NXP Semiconductors TFA9812 8.5.2 Digital volume control

Preliminary data sheet Rev. 02 — 22 January 2009 20 of 66

NXP Semiconductors TFA9812

BTL stereo Class-D audio ampliﬁer with I2S input

8.5.2 Digital volume control

In I2C control mode both audio channels have separate digital volume control. In Legacy

control mode the volume control of both channels is common and the volume control

setting depends on the supply voltage on the pin AVOL (32).

8-bit volume control is available per channel. This is dB-linear down to −124 dB in steps of

0.5 dB. The last step of the volume control is mute.

Table 16 shows the various settings and their related channel suppression:

Fig 7. Transfer functions for several center frequencies fc

Fig 8. Transfer functions for several gain factors G

010aaa223

Frequency (Hz)

101105

104

102103

Gain

(dB)

010aaa224

Frequency (Hz)

101105

104

102103

-6

Gain

(dB)

-12

Contents

Main 1. General description 2. Features 2.1 General features TFA9812 Rev. 02 22 January 2009 Preliminary data sheet BTL stereo Class-D audio amplier with I2S input NXP Semiconductors TFA9812 2.2 DSP features 3. Applications 4. Quick reference data =12V,V =0V,V = 3.3 V, ,f 5. Ordering information 6. Block diagram Fig 1. TFA9812 block diagram TFA9812 Preliminary data sheet Rev. 02 22 January 2009 6 of 66 7. Pinning information 7.1 Pinning 4 STABA O 1.8 V analog stabilizer output 5 REFA P Analog reference voltage 6V 7 TEST1 I T est signal input 1. F or test pur poses only (connect to V 8V TFA9812HN Page NXP Semiconductors TFA9812 8. Functional description 8.1 General Page 8.2.3 I2S master/slave modes and MCLK/BCK clock modes Page NXP Semiconductors TFA9812 8.3 Power-up/power-down 8.3.1 Power-up 8.3.2 Power-down 8.4 Digital audio data input 8.4.1 Digital audio data format support Remark: Only MSB-rst formats are supported. TFA9812_2 NXP B.V. 2009. All rights reserved. Fig 4. Serial interface input and output formats control mode 8.4.2 Digital audio data format control 8.5 Digital signal-processing features 8.5.1 Equalizer Page Page Preliminary data sheet Rev. 02 22 January 2009 20 of 66 8.5.2 Digital volume control Fig 7. T ransfer functions f or several center frequencies f Fig 8. Transfer functions for several gain factors G 8.5.3 Soft mute and mute 8.5.4 Output signal and word-select polarity control 8.5.5 Gain boost and clip level control 8.5.6 Output power limiter 8.5.7 PWM control for performance improvement Page 8.7.1 Thermal foldback 8.7.2 Overtemperature protection 8.7.3 Overcurrent protection 8.7.4 Overvoltage protection 8.7.5 Undervoltage protections 8.7.8 Lock protection 8.7.9 Underfrequency protection 8.7.10 Overfrequency protection 8.7.11 Invalid BCK protection 8.7.12 DC blocking 8.7.13 Overview protections Table 21 shows the overview of the protections. 9. I2C bus interface and register settings 9.1 I2C bus interface Voltage values applied to the I2C bus device address pins are interpreted as described in Table 23. 9.2 I2C bus TFA9812 device addresses 9.3 I2C write cycle description 9.4 I2C read cycle description 9.5 Top-level register map Reserved registers or bits will be indicated by RSD. 9.5.1 Interpolator settings and soft mute 9.5.2 Volume control 9.5.3 Digital input format 9.5.4 Equalizer conguration 9.5.5 Equalizer settings For word1 for equalizer 'yy' see Figure 9 For word2 for equalizer 'yy' see Figure 9 Page 9.5.6 PWM signal control 9.5.7 Digital-in clock conguration 9.5.8 Thermal foldback control 9.5.9 TFA9812 temperature 9.5.10 Miscellaneous status 9.6 Overview of functional control in each control mode D = xed control setting, determined by default I 10. Internal circuitry D = xed control setting, determined by default I Page Page 11. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). 12. Thermal characteristics In accordance with the Absolute Maximum Rating System (IEC 60134). 13. Characteristics 13.1 DC Characteristics = 400 kHz, 24-bit I = V = 0 V, V Page Page 13.2 AC characteristics < 0.1 = 3.3 V, T , R , f 13.3 Timing 14. Application information 14.1 Output power estimation 14.2 Output current limiting 14.3 Speaker conguration and impedance 14.4 Typical application schematics 14.4.1 I2S slave mode and Legacy control mode Fig 13. Simplied application diagram for I2S slave mode and Legacy control mode 14.4.2 I2S slave mode and I2C control mode Fig 14. Simplied application diagram for I2S slave mode and I2C control mode 14.4.3 I2S master mode and Legacy control mode Fig 15. Simplied application diagram for I2S master mode and Legacy control mode 14.4.4 I2S master mode and I2C control mode Fig 16. Simplied application diagram for I2S master mode and I2C control mode 14.5 Curves measured in typical application a. VP = 12 V; RL = 2 6 b. VP = 12 V; RL = 2 8 VP = 12 V; PO = 1 W (1) RL = 6 15 H / 680 F (2) RL = 8 15 H / 680 F Fig 19. Gain as a function of frequency Fig 20. Gain as a function of AVOL VP = 12 V; RL = 8 ; fi = 1 kHz (1) 0 dB (2) 24 dB gain boost VP = 12 V; Vripple = 500 mV (RMS) reference to ground; No input signal (1) RL = 8 (2) RL = 6 Fig 21. SVRR as a function of frequency Fig 22. S/N ratio as a function of output power VP = 15 V; 20 kHz AES17 lter (1) RL = 2 8 (2) RL = 2 6 Fig 23. Output power as a function of time a. VP = 15 V; RL = 2 6 BTL; fi = 1 kHz b. VP = 20 V; RL = 2 8 BTL; fi = 1 kHz (1) Tact(th_fold) = 125 C (2) Tact(th_fold) = 105 C (3) Tact(th_fold) = 90 C a. VP = 12 V; RL = 2 6 ; fi = 1 kHz; THD = 1 % b. VP = 12 V; RL = 2 6 ; fi = 1 kHz; THD = 10 % VP = 12 V; fi = 1 kHz; Power dissipation in junction only VP = 12 V; fi = 1 kHz; po = (2 Po) / (2 Po + Pd) VP = 12 V; PO = 1 W Fig 27. Channel separation as a function of frequency 15. Package outline Fig 28. Package outline SOT619-8 (HVQFN48) SOT619-8 Page 17. Revision history 18. Legal information 18.1 Data sheet status 18.2 Denitions 18.3 Disclaimers 18.4 Trademarks 20. Contents