Philips TDA8551T Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA8551

1 W BTL audio amplifier with digital
volume control

Product specification
Supersedes data of 1997 May 07
File under Integrated Circuits, IC01

1998 Feb 23

Philips Semiconductors Product specification

1 W BTL audio amplifier with digital volume control TDA8551

FEATURES

• One pin digital volume control

• Volume setting with UP/DOWN pulses

• Flexibility in use

• Few external components

• Low saturation voltage of output stage

• standby mode controlled by CMOS compatible levels

GENERAL DESCRIPTION

The TDA8551; TDA8551T is a one channel 1 W
Bridge-Tied Load (BTL) audio power amplifier capable of
delivering 1 W output power to an 8 Ω load at THD = 10%
using a 5 V power supply. The circuit contains a BTL
power amplifier, a digital volume control and standby/mute
logic. The TDA8551T comes in an 8 pin SO package and
the TDA8551 in a 8 pin DIP package.

• Low standby current

• No switch-on/switch-off plops

• High supply voltage ripple rejection

• Protected against electrostatic discharge

• Outputs short circuit safe to ground, V

P

and across the

APPLICATIONS

• Portable consumer products

• Personal computers

• Telephony.

load

• Thermally protected.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

P

I

q

I

stb

P

o

G

v

n

vol

THD total harmonic distortion P

supply voltage 2.7 5 5.5 V
quiescent current VP=5V − 610mA
standby current −−10 µA
output power THD = 10%; RL=8Ω; VP= 5 V 1 1.4 − W
voltage gain −60 − +20 dB
number of volume steps − 64 −

= 0.5 W − 0.15 − %

o

SVRR supply voltage ripple rejection 48 −−dB

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

TDA8551T SO8 plastic small outline package; 8leads; body width 3.9 mm SOT96-1
TDA8551 DIP8 plastic dual in-line package; 8 leads (300 mil) SOT97-1

1998 Feb 23 2

Philips Semiconductors Product specification

1 W BTL audio amplifier with digital volume control TDA8551

BLOCK DIAGRAM

handbook, full pagewidth

UP/DOWN

SVR

1

4

IN

3

OPERATING

INTERFACE

downup

UP/DOWN
COUNTER

VOLUME

CONTROL

STANDBY/

MUTE/

27

MODE

V

P

15 kΩ

15 kΩ

GND

TDA8551

V

P

6

MASTER

20 kΩ

5 kΩ

R
R

SLAVE

MGK363

8

OUT+

5

OUT−

Fig.1 Block diagram.

PINNING

SYMBOL PIN DESCRIPTION

UP/DOWN 1 digital trinary input for volume

control

MODE 2 digital trinary input for mode

selection (standby , mute, operating)

SVR 3 half supply voltage, decoupling

ripple rejection
IN 4 audio input
OUT− 5 negative loudspeaker output

terminal
V

P

6 supply voltage
GND 7 ground
OUT+ 8 positive loudspeaker output

terminal

1998 Feb 23 3

handbook, halfpage

UP/DOWN

1
2

TDA8551

3

SVR

4

IN

MGK362

Fig.2 Pin configuration.

8
7
6
5

OUT+
GNDMODE
V

P

OUT−

Philips Semiconductors Product specification

1 W BTL audio amplifier with digital volume control TDA8551

FUNCTIONAL DESCRIPTION

The TDA8551; TDA8551T is a 1 W BTL audio power
amplifier capable of delivering 1 W output power to an 8 Ω
load at THD = 10% using a 5 V power supply. The gain of
the amplifier can be set by the digital volume control. In the
maximum volume setting the gain is 20 dB. Using the
MODE pin the device can be switched to the standby
condition, the mute condition and the normal operating
condition. The device is protected by an internal thermal
shutdown protection mechanism.

Power amplifier

The power amplifier is a Bridge Tied Load (BTL) amplifier
with a complementary CMOS output stage. The total
voltage loss for both output power MOS transistors is
within 1 V and with a 5 V supply and an 8 Ω loudspeaker
an output power of 1 W can be delivered. The total gain of
this power amplifier is internally fixed at 20 dB.

Volume control

The volume control operates as a digital controlled
attenuator between the audio input pin and the power
amplifier. In the maximum volume control setting the
attenuation is 0 dB and in the minimum volume control
setting the typical attenuation is 80 dB. The attenuation
can be set in 64 steps by the UP/DOWN pin.
This UP/DOWN pin is a trinary input:

• Floating UP/DOWN pin: volume remains unchanged

• Negative pulses: setting volume towards minimum

• Positive pulses: setting volume towards maximum.

Each pulse on the UP/DOWN pin results in a change in
gain of 80/64 = 1.25 dB (typical value). In the basic
application the UP/DOWN pin is switched to ground or V
by a double push-button. When the supply voltage is
initially connected, after a complete removal of the supply,
the initial state of the volume control is an attenuation of
40 dB (low volume), so the gain of the total amplifier is

−20 dB. After powering-up, some positive pulses have to
be applied to the UP/DOWN pin for turning up to listening
volume. When the device is switched with the MODE
select pin to the mute or the standby condition, the volume
control attenuation setting remains on its value, assumed
that the voltage on pin VP does not fall below the minimum
supply voltage. After switching the device back to the
operation mode, the previous volume setting is
maintained.

Mode select pin

The device is in the standby mode (with a very low current
consumption) if the voltage at the MODE pin is between V
and VP− 0.5 V. At a mode select voltage level of less than

0.5 V the amplifier is fully operational. In the range
between 1 V and VP− 1.4 V the amplifier is in the mute
condition. The mute condition is useful for using it as a ‘fast
mute’; in this mode output signal is suppressed, while the
volume setting remains at its value. It is advised to keep
the device in the mute condition while the input capacitor
is being charged. This can be done by holding the MODE
pin at a level of 0.5VP, or by waiting approximately 100 ms
before giving the first volume-UP pulses.

P

P

1998 Feb 23 4

Philips Semiconductors Product specification

1 W BTL audio amplifier with digital volume control TDA8551

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134).

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

P

V

I

I

ORM

T

stg

T

amb

V

sc

P

tot

QUALITY SPECIFICATION

supply voltage −0.3 +5.5 V
input voltage −0.3 VP+ 0.3 V
repetitive peak output current − 1A
storage temperature −55 +150 °C
operating temperature −40 +85 °C
AC and DC short-circuit safe voltage − 5.5 V
maximum power dissipation SO8 − 0.8 W

DIP8 − 1.2 W

Quality according to
the

“Quality reference handbook”

“SNW-FQ-611 part E”

, order number 9397 750 00192.

, if this type is used as an audio amplifier. Quality specifications are listed in

THERMAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS VALUE UNIT

R

th j-a

thermal resistance from junction to ambient in free air

SO8 160 K/W
DIP8 100 K/W

1998 Feb 23 5

Philips Semiconductors Product specification

1 W BTL audio amplifier with digital volume control TDA8551

CHARACTERISTICS

V

=5V; T

P

test circuit of Fig.4.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

DC characteristics

V

P

I

q

I

stb

V

O

V

OUT+

Mode select pin

V

MODE

I

MODE

α mute attenuation note 3 80 90 − dB

=25°C; RL=8Ω; V

amb

supply voltage 2.7 5 5.5 V
quiescent current RL= ∞; note 1 − 610 mA
standby current V
DC output voltage note 2 − 2.5 − V

− V

 differential output offset −−50 mV

OUT−

input voltage standby mode VP− 0.5 − V

input current 0 < V

= 0 V; total gain setting at +7 dB (unless otherwise specified); measured in

MODE

MODE=VP

mute mode 1 − V

−−10 µA

P
P

operating mode 0 − 0.5 V

MODE<VP

−−100 nA

V

− 1.4 V

Volume control

t

rep

V

th(UP)

V

float(max)

V

float(min

V

th(DOWN)

I

UP/DOWN

G

v(max)

) UP/DOWN pin floating low level 1.0 −− V

pulse repetition time 100 −− ns
UP/DOWN pin up threshold level 4.2 − V

P

V

UP/DOWN pin floating high level −−3.4 V

UP/DOWN pin down threshold level 0 − 0.6 V
input current UP/DOWN pin 0 < V
maximum voltage gain (including

UP/DOWN<VP

−−200 µA
19 20 21 dB

power amplifier)

G

v(min)

minimum voltage gain (including

−62 −60 −58 dB

power amplifier)

n

vol

∆G

v

Z

i

V

i(rms)(max)

number of volume steps − 64 −
voltage gain variation per step − 1.25 − dB
input impedance 14 20 − kΩ
maximum input voltage (RMS value) −−2.0 V

AC characteristics (f = 1 kHz)

P

o

output power THD = 10% 1 1.4 − W

THD = 0.5% 0.6 1.0 − W
THD total harmonic distortion P
V

n(o)

noise output voltage note 5 − 60 100 µV

= 0.5 W; note 4 − 0.15 0.5 %

o

SVRR supply voltage ripple rejection note 6 48 53 − dB
V

i(IN)(max)

maximum input voltage on pin IN THD = 1%;

−−2.0 V
Gv= −50 dB
to 0 dB

1998 Feb 23 6