Data Sheet
29317.16E
2557
PROTECTED QUAD LOW-SIDE DRIVER
WITH FAULT DETECTION & SLEEP MODE
The A2557xB, A2557xEB, and A2557xLB have 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.
Over-current 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). Similar devices, for operation
to 1.3 A, are available as the UDx2547B/EB.
Continuous or multiple overload conditions causing the channel tempera-
ture to reach approximately 165°C will result in an additional linear decrease
in the output current of the affected driver. If the fault condition is corrected,
the output stage will return to its normal saturated condition.
The first character of the part number suffix determines the device
operating temperature range. Suffix ‘S-’ is the standard -20°C to +85°C;
suffix ‘E-’ is -40°C to +85°C; suffix ‘K-’ is for the industrial temperature
range of -40°C to +125°C. Package suffix ‘-B’ devices are 16-pin power
DIPs; suffix ‘-EB’ devices are 28-lead power PLCCs; and suffix ‘-LB’ are 16-
lead power wide-body SOICs for surface-mount applications. All packages
are of batwing construction to provide for maximum package power dissipa-
tion.
FEATURES
a73 300 mA Output Current per Channel
a73 Independent Over-Current Protection &Thermal Limiting for Each Driver
a73 Output Voltage to 60 V
a73 Output SOA Protection
a73 Fault-Detection Circuitry for Open or Shorted Load
a73 Low Quiescent Current Sleep Mode
a73 Integral Output Flyback/Clamp Diodes
a73 TTL- and 5 V CMOS-Compatible Inputs
1
2
3 14
4
5
6
7
8 9
10
11
12
13
15
16
ENABLE
GROUND
GROUND
OUT
3
FAULT

GROUND

GROUND
OUT
2
OUT
1
K
OUT
4
V
CC
IN
4
Dwg. PP-017-4
IN
1
IN
2
IN
3
A2557xLB
Note that the A2557xB (DIP) and the A2557xLB
(SOIC) are electrically identical and share a
common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Output Voltage, V
O
.............................. 60 V
Over-Current Protected Output Voltage,
V
O
..................................................... 32 V
Output Current, I
O
......................... 500 mA*
FAULT Output Voltage, V
FLT
............. 60 V
Logic Supply Voltage, V
CC
................. 7.0 V
Input Voltage, V
I
or V
OE
..................... 7.0 V
Package Power Dissipation,
P
D
........................................... See Graph
Operating Temperature Range, T
A
Suffix ‘S-’ ...................... -20°C to +85°C
Suffix ‘E-’ ...................... -40°C to +85°C
Suffix ‘K-’ ................... -40°C to +125°C
Junction Temperature,
T
J
............................................... +150°C*
Storage Temperature Range,
T
S
................................. -55°C to +150°C
*Outputs are current limited at approximately
500 mA per driver and junction temperature
limited if higher current is attempted.
Complete part number includes a suffix to identify operating temperature
range (E-, K-, or S-) and package type (-B, -EB, or -LB). Always order by
complete part number, e.g., A2557KLB .