TDA8932B Datasheet, PDF (7/48 Pages) NXP Semiconductors – Class-D audio amplifier

NXP Semiconductors
TDA8932B
Class-D audio amplifier
V_P
POWERUP
DREF
HVPREF
HVP1, HVP2
2.0 V (typical)
ENGAGE ^{1.2 V (typical)}
audio
OUT1, OUT2
PWM
AUDIO
PWM
AUDIO
AUDIO
PWM
≤ 0.8 V
DIAG
OSCIO
Fig 4. Start-up sequence
operating
mute
operating fault
operating
sleep
001aaf885
8.3 Pulse width modulation frequency
The output of the amplifier is a PWM signal with a carrier frequency of approximately
320 kHz. Using a 2nd-order low-pass filter in the application results in an analog audio
signal across the loudspeaker. The PWM switching frequency can be set by an external
resistor Rosc connected between pins OSCREF and V_SSD(HW). The carrier frequency can
be set between 300 kHz and 500 kHz. Using an external resistor of 39 kΩ, the carrier
frequency is set to an optimized value of 320 kHz (see Figure 5).
If two or more TDA8932B devices are used in the same audio application, it is
recommended to synchronize the switching frequency of all devices. This can be realized
by connecting all OSCIO pins together and configure one of the TDA8932B in the
application as clock master, while the other TDA8932B devices are configured in slave
mode.
Pin OSCIO is a 3-state input or output buffer. Pin OSCIO is configured in master mode as
an oscillator output and in slave mode as an oscillator input. Master mode is enabled by
applying a resistor while slave mode is entered by connecting pin OSCREF directly to pin
V_SSD(HW) (without any resistor).
The value of the resistor also sets the frequency of the carrier which can be estimated by
the following formula:
TDA8932B_4
Product data sheet
Rev. 04 — 18 December 2008
© NXP B.V. 2008. All rights reserved.
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