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TDA8946J
2 x 15 W stereo Bridge Tied Load (BTL) audio amplifier
Rev. 02 — 14 March 2000
Product specification
1. General description
load and a 18 V supply. The circuit contains two Bridge Tied Load
(BTL) amplifiers with an all-NPN output stage and standby/mute logic. The TDA8946J
comes in a 17-pin DIL-bent-SIL (DBS) power package. The TDA8946J 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.
´
15Watan8
W
2. Features
n
Few external components
n
Fixed gain
n
Standby and mute mode
n
No on/off switching plops
n
Low standby current
n
High supply voltage ripple rejection
n
Outputs short-circuit protected to ground, supply and across the load
n
Thermally protected
c
c
n
Printed-circuit board compatible.
3. Applications
n
Mains fed applications (e.g. TV sound)
n
PC audio
n
Portable audio.
4. Quick reference data
Table 1: Quick reference data
Symbol Parameter
Conditions
Min Typ
Max Unit
V CC
supply voltage
6
18
25
V
I q
quiescent supply current V CC =18V; R L =
¥
-
82A
I stb
standby supply current
-
-
10
m
A
The TDA8946J is a dual-channel audio power amplifier with an output power of
2
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Philips Semiconductors
TDA8946J
2 x 15 W stereo BTL audio amplifier
Table 1: Quick reference data …continued
Symbol Parameter
Conditions
Min Typ
Max Unit
P o
output power
THD = 10%; R L =8
W
;
13
15
-
W
V CC =18V
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
5. Ordering information
Table 2: Ordering information
Type number Package
Name
Description
Version
TDA8946J
DBS17P
plastic DIL-bent-SIL power package;
17 leads (lead length 12 mm)
SOT243-1
6. Block diagram
idth
V CC1
V CC2
3
16
1
OUT1 -
8
IN1
-
IN1 +
6
4
OUT1 +
TDA8946J
14
OUT2 -
9
IN2
-
IN2 +
12
17
OUT2
V CC
MODE
10
STANDBY/
MUTE LOGIC
20
k W
SHORT CIRCUIT
AND
TEMPERATURE
PROTECTION
11
SVR
20
k W
2
15
MBK929
GND1
GND2
Fig 1. Block diagram.
9397 750 06863
© Philips Electronics N.V. 2000. All rights reserved.
Product specification
Rev. 02 — 14 March 2000
2 of 23
+
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Philips Semiconductors
TDA8946J
2 x 15 W stereo BTL audio amplifier
7. Pinning information
7.1 Pinning
handbook, halfpage
OUT1 -
1
GND1
2
V CC1
OUT1 +
3
4
n.c.
5
IN1
+
6
n.c.
7
IN1 -
8
IN2
-
9
TDA8946J
MODE
10
SVR
11
IN2
+
12
n.c.
13
OUT2 -
14
GND2
15
V CC2
OUT2 +
16
17
MBK932
Fig 2. Pin configuration.
7.2 Pin description
Table 3: Pin description
Symbol
Pin
Description
OUT1
-
1
negative loudspeaker terminal 1
GND1
2
ground channel 1
V CC1
3
supply voltage channel 1
OUT1
+
4
positive loudspeaker terminal 1
n.c.
5
not connected
IN1
+
6
positive input 1
n.c.
7
not connected
IN1
-
8
negative input 1
IN2
-
9
negative input 2
MODE
10
mode selection input (standby, mute, operating)
SVR
11
half supply voltage decoupling (ripple rejection)
IN2
+
12
positive input 2
9397 750 06863
© Philips Electronics N.V. 2000. All rights reserved.
Product specification
Rev. 02 — 14 March 2000
3 of 23
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Philips Semiconductors
TDA8946J
2 x 15 W stereo BTL audio amplifier
Table 3: Pin description …continued
Symbol
Pin
Description
n.c.
13
not connected
OUT2
-
14
negative loudspeaker terminal 2
GND2
15
ground channel 2
V CC2
16
supply voltage channel 2
OUT2+
17
positive loudspeaker terminal 2
8. Functional description
The TDA8946J is a stereo BTL audio power amplifier capable of delivering 2
´
15 W
load at THD = 10%, using a 18 V power supply and an
external heatsink. The voltage gain is fixed at 32 dB.
W
With the three-level MODE input the device can be switched from ‘standby’ to ‘mute’
and to ‘operating’ mode.
The TDA8946J outputs are protected by an internal thermal shutdown protection
mechanism and a short-circuit protection.
8.1 Input configuration
The TDA8946J 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:
f i cut off
=
-----------------------------
1
(1)
(
–
)
2
p
(
R i
´
C i
)
For R i =45k
W
and C i = 220 nF:
f i cut off
=
----------------------------------------------------------------- 16 Hz
1
=
(2)
(
–
)
45 10 3
–
9
2
p
(
´
´
220
´
10
)
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.
9397 750 06863
© Philips Electronics N.V. 2000. All rights reserved.
Product specification
Rev. 02 — 14 March 2000
4 of 23
output power to an 8
207991535.048.png 207991535.049.png
Philips Semiconductors
TDA8946J
2 x 15 W stereo BTL audio amplifier
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 18 V and the maximum available output current: 2 A repetitive peak
current.
8.2.2 Headroom
and P o = 10 W at THD = 0.1% (see Figure 6 ), the
Average Listening Level (ALL) – music power – without any distortion yields:
P o(ALL) = 10 W/15.85 = 631 mW.
W
The power dissipation can be derived from Figure 11 on page 11 for 0 dB
respectively 12 dB headroom.
Table 4: Power rating as function of headroom
Headroom
Power output (THD = 0.1%)
Power dissipation (P)
0dB
P o =10W
18W
12 dB
P o(ALL) = 631 mW
8 W
For the average listening level a power dissipation of 8 W can be used for a heatsink
calculation.
8.3 Mode selection
The TDA8946J 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.
0.5 V) < V MODE <V CC , or when
the MODE pin is left floating (high impedance). The power consumption of the
TDA8946J will be reduced to <0.18 mW.
9397 750 06863
© Philips Electronics N.V. 2000. All rights reserved.
Product specification
Rev. 02 — 14 March 2000
5 of 23
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 =18V, R L =8
Standby — In this mode the current consumption is very low and the outputs are
floating. The device is in standby mode when (V CC -
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