TDF8599A_2 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 02 — 30 June 2009 11 of 54
NXP Semiconductors
TDF8599A
I
2
C-bus controlled dual channel class-D power amplifier
8.4 Operation mode selection
Pin MOD is used to select specific operating modes. The resistor (R
MOD
) connected
between pins MOD and AGND together with the non-I
2
C-bus/I
2
C-bus mode determine the
operating mode (see Table 8). The mode of operation depends on whether non-I
2
C-bus
mode or I
2
C-bus mode is active. This in turn is determined by the resistor value connected
between pins ADS and AGND.
In non-I
2
C-bus mode, pin MOD is used to select:
• AD or BD modulation (see Section 8.4.1).
•
1
⁄
2
π phase shift when oscillator is used in Slave mode (see Section 8.4.2).
• Parallel mode operation (see Section 8.4.3).
In I
2
C-bus mode, pin MOD can only select Parallel mode. In addition, the modulation
mode and phase shift are programmed using I
2
C-bus commands.
[1] R
ADS
≥ 4.7 kΩ; See Table 13 on page 23.
[2] R
ADS
= 0 Ω; pin ADS is short circuited to pin AGND.
[3] See Section 8.4.3 on page 14 for more detailed information.
In I
2
C-bus mode, pin MOD is latched using the I
2
C-bus command IB3[D7] = 1. This avoids
amplifier switching interference generating incorrect information on pin MOD.
In non-I
2
C-bus mode or when IB3[D7] = 0, the information on pin MOD is latched when
one of the TDF8599A’s outputs starts switching.
8.4.1 Modulation mode
In non-I
2
C-bus mode, pin MOD is used to select either AD or BD modulation mode (see
Table 8). In I
2
C-bus mode, the modulation mode is selected using an I
2
C-bus command.
• AD modulation mode: the bridge halves switch in opposite phase.
• BD modulation mode: the bridge halves switch in phase but the input signal for the
modulators is inverted.
Figure 10 and Figure 11 show simplified representations of AD and BD modulation.
Table 8. Operation mode selection with the MOD pin
R
MOD
(kΩ) I
2
C-bus mode
[1]
Non-I
2
C-bus mode
[2]
0 (short to AGND) Stereo mode AD modulation: no phase shift in Slave mode
4.7 BD modulation: no phase shift in Slave mode
13 AD modulation:
1
⁄
2
π phase shift in Slave mode
33 Parallel mode
[3]
BD modulation:
1
⁄
2
π phase shift in Slave mode
100 AD modulation: no phase shift in Slave mode
∞ (open) BD modulation: no phase shift in Slave mode
