A2550
Relay Driver with 5V Regulator
for Automotive Applications
Features and Benefits
Description
▪ Three independent low-side DMOS output drivers
▪ Short-circuit protection of drivers
▪ Eliminates need for flyback diodes on relays
▪ Thermal shutdown
Large numbers of relay-based applications require the use of a
microprocessor which implements complex system control. In
these systems, there is the need for microprocessor logic supply
voltage,power-onresetcircuitry,andwatchdogcapabilities.The
Allegro® A2550 combines the functions of voltage regulator,
watchdog, and reset, as well as three low-side DMOS relay
driver outputs. Primarily targeted at automotive applications,
thisICisdesignedtoproviderobustperformanceoverextended
voltage and temperature ranges.
▪ Separate precision 5 V regulator (2%)
▪ Current clamp on 5 V regulator
▪ 16-pin TSSOP package with exposed thermal pad
▪ Programmable reset (NPOR) delay time
▪ Programmable watchdog
▪ Automotive voltage and temperature ranges
▪ Active clamps for automotive load dump specifications
▪ Lead (Pb) free
Three low-side DMOS drivers can drive inductive loads, such
as relay coils. Each driver integrates rugged voltage clamps
which survive automotive load dump pulses up to 48 V. The
40 V rating on VBB also ensures adequate survival in harsh
automotive environments.
Package: 16 pin TSSOP (suffix LP) with
exposed pad
A 5 V linear regulator provides 40 mA of output current, with
a tolerance of 2% over the operating temperature range. To
enhance the usefulness of the IC in automotive applications,
the 5 V regulator output, as well as the three low-side driver
outputs are protected against overcurrent conditions.
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Approximate Scale
Typical Application
1
16
15
14
13
12
11
10
9
IN1
2
OUT1
OUT2
OUT3
PGND
CWD
Relays or other
inductive loads
IN2
3
4
5
6
7
8
System
Logic
A2550
IN3
LGND
NPOR
WDI
CPOR
ENBAT
VBB
EN
VREG5
0.47 μF
X7R
2550-DS