TDA8933B Datasheet, PDF (26/42 Pages) NXP Semiconductors – Class D audio amplifier

NXP Semiconductors
TDA8933B
Class D audio amplifier
• R1 = series resistors (Ω)
• R2 = series resistors (Ω)
R_EQ = -_RR----₃₃----₊^×-----^ZZ----ⁱⁱ
(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 TDA8933B devices are used in one application it is recommended that all
the devices are synchronized at the same switching frequency to avoid beat tones. This
can be done by connecting all OSCIO pins together and configuring one of the devices as
master while the others are configured as slaves (see Figure 10).
A device is configured as master when a resistor R_osc is connected between pin OSCREF
and pin V_SSD(HW), thus 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 pin V_SSD(HW), configuring pin OSCIO as an input.
master
IC1
TDA8933B
OSCREF ^VSSD(HW) OSCIO
slave
IC2
TDA8933B
OSCIO ^VSSD(HW) OSCREF
Cosc
100 nF
Rosc
39 kΩ
Fig 10. Master/slave concept in a two-chip application
010aaa138
TDA8933B_1
Preliminary data sheet
Rev. 01 — 23 October 2008
© NXP B.V. 2008. All rights reserved.
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