TDA3681J/N2S,112 NXP Semiconductors, TDA3681J/N2S,112 Datasheet - Page 8

• Manufacturer Part Number: TDA3681J/N2S,112
• Description: IC REG MULTIPLE VOLTAGE SOT243
• Manufacturer: NXP Semiconductors

Specifications of TDA3681J/N2S,112

• Package / Case: *
• Applications: Ignition Buffer, Regulator
• Current - Supply: 110µA
• Voltage - Supply: 9.5 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Number Of Outputs: 4
• Polarity: Positive
• Output Voltage: 8.5 V, 5 V, 3.3 V
• Output Type: Fixed
• Dropout Voltage (max): 0.7 V at 550 mA or 0.6 V at 100 mA
• Line Regulation: 75 mV
• Load Regulation: 150 mV
• Maximum Power Dissipation: 62 W
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 935289137112

Philips Semiconductors
FUNCTIONAL DESCRIPTION
The TDA3681 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
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 voltage detection circuit
which, when activated, pulls the hold output LOW
(enabled). The hold outputs of the regulators are
connected to an OR gate inside the IC so that the hold
circuit is activated when one or more regulators (1, 3 or 4)
are out of regulation for any reason. Each regulator enable
input controls its own hold triggering circuit, so that if a
regulator is disabled or switched off, the hold circuit for that
regulator is disabled.
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. When all regulators are
switched off, the hold output is controlled by the battery
line V
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.
2004 Mar 31
P2
Multiple voltage regulator with switch and
ignition buffer
> 4.5 V) are available, regulators 1 and 3 can be
P1
, temperature protection and load dump protection.
RES
). This start-up
P1
and
8
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 regulator voltage crosses the hold threshold
level. The hold output also becomes active when the
power switch is in foldback protection mode; see Fig.8.
The block diagram of the hold function is illustrated in
Fig.5.
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.
During an overload condition or a short circuit
(V
capacitor rises 0.6 V above the voltage of regulator 2. This
rise time depends on the capacitor connected to pin C
During this time, the power switch can deliver more than
3 A. When regulator 2 is out of regulation and generates a
reset, the power switch can only deliver 2 A and will
immediately go into foldback protection.
At supply voltages >17 V, the power switch is clamped at
16 V maximum (to avoid externally connected circuits
being damaged by an overvoltage) and the power switch
will switch off at load dump.
Interfacing with the microcontroller (simple full or semi
on/off logic applications) can be realized with an
independent ignition Schmitt trigger and ignition output
buffer (push-pull output).
The timing diagrams are illustrated in Figs 6 and 7.
The second supply voltage V
regulators 3 and 4. This input can be connected to a lower
supply voltage of 6 V to reduce the power dissipation of
the TDA3681. A DC-to-DC converter could be used for this
purpose.
P
SW
0.4 V. At operating temperature, the power switch
< V
P
3.7 V), the voltage on the reset delay
P
18 V).
P2
is used for the switchable
Product specification
RES
TDA3681
). During this
RES
.