STA541SA 2 x 20 W dual bridge amplifier Datasheet − production data Features ■ High output power capability – 2x 20 W into 8 Ω at 17 V with 10% THD – 2x 18 W into 4 Ω at 12 V with 10% THD ■ Minimum external components count: – No bootstrap capacitors – No Boucherot cells – Internally fixed gain 26 dB ■ Standby function (CMOS compatible) ■ No audible pop during standby operations ■ Diagnostic facilities: – Clip detector – Output to ground short-circuit detector – Output to supply short-circuit detector – Soft short-circuit check at turn-on – Thermal shutdown warning Clipwatt15 Protection ■ Output AC/DC short circuit ■ Soft short-circuit check at turn-on ■ Thermal cutoff/limiter to prevent chip from overheating ■ High inductive loads ■ ESD Table 1. The STA541SA is a dual bridge, class-AB audio amplifier designed for high quality sound applications. The amplifiers have outputs with integrated shortcircuit protection, thermal protection and diagnostic functions. The chip is housed in the 15-pin Clipwatt, environmentally friendly, ECOPACK® package. Device summary Order code STA541SA Description Operating temp. range 0 to 70 °C April 2012 This is information on a product in full production. Package Clipwatt15 Doc ID 16988 Rev 2 Packaging Tube 1/26 www.st.com 26 Contents STA541SA Contents 1 2 3 Block diagram and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Characterization curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1 For 4-Ω loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 For 8-Ω loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6 Thermal information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1 7 6.1.1 Rth_HS calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1.2 Calculations using music power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Practical information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.1 Internally fixed gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.2 Silent turn on/off and muting/standby function . . . . . . . . . . . . . . . . . . . . . 17 7.3 Driving circuit for standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.4 Built–in protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.5 2/26 Heatsink specification examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.4.1 Diagnostic facilities (pin 10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.4.2 Short-circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.4.3 Clipping detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.4.4 Thermal shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Handling the diagnostic information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Doc ID 16988 Rev 2 STA541SA Contents 7.6 PCB ground layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.7 Mute function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 8 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Doc ID 16988 Rev 2 3/26 List of figures STA541SA List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. 4/26 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pin connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Output power vs supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Quiescent current vs supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Efficiency, device dissipation vs output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Total harmonic distortion vs output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Crosstalk vs frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Output power vs supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Quiescent current vs supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Efficiency, device dissipation vs output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Total harmonic distortion vs output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Crosstalk vs frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Power supply rejection ratio vs frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Applications circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Demonstration board schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Clipping detection waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Configuration of pin DIAG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Fault waveforms on pin DIAG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Interface circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Optional mute function circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Doc ID 16988 Rev 2 STA541SA List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Recommended operating condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Package dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Doc ID 16988 Rev 2 5/26 Block diagram and pin description STA541SA 1 Block diagram and pin description 1.1 Block diagram Figure 1. Block diagram VCC2 VCC1 Vcc1 Vcc2 13 3 1 + IN 1 IN1 OUT 1+ OUT1+ – 4 2 + ST-BY STBY + 15 – IN 2 IN2 + 14 10 STA541SA 5 SVR SVR 6/26 OUT 2+ OUT2+ 12 – DIAG DIAG OUT 1OUT1- – 7 8 9 P-GND S-GND PGND Doc ID 16988 Rev 2 SGND OUT2OUT 2- STA541SA 1.2 Block diagram and pin description Pin description Figure 2. Pin connection (top view) OUT2+ OUT2VCC2 IN2 N.C. DIAG SGND PGND STBY N.C. SVR IN1 VCC1 OUT1OUT1+ Table 2. DIAG N.C SVR Pin description Pin Name Type Function 1 OUT1+ OUT Channel 1 non-inverting output 2 OUT1 - OUT Channel 1 inverting output 3 VCC1 PWR Power supply 4 IN1 IN Channel 1 input 5 SVR IN Supply voltage rejection 6 N.C. - No internal connection 7 STBY IN Standby control 8 PGND PWR Power ground 9 SGND PWR Signal ground 10 DIAG OUT Diagnostics output 11 N.C. - No internal connection 12 IN2 IN Channel 2 input 13 VCC2 PWR Power supply 14 OUT2- OUT Channel 2 inverting output 15 OUT2+ OUT Channel 2 non-inverting output Doc ID 16988 Rev 2 7/26 Electrical specifications STA541SA 2 Electrical specifications 2.1 Absolute maximum ratings Table 3. Absolute maximum ratings Symbol Parameter Max Unit - - 24 V Supply voltage operating - - 22 V Supply voltage AC-DC short safe - - 20 V Ptot Total power dissipation (Tcase = 85 °C) - - 32 W Tj Junction temperature -40 - 150 °C Tstg Storage temperature -40 - 150 °C Tamb Ambient temperature 0 - 70 °C Warning: Stresses beyond those listed in Table 3 above 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” are not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. In the real application, power supplies with nominal values rated within the recommended operating conditions, may rise beyond the maximum operating conditions for a short time when no or very low current is sunk (amplifier in mute state). In this case the reliability of the device is guaranteed, provided that the absolute maximum ratings are not exceeded. Thermal data Table 4. Symbol 8/26 Typ Supply voltage idle mode (no signal) VS 2.2 Min Thermal data Parameter Min Typ Max Unit Rth j-case Thermal resistance junction-case - - 2.5 °C/W Rth j-amb Thermal resistance junction-ambient - - 45 °C/W Doc ID 16988 Rev 2 STA541SA 2.3 Electrical specifications Recommended operating conditions Table 5. Recommended operating condition Symbol 2.4 Parameter Min Typ Max Unit VS Power supply voltage (VCC1, VCC2) 8 - 22 V Tamb Ambient temperature 0 - 70 °C Electrical characteristics The test conditions are VS = 17 V, RL = 8 Ω, f = 1 kHz, Tamb = 25 °C unless otherwise specified. Table 6. Symbol Electrical characteristics Parameter Test condition Min Typ Max Unit Id Total quiescent drain current - - 80 150 mA Vos Output offset voltage - -150 - 150 mV Output power THD = 10% THD = 1% - 20 15.6 - W Output power THD = 10%, RL = 4 Ω, VS = 12 V - 18 - W THD Total harmonic distortion Po = 0.1 to 4 W - 0.02 - % ISC Short-circuit output current - 3.0 3.5 CT Crosstalk f = 1 kHz f = 10 kHz 55 - 70 60 - dB Rin Input impedance - 10 15 - kΩ Gv Voltage gain - 25 26 27 dB Gv Voltage gain match - - - 0.5 dB EN Input noise voltage Rgen = 0, f = 22 Hz to 22 kHz - 3.5 - µV SVR Supply voltage rejection Rgen = 0, f = 300 Hz, CSVR = 470 µF 50 - - dB ASTBY Standby attenuation Po = 1 W 80 90 - dB ISTBY Current consumption in standby VSTBY = 0 to 1.5 V - - 100 µA ST_BY IN threshold voltage - - - 1.5 V ST_BY OUT threshold voltage - 3.5 - - V Po VSB Doc ID 16988 Rev 2 A 9/26 Electrical specifications Table 6. Symbol ISTBY 10/26 STA541SA Electrical characteristics (continued) Parameter Test condition Pin ST-BY current Min Typ Max Unit Play mode, VSTBY = 5 V - - 50 µA Max driving current under fault - - 5 mA Icd_off Clipping detector output average current THD = 1% - 90 - µA Icd_on Clipping detector output average current THD = 5% - 160 - µA VDIAG Saturation voltage on pin DIAG IDIAG = 1 mA sinking - - 0.7 V TW Thermal warning - - 140 - °C TM Thermal muting - - 150 - °C TS Thermal shutdown - - 160 - °C Doc ID 16988 Rev 2 STA541SA Characterization curves 3 Characterization curves 3.1 For 4-Ω loads Figure 3. Output power vs supply voltage Figure 4. RL = 4 Ω f = 1 kHz Tamb = 25 °C Quiescent current vs supply voltage RL = 4 Ω Tamb = 25 °C 10% THD 1% THD Figure 5. Efficiency, device dissipation vs output power Figure 6. Total harmonic distortion vs output power 10 5 THD % 2 1 η RL = 4 Ω VS = 12 V Tamb = 25 °C f = 15 kHz 0.5 RL = 4 Ω VS = 12 V f = 1 kHz Tamb = 25 °C 0.2 f = 100 Hz 0.1 f = 1 kHz 0.05 0.02 0.01 100 Figure 7. 200 500 1 2 5 Power out, W 10 20 30 Crosstalk vs frequency 0 -10 -20 Crosstalk -30 dB RL = 4 Ω VS = 12 V f = 1 kHz Po = 1 W Tamb = 25 °C Specification: < -45 dB -40 -50 -60 -70 -80 -90 -100 -110 -120 20 50 100 200 500 1k 2k Frequency, Hz 5k 10k 20k Doc ID 16988 Rev 2 11/26 Characterization curves STA541SA 3.2 For 8-Ω loads Figure 8. Output power vs supply voltage Figure 9. RL = 8 Ω f = 1 kHz Tamb = 25 °C Quiescent current vs supply voltage RL = 8 Ω Tamb = 25 °C 10% THD 1% THD Figure 10. Efficiency, device dissipation vs output power Figure 11. Total harmonic distortion vs output power 10 THD % Pd 5 RL = 8 Ω VS = 17 V Tamb = 25 °C 2 1 0.5 η f = 15 kHz 0.2 RL = 8 Ω VS = 17 V f = 1 kHz Tamb = 25 °C 0.1 f = 100 Hz 0.05 f = 1 kHz 0.02 0.01 0.1 Figure 12. Crosstalk vs frequency 0.2 0.5 1 2 5 Power output, W 10 20 30 Figure 13. Power supply rejection ratio vs frequency 0 0 -10 RL = 8 Ω VS = 17 V f = 1 kHz Po = 1 W Tamb = 25 °C Specification: < -45 dB -20 Crosstalk -30 dB 5 10 PSRR dBrA 15 RL = 8 Ω VS = 17 V Vr = 500 mV RMS Tamb = 25 °C Specification: > 50 dB 20 -40 25 -50 30 -60 35 -70 40 45 -80 50 -90 55 -100 60 -110 -120 12/26 65 20 50 100 200 500 1k 2k Frequency, Hz 5k 10k 20k Doc ID 16988 Rev 2 70 20 50 100 200 500 1k 2k Frequency, Hz 5k 10k 20k STA541SA Applications Figure 14. Applications circuit 6 6## '.$ + N& U& $)!'./34)#3 N& ).054 ).054 + $ )! ' 6## ). 6## /54 34!.$"9 34"9 /54 U& /54 3'.$ 34!3! ). /54 N& 4 Applications /54 362 U& /54 0'.$ Doc ID 16988 Rev 2 13/26 Demonstration board 5 STA541SA Demonstration board Figure 15. Demonstration board schematic N2 R8 1 5V D1 1.5 k FOR STA 541 2 5V1 DIAG C6 J3 R3 + C5 470 uF 25 V R4 C8 6R8 100 nF R5 C9 6R8 R6 100 nF C10 6R8 100 nF R7 C11 6R8 100 nF 100 nF 5V 10 k C1 4 3 220 nF 4 IN1 N1 IN2 3 1 1 2 C13 100 pF 2 S1 10 k 3 1 2 R2 S2 10 k FOR TDA7266SA STBY C3 10 uF 10 V 5V 7 OUT2+ 6 FOR STA541 J1 5 J2 8 C4 IC1 OUT1STA541SA (TDA7266SA) + PGND 10 uF 10 V C7 14/26 15 Doc ID 16988 Rev 2 OUT2- 14 N.C. 2 1 OUT1 2 MUTE (TDA7266SA) SVR (STA541SA) N3 1 SGND 12 220 nF 13 VCC OUT1+ IN2 R1 3 VCC C12 100 pF 9 C2 10 IN1 DIAG 11 N4 1 2 OUT2 STA541SA Demonstration board Figure 16. PCB layout Silkscreen (top) Top copper Bottom copper Doc ID 16988 Rev 2 15/26 Thermal information 6 STA541SA Thermal information In order to avoid the premature onset of the thermal protection, see Figure 6: Electrical characteristics on page 9, it is necessary to calculate the required thermal resistance, Rth_HS, for the heatsink. The parameters that influence the calculation are: ● maximum power dissipated in the device (PdMAX) ● maximum thermal resistance junction to case (Rth_j-case) ● maximum ambient temperature TambMAX There is also an additional term that depends on the quiescent current, Iq. 6.1 Heatsink specification examples 6.1.1 Rth_HS calculation Given that VS = 17 V, RL = 2x 8 Ω , PoutMAX = 2 x 20 W then the maximum power dissipated in the device is: PdMAX = 2 * (2 * VS / (π2 * RL)) = 2 * 7.32 = 14.6 W Using this value the required thermal resistance of the heatsink can be determined: Rth_HS = (150 - TambMAX) / PdMAX - Rth_j-case = (150 - 70) / 14.6 - 2.5 = 3.0 °C/W 6.1.2 Calculations using music power The thermal resistance value calculated in the above example specifies a heatsink capable of sustaining the maximum dissipated power. Realistically, however, and as explained in the Applications note (AN1965), the heatsink can be smaller when the application is musical content. When music power is considered the resulting dissipation is about 40% less than the calculated maximum. Thus, a smaller or cheaper heatsink can be employed. Using the values in the previous example, the maximum dissipated power reduces to: PdMAX = 14.6 - 40% = 8.8 W leading to a heatsink thermal resistance of Rth_HS = 6.6 °C/W. 16/26 Doc ID 16988 Rev 2 STA541SA Practical information 7 Practical information 7.1 Internally fixed gain The advantages in internally fixing the gain to 26 dB are: 7.2 ● components and space saving ● output noise, supply voltage rejection and distortion optimization. Silent turn on/off and muting/standby function The standby mode can be easily activated by means of a CMOS logic level applied to pin STBY through a RC filter. In standby, the device is turned of, drawing typically 1 mA from the supply and the output attenuation is 80 dB minimum. All switch-on and switch-off operations are virtually pop-free. Furthermore, at turn-on the device stays muted for a time determined by the value of the capacitor on pin SVR. This prevents transients coming from previous stages which otherwise could produce unpleasant acoustic effects at the speakers. 7.3 Driving circuit for standby mode Some precautions need to be taken when designing the driving circuit for pin 7, STBY. For instance, the pin cannot be directly driven by a voltage source having a current capability higher than 5 mA. In practical cases a series resistor must be inserted, giving it the double purpose of limiting the current at pin 7 and to smooth down the standby on/off transitions. When done in combination with a capacitor it prevents output pop. A capacitor of at least 100 nF from pin 7 to SGND is necessary to ensure correct turn-on (see also Figure 14: Applications circuit on page 13). Doc ID 16988 Rev 2 17/26 Practical information STA541SA 7.4 Built–in protection 7.4.1 Diagnostic facilities (pin 10) The STA541SA is equipped with diagnostic circuitry that is able to detect the following events: ● clipping of the output signal ● thermal shutdown ● output fault: – short circuit to ground – short circuit to supply – soft short circuit at turn-on The event is signalled when the open collector output of pin 10 (DIAG) begins to sink current. 7.4.2 Short-circuit protection Reliable and safe operation in the presence of all kinds of output short circuit is assured by the built-in protection. As well as the AC/DC short circuit to GND and to VS, and across the speaker, there is a soft short-circuit condition which is signalled on pin DIAG during the turn-on phase to verify output circuit integrity in order to ensure correct amplifier operation. As mentioned previously, it is important to limit the external current driving pin STBY to 5 mA, the reason being that the associated circuitry is normally disabled with currents greater than 5 mA. 7.4.3 Clipping detection Figure 17. Clipping detection waveforms Vo Audio output signal Iclip Clipping detector output current Time 0 A gain-compression function is initiated whenever the amplifier is overdriven. When a certain distortion level is reached at each output, pin 10 starts to sink current. 18/26 Doc ID 16988 Rev 2 STA541SA 7.4.4 Practical information Thermal shutdown With the thermal shutdown feature the diagnostics output on pin 10 signals the closeness of the junction temperature to the shutdown threshold. Typically, current sinking at pin 10 starts approximately 10 °C before the shutdown temperature is reached. Figure 18. Configuration of pin DIAG R 10 VREF Vpin10 STA541SA Figure 19. Fault waveforms on pin DIAG STBY pin voltage 2V t OUT to Vs short Output waveform Soft short t OUT to GND short Correct turn-on Vpin10 Fault detection t Check at turn-on (rest phase) D05AU1603mod Doc ID 16988 Rev 2 Short to GND or to Vs 19/26 Practical information 7.5 STA541SA Handling the diagnostic information As different diagnostic information (clipping detection, output fault, approaching thermal shutdown) becomes available at pin 10 so the behavior of the signal at this pin changes. In order to discriminate the event the signal on pin 10 must be interpreted correctly. Figure 20 shows a combination of events on the output waveform and the corresponding output on pin 10. These events could be diagnosed based on the timing of the output signal on pin 10. For example, the clip-detector signalling under fault conditions could produce a low level for a short time. On the other hand, an output short circuit would probably produce a low level for a much longer time. With these assumptions, an interface circuit based on the one shown in Figure 21 could differentiate the information and flag the appropriate circuits. Figure 20. Waveforms STBY PIN VOLTAGE t Vs OUTPUT WAVEFORM t Vpin 10 WAVEFORM t CLIPPING D05AU1604mod SHORT TO GND OR TO Vs THERMAL PROXIMITY Figure 21. Interface circuit diagram VREF 10 R1 Clip detector (to gain compressor / tone control) R2 VREF1 STA541SA VREF2 R1 << R2 VREF > VREF1 >> VREF2 20/26 Doc ID 16988 Rev 2 Fault, thermal shutdown (to power supply section, voltage regulator, flashing system) STA541SA 7.6 Practical information PCB ground layout The device has two distinct ground pins, PGND (power ground) and SGND (signal ground) which are disconnected from each other at chip level. For superior performance the pins PGND and SGND must be connected together on the PCB by low-resistance tracks. For the PCB ground configuration, a star-like arrangement, where the center is represented by the supply-filtering electrolytic capacitor ground, is recommended. In an arrangement such as this at least two separate paths must be provided, one for PGND and one for SGND. The correct ground assignments are as follows: ● ● on SGND: – standby capacitor (pin 7, or any other standby driving networks) – SVR capacitor (pin 5), to be placed as close as possible to the device – input signal ground (from active/passive signal processor stages) on PGND: – 7.7 power supply filtering capacitors for pins 3 and 13; the negative terminal of the electrolytic capacitor(s) must be directly tied to the battery negative line and this should represent the starting point for all the ground paths. Mute function If the mute function is desired, it can be implemented on pin 5, SVR, as shown in Figure 22. Figure 22. Optional mute function circuit IN BRIDGE R1 3.3K MUTE 5V 0 PLAY 0.47μF R2 10K 470μF 12 11 STA541SA 56 99 88 15 10 14 DIAGNOSTICS Vpin5 > 0.6 V: mute off Vpin5 < 0.2 V: mute on D06AU Using a different value for R1 than the suggested 3.3 kΩ, results in two different situations: ● ● R1 > 3.3 kΩ: – pop noise improvement – lower mute attenuation R1 < 3.3 kΩ: – pop noise degradation – higher mute attenuation Doc ID 16988 Rev 2 21/26 Package mechanical data 8 STA541SA Package mechanical data The STA541SA is housed in a Clipwatt 15-lead split vertical package. Figure 23 shows the package outline and Table 7 gives the dimensions. Figure 23. Package outline 22/26 Doc ID 16988 Rev 2 STA541SA Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Table 7. Package dimensions Dimensions in mm Dimensions in inches Reference Notes Min Typ Max Min Typ Max A - - 3.2 - - 0.126 - B - - 1.05 - - 0.041 - C - 0.15 - - 0.006 - - D - 1.5 - - 0.059 - - E 0.49 - 0.55 0.019 - 0.021 - F 0.65 - 0.73 0.026 - 0.029 - F1 - - 0.1 - - 0.004 (1) G 1.14 1.27 1.40 0.045 0.050 0.055 - G1 17.57 17.78 17.91 0.692 0.700 0.705 - H1 - 12 - - 0.472 - - H2 - 18.6 - - 0.732 - - H3 19.85 - - 0.781 - - (2) L - 17.9 - - 0.705 - - L1 - 14.55 - - 0.573 - - L2 10.70 11.00 11.20 0.421 0.433 0.441 (2) L3 - 5.5 - - 0.217 - - M - 2.54 - - 0.1 - - M1 - 2.54 - - 0.1 - - R - 1.50 - - 0.059 - - R1 - 3.30 - - 0.130 - - R2 - 0.30 - - 0.012 - - R3 - 0.50 - - 0.019 - - S - 0.70 - - 0.028 - - V - 10 deg - - 10 deg - - Doc ID 16988 Rev 2 23/26 Package mechanical data Table 7. STA541SA Package dimensions (continued) Dimensions in mm Dimensions in inches Reference Notes Min Typ Max Min Typ Max V1 - 5 deg - - 5 deg - - V2 - 75 deg - - 75 deg - - 1. No intrusion allowed inwards the leads 2. H3 and L2 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side 24/26 Doc ID 16988 Rev 2 STA541SA 9 Revision history Revision history Table 8. Document revision history Date Revision Changes 27-Jan-2010 1 Initial release. 02-Apr-2012 2 Updated document status from preliminary to full production data Modifed VSTBY to VSB and updated parameters in Table 6 Doc ID 16988 Rev 2 25/26 STA541SA Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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