TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 20-W MONO CLASS-D AUDIO POWER AMPLIFIER FEATURES • • • • • • DESCRIPTION 20 W Into 8-Ω Load From 18-V Supply (10% THD+N) Short Circuit Protection (Short to VCC, Short to GND, Short Between Outputs) Third-Generation Modulation Technique: – Replaces Large LC Filter With Small, Low-Cost Ferrite Bead Filter in Most Applications – Improved Efficiency – Improved SNR Low Supply Current: 8 mA Typ at 12 V Shutdown Control: < 1 µA Typ Space-Saving, Thermally-Enhanced PowerPAD™ Packaging The gain of the amplifier is controlled by two input terminals, GAIN1 and GAIN0. This allows the amplifier to be configured for a gain of 12, 18, 23.6, and 36 dB. The differential input stage provides high common mode rejection and improved power supply rejection. The amplifier also includes depop circuitry to reduce the amount of pop at power-up and when cycling SHUTDOWN. The TPA3001D1 (TPA3001) is available in the 24-pin thermally enhanced TSSOP package (PWP) which eliminates the need for an external heat sink. APPLICATIONS • • • The TPA3001D1 (sometimes referred to as TPA3001) is a 20-W mono bridge-tied load (BTL) class-D audio power amplifier (class-D amp) with high efficiency, eliminating the need for heat sinks. The TPA3001D1 (TPA3001) can drive 4-Ω or 8-Ω speakers with only a ferrite bead filter required to reduce EMI. LCD Monitors/TVs Hands-Free Car Kits Powered Speakers EFFICIENCY vs OUTPUT POWER MAXIMUM OUTPUT POWER vs LOAD IMPEDANCE 21 90 8Ω 80 PO − Output Power − W 70 Efficiency − % 19 4Ω 60 50 40 30 20 VCC = 18 V 0 0 4 8 12 PO − Output Power − W 16 17 15 20 VCC = 15 V 13 11 VCC = 12 V 9 7 10 VCC = 18 V TA = 25°C, 10% THD Maximum 5 3.6 4 5 6 7 8 9 RL − Load Impedance − Ω 10 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD is a trademark of Texas Instruments. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2002–2006, Texas Instruments Incorporated TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 AVAILABLE OPTIONS (1) PACKAGED DEVICES TA TSSOP (PWP) (2) –40°C to 85°C (1) (2) TPA3001D1PWP For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at www.ti.com. The PWP package is available taped and reeled. To order a taped and reeled part, add the suffix R to the part number (e.g., TPA3001D1PWPR). PWP PACKAGE (TOP VIEW) INN INP GAIN0 GAIN1 SHUTDOWN PGND VCLAMP BSN PVCC OUTN OUTN PGND 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 VCC VREF BYPASS COSC ROSC AGND AGND BSP PVCC OUTP OUTP PGND Terminal Functions TERMINAL NAME NO. AGND 18, 19 DESCRIPTION Analog ground terminal BSN 8 I Bootstrap terminal for high-side gate drive of negative BTL output (connect a 0.22-µF capacitor with a 51-Ω resistor in series from OUTN to BSN) BSP 17 I Bootstrap terminal for high-side gate drive of positive BTL output (connect a 0.22-µF capacitor with a 51-Ω resistor in series from OUTP to BSP) BYPASS 22 I Connect 1-µF capacitor to ground for BYPASS voltage filtering COSC 21 I Connect a 220-pF capacitor to ground to set oscillation frequency GAIN0 3 I Bit 0 of gain control (see Table 1 for gain settings) GAIN1 4 I Bit 1 of gain control (see Table 1 for gain settings) INN 1 I Negative differential input INP 2 I Positive differential input 10, 11 O Negative BTL output, connect Schottky diode from PGND to OUTN for short-circuit protection OUTP 14, 15 O Positive BTL output, connect Schottky diode from PGND to OUTP for short-circuit protection PGND 6, 12, 13 PVCC 9, 16 I High-voltage power supply (for output stages) ROSC 20 I Connect 120 kΩ resistor to ground to set oscillation frequency SHUTDOWN 5 I Shutdown terminal (negative logic), TTL compatible, 21-V compliant VCC 24 I Analog high-voltage power supply VCLAMP 7 O Connect 1-µF capacitor to ground to provide reference voltage for H-bridge gates VREF 23 O 5-V internal regulator for control circuitry (connect a 0.1-µF to 1-µF capacitor to ground) - - Connect to AGND and PGND - should be star point for both grounds. Internal resistive connection to AGND. Thermal vias on the PCB should connect this pad to a large copper area on an internal or bottom layer for the best thermal performance. The PAD must be soldered to the PCB for mechanical reliability. OUTN Thermal Pad 2 I/O Power ground Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 FUNCTIONAL BLOCK DIAGRAM VREF AGND VREF VCC VCLAMP VCC Clamp Reference BSN PVCC + _ Gain Adjust INN Deglitch Logic Gate Drive OUTN _ PGND + _ BSP + _ PVCC + Gain Adjust INP + _ _ + Deglitch Logic Gate Drive OUTP PGND SD SHUTDOWN GAIN1 2 GAIN0 Gain Biases and References Ramp Generator COSC ROSC BYPASS Short-Circuit Detect Start-Up Protection Logic Thermal VCC OK ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) UNIT Supply voltage: VCC, PVCC -0.3 V to 21 V ≥ 3.6 Ω Load impedance, RL SHUTDOWN Input voltage -0.3 V to VCC + 0.3 V GAIN0, GAIN1 -0.3 V to 5.5 V INN, INP -0.3 V to 7 V Continuous total power dissipation See Dissipation Rating Table Operating free-air temperature range, TA -40°C to 85°C Operating junction temperature range, TJ -40°C to 150°C Storage temperature range, Tstg -65°C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (1) 260°C Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATING TABLE PACKAGE TA ≤ 25°C DERATING FACTOR TA = 70°C TA = 85°C PWP 4.16 W 33.33 mW/°C (1) 2.67 W 2.16 W (1) The PowerPAD must be soldered to a thermal land on the printed circuit board. Please refer to the PowerPAD Thermally Enhanced Package application note (SLMA002). Submit Documentation Feedback 3 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 RECOMMENDED OPERATING CONDITIONS RL≥ Supply voltage, VCC, PVCC MIN MAX 8 18 3.6 (1) Load impedance, RL High-level input voltage, VIH GAIN0, GAIN1, SHUTDOWN Low-level input voltage, VIL GAIN0, GAIN1, SHUTDOWN Operating free-air temperature, TA (1) UNIT V 3.6 Ω 2 V -40 0.8 V 85 °C The TPA3001D1 must not be used with any speaker or load (including speaker with output filter) that could vary below 3.6 Ω over the audio frequency band. ELECTRICAL CHARACTERISTICS TA= 25°C, PVCC = VCC = 12 V (unless otherwise noted) PARAMETERS TEST CONDITIONS MIN TYP MAX UNIT |VOS| Output offset voltage (measured differentially) VI = 0 V, AV = 12 dB, 18, 23.6 dB 50 PSRR Power supply rejection ratio PVCC = 11.5 V to 12.5 V |IIH| High-level input current PVCC = 12 V, VI = PVCC 1 |IIL| Low-level input current PVCC = 12 V, VI = 0 V 1 µA 15 mA VI = 0 V, AV = 36 dB 100 -73 SHUTDOWN = 2.0 V, No load Supply current SHUTDOWN = VCC, VCC = 18 V, PO = 20 W, RL = 8Ω ICC(SD) Supply current, shutdown mode SHUTDOWN = 0.8 V fs Switching frequency ROSC = 120 kΩ, COSC = 220 pF rds(on) Output transistor on resistance (total) IO = 1 A, TJ = 25°C G Gain dB 8 ICC mV 1.3 µA A 1 2 250 µA kHz 0.2 0.3 0.7 Ω GAIN1 = 0.8 V, GAIN0 = 0.8 V 10.9 12 12.8 dB GAIN1 = 0.8 V, GAIN0 = 2 V 17.1 18 18.5 dB 23 23.6 24.3 dB 33.9 36 36.5 dB GAIN1 = 2 V, GAIN0 = 0.8 V GAIN1 = 2 V, GAIN0 = 2 V OPERATING CHARACTERISTICS PVCC = VCC = 12 V, TA = 25°C (unless otherwise noted) PARAMETER Continuous output power at 10% THD+N PO MIN TYP 12.8 f = 1 kHz, RL = 8 Ω 9 f = 1 kHz, RL = 4 Ω 10.3 f = 1 kHz, RL = 8 Ω MAX UNIT W 7.2 THD + N Total harmonic distortion plus noise PO = 10 W, RL = 4 Ω, f = 20 Hz to 20 kHz BOM Maximum output power bandwidth THD = 1% kSVR Supply ripple rejection ratio f = 1 kHz, C(BYPASS) = 1 µF SNR Signal-to-noise ratio PO = 10 W, RL = 4 Ω 95 dB C(BYPASS) = 1 µF, f = 20 Hz to 22 kHz,No weighting filter used, Gain = 12 dB 86 µV(rms) Vn Zi 4 Continuous output power at 1% THD+N TEST CONDITIONS f = 1 kHz, RL = 4 Ω Noise output voltage Input impedance 0.2% 20 kHz -70 dB -81 dBV C(BYPASS) = 1 µF, f = 20 Hz to 22 kHz,A-weighted filter, Gain = 12 dB 66 µV(rms) -84 dBV See Table 1, page 21 >23 kΩ Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 OPERATING CHARACTERISTICS PVCC = VCC = 18 V, TA = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS Output power at 10% THD+N PO Output power at 1% THD+N MIN TYP f = 1 kHz, RL = 4 Ω 12.8 f = 1 kHz, RL = 8 Ω 20 f = 1 kHz, RL = 4 Ω 10.3 f = 1 kHz, RL = 8 Ω PO = 15 W, RL = 8Ω, f = 20 Hz to 20 kHz MAX UNIT W 16 1% THD + N Total harmonic distortion plus noise BOM Maximum output power bandwidth THD = 1% 20 kHz kSVR Supply ripple rejection ratio f = 1 kHz, CBYPASS = 1 µF -70 dB SNR Signal-to-noise ratio PO = 15 W, RL = 8 Ω 102 dB 86 µV(rms) PO = 2 W, RL = 8Ω, f = 20 Hz to 20 kHz C(BYPASS) = 1 µF, f = 20 Hz to 20 kHz, No weighting filter used, Gain = 12 dB Vn Noise output voltage Zi Input impedance C(BYPASS) = 1 µF, f = 20 Hz to 22 kHz, A-weighted filter, Gain = 12 dB See Table 1, page 21 0.3% -81 dBV 66 µV(rms) 84 dBV >23 kΩ TYPICAL CHARACTERISTICS Table of Graphs FIGURE Efficiency vs Output power PO Output power vs Load Impedance ICC Supply current ICC(SD) Shutdown current THD+N Total harmonic distortion + noise kSVR Supply voltage rejection ratio vs Supply voltage vs Output power vs Frequency Gain and phase CMRR Common-mode rejection ratio VIO Input offset voltage 1 2, 3, 4 5 6 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 19, 20, 21, 22, 23, 24, 25 26 vs Frequency 27 28 vs Common-mode input voltage Submit Documentation Feedback 29 5 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 EFFICIENCY vs OUTPUT POWER MAXIMUM OUPUT POWER vs LOAD IMPEDANCE 21 90 8Ω 80 70 17 PO − Output Power − W Efficiency − % VCC = 18 V 19 4Ω 60 50 40 30 20 15 VCC = 15 V 13 11 VCC = 12 V 9 VCC = 12 V 7 10 0 0 2 4 6 8 10 12 TA = 25°C, 10% THD Maximum 5 3.6 4 14 5 6 PO − Output Power − W Figure 2. MAXIMUM OUPUT POWER vs LOAD IMPEDANCE MAXIMUM OUTPUT POWER vs LOAD IMPEDANCE 10 21 TA = 60°C 19 19 VCC = 18 V PO − Maximum Output Power − W PO − Maximum Output Power − W 9 Figure 1. TA = 45°C 17 15 VCC = 15 V 13 11 9 VCC = 12 V 7 17 VCC = 18 V 15 VCC = 15 V 13 11 9 VCC = 12 V 7 4 5 6 7 8 ZL − Load Impedance − Ω 9 10 5 3.6 Figure 3. 6 8 Load Impedance − Ω 21 5 3.6 7 4 5 6 7 8 ZL − Load Impedance − Ω Figure 4. Submit Documentation Feedback 9 10 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 SUPPLY CURRENT vs SUPPLY VOLTAGE SHUTDOWN CURRENT vs SUPPLY VOLTAGE 11 5 ICC(SD) − Shutdown Current − µA ICC − Supply Current − mA SHUTDOWN = 0.8 V 10 9 8 7 6 4 3 2 1 0 8 10 12 14 16 18 8 12 14 16 Figure 5. Figure 6. TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 VCC = 18 V, RL = 8 Ω, Gain = 12 dB 1 1 kHz 0.1 20 kHz 0.01 20 Hz 0.001 0 10 5 10 18 VCC − Supply Voltage − V THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % VCC − Supply Voltage − V 15 20 10 VCC = 18 V, RL = 8 Ω, Gain = 36 dB 1 1 kHz 20 kHz 0.1 20 Hz 0.01 0 PO − Output Power − W Figure 7. 5 10 15 PO − Output Power − W 20 Figure 8. Submit Documentation Feedback 7 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 THD+N − Total Harmonic Distortion Plus Noise − % 10 VCC = 15 V, RL = 8 Ω, Gain = 12 dB 1 1 kHz 20 kHz 20 Hz 0.1 0.01 0.001 0 THD+N − Total Harmonic Distortion Plus Noise − % TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 5 10 15 PO − Output Power − W 10 VCC = 15 V, RL = 8 Ω, Gain = 36 dB 1 20 kHz 1 kHz 0.01 0 5 10 15 PO − Output Power − W Figure 9. Figure 10. TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 VCC = 15 V, RL = 4 Ω, Gain = 12 dB 1 1 kHz 0.1 20 Hz 20 kHz 0.01 0 5 10 PO − Output Power − W 10 VCC = 15 V, RL = 4 Ω, Gain = 36 dB 1 1 kHz 0.1 20 Hz 20 kHz 0.01 0 Figure 11. 8 20 Hz 0.1 20 THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 5 10 PO − Output Power − W Figure 12. Submit Documentation Feedback 20 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 1 1 kHz 20 kHz 20 Hz 0.1 0.01 0.001 0 THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % VCC = 12 V, RL = 8 Ω, Gain = 12 dB 5 10 PO − Output Power − W 10 VCC = 12 V, RL = 8 Ω, Gain = 36 dB 1 1 kHz 20 kHz 20 Hz 0.1 0.01 0 15 5 10 PO − Output Power − W 15 Figure 13. Figure 14. TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 VCC = 12 V, RL = 4 Ω, Gain = 12 dB 1 1 kHz 0.1 20 Hz 20 kHz 0.01 0.001 0 5 10 PO − Output Power − W THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % 10 10 VCC = 12 V, RL = 4 Ω, Gain = 36 dB 1 1 kHz 0.1 20 kHz 20 Hz 0.01 0 Figure 15. 5 PO − Output Power − W 10 Figure 16. Submit Documentation Feedback 9 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 VCC = 8 V, RL = 4 Ω, Gain = 12 dB 1 1 kHz 0.1 20 Hz 20 kHz 0.01 THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % 10 0 2 4 PO − Output Power − W TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 10 VCC = 8 V, RL = 4 Ω, Gain = 36 dB 1 1 kHz 0.1 20 kHz 20 Hz 0.01 0 6 2 4 PO − Output Power − W Figure 18. TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 1 VCC = 18 V RL = 8 Ω PO = 10 W PO = 500 mW 0.1 PO = 2 W 0.01 0.001 20 100 1k 10 k 20 k 1 VCC = 15 V RL = 8 Ω PO = 10 W 0.1 PO = 500 mW 0.01 0.001 20 f − Frequency − Hz Figure 19. 10 6 Figure 17. THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER PO = 2 W 100 1k f − Frequency − Hz Figure 20. Submit Documentation Feedback 10 k 20 k TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 THD+N − Total Harmonic Distortion Plus Noise − % 1 VCC = 15 V RL = 4 Ω PO = 10 W 0.1 PO = 500 mW PO = 2 W 0.01 0.001 20 100 1k TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 10 k 20 k 1 VCC = 12 V RL = 8 Ω 0.1 PO = 5 W PO = 250 mW 0.01 PO = 1 W 0.001 20 f − Frequency − Hz 1k f − Frequency − Hz Figure 21. Figure 22. TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 1 THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % THD+N − Total Harmonic Distortion Plus Noise − % TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY VCC = 12 V RL = 4 Ω 0.1 PO = 2 W PO = 500 mW 0.01 PO = 7.5 W 0.001 20 100 100 10 VCC = 8 V RL = 8 Ω 1 PO = 3 W PO = 250 mW 0.1 PO = 1 W 0.01 0.001 20 f − Frequency − Hz 1k f − Frequency − Hz Figure 23. Figure 24. 1k 10 k 20 k 10 k 20 k Submit Documentation Feedback 100 10 k 20 k 11 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 SUPPLY VOLTAGE REJECTION RATIO vs FREQUENCY −50 10 kSVR − Supply Voltage Rejection Ratio − dB VCC = 8 V RL = 4 Ω PO = 5 W 1 PO = 1 W 0.1 PO = 250 mW 0.01 0.001 20 100 1k f − Frequency − Hz VDD = 15 V −80 100 10k COMMON-MODE REJECTION RATIO vs FREQUENCY −40 20 10 0 10 8 −20 Phase −30 6 −40 4 −50 −60 VCC = 8 V RL = 8 Ω Gain = 12 dB −70 1k 10k −80 100k Phase − ° −10 VCC = 8 V to 18 V RL = 8 Ω −41 −42 −43 −44 −45 −46 20 f − Frequency − Hz Figure 27. 12 1k GAIN AND PHASE vs FREQUENCY 12 Gain − dB −70 f − Frequency − Hz 30 100 VCC = 8 V Figure 26. Gain 0 20 −60 Figure 25. 14 2 C(Bypass) = 1 µF RL = 8 Ω −90 20 10 k 20 k CMRR − Common-Mode Rejection Ratio − dB THD+N − Total Harmonic Distortion Plus Noise − % TOTAL HARMONIC DISTORTION PLUS NOISE vs FREQUENCY 100 1k f − Frequency − Hz Figure 28. Submit Documentation Feedback 10 k TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 INPUT OFFSET VOLTAGE vs COMMON-MODE INPUT VOLTAGE 6 VIO − Input Offset Voltage − mV 5 VCC = 8 V to 18 V 4 3 2 1 0 −1 −2 −3 −4 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VIC − Common-Mode Input Voltage − V Figure 29. Submit Documentation Feedback 13 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION APPLICATION CIRCUIT U1 TPA3001D1 C1 IN– 0.47 µF 1 2 IN+ C2 0.47 µF 3 GAIN SELECT 4 GAIN SELECT 5 SHUTDOWN CONTROL 6 7 C10 1 µF VCC R2 C8 0.22 µF 51 Ω 8 9 10 C7 10 µF C5 1 µF 11 12 INN VCC VCC VREF INP GAIN0 BYPASS GAIN1 COSC 23 22 21 20 SHUTDOWN ROSC PGND AGND C3 1 µF C4 1 µF C11 1 µF C12 220 pF R1 120 kΩ 19 18 VCLAMP AGND BSN BSP PVCC PVCC OUTN OUTP OUTN OUTP PGND PGND D2 24 17 R3 16 51 Ω C9 0.22 µF 15 VCC C6 1 µF 14 13 D1 PowerPAD L2 (Ferrite Bead) L1 (Ferrite Bead) C15 1 nF C14 1 nF L1, L2: Fair-Rite, Part Number 2512067007Y3 D1, D2: Diodes, Inc., Part Number B130 Figure 30. Typical Application Circuit CLASS-D OPERATION This section focuses on the class-D operation of the TPA3001D1. TRADITIONAL CLASS-D MODULATION SCHEME The traditional class-D modulation scheme, which is used in the TPA032D0x family, has a differential output where each output is 180 degrees out of phase and changes from ground to the supply voltage, VCC. Therefore, the differential prefiltered output varies between positive and negative VCC, where filtered 50% duty cycle yields 0 V across the load. The traditional class-D modulation scheme with voltage and current waveforms is shown in Figure 31. Note that even at an average of 0 V across the load (50% duty cycle), the current to the load is high, causing high loss, thus causing a high supply current. 14 Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) OUTP OUTN +12 V Differential Voltage Across Load 0V –12 V Current Figure 31. Traditional Class-D Modulation Scheme's Output Voltage and Current Waveforms Into an Inductive Load With No Input TPA3001D1 MODULATION SCHEME The TPA3001D1 uses a modulation scheme that still has each output switching from ground to VCC. However, OUTP and OUTN are now in phase with each other with no input. The duty cycle of OUTP is greater than 50% and OUTN is less than 50% for positive output voltages. The duty cycle of OUTP is less than 50% and OUTN is greater than 50% for negative output voltages. The voltage across the load is 0 V throughout most of the switching period, greatly reducing the switching current, which reduces any I2R losses in the load. (See Figure 32 on the following page.) Submit Documentation Feedback 15 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) OUTP OUTN Differential Voltage Across Load Output = 0 V +12 V 0V –12 V Current OUTP OUTN Differential Voltage Output > 0 V +12 V 0V Across Load –12 V Current Figure 32. The TPA3001D1 Output Voltage and Current Waveforms Into an Inductive Load MAXIMUM ALLOWABLE OUTPUT POWER (SAFE OPERATING AREA) The TPA3001D1 can drive load impedances as low as 3.6 Ω from power supply voltages ranging from 8 V to 18 V. To prevent device failure, however, the output power of the TPA3001D1 must be limited. Figure 33 shows the maximum allowable output power versus load impedance for three power supply voltages at an ambient temperature of 25°C. (For ambient temperatures of 45°C and 60°C, see Figures 3 and 4 on page 6.) 16 Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) MAXIMUM OUTPUT POWER vs LOAD IMPEDANCE 21 PO – Output Power – W 19 VCC = 18 V 17 15 VCC = 15 V 13 11 VCC = 12 V 9 7 TA = 25°C, 10% THD Maximum 5 3.6 4 5 6 7 8 Load Impedance – Ω 9 10 Figure 33. Output Power driving a low-impedance load from a high power supply voltage When driving low-impedance loads (e.g., a 4-Ω speaker), the output power can be limited by reducing the maximum audio input signal level or by reducing the gain of the TPA3001D1. The maximum input voltage may be calculated with Equation 1. V in(pp),max + Ǹ8PO(avg),max R L Av where PO(avg), max = maximum continuous output power (W) RL = load impedance (Ω) A v + voltage gain (VńV) + ǒG(dB) Ǔ 20 (1) For example, consider an application in which the TPA3001D1 drives a 4-Ω speaker from an 18-V power supply. The gain is selected to be 18 dB. The maximum allowable output power for a 4-Ω load impedance is 12.8 W. From Equation 1, the input voltage must not exceed 2.54 Vpp. In this same example, however, if the maximum output voltage of audio signal source is 5 Vpp, then the gain of the TPA3001D1 should be reduced to 12 dB to eliminate the need for limiting the input signal. The input voltage may be limited using a variety of methods, depending on what is known about the audio signal source. If the maximum output voltage of the source is known, a resistive voltage divider in conjunction with proper TPA3001D1 gain selection may be used to prevent distortion. If the maximum audio source voltage is unknown, diodes may be used to clamp the input voltage, at the cost of distortion when the input signal level exceeds the required clamping voltage. DRIVING THE OUTPUT INTO CLIPPING The output of the TPA3001D1 may be driven into clipping to attain a higher output power than is possible with no distortion. Clipping is typically quantified by a THD measurement of 10%. The amount of additional power into the load may be calculated with Equation 2. Submit Documentation Feedback 17 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) P O(10% THD) + P O(1% THD) 1.25 (2) For example, consider an application in which the TPA3001D1 drives an 8-Ω speaker from an 18-V power supply. The maximum output power with no distortion (less than 1% THD) is 16 W, which corresponds to a maximum peak output voltage of 16 V. For the same output voltage level driven into clipping (10% THD), the output power is increased to 20 W. OUTPUT FILTER CONSIDERATIONS A ferrite bead filter (shown in Figure 34) should be used in order to pass FCC and/or CE radiated emissions specifications and if a frequency sensitive circuit operating higher than 1 MHz is nearby. The ferrite filter reduces EMI around 1 MHz and higher (FCC and CE only test radiated emissions greater than 30 MHz). When selecting a ferrite bead, choose one with high impedance at high frequencies, but very low impedance at low frequencies. Use an additional LC output filter if there are low frequency (<1 MHz) EMI sensitive circuits and/or there are long wires (greater than 11 inches) from the amplifier to the speaker, as shown in Figure 35 and Figure 36. Ferrite Chip Bead OUTP 1 nF 4 Ω or Greater Ferrite Chip Bead OUTN 1 nF Figure 34. Typical Ferrite Chip Bead Filter (Chip bead example: Fair-Rite 2512067007Y3) 15 µH Ferrite Chip Bead OUTP 0.22 mF 15 µH 1 nF 1 µF Ferrite Chip Bead 4Ω OUTN 0.22 mF 1 nF Figure 35. Typical LC Output Filter for 4-Ω Speaker, Cutoff Frequency of 27 kHz 33 µH Ferrite Chip Bead OUTP 0.1 mF 33 µH 1 nF 0.47 µF Ferrite Chip Bead 8Ω OUTN 0.1 mF 1 nF Figure 36. Typical LC Output Filter for 8-Ω Speaker, Cutoff Frequency of 27 kHz 18 Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) SHORT-CIRCUIT PROTECTION The TPA3001D1 has short circuit protection circuitry on the outputs that prevents damage to the device during output-to-output shorts, output-to-GND shorts, and output-to-VCC shorts. When a short-circuit is detected on the outputs, the part immediately disables the output drive and enters into shutdown mode. This is a latched fault and must be reset by cycling the voltage on the SHUTDOWN pin to a logic low and back to the logic high state for normal operation. This will clear the short-circuit flag and allow for normal operation if the short was removed. If the short was not removed, the protection circuitry will again activate. Two Schottky diodes are required to provide short-circuit protection. The diodes should be placed as close to the TPA3001D1 as possible, with the anodes connected to PGND and the cathodes connected to OUTP and OUTN as shown in the application circuit schematic. The diodes should have a forward voltage rating of 0.5 V at a minimum of 1-A output current and a DC blocking voltage rating of at least 30 V. The diodes must also be rated to operate at a junction temperature of 150°C. If short-circuit protection is not required, the Schottky diodes may be omitted. THERMAL PROTECTION Thermal protection on the TPA3001D1 prevents damage to the device when the internal die temperature exceeds 150°C. There is a ±15°C tolerance on this trip point from device to device. Once the die temperature exceeds the thermal set point, the device enters into the shutdown state and the outputs are disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by 15°C. The device begins normal operation at this point with no external system interaction. THERMAL CONSIDERATION: OUTPUT POWER AND MAXIMUM AMBIENT TEMPERATURE To calculate the maximum ambient temperature, Equation 3 may be used: T Amax + T Jmax * QJAP Dissipated (3) where: TJmax = 150°C θJA = 1 / derating factor = 1 / 0.03333 = 30°C/W (The derating factor for the 24-pin PWP package is given in the dissipation rating table on page 3.) To estimate the power dissipation, Equation 4 may be used: P Dissipated + PO(average) ((1ńEfficiency) * 1) (4) Efficiency = ~85% for an 8-Ω load = ~75% for a 4-Ω load Example. What is the maximum ambient temperature for an application that requires the TPA3001D1 to drive 10 W into an 8-Ω speaker? PDissipated = 10 W x ((1 / 0.85) - 1) = 1.76 W TAmax = 150°C - (30°C/W x 1.76 W) = 97.2°C This calculation shows that the TPA3001D1 can drive 10 W into an 8-Ω speaker up to the absolute maximum ambient temperature rating of 85°C, which must never be exceeded. Also, refer to Figures 2, 3, and 4 to determine the minimum load impedance for the desired output power. GAIN SETTING VIA GAIN0 AND GAIN1 INPUTS The gain of the TPA3001D1 is set by two input terminals, GAIN0 and GAIN1. The gains listed in Table 1 are realized by changing the taps on the input resistors inside the amplifier. This causes the input impedance (Zi) to be dependent on the gain setting. The actual gain settings are controlled by ratios of resistors, so the gain variation from part-to-part is small. However, the input impedance may shift by 30% due to shifts in the actual resistance of the input resistors. Submit Documentation Feedback 19 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 APPLICATION INFORMATION (continued) For design purposes, the input network (discussed in the next section) should be designed assuming an input impedance of 23 kΩ, which is the absolute minimum input impedance of the TPA3001D1. At the lower gain settings, the input impedance could increase as high as 313 kΩ. Table 1. Gain Settings GAIN1 GAIN0 AMPLIFIER GAIN (dB) INPUT IMPEDANCE (kΩ) TYP TYP 0 0 12 241 0 1 18 168 1 0 23.6 104 1 1 36 33 INPUT RESISTANCE Each gain setting is achieved by varying the input resistance of the amplifier, which can range from its smallest value to over six times that value. As a result, if a single capacitor is used in the input high-pass filter, the -3dB or cutoff frequency also changes by over six times. Zf Ci IN Input Signal Zi The -3-dB frequency can be calculated using Equation 5. Use Table 1 for Zi values. 1 f+ 2p Z iCi (5) INPUT CAPACITOR, Ci In the typical application an input capacitor (Ci) is required to allow the amplifier to bias the input signal to the proper dc level for optimum operation. In this case, Ci and the input impedance of the amplifier (Zi) form a high-pass filter with the corner frequency determined in Equation 6. −3 dB fc + 1 2 p Zi C i fc (6) The value of Ci is important, as it directly affects the bass (low frequency) performance of the circuit. Consider the example where Zi is 241 kΩ and the specification calls for a flat bass response down to 20 Hz. Equation 6 is reconfigured as Equation 7. 20 Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 Ci + 1 2p Z i f c (7) In this example, Ci is 33 nF, so one would likely choose a value of 0.1 µF as this value is commonly used. If the gain is known and will be constant, use Zi from Table 1 to calculate Ci. A further consideration for this capacitor is the leakage path from the input source through the input network (Ci) and the feedback network to the load. This leakage current creates a dc offset voltage at the input to the amplifier that reduces useful headroom, especially in high gain applications. For this reason a low-leakage tantalum or ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor should face the amplifier input in most applications as the dc level there is held at 2.5 V, which is likely higher than the source dc level. Note that it is important to confirm the capacitor polarity in the application. POWER SUPPLY DECOUPLING The TPA3001D1 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to ensure the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is achieved by using two capacitors of different types that target different types of noise on the power supply leads. For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically 1 µF placed as close as possible to the device VCC lead works best. For filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near the audio power amplifier is recommended. BSN AND BSP CAPACITORS The full H-bridge output stage uses only NMOS transistors. It therefore requires bootstrap capacitors for the high side of each output to turn on correctly. A 0.22-µF ceramic capacitor, rated for at least 25 V, must be connected from each output to its corresponding bootstrap input. Specifically, one 0.22-µF capacitor must be connected from OUTP to BSP, and one 0.22-µF capacitor must be connected from OUTN to BSN. (See Figure 30.) BSN AND BSP RESISTORS To limit the current when charging the bootstrap capacitors, a resistor with a value of approximately 50 Ω (±10% maximum) must be placed in series with each bootstrap capacitor. The current will be limited to less than 500 µA. VCLAMP CAPACITOR To ensure that the maximum gate-to-source voltage for the NMOS output transistors is not exceeded, an internal regulator clamps the gate voltage. A 1-µF capacitor must be connected from VCLAMP (pin 7) to ground and must be rated for at least 25 V. The voltage at VCLAMP (pin 7) varies with VCC and may not be used for powering any other circuitry. MIDRAIL BYPASS CAPACITOR The midrail bypass capacitor (C11 of Figure 30) is the most critical capacitor and serves several important functions. During start-up or recovery from shutdown mode, CBYPASS determines the rate at which the amplifier starts up. The second function is to reduce noise produced by the power supply caused by coupling into the output drive signal. This noise is from the midrail generation circuit internal to the amplifier, which appears as degraded PSRR and THD+N. Bypass capacitor (C11) values of 0.47-µF to 1-µF ceramic or tantalum low-ESR capacitors are recommended for the best THD noise, and depop performance. The bypass capacitor must be a value greater than the input capacitors for optimum depop performance. VREF DECOUPLING CAPACITOR The VREF terminal (pin 23) is the output of an internally-generated 5-V supply, used for the oscillator and gain setting logic. It requires a 0.1-µF to 1-µF capacitor to ground to keep the regulator stable. The regulator may not be used to power any additional circuitry. Submit Documentation Feedback 21 TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 DIFFERENTIAL INPUT The differential input stage of the amplifier cancels any noise that appears on both input lines of the channel. To use the TPA3001D1 EVM with a differential source, connect the positive lead of the audio source to the INP input and the negative lead from the audio source to the INN input. To use the TPA3001D1 with a single-ended source, ac ground the INN input through a capacitor and apply the audio signal to the INP input. In a single-ended input application, the INN input should be ac-grounded at the audio source instead of at the device input for best noise performance. SWITCHING FREQUENCY The switching frequency is determined using the values of the components connected to ROSC (pin 20) and COSC (pin 21) and may be calculated with Equation 8: 6.6 fs + ROSC C OSC (8) The frequency may be varied from 225 kHz to 275 kHz by adjusting the values chosen for ROSC and COSC. SHUTDOWN OPERATION The TPA3001D1 employs a shutdown mode of operation designed to reduce supply current (ICC) to the absolute minimum level during periods of nonuse for battery-power conservation. The SHUTDOWN input terminal should be held high during normal operation when the amplifier is in use. Pulling SHUTDOWN low causes the outputs to mute and the amplifier to enter a low-current state, ICC(SD) = 1 µA. SHUTDOWN should never be left unconnected, because amplifier operation would be unpredictable. Ideally, the device should be held in shutdown when the system powers up and brought out of shutdown once any digital circuitry has settled. However, if SHUTDOWN is to be left unused, the terminal may be connected directly to VCC. USING LOW-ESR CAPACITORS Low-ESR capacitors are recommended throughout this application section. A real (as opposed to ideal) capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this resistance the more the real capacitor behaves like an ideal capacitor. STARTUP TIME The startup time can be calculated with Equation 9: t startup + 8.2 ms ) 2 100 kW C 11 (9) where C11 is the value of the bypass capacitor as shown in Figure 30. PRINTED CIRCUIT BOARD (PCB) LAYOUT Because the TPA3001D1 is a class-D amplifier that switches at a high frequency, the layout of the printed circuit board (PCB) should be optimized according to the following guidelines for the best possible performance. • Decoupling capacitors — As described on page 22, the high-frequency 0.1-uF decoupling capacitors should be placed as close to the PVCC (pin 9 and pin 16) and VCC (pin 24) terminals as possible. The BYPASS (pin 22) capacitor, VREF (pin 23) capacitor, and VCLAMP (pin 7) capacitor should also be placed as close to the device as possible. The large (10 µF or greater) bulk power supply decoupling capacitor should be placed near the TPA3001D1. • Grounding — The VCC (pin 24) decoupling capacitor, VREF (pin 23) capacitor, BYPASS (pin 22) capacitor, COSC (pin 21) capacitor, and ROSC (pin 20) resistor should each be grounded to analog ground (AGND, pin 18 and pin 19). The PVCC (pin 9 and pin 16) decoupling capacitors should each be grounded to power ground (PGND, pin 12 and pin 13). Analog ground and power ground may be connected at the PowerPAD, which should be used as a central ground connection or star ground for the TPA3001D1. 22 Submit Documentation Feedback TPA3001D1 www.ti.com SLOS398C – DECEMBER 2002 – REVISED JULY 2006 • • Output filter — The ferrite filter (Figure 34, page 18) should be placed as close to the output terminals (pins 10, 11, 14, and 15) as possible for the best EMI performance. The LC filter (Figure 35, page 18 and Figure 36, page 19) should be placed close to the ferrite filter. The capacitors used in both the ferrite and LC filters should be grounded to power ground. PowerPAD — The PowerPAD must be soldered to the PCB for proper thermal performance and optimal reliability. The dimensions of the PowerPAD thermal land should be 1.6 mm by 6.0 mm (63 mils by 236.2 mils). Two rows of solid vias (four vias per row, 0.3302 mm or 13 mils diameter) should be equally spaced underneath the thermal land. The vias should connect to a solid copper plane, either on an internal layer or on the bottom layer of the PCB. The vias must be solid vias, not thermal relief or webbed vias. For additional information, please refer to the PowerPAD Thermally Enhanced Package application note, TI literature number SLMA002. For an example layout, refer to the TPA3001D1 Evaluation Module (TPA3001D1EVM) User Manual, TI literature number SLOU156. Both the EVM user manual and the PowerPAD application note are available on the TI web site at http://www.ti.com. Submit Documentation Feedback 23 PACKAGE OPTION ADDENDUM www.ti.com 18-Jul-2006 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty TPA3001D1PWP ACTIVE HTSSOP PWP 24 60 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPA3001D1PWPG4 ACTIVE HTSSOP PWP 24 60 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPA3001D1PWPR ACTIVE HTSSOP PWP 24 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPA3001D1PWPRG4 ACTIVE HTSSOP PWP 24 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. 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