March 2004

3

M9999-031504

MIC2589/2595

Micrel

Pin Description

Pin Number

Pin Name

Pin Function

PWRGD1

Power-Good Output 1: Asserted when the voltage on the DRAIN pin

(MIC25XX-1)

(V

Active-High

proper specifications. For the MIC2589-1 and MIC2985-1, PWRGD1 will be

1

high impedance when V

/PWRGD1

V

(MIC25XX-2)

MIC2595-2, /PWRGD1 will pull-down to V

Active-Low

V

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: Undervoltage Threshold Input. When the voltage

Threshold

at the UV pin is less than the V

pulled low by an internal 100

µA 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 which define the limits of

V

3

OFF

MIC2595 and MIC2595R: Turn-Off Threshold. When the voltage at the OFF

(Turn-Off Threshold)

pin is less than the V

low by an internal 100

µA 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

Threshold

at the OV pin is greater than the V

pulled low by an internal 100

µA current pull-down.

4

ON

MIC2595 and MIC2595R: Turn-On Threshold. At initial system power-up or

(Turn-On Threshold)

after the part has been shut off by the OFF pin, the voltage on the ON pin

must be above the V

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 delay, t

signaling a fault condition and latching the output off. The minimum time for

t

during start-up. This pin is held to VEE with a 3

µA current pull-down when

no current limit condition exists. See the “Functional Description” for further

details.

6

CNLD

No-Load Detect Timer: A capacitor between this pin and VEE sets the

interval, t

below 10% of full-scale current limit before the circuit breaker is tripped.

Tying this pin to V

internal NMOS when there is no undercurrent condition.

7

VEE

Negative Supply Voltage Input.

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 exceeded for t

immediately pulled low. Toggling UV or OV will reset the circuit breaker. To

disable the circuit breaker, externally tie SENSE and VEE can be connected

together.

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.