A2557_09 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Protected Quad Driver with Fault Detection and Sleep Mode

A2557
Protected Quad Driver
with Fault Detection and Sleep Mode
Features and Benefits
▪ 300 mA output current per channel
▪ Independent overcurrent protection and thermal limiting
for each driver
▪ Output voltage to 60 V
▪ Output SOA protection
▪ Fault-detection circuitry for open or shorted load
▪ Low quiescent current Sleep Mode
▪ Integral output flyback/clamp diodes
▪ TTL- and 5 V CMOS-compatible inputs
Packages:
Package B, 16-pin DIP
with exposed tabs
Package EB, 28-pin PLCC
with internally fused pins
Description
The A2557 has been specifically designed to provide cost-
effective solutions to relay-driving applications with up to
300 mA drive current per channel. They may also be used for
driving incandescent lamps in applications where turn-on time
is not a concern. Each of the four outputs will sink 300 mA in
the on state. The outputs have a minimum breakdown voltage
of 60 V and a sustaining voltage of 40 V. A low-power Sleep
Mode is activated with either ENABLE low or all inputs low.
In this mode, the supply current drops to below 100 μA.
Overcurrent protection for each channel has been designed into
these devices and is activated at a nominal 500 mA. It protects
each output from short circuits with supply voltages up to 32 V.
When an output experiences a short circuit, the output current
is limited at the 500 mA current clamp. In addition, foldback
circuitry decreases the current limit if an excessive voltage
is present across the output and assists in keeping the device
within its SOA (safe operating area). An exclusive-OR circuit
compares the input and output state of each driver. If either a
short or open load condition is detected, a single FAULT output
is turned on (active low).
Not to scale
Package LB, 16-pin SOIC
with internally fused pins
Continued on the next page…
Functional Block Diagram
ENABLE
IN _N
SLEEP
CONTROL
V _CC
COMMON CONTROL
ONE OF FOUR DRIVERS
60 A
2.5 V
THERMAL
LIMIT
CURRENT
LIMIT
FAULT
K
OUTN
30 A
<<1
29317.16L