L7987 Datasheet, PDF (1/37 Pages) STMicroelectronics – Adjustable current limitation

L7987
61 V 3 A asynchronous step-down switching regulator with
adjustable current limitation
Datasheet - production data
HTSSOP16 (R_TH = 40 °C/W)
Features
 3 A DC output current
 4.5 V to 61 V operating input voltage
 R_DS,ON = 250 m typ.
 Adjustable f_SW (250 kHz - 1.5 MHz)
 Low IQ-SHD (11 µA typ. from V_IN)
 Low IQ (1 mA typ. - V_IN 24 V - V_OUT 3.3 V)
 Output voltage adjustable from 0.8 V to V_IN
 Synchronization
 Adjustable soft-start time
 Adjustable current limitation
 Low dropout operation (12 µs max.)
 V_BIAS improves efficiency at light load
 PGOOD open collector output
 Output voltage sequencing
 Digital frequency foldback in short-circuit
 Peak current foldback in short-circuit
 Auto-recovery thermal shutdown
Description
The L7987 device is a step-down monolithic
switching regulator able to deliver up to 3 A DC.
The output voltage adjustability ranges from 0.8 V
to V_IN. The wide input voltage range and the
100% duty cycle capability meet the fail safe
specifications for industrial systems. The
embedded switchover feature on the V_BIAS pin
maximizes the efficiency at light load. The
adjustable current limitation, designed to select
the inductor RMS current accordingly with the
nominal output current, and the high switching
frequency capability make the size of the
application compact. Pulse-by-pulse current
sensing with digital frequency foldback
implements an effective constant current
protection over the different application
conditions. The peak current foldback decreases
the stress of the power components in heavy
short-circuit condition. The PGOOD open
collector output can also implement output
voltage sequencing during the power-up phase.
Multiple devices can be synchronized sharing the
SYNCH pin to prevent beating noise in low noise
applications like sensors with A/D conversion.
Applications
 Designed for 24 V bus
 Fail safe tolerant system
 Programmable logic controllers (PLCs)
March 2015
This is information on a product in full production.
DocID025589 Rev 3
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