Philips Semiconductors
TDA8947J
4-channel audio amplifier
On — The amplifier is operating normally. The On mode is activated at
VMODE1 > (VCC − 2.0 V). The output of channels 3 and 4 can be set to Mute or On mode.
The output channels 3 and 4 can be switched on/off by applying a proper DC voltage to
pin MODE2, under the condition that the output channels 1 and 2 are in the On mode (see
Figure 3).
Table 5: Mode selection
Voltage on pin
MODE1
MODE2
0 V to 0.8 V
4.5 V to (VCC − 3.5 V)
(VCC − 2.0 V) to VCC
0 V to VCC
0 V to VCC
0 V to (VCC − 3.5 V)
(VCC − 2 V) to VCC
Channel 1 and 2
Standby mode
Mute mode
On mode
On mode
Channel 3 and 4
(sub woofer)
Standby mode
Mute mode
Mute mode
On mode
all standby
all mute
channels 1 + 2: on
channels 3 + 4: on or mute
0.8
4.5
VCC−3.5 VCC−2.0 VCC
VMODE1
channels 3 + 4: mute
channels 3 + 4: on
mdb016
Fig 3. Mode selection
VCC−3.5 VCC−2.0 VCC
VMODE2
8.4 Supply voltage ripple rejection
The Supply Voltage Ripple Rejection (SVRR) is measured with an electrolytic capacitor of
150 µF on pin SVR using a bandwidth of 20 Hz to 22 kHz. Figure 11 illustrates the SVRR
as function of the frequency. A larger capacitor value on pin SVR improves the ripple
rejection behavior at the lower frequencies.
9397 750 14938
Product data sheet
Rev. 02 — 16 June 2005
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
7 of 24