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February 2011 Doc ID 18376 Rev 1 1/47

AN3329

Application note

170 W power supply with PFC and standby supply for flat TV

using the L6564, L6599A, and Viper27LN

Introduction

This application note describes the characteristics and features of a 170 W, wide input

mains range, power-factor-corrected, demonstration board for flat TVs or industrial

applications. The electrical specifications are tailored to a typical flat TV.

The architecture is made up of three stages: a front-end PFC pre-regulator based on the

L6564 TM (transition mode) boost PFC controller and a downstream LLC resonant half

bridge converter stage, built around the new L6599A resonant controller, which provides two

regulated output voltages at 12 V and 24 V. In addition, a flyback-based standby supply

delivers 10 W to a 5 V output. Thanks to the chipset used, this design achieves very high

efficiency, compliant with ENERGY STAR

eligibility criteria (EPA rev. 2.0 EPS), as well as

very low input consumption during standby operation.

Figure 1. EVL170W-FTV: 170 W demonstration board

www.st.com

Summary of content (47 pages)

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AN3329 Application note 170 W power supply with PFC and standby supply for flat TV using the L6564, L6599A, and Viper27LN Introduction This application note describes the characteristics and features of a 170 W, wide input mains range, power-factor-corrected, demonstration board for flat TVs or industrial applications. The electrical specifications are tailored to a typical flat TV.
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Contents AN3329 Contents 1 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 6 2 Efficiency measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3 Harmonic content measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Functional check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Conducted emission pre-compliance test . . . . . . . . . . . . . . . . . . . .
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AN3329 List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Overall efficiency measured at different AC input voltages . . . . . . . . . . . . . . . . . . . . . . . . . 9 Bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 PFC coil winding data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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List of figures AN3329 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. Figure 24. Figure 25. Figure 26. Figure 27. Figure 28. Figure 29. Figure 30. Figure 31. Figure 32. Figure 33. Figure 34. Figure 35. Figure 36. Figure 37. Figure 38. Figure 39. Figure 40. Figure 41. Figure 42. Figure 43.
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AN3329 Figure 50. Figure 51. Figure 52. Figure 53. Figure 54. Figure 55. Figure 56. Figure 57. Figure 58. Figure 59. Figure 60. Figure 61. Figure 62. Figure 63. Figure 64. Figure 65. Figure 66. Figure 67. Figure 68. List of figures Startup by on-off signal at full load and 115 Vac - 60 Hz . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Startup by on-off signal at full load and 115 Vac - 60 Hz - L6599A signals . . . . . . . . . . . .
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Main characteristics and circuit description 1 AN3329 Main characteristics and circuit description The main features of the SMPS are: ● Universal input mains range: 90 ÷ 264 Vac - frequency 45 ÷ 65 Hz ● Output voltage 1: 24 V ± 5 % at 6 A for backlight and audio supply ● Output voltage 2: 12 V ± 3 % at 2 A for TV panel supply ● Output voltage 3: 5 V ± 2 % at 2 A for microprocessor supply ● Mains harmonics: acc.
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AN3329 Main characteristics and circuit description Resonant power stage The downstream converter features the ST L6599A, which embeds all the functions needed to drive properly the resonant converter with 50 % fixed duty cycle and variable frequency. The converter makes use of a transformer designed with the integrated magnetic approach, using the primary leakage as the resonant series inductance and the magnetizing inductance as the resonant shunt inductance.
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AN3329 2 Efficiency measurement Efficiency measurement Table 1 shows the overall efficiency, measured at different mains voltages. The full load efficiency is 90.09 % at 115 Vac, and 91.85 % at 230 Vac. Both values are considerably high and maintained high even decreasing the load as reported in Table 1. Measurements are also reported in the graph of Figure 3. Table 1. Overall efficiency measured at different AC input voltages Load = 100 % 5V 12 V 24 V Pout Pin Eff.
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Efficiency measurement AN3329 The average efficiency has been calculated according to ENERGY STAR 2.0 criteria. Results are summarized in Figure 3 and 4. Figure 3. Overall efficiency vs. output power Figure 4. $9* (IILFLHQF\ > @ 2YHUDOO (IILFLHQF\ > @ Average efficiency acc.
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AN3329 Harmonic content measurement 3 Harmonic content measurement The main purpose of a PFC pre-regulator is the input current shaping to reduce the harmonic content below the limits of the relevant regulations. This demonstration board has been tested according to the European standard EN61000-3-2 Class-D and Japanese standard JEITA-MITI Class-D, at full load and 75 W input power, at both the nominal input voltage mains. Figure 7 to Figure 10 show the test results.
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Harmonic content measurement AN3329 InFigure 11 and 12 the AC input voltage and current waveform at nominal input mains and full load are reported for reference. Figure 11. Input voltage and current at 100 Vac, full load CH3: AC input voltage CH4: input current 12/47 Figure 12.
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AN3329 4 Functional check Functional check Standby supply Some salient waveforms of the standby supply during full load operation are reported in Figure 13 and 14. This converter is based on the Viper27LN, a device integrating the controller and the MOSFET in a single DIP-7 package. The Viper27LN version operates in fixed frequency mode at about 60 kHz, and frequency jitter technique is implemented to reduce EMI noise.
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Functional check AN3329 Figure 15. Standby supply waveforms at 400 Vdc, full load CH1: DRAIN (pin #8) CH3: CONT (pin #3) CH2: VDD (pin #2) CH4: FB (pin #4) Figure 16. Standby supply output rectifiers PIV at 400 Vdc, full load CH3: PIV D22 CH4: PIV D18 In Figure 17 the 5 V standby output voltage ripple has been captured during operation at 115 Vac of the standby converter only. Ripple and noise measured at full load are very limited.
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AN3329 Functional check Figure 19 and Figure 20 illustrate the waveforms during light load operation. Viper27LN operates in burst-mode, with just a few pulses per burst, minimizing switching losses and therefore improving efficiency under light load operation, making it suitable for equipment with low standby consumption requirements. Figure 19. Standby supply burst mode Figure 20.
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Functional check AN3329 and switching starts again. This protection and restart sequence lasts as long as the OVP condition is removed. It is important to highlight that the Viper27LN OVP protection, thanks to the internal logic, ensures a stable OVP intervention point, independent of the output load, even if the voltage sensing is done on auxiliary winding at primary side.
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AN3329 Functional check In Figure 26 details of Viper27LN operation at short detection is captured; once an output short-circuit is detected, an internal current source charges the device internal circuitry and stops the auxiliary converter operation until the VDD voltage drops down to VDD_RESTART (4.5 V). At that time the internal HV current source is activated and charges the VDD capacitor until it reaches the VDDon threshold, then the Viper27LN restarts switching via a soft-start cycle.
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Functional check AN3329 Power factor corrector stage Figure 29 shows the PFC MOSFET's drain voltage, inductor current, and voltages on the CS (#4) and MULT (#3) pins along a line half-period at 115Vac. Low current distortion and high power factor are achieved as the peak inductor current waveform follows the MULT pin. THD (total harmonic distortion) is considerably reduced by the L6564 THD optimizer. In Figure 30 the same signals are captured at the top of the input sine wave.
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AN3329 Functional check Figure 31. PFC Vds and inductor current at 230 Vac - 50 Hz, full load Figure 32. PFC Vds and inductor current at 230 Vac - 50 Hz, full load - detail CH1: Q1 drain voltage CH3: CS (pin #4) CH1: Q1 drain voltage CH3: CS (pin #4) CH2: MULT (pin #3) CH4: L1 inductor current CH2: MULT (pin #3) CH4: L1 inductor current L6564 signals are shown in Figure 33 and 34 for reference. Figure 33. L6564 signals-1 at 115 Vac - 60 Hz, full load Figure 34.
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Functional check AN3329 Figure 35. PFC signals-1 at 115 Vac - 60 Hz, full load Figure 36.
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AN3329 Functional check Resonant stage Some waveforms relevant to the resonant stage during steady-state operation are reported in Figure 37, 38, 39, 40, and 41. The switching frequency at full load and nominal input voltage is around 75 kHz, in order to achieve a good trade-off between transformer losses and size. Figure 37 shows the resonant ZVS operation.
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Functional check AN3329 Figure 39. Output rectifiers PIV waveforms CH1: D4 anode voltage CH3: D9A anode voltage CH2: D11 anode voltage CH4: D9B anode voltage No load operation In Figure 40 and 41 operation at no load is shown. This check has been done for reference only, as typically a TV SMPS never works in such conditions. As seen, PFC is working in burst-mode, while the resonant stage is operating in continuous switching.
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AN3329 Functional check Dynamic load operation and output voltage regulation Figure 42 and 43 show the output voltage regulation in the case of load transients on both the resonant stage outputs. The waveforms have been captured applying a load transient from 0 to full load to one output while the other is delivering full load.
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Functional check AN3329 Figure 44. 12 V - 2 A; 24 V 0 ÷ 6 A - 300 Hz transition at 115 Vac - 60 Hz CH2: +12 V O/P voltage CH3: +24 V O/P voltage CH4: +24 V O/P current Figure 45. 24 V - 6 A; 12 V 1 ÷ 2 A - 300 Hz transition at 115 Vac - 60 Hz CH2: +12 V O/P voltage CH3: +24 V O/P voltage CH4: +12 V O/P current Overcurrent and short-circuit protection The L6599A is provided with a current sensing input (pin #6, ISEN) and a dedicated overcurrent management system.
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AN3329 Functional check Figure 46. 12 V short-circuit at full load and 115 Vac - 60 Hz CH1: HB voltage CH3: ISEN (pin #6) CH2: DELAY (pin #2) CH4: 12 V O/P current Figure 48. 24 V short-circuit at full load and 115 Vac - 60 Hz CH1: HB voltage CH3: ISEN (pin #6) CH2: DELAY (pin #2) CH4: 12 V O/P current Figure 47. 12 V short-circuit at full load and 115 Vac - 60 Hz - detail CH1: HB voltage CH4: C39 current CH3: ISEN (pin #6) Figure 49.
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Functional check AN3329 Startup Figure 50 shows waveforms during startup at 115 Vac and full load of PFC and resonant stages. It is possible to note the sequence of the two stages; once the on/off signal is asserted high, voltage on C44 increases up to the Vcc turn-on thresholds of the L6564 and L6599A. The PFC starts first and its output voltage starts increasing from the mains rectified voltage to its nominal value.
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AN3329 Functional check Figure 52. Startup by on/off signal at full load Figure 53. Turn-off at full load and 115 Vac - 60 and 115 Vac - 60 Hz O/P voltage Hz by on/off signal rising CH1: On/off signal CH3: 24 V output CH2: CSS (pin #1) CH4: 12 V output CH1: HB voltage CH3: V_C44 CH2: PFC drain CH4: On/off signal Overvoltage protection Figure 54 and 55 show the OVP response, observed opening the resonant stage feedback loop.
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Functional check AN3329 Mains sags/dips Figure 56 and 57 show the converter behavior in the case of half-cycle (8.3 ms) or a complete cycle (16.6 ms) mains dip. As can be noted, in both cases the PFC output voltage drops but the L6599A still works correctly, and output voltages do not show any disturbance, therefore demonstrating a good immunity of the circuit against mains dips. Figure 56. Half cycle mains dip at full load and Figure 57.
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AN3329 5 Conducted emission pre-compliance test Conducted emission pre-compliance test Figure 58, 59, 60, and 61 are the peak measurements of the conducted emission noise at full load and nominal mains voltages. The limits shown in the diagrams are EN55022 ClassB, which is the most popular norm for domestic equipment and has more severe limits compared to Class-A, dedicated to IT technology equipment. As visible in the diagrams, in all test conditions the measurements are far below the limits. Figure 58.
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Conducted emission pre-compliance test Figure 60. CE peak measurement at 230 V - 50 Hz and full load - phase wire Figure 61.
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AN3329 Bill of materials 6 Bill of materials Table 2. Bill of materials Part type / Case style part value / package C1 2.2 nF C10 Des. Description Supplier DWG Y1 - safety cap. DE1E3KX222M MURATA 100 nF 0805 50 V Cercap - general purpose - X7R - 10 % KEMET C12 100 nF 1206 50 V Cercap - general purpose - X7R - 10 % KEMET C13 47 nF 0805 50 V Cercap - general purpose - X7R - 10 % KEMET C14 1000 µF - 35 V Dia.12x25 p.
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Bill of materials Table 2. AN3329 Bill of materials (continued) Part type / Case style part value / package C34 220 pF C35 Des. Description Supplier 0805 50 V Cercap - general purpose - COG - 5 % KEMET 4.7 nF 1206 50 V Cercap - general purpose - X7R - 10 % KEMET C36 220 pF 1206 500 V Cercap - 12067A221JAT2A - C0G - 5 % AVX C38 220 nF 0805 16 V Cercap - general purpose - X7R - 10 % KEMET C39 33 nF 5.0 x 18.0 p.
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AN3329 Table 2. Bill of materials Bill of materials (continued) Part type / Case style part value / package C62 10 µF - 50 V C63 Des. Description Supplier Dia 6.3X11 (MM) p. 2.5 mm Aluminium ELCAP - YXF series - 105°C Rubycon 10 nF 0805 50 V Cercap - general purpose - X7R - 10 % KEMET C64 1 nF 1206 100 V Cercap - general purpose - X7R - 10 % KEMET C65 220 pF 0805 50 V Cercap - general purpose - COG - 5 % KEMET C7 100 µF - 450 V Dia. 18x35 mm p.
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Bill of materials Table 2. AN3329 Bill of materials (continued) Part type / Case style part value / package HS2 Heatsink DWG Heatsink for Q3 and Q6 HS3 Heatsink DWG Heatsink for D4 and D11 HS4 Heatsink DWG Heatsink for D18 HS5 Heatsink DWG Heatsink for D9 J1 09-65-2038 DWG Connector-pitch 3.96 mm - 2 pins (1 removed) KK Molex J2 280385-2 DWG Connector - p. 2.54 mm - 8 x 2 rows - MODU-II AMP J3 280384-2 DWG Connector - p. 2.
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AN3329 Table 2. Bill of materials Bill of materials (continued) Part type / Case style part value / package L2 3 mH L3 Des. Description Supplier DWG 1606.0007 EMI filter MAGNETICA 70 µH 26x13 mm 2190.0001 DM inductor MAGNETICA L4 2.2 µH DIA12 p. 5 mm 10610041 - 3 µH - 11 A inductor MAGNETICA L5 1 µH DIA8 p. 5 mm 10710083 - 1 µ - 5 A inductor MAGNETICA L6 1 µH DIA8 p. 5 mm 10710083 - 1 µ - 5 A inductor MAGNETICA PCB PCB rev.
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Bill of materials Table 2. AN3329 Bill of materials (continued) Part type / Case style part value / package R32 22 Ω R33 Des. Description Supplier 0805 SMD standard film res - 1/8 W - 5 % - 250 ppm/°C VISHAY 200 kΩ 0805 SMD standard film res - 1/8 W - 1 % - 100 ppm/°C VISHAY R34 10 Ω 0805 SMD standard film res - 1/8 W - 5 % - 250 ppm/°C VISHAY R36 13 kΩ 0805 SMD standard film res - 1/8 W - 1 % - 100 ppm/°C VISHAY R37 6.
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AN3329 Table 2. Bill of materials Bill of materials (continued) Part type / Case style part value / package R7 2.2 MΩ R70 Des. Description Supplier 1206 SMD standard film res - 1/4 W - 1 % - 100 ppm/°C VISHAY 10 kΩ 0805 SMD standard film res - 1/8 W - 5 % - 250 ppm/°C VISHAY R71 4.
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Bill of materials Table 2. Des. AN3329 Bill of materials (continued) Part type / Case style part value / package Description Supplier T1 1860.0014 Rev. 0.1 Resonant transformer MAGNETICA T2 1715.0059 Standby flyback TRAFO MAGNETICA U1 L6564D SSOP10 10-pin transition mode PFC controller STMicroelectronics U2 L6599AD SO-16 Improved HV resonant controller STMicroelectronics U3 SFH610A-2 DIP-4 10.
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AN3329 7 PFC coil specifications PFC coil specifications General description and characteristics ● Application type: consumer, home appliance ● Transformer type: open ● Coil former: vertical type, 6+6 pins ● Max. temp. rise: 45 ºC ● Max. operating ambient temperature: 60 ºC ● Mains insulation: n.a. ● Unit finishing: varnished Electrical characteristics ● Converter topology: boost, transition mode ● Core type: PQ32/20-PC44 or equivalent ● Min.
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PFC coil specifications AN3329 Mechanical aspect and pin numbering ● Maximum height from PCB: 22 mm ● Coil former type: vertical, 6+6 pins (pins #3, 4, 7, 12 are removed) ● Pin distance: 5.08 mm ● Row distance: 30.5 mm Figure 63. PFC coil mechanical aspect 33 MAX 35 MAX 21 MAX 6 8 1 30.5 2 9 5 6 ∅ 0.8 (X7) RECOMMENDED PCB HOLE ∅1.2 (X7) 1 2 11 9 8 5 5.
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AN3329 8 Resonant power transformer specifications Resonant power transformer specifications General description and characteristics ● Application type: consumer, home appliance ● Transformer type: open ● Coil former: horizontal type, 7+7 pins, two slots ● Max. temp. rise: 45 ºC ● Max. operating ambient temperature: 60 ºC ● Mains insulation: acc. to EN60065 Electrical characteristics ● Converter topology: half bridge, resonant ● Core type: ETD34-PC44 or equivalent ● Min.
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Resonant power transformer specifications Table 4. AN3329 Resonant transformer winding data (continued) Pins Winding DC resistance Number of turns Wire type 8 - 11 SEC - A 4.4 mΩ 2 90xφ 0.1 mm – G1 9 - 10 SEC - B 4.4 mΩ 2 90xφ 0.1 mm – G1 10 - 13 SEC - C 4.4 mΩ 2 90xφ 0.1 mm – G1 12 - 14 SEC - D 4.4 mΩ 2 90xφ 0.1 mm – G1 Mechanical aspect and pin numbering ● Maximum height from PCB: 30 mm ● Coil former type: horizontal, 7+7 pins (pins #1 and 7 are removed) ● Pin distance: 5.
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AN3329 9 Auxiliary flyback transformer specifications Auxiliary flyback transformer specifications General description and characteristics ● Application type: consumer, home appliance ● Transformer type: open ● Winding type: layer ● Coil former: horizontal type, 4+5 pins, two slots ● Max. temp. rise: 45 ºC ● Max. operating ambient temperature: 60 ºC ● Mains insulation: acc.
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Auxiliary flyback transformer specifications AN3329 Figure 66. Transformer construction 0RIMAR 6 6 !UX !- V Winding characteristics Table 6. Standby transformer winding data Pins Winding O/P rms current Number of turns Number of layers Wire type 4-5 Primary 0.17 ARMS 93 2 G2 - φ 0.224 mm 2-1 Aux 0.05 ARMS 18 spaced 1 G2 - φ 0.224 mm 6-8 7-9 5V 2.6 ARMS (TOTAL) 6 1 TIW - 2 x φ 0.7 mm in parallel Figure 67.
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AN3329 Auxiliary flyback transformer specifications Figure 68. Mechanical aspect and pin numbering 0$; 0,1 0$; 0$; 0$; 3LQ LV PLVVLQJ ; 5(&200(1'(' 3&% +2/( ; %27720 9,(: 3,1 6,'( !- V Manufacturer ● MAGNETICA ● Inductor P/N: 1715.
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Revision history 10 AN3329 Revision history Table 7. 46/47 Document revision history Date Revision 25-Feb-2011 1 Changes Initial release.
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AN3329 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.