TDA8932B_15 Datasheet, PDF (26/48 Pages) NXP Semiconductors – Class-D audio amplifier

NXP Semiconductors
TDA8932B
Class-D audio amplifier
R_EQ
=
-^R----³----^×-----^Z----ⁱ
R3 + Z_i
(9)
Where:
R_EQ = equivalent resistance (Ω)
R3 = parallel resistor (Ω)
Z_i = internal input impedance (Ω)
Example:
Substituting R1 = R2 = 4.7 kΩ, Z_i = 100 kΩ and R3 = 22 kΩ in Equation 8 and Equation 9
results in a gain of G_v(tot) = 26.3 dB.
14.6 Device synchronization
If two or more TDA8932B devices are used in one application it is recommended that all
devices are synchronized running at the same switching frequency to avoid beat tones.
Synchronization can be realized by connecting all OSCIO pins together and configuring
one of the TDA8932B devices as master, while the other TDA8932B devices are
configured as slaves (see Figure 11).
A device is configured as master when connecting a resistor between pins OSCREF and
V_SSD(HW) setting the carrier frequency. Pin OSCIO of the master is then configured as an
oscillator output for synchronization. The OSCREF pins of the slave devices should be
shorted to V_SSD(HW) configuring pin OSCIO as an input.
master
IC1
TDA8932B
OSCREF V_SSD(HW) OSCIO
slave
IC2
TDA8932B
OSCIO V_SSD(HW) OSCREF
Cosc
100 nF
Rosc
39 kΩ
Fig 11. Master slave concept in two chip application
001aaf600
14.7 Thermal behavior (printed-circuit board considerations)
The TDA8932B is available in two different thermally enhanced packages:
TDA8932BT in a SO32 (SOT287-1) package for reflow and wave solder process
TDA8932BTW in an HTSSOP32 (SOT549-1) package for reflow solder process only
The SO32 package has special thermal corner-leads, increasing the power capability
(reducing the overall R_th(j-a). To benefit from the corner leads pins V_SSD(HW) (pins 1, 16, 17
and 32) should be attached to a copper plane. The SO32 package is very suitable for
applications with limited space for a thermal plane (in a single layer PCB design).
TDA8932B_4
Product data sheet
Rev. 04 — 18 December 2008
© NXP B.V. 2008. All rights reserved.
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