TDA8942P Datasheet, PDF (4/23 Pages) NXP Semiconductors – 2 x 1.5 W stereo Bridge Tied Load BTL audio amplifier

Philips Semiconductors
TDA8942P
2 x 1.5 W stereo BTL audio amplifier
8. Functional description
The TDA8942P is a stereo BTL audio power amplifier capable of delivering 2 × 1.5 W
output power to a 16 Ω load at THD = 10%, using a 9 V power supply. 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 TDA8942P outputs are protected by an internal thermal shutdown protection
mechanism and a short-circuit protection.
8.1 Input configuration
The TDA8942P 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 )} = ₂----_π---₍---_R---¹-_i---_×----_C-----_i-₎-
(1)
For R_i = 45 kΩ and C_i = 220 nF:
f _{i(cut – off )} = -₂---_π---₍---₄---₅----_×-----₁---₀---₃---¹-_×-----₂---₂---₀----_×-----₁---₀---_–---₉--₎- = 16 Hz
(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.
9397 750 06862
Product specification
Rev. 02 — 14 March 2000
© Philips Electronics N.V. 2000. All rights reserved.
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