. Taken together, the OV and UV pins form a window comparator that defines

3

OFF

(MIC2595

and

MIC2595R)

threshold, the GATE pin is immediately pulled low by an internal 100µA current pull-

down. The OFF pin is also used to cycle the device off and on to reset the circuit

breaker. Taken together, the ON and OFF pins provide programmable hysteresis for

the MIC2595 to be enabled.

4

OV

(MIC2589

and

MIC2589R)

Overvoltage Threshold Input: When the voltage at the OV pin is greater than the

pull-down.

4

ON

(MIC2595

and

MIC2595R)

Turn-On Threshold: At initial system power-up or after the part has been shut off by

the MIC2595 to be enabled.

5

CFILTER

Current Limit Response Timer: A capacitor connected between this pin and VEE

provides filtering against nuisance tripping of the circuit breaker by setting a time

output (capacitance) to charge to VEE during start-up. This pin is held to VEE with a

3µA current pull-down when no current limit condition exists. See the “Functional

Description” for further details.

6

CNLD

No-Load Detect Timer: The absence of a load for the MIC2589/MIC2589R is defined

for any current load that is less than 20% of the full-scale current limit (i.e., 0.20

×

that is 80% (or greater) below the full-scale current limit before the circuit breaker is

tripped.

7

VEE

Negative Supply Voltage Input: Connect the negative, or low side, terminal of the

input power supply.

8

NC

No Internal Connection

9

SENSE

Circuit Breaker Sense Input: A resistor between this pin and VEE sets the current

limit trip point for the circuit. When the current limit threshold of IR = 50mV is

(short) the SENSE pin to VEE and also connect the CNLD pin to VEE to disable the

no-load detection feature.

10

GATE

Gate Drive Output: Connects to the Gate of an N-Channel MOSFET.

11

DRAIN

Drain Sense Input: Connects to the Drain of an N-Channel MOSFET.