2 x 1.4 W BTL audio amplifiers with
digital volume control and
headphone sensing
Product specification
Supersedes data of 1998 Jun 02
File under Integrated Circuits, IC01
2002 Jan 04
Philips SemiconductorsProduct specification
2 x 1.4 W BTL audio amplifiers with digital
volume control and headphone sensing
FEATURES
• One pin digital volume control (for each channel)
• Volume setting with up/down pulses
• Auto repeat function on volume setting
• Headphone sensing
• Maximum gain set by selection pin
• Low sensitivity for EMC radiation
• Internal feedback resistors
• Flexibility in use
• Few external components
• Low saturation voltage of output stage
• Standby mode controlled by CMOS compatible levels
• Low standby current
• No switch-on/switch-off plops
• High supply voltage ripple rejection
• Protected against electrostatic discharge
• Outputs short-circuitsafe to ground, VDDand across the
load
• Thermally protected.
APPLICATIONS
GENERAL DESCRIPTION
TheTDA8552T isatwo channelaudiopower amplifierthat
provides an output power of 2 × 1.4 W into an 8 Ω load
using a 5 V power supply. The circuit contains two BTL
power amplifiers, two digital volume controls and
standby/mute logic. Volume and balance of the amplifiers
are controlled using two digital input pins which can be
driven by simple push-buttons or by a microcontroller.
Using the selection pin(GAINSEL) the maximum gain can
be set at 20 or 30 dB. The headphone sense input (HPS)
can be used to detect if a headphone is plugged into the
jack connector. If a headphone is plugged into the jack
connector the amplifier switches from the BTL to the SE
mode and the BTL loudspeakers are switched off. This
also results in a reduction of quiescent current
consumption.
The TDA8552T is contained in a 20-pin small outline
package. For the TDA8552TS, which is contained in a
20-pin very small outline package, the maximum output
power is limited by the maximum allowed ambient
temperature. More information can be found in Section
“Thermal design considerations”. The SO20 package has
the four corner leads connected to the die pad so that the
thermal behaviour can be improved by the PCB layout.
TDA8552T; TDA8552TS
• Portable consumer products
• Notebook computers
• Communication equipment.
ORDERING INFORMATION
TYPE
NUMBER
TDA8552TSO20plastic small outline package; 20 leads; body width 7.5 mmSOT163-1
TDA8552TSSSOP20 plastic shrink small outline package; 20 leads; body width 4.4 mmSOT266-1
NAMEDESCRIPTIONVERSION
PACKAGE
2002 Jan 042
Philips SemiconductorsProduct specification
2 x 1.4 W BTL audio amplifiers with digital
TDA8552T; TDA8552TS
volume control and headphone sensing
QUICK REFERENCE DATA
SYMBOLPARAMETERCONDITIONSMIN.TYP.MAX.UNIT
V
DD
I
q
I
stb
P
o
G
v
N
step
THDtotal harmonic distortionP
SVRRsupply voltage ripple
GAINSEL14digital input for gain selection
IN215audio input channel 2
SVR16halfsupplyvoltage, decoupling
IN117audio input channel 1
V
DD4
OUT1−19negative loudspeaker terminal
GND420ground 4, substrate/leadframe
(1)
DESCRIPTION
output channel 2
3supply voltage 1
sensing
selection (standby, mute and
operating)
control channel 1
control channel 2
8supply voltage 2
output channel 2
output channel 1
13supply voltage 3
ripple rejection
18supply voltage 4
output channel 1
handbook, halfpage
UP/DOWN1
UP/DOWN2
TDA8552T; TDA8552TS
GND1
1
OUT2+
2
V
3
DD1
HPS
4
MODE
5
TDA8552T
6
7
V
8
DD2
OUT2−
9
GND2
10
MGM610
Fig.2 Pin configuration.
20
19
18
17
16
15
14
13
12
11
GND4
OUT1−
V
DD4
IN1
SVR
IN2
GAINSEL
V
DD3
OUT1+
GND3
Note
1. For the SO20 (SOT163-1) package only: the ground
pins 1, 10, 11 and 20 are mechanically connected to
the leadframe and electrically to the substrate of the
die. On the PCB the ground pins can be connected to
a copper area to decrease the thermal resistance.
2002 Jan 045
Philips SemiconductorsProduct specification
2 x 1.4 W BTL audio amplifiers with digital
volume control and headphone sensing
FUNCTIONAL DESCRIPTION
The TDA8552T is a 2 × 1.4 W BTL audio power amplifier
capable of delivering 2 × 1.4 W output power into 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.
The gain in the maximum volume setting is 20 dB (low
gain) or 30 dB (high gain). This maximum gain can be
selected by the gain selection pin. The headphone sense
input (HPS) can be used to detect if a headphone is
pluggedinto thejack connector.If a headphoneis plugged
intothe jackconnector theamplifier switchesfrom the BTL
to the SE mode and the BTL loudspeakers are switched
off. This also results in a reduction of quiescent current
consumption. Using the MODE pin the device can be
switched to the standby condition, the mute condition or
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 1.4 W can be delivered. The total gain
of this power amplifier can be set at 20 or 30 dB by the
gain selection pin.
Gain selection
The gain selection can be used for a fixed gain setting,
depending on the application. The gainselection pin must
be hard wired to ground (20 dB) or to VDD (30 dB). Gain
selecting during the operation is not advised, switching is
not guaranteed plop free.
Input attenuator
The volume control operates as adigitally controlled input
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. Both
attenuators forchannels 1 and 2 are separated from each
other and are controlled by there own UP/DOWN pin.
Balance control can be arranged by applying UP/DOWN
pulses only on pins 6 and 7, see Fig.5.
TDA8552T; TDA8552TS
Volume control
Each attenuator is controlled with its own UP/DOWN pin
(trinary input):
• Floating UP/DOWN pin: volume remains unchanged
• Negative pulses: decreasing volume
• Positive pulses: increasing volume.
Each pulse on the UP/DOWN pin results in a change in
80
gain of (typical value).
In the basic application the UP/DOWN pin is switched to
ground or VDDby 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 in the low gain setting or −10 dB in the
high gainsetting. After powering-up, some positive pulses
have to be applied to the UP/DOWN pin for turning up to
listening volume.
Auto repeat
If the UP/DOWN pin is LOW or HIGH for the wait time (t
in seconds) (one of the keys is pressed) then the device
starts making up or down pulses by itself with a frequency
given by (repeat function).
The wait time and the repeat frequency are set using an
internal RC oscillator with an accuracy of ±10%.
Volume settings in standby mode
When the device is switched with the MODE select pin to
the mute or the standby condition, the volume control
attenuation setting keeps its value, under the assumption
that the voltage on the V
minimum supply voltage. After switching the device back
to the operation mode, the previous volume setting is
maintained. In the standby mode the volume setting is
maintained as long as the minimum supply voltage is
available. The current consumption is very low,
approximately 1 µA (typ.). In battery fed applications the
volumesetting can bemaintained during batteryexchange
if there is a supply capacitor available.
-----64
-------t
rep
1.25 dB=
wait
1
pin does not fall below the
DD
2002 Jan 046
Philips SemiconductorsProduct specification
2 x 1.4 W BTL audio amplifiers with digital
volume control and headphone sensing
Mode select pin
The deviceis in thestandby mode (with a very low current
consumption) if the voltage at the MODE pin is between
VDDandVDD− 0.5 V.At a modeselectvoltage levelofless
than 0.5 V the amplifier is fully operational. In the range
between 1 V and VDD− 1 V the amplifier is in the mute
condition.The muteconditionis usefulforusing itasa ‘fast
mute’, in this mode the 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 achieved by
holding the MODE pin at a level of 0.5VDD, or by waiting
approximately 100 ms before giving the first volume-UP
pulses.
Headphone sense pin (HPS)
A headphone can beconnected tothe amplifier by using a
coupling capacitorfor each channel. The common ground
pin of the headphone is connected to the ground of the
amplifier, see Fig.4. By using the HPS pin as illustrated in
Fig.4, the TDA8552T detects if a headphone jack plug is
inserted into the connector.
TDA8552T; TDA8552TS
When noheadphone is plugged in, thevoltage level at the
HPSpin willremain LOW.A voltage lessthan VDD− 1Vat
the HPS pin will keep the device in theBTL mode,thus the
loudspeakers can be operational. If the HPS pin is not
connected then the device will remain in the BTL mode.
When a headphone is plugged into the connector, the
voltage at the HPS pin will be set to VDD. The device then
switches to the Single-Ended (SE) mode, this means that
the slave power amplifiers at the outputs OUT1− and
OUT2− will be switched to the standby mode. This results
in floating outputs OUT1− and OUT2−, the loudspeaker
signal isthus attenuated byapproximately 80 dB and only
the headphone can operate.
One of the benefits of this system is that the loudspeaker
current does not flow through the jack connector switch,
which could give some output power loss. The other
benefit is that the quiescent current is reduced when the
headphone jack is inserted.
2002 Jan 047
Philips SemiconductorsProduct specification
2 x 1.4 W BTL audio amplifiers with digital
TDA8552T; TDA8552TS
volume control and headphone sensing
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 60134).
SYMBOLPARAMETERCONDITIONSMIN.MAX.UNIT
V
DD
V
i
I
ORM
T
stg
T
amb
V
sc
P
tot
THERMAL CHARACTERISTICS
See Section “Thermal design considerations” in Chapter “Test and application information”.
SYMBOLPARAMETERCONDITIONSVALUEUNIT
R
th(j-a)
supply voltageoperating−0.3+5.5V
input voltage−0.3VDD+ 0.3V
repetitive peak output current−1A
storage temperature−55+150°C
operating ambient temperature−40+85°C
AC and DC short-circuit safe voltage−5.5V
maximum power dissipationSO20−2.2W
SSOP20−1.1W
thermal resistance from junction to ambient
for the TDA8552T (SO20)in free air60K/W
extra copper55K/W
for the TDA8552TS (SSOP20)in free air110K/W
extra copper80K/W
Table 1 Power rating; note 1
MUSIC POWER
P
V
(V)RL (Ω)
DD
o (w)
THD = 10%
OPERATION
T
P
(W)
max
amb(max)
SO20SSOP20
3.340.9BTL0.55120106
3.380.6BTL0.28134127
3.3160.3BTL0.14142139
3.332SE0.035headphone0.03150150
5.042.0BTL1.258150
5.081.4BTL0.6511498
5.0160.8BTL0.32132124
5.032SE0.09headphone0.07146144
continuous sine wave
3.340.9BTL1.18962
581.4BTL1.258150
Note
1. The power rating is based on R
with recommended copperpattern of at least 4 × 1cm2to the cornerleads and