Philips Semiconductors
Product specification
Multiple voltage regulator with
switch and ignition buffer
FEATURES
General
•
Extremely low noise behaviour and good stability with
very small output capacitors
•
Second supply pin for regulators 3 and 4 to reduce
power dissipation (e.g. via a DC-to-DC converter)
•
Three V
P
-state controlled regulators (regulators 1, 3
and 4) and a power switch
•
Regulator 2, reset and ignition buffer operational during
load dump and thermal shutdown
•
Combined control pin for switching regulators 1 and 3
•
Separate control pins for switching regulator 4 and the
power switch
•
Supply voltage range from
−18
V to +50 V
•
Low quiescent current in standby mode (when
regulators 1, 3 and 4 and power switch are switched off
and ignition input is low)
•
Hold output for low V
P
, load dump and temperature
protection
•
Reset (push-pull output stage) for regulator 2 and hold
output (open-collector output)
•
Adjustable reset delay time
•
High supply voltage ripple rejection
•
Backup capacitor for regulator 2
•
One independent ignition buffer (active HIGH).
Protections
•
Reverse polarity safe (down to
−18
V without high
reverse current)
•
Able to withstand voltages up to 18 V at the outputs
(supply line may be short-circuited)
•
ESD protection on all pins
•
Thermal protections
•
Load dump protection
ORDERING INFORMATION
TYPE
NUMBER
TDA3681ATH
PACKAGE
NAME
HSOP20
DESCRIPTION
TDA3681A
•
Foldback current limit protection for regulators 1, 2, 3
and 4
•
Delayed second current limit protection for the power
switch (at short circuit)
•
The regulator outputs and the power switch are
DC short-circuit safe to ground and supply (V
P
).
GENERAL DESCRIPTION
The TDA3681A is a multiple output voltage regulator with
a power switch and an ignition buffer. It is intended for use
in car radios with or without a microcontroller.
The TDA3681A contains the following:
•
Four fixed voltage regulators with a foldback current
protection (regulators 1, 2, 3 and 4). Regulator 2, which
is intended to supply a microcontroller, also operates
during load dump and thermal shutdown
•
Regulators 3 and 4 have a second supply pin that can
be connected to a lower supply voltage (> 6.5 V) to
reduce the power dissipation
•
A power switch with protection, operated by a control
input
•
Reset and hold outputs that can be used to interface
with the microcontroller; the reset signal can be used to
call up the microcontroller
•
Both supply pins can withstand load dump pulses and
negative supply voltages
•
Regulator 2, which is in regulation at a backup voltage
above 6.5 V
•
A provision for the use of a reserve supply capacitor that
will hold enough energy for regulator 2 (5 V continuous)
to allow a microcontroller to prepare for loss of voltage
•
An ignition input Schmitt trigger with push-pull output
stage.
VERSION
SOT418-3
plastic, heatsink small outline package; 20 leads; low stand-off height
2003 Aug 29
2
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