2002 Apr 10

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

-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

(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

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

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

QUICK REFERENCE DATA

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

Supplies

supply voltage 1

operating

9.5

14.4

reverse polarity

non-operating

regulator 2 on

14.4

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

supply voltage 2

operating

6.5

14.4

reverse polarity

non-operating

regulator 2 on

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

q(tot)

total quiescent supply current

standby mode

110

150

junction temperature

150

Voltage regulators

o(REG1)

output voltage of regulator 1

1 mA

REG1

600 mA; V

= 14.4 V

8.0

8.5

9.0

o(REG2)

output voltage of regulator 2

1 mA

REG2

300 mA; V

= 14.4 V

4.75

5.0

5.25

o(REG3)

output voltage of regulator 3

1 mA

REG3

1400 mA; V

= 14.4 V

4.75

5.0

5.25

o(REG4)

output voltage of regulator 4

1 mA

REG4

1 A; V

= 14.4 V

3.14

3.3

3.46

Power switch

drop(SW)

drop-out voltage

= 1 A; V

= 13.5 V

0.45

0.65

= 1.8 A; V

= 13.5 V

1.0

1.8

M(SW)

peak current

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

PINNING

Pin description of TDA3681J and TDA3681JR

SYMBOL

PIN

DESCRIPTION

REG1

regulator 1 output

REG3

regulator 3 output

second supply voltage

REG4

regulator 4 output

IGN

ignition input

IGN

OUT

ignition output (active HIGH)

RES

reset output (active LOW)

RES

reset delay capacitor

EN4

enable input for regulator 4

EN1/3

enable input for regulators 1 and 3

ENSW

enable input for power switch

HOLD

hold output (active LOW)

GND

ground

backup switch output

REG2

regulator 2 output

power switch output

supply voltage

heat tab

heat tab; it is strongly
recommended to connect the heat
tab to ground

handbook, halfpage

TDA3681J

TDA3681JR

MGL903

VP2

REG1

REG3

REG4

IGNIN

IGNOUT

CRES

EN4

RES

EN1/3

ENSW

HOLD

GND

REG2

VP1

Fig.3

Pin configuration for TDA3681J and
TDA3681JR.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

Pin description of TDA3681TH

Note

1. The pin is used for final test purposes. In the

application it should be connected directly to ground.

SYMBOL

PIN

DESCRIPTION

REG4

regulator 4 output

IGN

ignition input

IGN

OUT

ignition output (active HIGH)

RES

reset output (active LOW)

RES

reset delay capacitor

EN4

enable input for regulator 4

EN1/3

enable input for regulators 1 and 3

ENSW

enable input for power switch

HOLD

hold output (active LOW)

GND

ground

HEATTAB

heat tab connection; note 1

REG2

regulator 2 output

backup switch output

supply voltage

n.c.

not connected

power switch output

REG1

regulator 1 output

n.c.

not connected

REG3

regulator 3 output

second supply voltage

handbook, halfpage

TDA3681TH

MGU329

REG4

IGNIN

IGNOUT

RES

CRES

EN4

EN1/3

ENSW

HOLD

GND

VP2

REG3

n.c.

REG1

n.c.

VP1

REG2

HEATTAB

Fig.4 Pin configuration for TDA3681TH.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

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

RES

). This 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

and

> 4.5 V) are available, regulators 1 and 3 can be

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

, temperature protection and load dump protection.

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 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

RES

). During this

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

18 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

0.4 V. At operating temperature, the power switch

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

< V

3.7 V), the voltage on the reset delay

capacitor rises 0.6 V above the voltage of regulator 2. This
rise time depends on the capacitor connected to pin C

RES

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

is used for the switchable

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.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 60134).

THERMAL CHARACTERISTICS

QUALITY SPECIFICATION

In accordance with

"General Quality Specification For Integrated Circuits (SNW-FQ-611D)".

SYMBOL

PARAMETER

CONDITIONS

MIN.

MAX.

UNIT

supply voltage 1

operating

reverse polarity

non-operating

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

supply voltage 2

operating

reverse polarity

non-operating

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

tot

total power dissipation

stg

storage temperature

non-operating

+150

amb

ambient temperature

operating

+85

junction temperature

operating

+150

SYMBOL

PARAMETER

CONDITIONS

VALUE

UNIT

th(j-c)

thermal resistance from junction to case

K/W

th(j-a)

thermal resistance from junction to ambient

in free air

K/W

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

CHARACTERISTICS
V

= V

= 14.4 V; T

amb

= 25

C; measured in test circuits of Figs 10 and 11; unless otherwise specified.

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

Supplies

supply voltage 1

operating

9.5

14.4

reverse polarity

non-operating

regulator 2 on

note 1

14.4

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

supply voltage 2

operating

6.5

14.4

reverse polarity

non-operating

regulator 2 on

jump start

10 minutes

load dump protection

50 ms; t

2.5 ms

bat(loaddump)

battery overvoltage
shutdown

and/or V

q(tot)

total quiescent supply
current

= 12.4 V; note 2

105

145

= 14.4 V; note 2

110

150

Schmitt trigger for power supply (regulators 1, 3 and 4)

th(r)

rising threshold voltage

rising

6.5

7.0

7.5

th(f)

falling threshold voltage

falling

4.0

4.5

5.0

hys

hysteresis voltage

2.5

Schmitt trigger for enable input (regulators 1, 3, 4 and power switch)

th(r)

rising threshold voltage

1.4

1.8

2.4

th(f)

falling threshold voltage

0.9

1.3

1.9

hys

hysteresis voltage

REG

= I

= 1 mA

0.5

input leakage current

= 5 V

Reset trigger level of regulator 2

th(r)

rising threshold voltage

rising; I

REG1

= 50 mA;

note 3

4.43

REG2

0.15 V

REG2

0.1

th(f)

falling threshold voltage

falling; I

REG1

= 50 mA;

note 3

4.4

REG2

0.25 V

REG2

0.13

Schmitt triggers for hold circuit output

th(r)(REG1)

rising threshold voltage
of regulator 1

rising; note 3

REG1

0.15 V

REG1

0.075 V

th(f)(REG1)

falling threshold voltage
of regulator 1

falling; note 3

7.67

REG1

0.35

hys(REG1)

hysteresis voltage due to
regulator 1

0.2

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

th(r)(REG3)

rising threshold voltage
of regulator 3

rising; note 3

REG3

0.15 V

REG3

0.075 V

th(f)(REG3)

falling threshold voltage
of regulator 3

falling; note 3

4.3

REG3

0.35

hys(REG3)

hysteresis voltage due to
regulator 3

0.2

th(r)(REG4)

rising threshold voltage
of regulator 4

rising; note 3

REG4

0.15 V

REG4

0.075 V

th(f)(REG4)

falling threshold voltage
of regulator 4

falling; note 3

2.7

REG4

0.3

hys(REG4)

hysteresis voltage due to
regulator 4

0.15

th(r)(VP)

rising threshold voltage
of supply voltage

= 0 V

9.1

9.7

10.3

th(f)(VP)

falling threshold voltage
of supply voltage

= 0 V

9.0

9.4

9.8

hys(VP)

hysteresis voltage of
supply voltage

= 0 V

0.3

Reset and hold buffer

sink(L)

LOW-level sink current

RES

0.8 V; V

HOLD

0.8 V

output leakage current

= 14.4 V; V

HOLD

= 5 V

0.1

source(H)

HIGH-level source
current

= 14.4 V; V

RES

= 5 V

240

400

900

rise time

note 4

fall time

note 4

Reset delay

reset delay capacitor
charge current

CRES

= 0 V

dch

reset delay capacitor
discharge current

CRES

= 3 V;

= V

= 4.3 V

1.0

1.6

th(r)(RES)

rising voltage threshold
reset signal

2.5

3.0

3.5

th(f)(RES)

falling voltage threshold
reset signal

1.0

1.2

1.4

d(RES)

delay reset signal

RES

= 47 nF; note 5

d(SW)

delay power switch
foldback protection

RES

= 47 nF; note 6

17.6

Regulator 1 (I

REG1

= 5 mA; unless otherwise specified)

o(off)

output voltage off

400

o(REG1)

output voltage

1 mA

REG1

600 mA

8.0

8.5

9.0

9.5 V

18 V

8.0

8.5

9.0

line

line regulation

9.5 V

18 V

load

load regulation

1 mA

REG1

600 mA

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

quiescent current

REG1

= 600 mA

SVRR

supply voltage ripple
rejection

= 3 kHz; V

= 2 V (p-p)

drop(REG1)

drop-out voltage

REG1

= 550 mA; V

= 8.55 V;

note 7

0.4

0.7

m(REG1)

current limit

REG1

> 7 V; note 8

0.65

1.2

sc(REG1)

short-circuit current

0.5

; note 9

250

800

Regulator 2 (I

REG2

= 5 mA; unless otherwise specified)

o(REG2)

output voltage

0.5 mA

REG2

300 mA

4.75

5.0

5.25

7 V

18 V

4.75

5.0

5.25

18 V

50 V;

REG2

150 mA

4.75

5.0

5.25

line

line regulation

6 V

18 V

6 V

50 V

load

load regulation

1 mA

REG2

150 mA

1 mA

REG2

300 mA

100

SVRR

supply voltage ripple
rejection

= 3 kHz; V

= 2 V (p-p)

drop(REG2)

drop-out voltage

REG2

= 100 mA; V

= 4.75 V;

note 7

0.4

0.6

REG2

= 200 mA; V

= 5.75 V;

note 7

0.8

1.2

REG2

= 100 mA; V

= 4.75 V;

note 10

0.2

0.5

REG2

= 200 mA; V

= 5.75 V;

note 10

0.8

1.0

m(REG2)

current limit

REG2

> 4.5 V; note 8

0.32

0.37

sc(REG2)

short-circuit current

0.5

; note 9

120

Regulator 3 (I

REG3

= 5 mA; unless otherwise specified)

o(off)

output voltage off

400

o(REG3)

output voltage

1 mA

REG3

1400 mA

4.75

5.0

5.25

7 V

and/or V

18 V

4.75

5.0

5.25

line

line regulation

7 V

and/or V

18 V

load

load regulation

1 mA

REG3

1400 mA

150

quiescent current

REG3

= 1400 mA

SVRR

supply voltage ripple
rejection

= 3 kHz; V

= 2 V (p-p)

drop(REG3)

drop-out voltage

REG3

= 1400 mA ; V

= 6 V;

note 7

1.5

m(REG3)

current limit

REG3

> 4.5 V; note 8

1.5

1.7

sc(REG3)

short-circuit current

0.5

; note 9

430

750

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

Regulator 4 (I

REG4

= 5 mA; unless otherwise specified)

o(off)

output voltage off

400

o(REG4)

output voltage

1 mA

REG4

1 A

3.14

3.3

3.46

6.5 V

and/or V

18 V

3.14

3.3

3.46

line

line regulation

6.5 V

and/or V

18 V

load

load regulation

1 mA

REG4

1 A

quiescent current

REG4

= 1 A

SVRR

supply voltage ripple
rejection

= 3 kHz; V

= 2 V (p-p)

drop(REG4)

drop-out voltage

REG4

= 1 A; V

= 5 V; note 7

1.7

2.4

m(REG4)

current limit

REG4

> 3.0 V; note 8

1.1

1.5

sc(REG4)

short-circuit current

0.5

; note 9

470

750

Power switch

drop(SW)

drop-out voltage

= 1 A; V

= 13.5 V;

note 11

0.45

0.65

= 1.8 A; V

= 13.5 V;

note 11

1.0

1.8

DC(SW)

continuous current

= 16 V; V

= 13.5 V

1.8

2.0

clamp(SW)

clamping voltage

17 V;

1 mA < I

< 1.8 A

13.5

15.0

16.0

M(SW)

peak current

< 17 V;

notes 6, 12 and 13

fb(SW)

flyback voltage
behaviour

100 mA

+ 3

sc(SW)

short-circuit current

= 14.4 V; V

< 1.2 V;

note 13

0.5

1.7

Backup switch

DC(BU)

continuous current

> 5 V

0.3

0.35

clamp(BU)

clamping voltage

16.7 V; I

REG2

= 100 mA

r(BU)

reverse current

= 0 V; V

= 12.4 V

900

Schmitt trigger for enable ignition input

th(r)(IGNIN)

rising threshold voltage
of ignition input

> 3.5 V

1.9

2.2

2.5

th(f)(IGNIN)

falling threshold voltage
of ignition input

> 3.5 V

1.7

2.0

2.3

hys(IGNIN)

hysteresis voltage

> 3.5 V

0.1

0.2

0.5

input leakage current

IGNIN

= 5 V

1.0

i(clamp)

input clamp current

IGNIN

> 50 V

IH(clamp)

HIGH-level input
clamping voltage

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

Notes

1. Minimum operating voltage, only if V

has exceeded 6.5 V.

2. The total quiescent current is measured in the standby mode. Therefore, the enable inputs of regulators 1, 3, 4 and

the power switch are grounded and R

L(REG2)

; see Figs 10 and 11.

3. The voltage of the regulator drops as a result of a V

drop for regulators 1 and 2. Regulators 3 and 4 drop as a result

of V

drop.

4. The rise and fall times are measured with a 10 k

pull-up resistor and a 50 pF load capacitor.

5. The delay time depends on the value of the reset delay capacitor:

6. The delay time depends on the value of the reset delay capacitor:

7. The drop-out voltage of regulators 1 and 2 is measured between pins V

and REGn. The drop-out voltage of

regulators 3 and 4 is measured between pins V

and REGn.

8. At current limit, I

m(REGn)

is held constant (see Fig.8).

9. The foldback current protection limits the dissipated power at short-circuit (see Fig.8).

10. The drop-out voltage is measured between pins BU and REG2.

11. The drop-out voltage of the power switch is measured between pins V

and SW.

12. The maximum output current of the power switch is limited to 1.8 A when the supply voltage exceeds 18 V.

13. At short-circuit, I

sc(SW)

of the power switch is held constant to a lower value than the continuous current after a delay

of at least 10 ms.

IL(clamp)

LOW-level input
clamping voltage

0.6

Ignition buffer

LOW-level output voltage I

IGNOUT

= 0 mA

0.2

0.8

HIGH-level output
voltage

IGNOUT

= 0 mA

4.5

5.0

5.25

LOW-level output current V

IGNOUT

0.8 V

0.45

0.8

HIGH-level output
current

IGNOUT

4.5 V

0.45

2.0

output leakage current
(source)

IGNOUT

= 5 V; V

IGNIN

= 0 V

1.0

PLH

LOW-to-HIGH
propagation time

IGNIN

rising from 1.7 to 2.5 V

500

PHL

HIGH-to-LOW
propagation time

IGNIN

falling from 2.5 to 1.7 V

500

Temperature protection

j(sd)

junction temperature for
shutdown

150

160

170

j(hold)

junction temperature for
hold trigger

150

160

170

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

d(RES)

------

C(th)

750

(

)

[ ]

d(SW)

------

C(th)

375

(

)

[ ]

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

TEST AND APPLICATION INFORMATION

Test information

handbook, full pagewidth

MGL911

enable input regulator 4

supply voltage 2

regulator 4
output

C3
10

C2
10

220 nF

C4
10

hold output

ignition output

RL(REG2)
5 k

RL(SW)
12 k

5 V

8.5 V

regulator 3
output

regulator 1
output

regulator 2
output

C5
10

C9
50 pF

C12
50 pF

RL(REG1)
10 k

RL(REG3)
5 k

3.3 V

C6
10

RL(REG4)
5 k

power switch output

reset
output

(1)

(2)

(3)

TDA3681J

TDA3681JR

ground

VP1

supply voltage 1

VENSW

VEN4

enable input regulator 1/3

enable input power switch

VEN1/3

reset delay

capacitor

ignition input

10 k

C11
1 nF

backup

VIGNIN

C10
100

VBU

VP2

C8
47 nF

R3
10 k

Fig.10 Test circuit of TDA3681J and TDA3681JR.

(1) A minimum capacitor of 220 nF on the supply lines V

and V

is required for stability.

(2) A minimum capacitor of 1

F for backup supply is required for stability.

(3) Capacitor represents the typical input capacitance of CMOS logic connected to the reset and hold outputs.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

handbook, full pagewidth

MGU355

enable input regulator 4

supply voltage 2

regulator 4
output

C3
10

C2
10

220 nF

C4
10

hold output

ignition output

RL(REG2)
5 k

RL(SW)
12 k

5 V

8.5 V

regulator 3
output

regulator 1
output

regulator 2
output

C5
10

C9
50 pF

C12
50 pF

RL(REG1)
10 k

RL(REG3)
5 k

3.3 V

C6
10

RL(REG4)
5 k

power switch output

reset
output

(1)

(2)

(3)

TDA3681TH

ground

heat tab

VP1

supply voltage 1

VENSW

VEN4

enable input regulator 1/3

enable input power switch

VEN1/3

reset delay

capacitor

ignition input

10 k

C11
1 nF

backup

VIGNIN

C10
100

VBU

VP2

C8
47 nF

R3
10 k

Fig.11 Test circuit of TDA3681TH.

(1) A minimum capacitor of 220 nF on the supply lines V

and V

is required for stability.

(2) A minimum capacitor of 1

F for backup supply is required for stability.

(3) Capacitor represents the typical input capacitance of CMOS logic connected to the reset and hold outputs.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

Application information

OISE

Table 1

Noise figures

Note

1. Measured at a bandwidth of 30 kHz.

The noise on the supply line depends on the value of the
supply capacitor and is caused by a current noise (the
output noise of the regulators is translated to a current
noise by the output capacitors). The noise is minimal when
a high frequency capacitor of 220 nF in parallel with an
electrolytic capacitor of 100

F is connected directly to the

supply pins V

, V

and GND.

TABILITY

The regulators are stabilized by the externally connected
output capacitors.

The output capacitors can be selected by using the graphs
given in Figs 12 and 13. When an electrolytic capacitor is
used, its temperature behaviour can cause oscillations at
a low temperature. The two examples below show how an
output capacitor value is selected.

Example 1

Regulators 1, 3 and 4 are stabilized with an electrolytic
output capacitor of 220

F (ESR = 0.15

). At

amb

= -

C, the capacitor value is decreased to 73

and the ESR is increased to 1.1

. The regulator remains

stable at T

amb

C (see Fig.12).

Example 2

Regulator 2 is stabilized with a 10

F electrolytic capacitor

(ESR = 3

). At T

amb

C, the capacitor value is

decreased to 3

F and the ESR is increased to 23.1

As can be seen from Fig.13, the regulator will be unstable
at T

amb

Solution

To avoid problems with stability at low temperatures, the
use of tantalum capacitors is recommended. Use a
tantalum capacitor of 10

F or a larger electrolytic

capacitor.

REGULATOR

NOISE FIGURE (

(1)

= 10

= 47

= 100

170

110

440

240

190

120

100

handbook, halfpage

0.1

C (

MGL912

stable region

maximum ESR

100

ESR

(

)

Fig.12 Curve for selecting the value of the output

capacitor for regulators 1, 3 and 4.

handbook, halfpage

0.22

C (

MGL913

stable region

maximum ESR

minimum ESR

100

ESR

(

)

Fig.13 Curve for selecting the value of the output

capacitor for regulator 2.

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

SOLDERING

Introduction

This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our

"Data Handbook IC26; Integrated Circuit Packages"

(document order number 9398 652 90011).

There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mount components are mixed on
one printed-circuit board. Wave soldering can still be used
for certain surface mount ICs, but it is not suitable for fine
pitch SMDs. In these situations reflow soldering is
recommended.

Through-hole mount packages

OLDERING BY DIPPING OR BY SOLDER WAVE

The maximum permissible temperature of the solder is
260

C; solder at this temperature must not be in contact

with the joints for more than 5 seconds. The total contact
time of successive solder waves must not exceed
5 seconds.

The device may be mounted up to the seating plane, but
the temperature of the plastic body must not exceed the
specified maximum storage temperature (T

stg(max)

). If the

printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.

ANUAL SOLDERING

Apply the soldering iron (24 V or less) to the lead(s) of the
package, either below the seating plane or not more than
2 mm above it. If the temperature of the soldering iron bit
is less than 300

C it may remain in contact for up to

10 seconds. If the bit temperature is between
300 and 400

C, contact may be up to 5 seconds.

Surface mount packages

EFLOW SOLDERING

Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.

Several methods exist for reflowing; for example,
convection or convection/infrared heating in a conveyor
type oven. Throughput times (preheating, soldering and
cooling) vary between 100 and 200 seconds depending
on heating method.

Typical reflow peak temperatures range from
215 to 250

C. The top-surface temperature of the

packages should preferable be kept below 220

C for

thick/large packages, and below 235

C for small/thin

packages.

AVE SOLDERING

Conventional single wave soldering is not recommended
for surface mount devices (SMDs) or printed-circuit boards
with a high component density, as solder bridging and
non-wetting can present major problems.

To overcome these problems the double-wave soldering
method was specifically developed.

If wave soldering is used the following conditions must be
observed for optimal results:

Use a double-wave soldering method comprising a
turbulent wave with high upward pressure followed by a
smooth laminar wave.

For packages with leads on two sides and a pitch (e):

larger than or equal to 1.27 mm, the footprint

longitudinal axis is preferred to be parallel to the
transport direction of the printed-circuit board;

smaller than 1.27 mm, the footprint longitudinal axis

must be parallel to the transport direction of the
printed-circuit board.

The footprint must incorporate solder thieves at the
downstream end.

For packages with leads on four sides, the footprint must
be placed at a 45

angle to the transport direction of the

printed-circuit board. The footprint must incorporate
solder thieves downstream and at the side corners.

During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.

Typical dwell time is 4 seconds at 250

A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.

ANUAL SOLDERING

Fix the component by first soldering two
diagonally-opposite end leads. Use a low voltage (24 V or
less) soldering iron applied to the flat part of the lead.
Contact time must be limited to 10 seconds at up to
300

C. When using a dedicated tool, all other leads can

be soldered in one operation within 2 to 5 seconds
between 270 and 320

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

Suitability of IC packages for wave, reflow and dipping soldering methods

Notes

1. All surface mount (SMD) packages are moisture sensitive. Depending upon the moisture content, the maximum

temperature (with respect to time) and body size of the package, there is a risk that internal or external package
cracks may occur due to vaporization of the moisture in them (the so called popcorn effect). For details, refer to the
Drypack information in the

"Data Handbook IC26; Integrated Circuit Packages; Section: Packing Methods".

2. For SDIP packages, the longitudinal axis must be parallel to the transport direction of the printed-circuit board.

3. These packages are not suitable for wave soldering as a solder joint between the printed-circuit board and heatsink

(at bottom version) can not be achieved, and as solder may stick to the heatsink (on top version).

4. If wave soldering is considered, then the package must be placed at a 45

angle to the solder wave direction.

The package footprint must incorporate solder thieves downstream and at the side corners.

5. Wave soldering is only suitable for LQFP, QFP and TQFP packages with a pitch (e) equal to or larger than 0.8 mm;

it is definitely not suitable for packages with a pitch (e) equal to or smaller than 0.65 mm.

6. Wave soldering is only suitable for SSOP and TSSOP packages with a pitch (e) equal to or larger than 0.65 mm; it is

definitely not suitable for packages with a pitch (e) equal to or smaller than 0.5 mm.

MOUNTING

PACKAGE

SOLDERING METHOD

WAVE

REFLOW

(1)

DIPPING

Through-hole mount DBS, DIP, HDIP, SDIP, SIL

suitable

(2)

suitable

Surface mount

BGA, HBGA, LFBGA, SQFP, TFBGA

not suitable

suitable

HBCC, HLQFP, HSQFP, HSOP, HTQFP,
HTSSOP, HVQFN, SMS

not suitable

(3)

suitable

PLCC

(4)

, SO, SOJ

suitable

LQFP, QFP, TQFP

not recommended

(4)(5)

suitable

SSOP, TSSOP, VSO

not recommended

(6)

suitable

2002 Apr 10

Philips Semiconductors

Product specification

Multiple voltage regulator with switch and
ignition buffer

TDA3681

DATA SHEET STATUS

Notes

1. Please consult the most recently issued data sheet before initiating or completing a design.

2. The product status of the device(s) described in this data sheet may have changed since this data sheet was

published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com.

DATA SHEET STATUS

(1)

PRODUCT

STATUS

(2)

DEFINITIONS

Objective data

Development

This data sheet contains data from the objective specification for product
development. Philips Semiconductors reserves the right to change the
specification in any manner without notice.

Preliminary data

Qualification

This data sheet contains data from the preliminary specification.
Supplementary data will be published at a later date. Philips
Semiconductors reserves the right to change the specification without
notice, in order to improve the design and supply the best possible
product.

Product data

Production

This data sheet contains data from the product specification. Philips
Semiconductors reserves the right to make changes at any time in order
to improve the design, manufacturing and supply. Changes will be
communicated according to the Customer Product/Process Change
Notification (CPCN) procedure SNW-SQ-650A.

DEFINITIONS

Short-form specification

The data in a short-form

specification is extracted from a full data sheet with the
same type number and title. For detailed information see
the relevant data sheet or data handbook.

Limiting values definition

Limiting values given are in

accordance with the Absolute Maximum Rating System
(IEC 60134). Stress above one or more of the limiting
values may cause permanent damage to the device.
These are stress ratings only and operation of the device
at these or at any other conditions above those given in the
Characteristics sections of the specification is not implied.
Exposure to limiting values for extended periods may
affect device reliability.

Application information

Applications that are

described herein for any of these products are for
illustrative purposes only. Philips Semiconductors make
no representation or warranty that such applications will be
suitable for the specified use without further testing or
modification.

DISCLAIMERS

Life support applications

These products are not

designed for use in life support appliances, devices, or
systems where malfunction of these products can
reasonably be expected to result in personal injury. Philips
Semiconductors customers using or selling these products
for use in such applications do so at their own risk and
agree to fully indemnify Philips Semiconductors for any
damages resulting from such application.

Right to make changes

Philips Semiconductors

reserves the right to make changes, without notice, in the
products, including circuits, standard cells, and/or
software, described or contained herein in order to
improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for
the use of any of these products, conveys no licence or title
under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that
these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified.

Document Outline

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Document Outline

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