TDA3681ATH/N1C,512 NXP Semiconductors, TDA3681ATH/N1C,512 Datasheet - Page 6

• Manufacturer Part Number: TDA3681ATH/N1C,512
• Description: IC VOLT REG W/SW & IGNIT 20-HSOP
• Manufacturer: NXP Semiconductors

Specifications of TDA3681ATH/N1C,512

• Applications: Ignition Buffer, Regulator
• Current - Supply: 110µA
• Voltage - Supply: 9.5 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-HSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935285812512; TDA3681ATH/N1C; TDA3681ATH/N1C

Philips Semiconductors
FUNCTIONAL DESCRIPTION
The TDA3681A is a multiple output voltage regulator with
a power switch, intended for use in car radios with or
without a microcontroller. Because of the low voltage
operation of the car radio, low voltage drop regulators are
used.
Regulator 2 is in regulation when the backup voltage
exceeds 6.5 V for the first time. When regulator 2 is
switched on and its output voltage is within its voltage
range, the reset output is disabled to release the
microcontroller. The reset delay time before release can
be extended by an external capacitor (C
start-up feature is included to secure a smooth start-up of
the microcontroller at first connection, without uncontrolled
switching of regulator 2 during the start-up sequence.
The charge on the backup capacitor can be used to supply
regulator 2 for a short period when the external supply
voltage drops to 0 V (the time depends on the value of the
backup capacitor).
The output stages of all switchable regulators have an
extremely low noise behaviour and good stability, even for
small values of the output capacitors.
When both regulator 2 and the supply voltages (V
V
operated by means of one enable input.
Regulator 4 and the power switch have a separate enable
input.
Pin HOLD is normally HIGH but is active LOW. Pin HOLD
is connected to an open-collector NPN transistor and must
have an external pull-up resistor to operate. The hold
output is controlled by a low battery voltage (V
circuit which, when activated, pulls the hold output LOW
(enabled).
2003 Aug 29
handbook, full pagewidth
P2
Multiple voltage regulator with
switch and ignition buffer
> 4.5 V) are available, regulators 1 and 3 can be
V P1
voltage reference
TDA3681A
internal
Fig.3 Block diagram of the hold circuit.
CRES
). This
P1
TEMPERATURE
PROTECTION
) detection
low battery
detector
P1
and
6
The hold circuit is also controlled by the temperature and
load dump protection. Activating the temperature or load
dump protection causes a hold (LOW) during the time that
the protection is activated.
The hold circuit is enabled at low battery voltages. This
indicates that it is not possible to get regulator 1 into
regulation when switching it on: regulator 1 has the highest
output voltage (8.5 V) of all switchable regulators.
Therefore, regulator 1 is the most critical regulator with
respect to an out of regulation condition caused by a low
battery voltage.
The hold function includes hysteresis to avoid oscillations
when the battery voltage crosses the hold threshold levels
for low V
function is illustrated in Fig.3.
All output pins are fully protected. The regulators are
protected against load dump (regulators 1, 3 and 4 switch
off at supply voltages > 18 V) and short-circuit (foldback
current protection).
The power switch contains a current protection. However,
this protection is delayed at short-circuit by the reset delay
capacitor (it should be noted that this is the second
function of the reset delay capacitor C
time, the output current is limited to a peak value of at
least 3 A (after a delay, the power switch can deliver 1.8 A
continuous if V
In a normal situation, the voltage on the reset delay
capacitor is approximately 3.5 V (depending on the
temperature). The power switch output is approximately
V
can deliver at least 3 A. At high temperature, the switch
can deliver approximately 2 A.
P
LOAD DUMP
0.4 V. At operating temperature, the power switch
P
and load dump. The block diagram of the hold
P
OR
18 V).
buffer
MGU564
HOLD
Product specification
CRES
TDA3681A
). During this