Philips Semiconductors Product specification
Multiple voltage regulator with switch and
ignition buffer
TDA3681
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 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
(regulators 1, 3 and 4 and power
switch off)
• Hold output when one of regulators 1 and 3 and/or 4 is
out of regulation
• Hold output for foldback mode of power switch and
regulators 1, 3 and 4
• Hold output for 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
• 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 TDA3681 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 TDA3681
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.
ORDERING INFORMATION
TYPE
NUMBER
PACKAGE
NAME DESCRIPTION VERSION
TDA3681J DBS17P plastic DIL-bent-SIL power package; 17 leads (lead length 7.7 mm) SOT243-3
TDA3681JR DBS17P plastic DIL-bent-SIL (special bent) power package; 17 leads
(lead length 12 mm)
SOT475-1
TDA3681TH HSOP20 plastic, heatsink small outline package; 20 leads; low stand-off height SOT418-2
MS-8
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