TDA8946 Philips Semiconductors, TDA8946 Datasheet - Page 6

• Manufacturer Part Number: TDA8946
• Description: 2 x 15 W stereo Bridge Tied Load BTL audio amplifier
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 06863
Product specification
8.3.1 Switch-on and switch-off
8.5.1 Short-circuit protection
8.5.2 Thermal shutdown protection
8.4 Supply Voltage Ripple Rejection (SVRR)
8.5 Built-in protection circuits
Mute — In this mode the amplifier is DC-biased but not operational (no audio output);
the 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
Operating — In this mode the amplifier is operating normally. The operating mode is
activated at V
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.
The SVRR is measured with an electrolytic capacitor of 10 F on pin SVR at a
bandwidth of 10 Hz to 80 kHz.
of the frequency. A larger capacitor value on the SVR pin improves the ripple rejection
behaviour at the lower frequencies.
The TDA8946J contains two types of protection circuits, i.e. short-circuit and thermal
shutdown.
Short-circuit to ground or supply line — This is detected by a so-called ‘missing
current’ detection circuit which measures the current in the positive supply line and
the current in the ground line. A difference between both currents larger than 0.7 A,
switches the power stage to standby mode (high impedance).
Short-circuit across the load — This is detected by an absolute-current
measurement. An absolute-current larger than 3 A, switches the power stage to
standby mode (high impedance).
The junction temperature is measured by a temperature sensor; at a junction
temperature of approximately 150 C this detection circuit switches the power stage
to standby mode (high impedance).
MODE
< (V
MODE
CC
Rev. 02 — 14 March 2000
< 0.5 V.
1.5 V).
Figure 13 on page 12
2 x 15 W stereo BTL audio amplifier
illustrates the SVRR as function
© Philips Electronics N.V. 2000. All rights reserved.
TDA8946J
6 of 23