TDA8943SF
6 W mono Bridge Tied Load (BTL) audio amplifier
Rev. 02 -- 7 April 2000
Product specification
c
c
1.
General description
The TDA8943SF is a single-channel audio power amplifier with an output power of
6 W at an 8
load and a 12 V supply. The circuit contains a Bridge Tied Load (BTL)
amplifier with an all-NPN output stage and standby/mute logic. The TDA8943SF
comes in a 9-lead single in-line (SIL) medium power package. The TDA8943SF is
printed-circuit board (PCB) compatible with all other types in the TDA894x family.
One PCB footprint accommodates both the mono and the stereo products.
2.
Features
s
Few external components
s
Fixed gain
s
Standby and mute mode
s
No on/off switching plops
s
Low standby current
s
High supply voltage ripple rejection
s
Outputs short-circuit protected to ground, supply and across the load
s
Thermally protected
s
Printed-circuit board compatible.
3.
Applications
s
Mains fed applications (e.g. TV sound)
s
PC audio
s
Portable audio.
4.
Quick reference data
Table 1:
Quick reference data
Symbol Parameter
Conditions
Min
Typ
Max
Unit
V
CC
supply voltage
6
12
18
V
I
q
quiescent supply current
V
CC
= 12 V; R
L
=
-
15
22
mA
I
stb
standby supply current
-
-
10
A
Philips Semiconductors
TDA8943SF
6 W mono Bridge Tied Load (BTL) audio amplifier
Product specification
Rev. 02 -- 7 April 2000
2 of 20
9397 750 06865
Philips Electronics N.V. 2000. All rights reserved.
5.
Ordering information
6.
Block diagram
P
o
output power
THD = 10%; R
L
= 8
;
V
CC
= 12 V
5
6
-
W
THD
total harmonic distortion
P
o
= 1 W
-
0.03
0.1
%
G
v
voltage gain
31
32
33
dB
SVRR
supply voltage
ripple rejection
50
65
-
dB
Table 1:
Quick reference data
...continued
Symbol Parameter
Conditions
Min
Typ
Max
Unit
Table 2:
Ordering information
Type number
Package
Name
Description
Version
TDA8943SF
SIL9MPF
plastic single in-line medium power package
with fin; 9 leads
SOT110-1
Fig 1.
Block diagram.
idth
MBK942
STANDBY/
MUTE LOGIC
SHORT CIRCUIT
AND
TEMPERATURE
PROTECTION
20
k
20
k
5
TDA8943SF
4
3
1
7
6
VCC
VCC
8
2
OUT
+
GND
SVR
OUT
-
IN
-
IN
+
MODE
Philips Semiconductors
TDA8943SF
6 W mono Bridge Tied Load (BTL) audio amplifier
Product specification
Rev. 02 -- 7 April 2000
3 of 20
9397 750 06865
Philips Electronics N.V. 2000. All rights reserved.
7.
Pinning information
7.1 Pinning
7.2 Pin description
8.
Functional description
The TDA8943SF is a mono BTL audio power amplifier capable of delivering 6 W
output power to an 8
load at THD = 10%, using a 12 V power supply and an
external heatsink. The voltage gain is fixed at 32 dB.
With the three-level MODE input the device can be switched from `standby' to `mute'
and to `operating' mode.
The TDA8943SF outputs are protected by an internal thermal shutdown protection
mechanism and a short-circuit protection.
Fig 2.
Pin configuration.
handbook, halfpage
TDA8943SF
MBK941
1
2
3
4
5
6
7
8
9
OUT
-
VCC
OUT
+
IN
+
IN
-
SVR
MODE
GND
n.c.
Table 3:
Pin description
Symbol
Pin
Description
OUT
-
1
negative loudspeaker terminal
V
CC
2
supply voltage
OUT+
3
positive loudspeaker terminal
IN+
4
positive input
IN
-
5
negative input
SVR
6
half supply voltage decoupling (ripple rejection)
MODE
7
mode selection input (standby, mute, operating)
GND
8
ground
n.c.
9
not connected
Philips Semiconductors
TDA8943SF
6 W mono Bridge Tied Load (BTL) audio amplifier
Product specification
Rev. 02 -- 7 April 2000
4 of 20
9397 750 06865
Philips Electronics N.V. 2000. All rights reserved.
8.1 Input configuration
The TDA8943SF inputs can be driven symmetrical (floating) as well as asymmetrical.
In the asymmetrical mode one input pin is connected via a capacitor to the signal
ground which should be as close as possible to the SVR (electrolytic) capacitor
ground. Note that the DC level of the input pins is half of the supply voltage V
CC
, so
coupling capacitors for both pins are necessary.
The input cut-off frequency is:
(1)
For R
i
= 45 k
and C
i
= 220 nF:
(2)
As shown in
Equation 1
and
2
, large capacitor values for the inputs are not
necessary
;
so the switch-on delay during charging of the input capacitors, can be
minimized. This results in a good low frequency response and good switch-on
behaviour.
Remark: To prevent HF oscillations do not leave the inputs open, connect a capacitor
of at least 1.5 nF across the input pins close to the device.
8.2 Power amplifier
The power amplifier is a Bridge Tied Load (BTL) amplifier with an all-NPN output
stage, capable of delivering a peak output current of 2 A.
The BTL principle offers the following advantages:
Lower peak value of the supply current
The ripple frequency on the supply voltage is twice the signal frequency
No expensive DC-blocking capacitor
Good low frequency performance.
8.2.1
Output power measurement
The output power as a function of the supply voltage is measured on the output pins
at THD = 10%; see
Figure 8
. The maximum output power is limited by the maximum
supply voltage of 12 V and the maximum available output current: 2 A repetitive peak
current.
f
i cut
off
(
)
1
2
R
i
C
i
(
)
-----------------------------
=
f
i cut
off
(
)
1
2
45
10
3
220
10
9
(
)
-----------------------------------------------------------------
16 Hz
=
=
Philips Semiconductors
TDA8943SF
6 W mono Bridge Tied Load (BTL) audio amplifier
Product specification
Rev. 02 -- 7 April 2000
5 of 20
9397 750 06865
Philips Electronics N.V. 2000. All rights reserved.
8.2.2
Headroom
Typical CD music requires at least 12 dB (factor 15.85) dynamic headroom
compared to the average power output for transferring the loudest parts without
distortion. At V
CC
= 12 V, R
L
= 8
and P
o
= 4 W at THD = 0.1% (see
Figure 6
), the
Average Listening Level (ALL) music power without any distortion yields:
P
o(ALL)
= 4 W/15.85 = 252 mW.
The power dissipation can be derived from
Figure 11 on page 10
for 0 dB
respectively 12 dB headroom.
For the average listening level a power dissipation of 1.8 W can be used for a
heatsink calculation.
8.3 Mode selection
The TDA8943SF has three functional modes, which can be selected by applying the
proper DC voltage to pin MODE. See
Figure 4
and
5
for the respective DC levels,
which depend on the supply voltage level. The MODE pin can be driven by a 3-state
logic output stage: e.g. a microcontroller with additional components for DC-level
shifting.
Standby -- In this mode the current consumption is very low and the outputs are
floating. The device is in standby mode when (V
CC
-
0.5 V) < V
MODE
< V
CC
, or when
the MODE pin is left floating (high impedance). The power consumption of the
TDA8943SF will be reduced to <0.18 mW.
Mute -- In this mode the amplifier is DC-biased but not operational (no audio output);
t
he DC level of the input and output pins remain on half the supply voltage. This
allows the input coupling and Supply Voltage Ripple Rejection (SVRR) capacitors to
be charged to avoid pop-noise. The device is in mute mode when
3 V < V
MODE
< (V
CC
-
1.5 V).
Operating -- In this mode the amplifier is operating normally. The operating mode is
activated at V
MODE
< 0.5 V.
8.3.1
Switch-on and switch-off
To avoid audible plops during supply voltage switch-on or switch-off, the device is set
to standby mode before the supply voltage is applied (switch-on) or removed
(switch-off).
The switch-on and switch-off time can be influenced by an RC-circuit on the MODE
pin. Rapid on/off switching of the device or the MODE pin may cause `click- and
pop-noise'. This can be prevented by proper timing of the RC-circuit on the MODE
pin.
Table 4:
Power rating as function of headroom
Headroom
Power output (THD = 0.1%)
Power dissipation (P)
0 dB
P
o
= 4 W
3.8 W
12 dB
P
o(ALL)
= 252 mW
1.8 W
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