TDA8950_2 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 02 — 11 June 2009 5 of 39
NXP Semiconductors
TDA8950
2 × 150 W class-D power amplifier
7.2 Pin description
8. Functional description
8.1 General
The TDA8950 is a two-channel audio power amplifier that uses Class D technology.
For each channel, the audio input signal is converted into a digital PWM signal using an
analog input stage and a PWM modulator; see Figure 1. To drive the output power
transistors, the digital PWM signal is fed to a control and handshake block and to high-
and low-side driver circuits. This level-shifts the low-power digital PWM signal from a logic
level to a high-power PWM signal switching between the main supply lines.
A 2nd-order low-pass filter converts the PWM signal to an analog audio signal that can be
used to drive a loudspeaker.
Table 3. Pin description
Symbol Pin Description
TDA8950TH TDA8950J
VSSA 1 18 negative analog supply voltage
SGND 2 19 signal ground
VDDA 3 20 positive analog supply voltage
IN2M 4 21 channel 2 negative audio input
IN2P 5 22 channel 2 positive audio input
MODE 6 23 mode selection input: Standby, Mute or Operating
mode
OSC 7 1 oscillator frequency adjustment or tracking input
IN1P 8 2 channel 1 positive audio input
IN1M 9 3 channel 1 negative audio input
n.c. 10 4 not connected
n.c. 11 5 not connected
n.c. 12 6 not connected
PROT 13 7 decoupling capacitor for protection (OCP)
VDDP1 14 8 channel 1 positive power supply voltage
BOOT1 15 9 channel 1 bootstrap capacitor
OUT1 16 10 channel 1 PWM output
VSSP1 17 11 channel 1 negative power supply voltage
STABI 18 12 decoupling of internal stabilizer for logic supply
n.c. 19 - not connected
VSSP2 20 13 channel 2 negative power supply voltage
OUT2 21 14 channel 2 PWM output
BOOT2 22 15 channel 2 bootstrap capacitor
VDDP2 23 16 channel 2 positive power supply voltage
VSSD 24 17 negative digital supply voltage
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