May 2007

Rev 5

1/12

12

Features

overcurrent logic output

Description

The ST2042 power distribution switches is

intended for application where heavy capacitive

loads and short circuits are likely to be

encountered. These devices incorporate 80m

.

N-channel MOSFET high-side power switches for

power-distribution systems that require multiple

powers switches in a single package. Each switch

is controlled by an independent logic enable input.

Gate drive is provided by an internal charge pump

designed to control the power-switch rise times

and fall times to minimize current surges during

switching.

The charge pump requires no external

components and allows operation from supplies

as low as 2.7 V. When the output load exceeds

the current-limit threshold or a short is present,

these devices limit the output current to a safe

level by switching into a constant-current mode,

pulling the overcurrent (OCx) logic output low. A

10ms deglitching circuit provides fault-blanking

feature, preventing the OC_N pin to be asserted

during hot-insertion or short spikes of overcurrent

conditions. When continuous heavy overloads

and short circuits increase the power dissipation

in the switch, causing the junction temperature to

rise, a thermal protection circuit shuts off the

switch to prevent damage. Recovery from a

thermal shutdown is automatic once the device

has cooled sufficiently. Internal circuitry ensures

the switch remains off until valid input voltage is

present. These power-distribution switches are

designed to

current limit at 0.9 A.

SO-8

ST2042

Enhanced power switch

www.st.com

Table 1.

Device summary

Part number

Package

Packaging

ST2042BD

SO-8

Tube

(50 parts per tube, 40 tube per box)

ST2042BDR

SO-8

Tape and reel (2500 parts per reel)