NXP Semiconductors TFA9810 14.2 Output current limiting,

Product data sheet Rev. 03 — 20 February 2008 19 of 29

NXP Semiconductors TFA9810

Audio ampliﬁer 2 x 12 W

14.2 Output current limiting

The peak output current is internally limited above a level of 3 A minimum. During normal

operation the output current should not exceed this threshold level of 3 A, otherwise the

output signal will be distorted. The peak output current in BTL can be estimated using

Equation 3:

(3)

Where:

•VP = supply voltage (VDDPx −VSSPx) [V].

(1) RL = 4 Ω

(2) RL = 6 Ω

(3) RL= 8 Ω

Fig 26. BTL output power as function of supply voltage: THD = 0.5 %. 3 A

(1) RL = 4 Ω

(2) RL = 6 Ω

(3) RL = 8 Ω

Fig 27. BTL output power as function of supply voltage: THD = 10 %. 3 A

(1)

(2)

(3)

VP (V)

8 201612

010aaa019

(W)

(1)

(2)

(3)

VP (V)

8 201612

010aaa020

(W)

IOmax VP

RL2R

DSon Rs

+()×+

------------------------------------------------------3 A≤≤

Contents

Main 1. General description 2. Features 4. Quick reference data TFA9810 Stereo full-bridge audio amplier 2 x 12 W Rev. 03 20 February 2008 Product data sheet Audio amplier 2 x 12 W = 25 5. Ordering information = 12 V; f = 550 kHz; Figure 33 unless otherwise specied Product data sheet Rev. 03 20 February 2008 3 of 29 6. Block diagram Fig 1. Block diagram 7. Pinning information 7.1 Pinning Fig 2. Pin conguration 7.2 Pin description 8. Functional description 8.1 General 8.2 Interfacing 8.3 Input comparators 8.3.1 Operating in self-oscillating conguration 8.3.2 Operating in open-loop conguration 8.4 Diagnostic 8.5 Protections Page Product data sheet Rev. 03 20 February 2008 8 of 29 NXP Semiconductors TFA9810 9. Internal circuitry Fig 4. Internal circuitry 0001 8.6 Start-up sequence Fig 3. Start-up sequence Product data sheet Rev. 03 20 February 2008 9 of 29 NXP Semiconductors TFA9810 Fig 5. Internal circuitry 0002 Fig 7. Internal circuitry 0004 Fig 6. Internal circuitry 0003 NXP Semiconductors TFA9810 Fig 8. Internal circuitry 0005 Fig 10. Internal circuitry 0007 Fig 9. Internal circuitry 0006 Fig 11. Internal circuitry 0008 Fig 12. Internal circuitry 0009 Fig 14. Internal circuitry 0011 Fig 13. Internal circuitry 0010 Audio amplier 2 x 12 W Fig 15. Internal circuitry 0012 Fig 18. Internal circuitry 0015 Fig 16. Internal circuitry 0013 Fig 17. Internal circuitry 0014 Fig 19. Internal circuitry 0016 Fig 20. Internal circuitry 0017 Fig 22. Internal circuitry 0019 Fig 21. Internal circuitry 0018 10. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). 11. Thermal characteristics 12. Characteristics = 25 12.1 Static characteristics In accordance with the Absolute Maximum Rating System (IEC 60134). 12.2 Dynamic characteristics = 25 = 12 V; f = 550 kHz; Figure 33 unless otherwise specied = 12 V; R 12.3 AC characteristics measured in a typical application = 25 = 8 = 25 = 12 V; R 13. Quality specication 14. Application information 14.1 Output power estimation 14.2 Output current limiting ------------------------------------------------------3 A +()+ DSon Rs (1) RL = 4 (2) RL = 6 (3) RL= 8 14.3 Speaker conguration and impedance 14.4 Differential input 14.5 Single-ended input 14.6 Curves measured in a typical application Fig 29. Input conguration for single-ended input Fig 30. Gain as a function of frequency VP= 12 V, Vi = 100 mV 14.7 Typical application diagram TFA9810 VP=12V,R Fig 32. Total harmonic distortion as a function of output power Fig 31. Total harmonic distortion + noise as a function of frequency VP=12V,R Fig 33. Typical application diagram TFA9810 Fig 34. Typical application diagram TFA9810 with externally adjusted switch-on time 14.8 Typical application: bill of materials 14.9 Snubber network 15. Test information 16. Package outline Fig 35. Package outline SOT287-1 (SO23) SO32: plastic small outline package; 32 leads; body width 7.5 mm SOT287-1 17. Revision history 18. Legal information 18.1 Data sheet status 18.2 Denitions 18.3 Disclaimers 18.4 Trademarks 20. Contents