APPLICATION NOTE Application information for TDA6107JF/07AJF/08JF/08AJF triple video output amplifiers AN10227-01 Version 1.2 July 2004 Philips Semiconductors E W Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 ABSTRACT This report gives a description of the application aspects of the TDA6107JF/07AJF/08JF/08AJF Philips Electronics N.V. 2004 All rights are reserved. Reproduction in whole or in part is prohibited without the prior consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights. 2 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 APPLICATION NOTE Application information for TDA6107JF/07AJF/08JF/08AJF triple video output amplifiers AN10227-01 Authors: Roland Peters Pieter van Oosten Systems & Applications, Innovation Center Nijmegen, Philips Semiconductors, Consumer Businesses Keywords Triple video amplifier Black current stabilisation Robust against flashover Very simple application Fixed gain Date: July 2004 3 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 Summary In this application note you can find an application description of the triple video output amplifiers with the type numbers TDA6107JF, TDA6107AJF, TDA6108JF and TDA6108AJF. All types include three video output amplifiers in a DBS9MPF package, version SOT111-1. The types are all functional the same, but the bandwidth level and gain level is different. A description of the differences between the types is given. Furthermore the video amplifiers are provided with a black current measurement output for automatic black current stabilisation. An optimal application and PCB-layout for flash protection is given. 4 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TABLE OF CONTENTS: 1. INTRODUCTION .................................................................................................... 7 2. FUNCTIONAL PIN DESCRIPTION. ....................................................................... 8 2.1 Input pins 1, 2 and 3. ........................................................................................................................ 8 2.2 Pin 4. .................................................................................................................................................. 8 2.3 Pin 5. .................................................................................................................................................. 9 2.4 Pin 6. ................................................................................................................................................ 10 2.5 Output pins 7, 8 and 9 .................................................................................................................... 10 3. DISSIPATION AND HEATSINK CALCULATION ................................................ 11 3.1 Dissipation ...................................................................................................................................... 11 3.2 Heatsink calculation ....................................................................................................................... 12 4. FLASHOVER PROTECTION ............................................................................... 14 4.1 Checklist TDA6107JF / 07AJF for optimal flashover robustness.............................................. 15 4.2 Checklist TDA6108JF / 08AJF for optimal flashover robustness.............................................. 19 5. THE TDA6107JF / 07AJF AND TDA6108JF / 08AJF REFERENCE / DEMO BOARD ......................................................................................................................... 23 5 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 LIST OF FIGURES: Figure 1: Internal circuitry ....................................................................................................................................8 Figure 2: Switch off behaviour...........................................................................................................................10 Figure 3: Thermal resistance..............................................................................................................................12 Figure 4: Power dissipation as a function of the input frequency .................................................................13 Figure 5: Grounding of aquadag and CRT board.............................................................................................14 Figure 6: Application diagram of the TDA6107JF/07AJF ................................................................................15 Figure 7: Optimal CRT PCB-layout with TDA6107JF/07AJF ...........................................................................18 Figure 8: Application diagram TDA6108JF/08AJF ...........................................................................................19 Figure 9: Optimal CRT PCB-layout with TDA6108JF/08AJF ...........................................................................22 Figure 10: Application diagram of the TDA6107JF / 07AJF reference / demo board ...................................23 Figure 11: TDA6107JF / 07AJF reference / demo board layout ......................................................................24 Figure 12: Components TDA6107JF / 07AJF reference / demo board...........................................................25 Figure 13: Application diagram of the TDA6108JF / 08AJF reference / demo board ...................................26 Figure 14: TDA6108JF / 08AJF reference / demo board layout ......................................................................27 Figure 15: Components TDA6108JF / 08AJF reference / demo board...........................................................28 6 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 1. INTRODUCTION This application note provides a design guide for successful implementation and design-in of the TDA6107JF/07AJF/08JF/08AJF family. It is meant as a complement of the data sheet, and should not be used without the specific datasheet of the video amplifier that is being designed in. The TDA6107JF/07AJF/08JF/08AJF family consists of a complete range of triple video amplifiers to cover the low and midrange TV sets. All types include three video output amplifiers in a DBS9MPF package, version SOT111-1. The features of these amplifiers are: • • • • • • • Single package for three amplifiers One supply voltage Fixed gain (less spread and saving external resistors) Black current stabilisation output Internal flash protection Low power dissipation Internal thermal protection Table 1 gives an overview of the bandwidth and gain factors. Type TDA6107JF TDA6107AJF TDA6108JF TDA6108AJF Typical Gain Large signal bandwidth 51 81 51 81 4.5 MHz 4.5 MHz 8.0 MHz 8.0 MHz Table 1 7 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 2. FUNCTIONAL PIN DESCRIPTION. The internal circuitry of the video amplifier can be seen as an operational amplifier with negative feedback, see Figure 1 below. TDA610XX Rf Vin – Ri Vout Ra + + Vref = 2.5V – Figure 1: Internal circuitry 2.1 Input pins 1, 2 and 3. These pins are the inputs of channel 1, 2 and 3. The internal resistor Ri is given in the datasheet, and can be used to calculate Ra and Rf. This is normally not useful, however if adding external resistors for EMC reasons or suppressing interference it can be useful. The gain and the gain difference depend on the ratio between Rf and Ri, so if the value of Ri changes due to adding external resistors, the gain will change. The new gain can be calculated with the following equation. GNEW = GSPEC * RISPEC RISPEC + RS Where: GNEW GSPEC RISPEC RS is the new gain. is the typical gain mentioned in the datasheet. is the typical input resistance as mentioned in the datasheet. is the added series resistance. We do not recommend to add these extra series resistance, because there will be a bigger spread in gain between products due to the spread in Ri. Furthermore adding extra series resistance makes the step response worse. This means that the ringing and overshoot will increase. 2.2 Pin 4. This pin is the ground connection of the amplifier. It should be directly connected to the small signal GND, with a trace as short as possible (see chapter 4). 8 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 2.3 Pin 5. Pin 5 is the black current measurement output of the amplifier. The current flowing out of this pin is equivalent to the sum of the currents flowing in the cathodes of the CRT (between certain limits). This output is intended to be used in the cathode calibration loop (black current stabilization), but can also be used for discharging the CRT after set switch-off (except the TDA6108JF). This pin can be directly connected to the TV-signal processor, but for stability it is allowed to add a series resistance and a capacitor to ground. When calculating this RC combination, keep in mind that the output must be stable within 39µs (due to timing of the TV-signal processor) after start of the measurement line. Another possibility to minimize disturbances is to shield the return wire and to embed the Iom track in a ground plane on the PCB layout. The maximum average current for the TDA6108AJF must be limited to 5.6mA; therefore a series resistance must be used. An internal zener diode is connected to the Iom pin, and limits the voltage of this output between 6V and 10V. By means of this data, the minimal value of the resistor can be calculated with: R min = Vomclamp max − Vbias Iom max Where: VOMCLAMPmax VBIAS IomMAX is the maximal clamp voltage of the internal zener diode is the minimal bias voltage of the Iom input of the TV-signal processor is the maximal allowed average current of the RGB amplifier For the TDA110XXH/TDA120XXH family (UOCIII series) this results in a minimal resistance of: R min = 10V − 3V = 1250Ω 5.6mA The maximal value of this resistor is determined by the TV-signal processor. If the resistor value is chosen too high, the feedback current will be influenced. As the voltage drop across the resistor will be too high and thus the zener diode will conduct and therefore a part of the current will flow through the zener diode instead of into the TV-signal processor. The maximal value can be calculated by: Vomclamp min − Vbias R max = Imax Where: VOMCLAMPmin VBIAS IMAX is the minimal clamp voltage of the internal zener diode is the minimal bias voltage of the Iom input of the TV-signal processor is the maximal current running into the TV-signal processor during discharge or during a measuring line (if no discharge function is used). For the TDA110XXH/TDA120XXH family (UOCIII series) this results in a maximal resistance of: R max = 6 − 3V = 3kΩ 1mA 9 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TDA6107A / TDA6108A – Vin + + Vref – 6V-10V Iom 1k2 560pF & Fixed current discharge 1 mA During a transition of the video signal, there will be some voltage spikes on the Iom output. These spikes are a result of fast charging and discharging parasitic capacitance. The amplitude of the spikes is limited to the clamp voltage of the internal zener diode and will cause no problems. 2.4 Pin 6. This pin is the VDD connection, it must be decoupled to ground with a capacitor and an electrolytic capacitor to ground, to protect the video amplifier for flashover, see the chapter 4 2.5 Output pins 7, 8 and 9 These are the outputs of channel 3, 2 and 1, with a defined switch-off behavior. These pins stay under control of the input voltage even for low values of VDD. This means that the output voltage VOC follows the discharge curve of VDD when the TV set is switched off. See Figure 2: Switch off behaviour. 1 2 CH 1 50V CH2 5 0V M 250m s C H 1 Figure 2: Switch off behaviour 10 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 3. DISSIPATION AND HEATSINK CALCULATION 3.1 Dissipation The total amount of dissipation in the triple video amplifiers consists of a sum of two powers. The first part is the static dissipation, which is the result of the quiescent current and can be calculated with: PSTAT = VDD * IDD + 3 * (VOCdc * IOCdc ) Where: VDD IDD VOCdc IOCdc is the supply voltage. is the supply current. is the value of the cathode offset. is the value of the dc output current. The second part is the dynamic dissipation, which is a result of continuously switching of the internal circuitry and thus charging and discharging of on-chip parasitic and load capacitance. For a sinusoidal signal, it can be calculated with: PDYN 1 = 3 * VDD * CTOT * fIN * VOCpp * δ * fIN 1+ BL Where: VDD CTOT fIN VOCpp δ BL is the supply voltage. is the sum of the internal- and load capacitance. Frequency of the input signal. Peak to peak AC component of the output signal. Non-blanking duty cycle. Large signal bandwidth of the video amplifier. This formula however is not representative for a real condition in a TV set. A nominal TV picture consists of a complex variety of signals. If we would use these formulas to calculate a heatsink, the heatsink would be far too big and too expensive. So to calculate a proper heatsink, it is better to see what the video amplifier dissipates in a worst-case condition. Figure 4 shows the power dissipation as a function of the input frequency. The test conditions for these graphs are given in Table 3: Test conditions. All video amplifiers are equipped with an internal thermal protection. This circuit gives a decrease of the slew rate if the temperature of the die is higher than 130°C. This prevents thermal ageing and reduces the necessary heatsink size. Taking this into account, the worst-case condition whereby the slew rate should not be influenced is a multiburst video signal. So the heatsink should be calculated for this condition. 11 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 3.2 Heatsink calculation How the heatsink can be calculated is shown underneath. Ptot TJMAX − TA − (RTH , J − F + RTH , F − H ) RTH , H − A = PTOT Tj Rth,j-f Where: RTH,H-A RTH,J-F RTH,F-H TJMAX TA PTOT Rth,f-h is the thermal resistance from heatsink to ambient. is the thermal resistance from junction to fin. is the thermal resistance from fin to heatsink. is the maximum junction temperature. is the ambient temperature in a TV set. is the total of dissipated power. Rth,h-a Ta Figure 3: Thermal resistance The value for RTH,J-F can be found in the datasheet, which is 11K/W for the DBS9MPF (SOT111-1) package. The value for RTH,F-H depends on the mounting method and will be under normal conditions about 0.5K/W. TJMAX is the temperature where the internal thermal protection starts to operate, and is approximately 130°C. The maximum ambient temperature in a TV set can be about 65°C, and PTOT can be found in Figure 4. Using this equation for the TDA6108AJF, this would result in a heatsink with a thermal resistance of at least 13.9K/W. The power curves given in Figure 4, are typical values, considering this, we should subtract 2K/W because of the variation in power dissipation. To minimise the dissipated power, it is advised to use the supply voltage VDD as low as possible. Table 2 gives a summery for the recommended heatsink values. Amplifier type: TDA6107JF/TDA6107AJF TDA6108JF/TDA6108AJF Power (multiburst) Calculated heatsink value 1.9W 2.56W 21.5 K/W 12 K/W Table 2 12 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 Typical performance characteristics. Table 3: Test conditions VDD = 200V Type VOCdc = 100V VOCpp TDA6107JF/AJF TDA6108JF/AJF 100 100 δ=0.8 CTOT 4.5 pF 5.3 pF P=f(Fsin) (80% because of Fly Back) 4,00 TDA6108AJF 3,50 3,00 TDA6108JF Ptot (W) 2,50 2,00 TDA6107JF TDA6107AJF 1,50 1,00 0,50 0,00 0 1000 Nominal Picture 2000 3000 Multiburst 4000 Noise 5000 6000 7000 8000 F (kHz) Figure 4: Power dissipation as a function of the input frequency 13 9000 10000 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 4. FLASHOVER PROTECTION A picture tube has generally several high voltage discharges (flashovers) in its lifetime. During the flashovers, a high voltage will be present on the cathodes. The video amplifier must be protected from these flashovers. For optimal flashover protection the grounding wire from aquadag to CRT-board and from CRT-board to main board must be connected like in Figure 5 below. Vdd CRT-board C1 D1 100nF BAV21 250V C2 10uF 250V 6 7,(8,9) 3x EHT R1 100 ohm R FLASH KB video amplifier Spark gap KG G2 KR 4 G1 G3 f f aquadag To GND of main board close to LOT/FBT To GND of main board Figure 5: Grounding of aquadag and CRT board. The TDA6107JF / 07AJF does not need an external flash protection, when RFLASH is larger than 1k. The TDA6108JF / 08AJF always needs external flash protection to protect against flashovers. The external flash protection consists of an external diode D1 and external resistor R1. The diode clamps the output voltage to the VDD. To limit the diode current an external surge resistor (high voltage resistor) RFLASH must be used together with a 2kV spark gap. A more detailed description about the external flash protection is given in the checklist in the next paragraph: 4.1. 14 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 4.1 Checklist TDA6107JF / 07AJF for optimal flashover robustness C3 220pF - 4.7nF 250V 2 TV-signal processor Vi(2) R3 100 ohm R FLASH3 1k5 / 0.5W R2 100 ohm 8 Voc(2) R1 100 ohm 9 RFLASH2 1k5 / 0.5W 7 Voc(3) Vi(3) TDA6107JF/ 07AJF 1 C2 C4 10uF 220pF - 2.7nF 250V 250V D3 *1 BAV21 D2 BAV21 D1 BAV21 C1 100 nF VDD 6 250V 3 R4 47 ohm - 100 ohm RFLASH1 1k5 / 0.5W V Vi(1) Internal block diagram oc(1) 5 is drawn in the Iom datasheet on page 2 4 GND EHT KB KG KR f f C5 1nF 2kV *1 = D1,2,3 and R1,2,3 only needed when RFLASH1,2,3 =< 1k5 VDD = 200V G1 G2 G3 R5 1k5 / 0.5W = Small signal GND VG2 = Large signal GND Figure 6: Application diagram of the TDA6107JF/07AJF Checklist: TDA6107JF / 07AJF 1. 2. Recommended value / type Grounding of the CRT PCB-layout On the CRT PCB-layout the large signal GND must be isolated from the small signal GND. So pin 4 GND of the TDA6118JF must not be connected directly to the spark gap GND (focus, G2 and cathodes) of the CRTsocket. See Figure 7. It is also strongly recommended to place no components (capacitors, resistors and coils) between the small signal GND and the large signal GND. See Figure 7. 15 Explanation Prevents that large flashover voltage / current peaks can directly flow through the small signal GND. Prevents that large flashover voltage / current peaks can directly flow through the small signal GND Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers 3. 4. 5. 6. 7. 8. 9. Application Note AN10227-01 Ground loops in the small Ground loops could reveal in large voltage signal GND must be avoided. peaks due to long tracks. V = L*di/dt So pin 4 GND must have one generated during a flashover connection to the connector to the main board. See Figure 7. Small signal ground track To avoid current / voltage peaks at pin 4 must be around the GND during a flashover. TDA6107JF / 07AJF. See Figure 7. External protection components, decoupling circuits High frequency decoupling 100nF / 250V C1 has to reduce fast large voltage peaks capacitor, C1 between pin 6 VDD and pin 4 GND due to V = L*di/dt. (See points x + x for optimal PCB layout) Low frequency current peaks from a Low frequency decoupling • 4.7uF / 250V for flashover flows via D1, D2 and D3 into C2. capacitor, C2 ≤21 inch picture tube size • 10uF / 250V for >21 inch picture tube size High frequency decoupling 220pF - 2.7nF / 250V C3 has to reduce fast large voltage peaks capacitor, C3 between pin 6 VDD and pin 4 GND due to V = L*di/dt. Series resistor, R4 In combination with C3 and C4 for optimal 47Ω - 100Ω / 0.25W flash robustness. High frequency decoupling 220pF - 2.7nF / 250V C4 has to reduce fast large voltage peaks capacitor, C4 between pin 6 VDD and pin 4 GND due to V = L*di/dt. All external capacitors of the TDA6107JF / 07AJF application must be grounded to the small signal GND The value of C3, C4 and R4 depend on the layout of the CRT-board. During a flashtest can be checked which values give the lowest voltage peaks between pin 6 VDD and pin 4 GND. These voltage peaks can be measured with a digital oscilloscope with probes and grounding as close as possible to pin 6 VDD and pin 4 GND. A special provision can be made on the probe to be close to the pins. It is very important that the grounding wire of the probe is short for not picking up spikes in the GND. 10. External protection components, diodes and resistors Flash resistor, RFLASH 1.5kΩ / 0.5W surge • => Always needed in resistor (high voltage • application resistor). RFLASH must be capable of handling • large peak voltages from a flashover • 16 Limits flashover current peaks When the value is larger than 1.5kΩ, the bandwidth will be reduced. When the value is smaller than 1.5kΩ, larger than 3A flash current peaks can be expected and external flash protection (D1 + R1) must be used. When the value ≥ 1.5kΩ, a maximum value of 3A flash current peaks can be expected and the external flash protection (D1 + R1) is NOT needed. The internal flash diodes are capable of handling a maximum value of 3A flash current peaks. Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers 11. Diode, D1, D2 and D3 => Only needed when the value of RFLASH is lower than 1.5kΩ 12. Resistor, R1, R2 and R3 => Only needed when the value of RFLASH is lower than 1.5kΩ Resistor, R5 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. Application Note AN10227-01 BAV21 or equivalent. D1 must have a fast transient response, low shunt capacitance and capable of handling large peak currents from a flashover. 100Ω / 0.25W D1, D2 and D3 clamp the output to the VDD supply during a flashover. Limits current into video amplifier 1.5kΩ / 0.5W surge Limits flashover current peaks on the CRTresistor (high voltage board resistor). R5 must be capable of handling large peak voltages from a flashover Optimal PCB-layout to have optimal flash robustness If D1, D2 and D3 are needed, <5mm A small discharge loop. The track between the cathodes of D1, D2 and diodes and capacitor must be short to D3 must be close to C1 in the avoid high voltages V = L*di/dt generated layout. See Figure 7 below. during a flashover. C1 must be as close as <5mm Prevent that large flashover voltage / possible to pin 6 VDD and pin current peaks can directly flow through the 4 GND of the video amplifier. small signal GND. See Figure 7 below. Distance of G2, G1, R, G and > 3 mm Prevent arcing during flash over. B copper tracks to adjacent tracks G2 CRT pins must have 2 Prevent arcing during flash over. slots cut on the PCB to increase the distance from the adjacent R and B pins. No copper track in between Prevent arcing during flash over. CRT pins. No sharp edges on the Prevent arcing during flash over. copper track. Large signal GND and (if Prevent arcing during flash over. > 2mm used) EHT info track distance must be 2mm from all other tracks. CRT wire between aquadag A small discharge loop during flashover. layer and CRT-board must be as short as possible. CRT wire between aquadag Low impedance discharge loop during layer and CRT-board must flashover. not be too thin. 17 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 Figure 7 shows the optimal CRT PCB-layout for good flashover robustness. Figure 7: Optimal CRT PCB-layout with TDA6107JF/07AJF 18 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 4.2 Checklist TDA6108JF / 08AJF for optimal flashover robustness C3 220pF - 2.7nF 250V R4 47 ohm - 100 ohm D3 BAV21 VDD 6 7 3 V i(3) TV-signal processor 2 V i(2) 1 V i(1) 5 I om D2 BAV21 D1 BAV21 C1 100 nF 250V Voc(3) TDA6108JF/ 08AJF Internal block diagram is drawn in the datasheet on page 2 8 Voc(2) 9 VDD = 200V C2 10uF 250V R3 100 ohm R FLASH3 1k / 0.5W R2 100 ohm R FLASH2 1k / 0.5W R1 100 ohm R FLASH1 1k / 0.5W Voc(1) 4 GND C4 220pF - 2.7nF 250V EHT KB KG KR f f G1 G2 G3 C5 1nF 2kV = Small signal GND = Large signal GND R5 1k5 / 0.5W VG2 Figure 8: Application diagram TDA6108JF/08AJF Checklist: TDA6108JF / 08AJF 1. 2. 3. Recommended value / type Grounding of the CRT PCB-layout On the CRT PCB-layout the large signal GND must be isolated from the small signal GND. So pin 4 GND of the TDA6108JF / 08AJF must not be connected directly to the spark gap GND (focus, G2 and cathodes) of the CRT-socket. See Figure 9. It is also strongly recommended to place no components (capacitors, resistors and coils) between the small signal GND and the large signal GND. See Figure 9. Ground loops in the small signal GND must be avoided. So pin 4 GND must have one connection to the connector to the main board. See Figure 9. 19 Explanation Prevents that large flashover voltage / current peaks can directly flow through the small signal GND. Prevents that large flashover voltage / current peaks can directly flow through the small signal GND Ground loops could reveal in large voltage peaks due to long tracks. V = L*di/dt generated during a flashover Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers 4. 5. Small signal ground track must be around the TDA6108JF / 08AJF. See Figure 9. External protection components, decoupling circuits High frequency decoupling 100nF / 250V capacitor, C1 6. Low frequency decoupling capacitor, C2 7. High frequency decoupling capacitor, C3 8. 9. Application Note AN10227-01 • 4.7uF / 250V for ≤21 inch picture tube size • 10uF / 250V for >21 inch picture tube size 220pF – 2.7nF / 250V To avoid current / voltage peaks at pin 4 GND during a flashover. C1 has to reduce fast large voltage peaks between pin 6 VDD and pin 4 GND due to V = L*di/dt. (See points x + x for optimal PCB layout) Low frequency current peaks from a flashover flows via D1, D2 and D3 into C2. C3 has to reduce fast large voltage peaks between pin 6 VDD and pin 4 GND due to V = L*di/dt. Series resistor, R4 In combination with C3 and C4 for optimal 47Ω - 100Ω / 0.25W flash robustness. High frequency decoupling 220pF – 2.7nF / 250V C4 has to reduce fast large voltage peaks capacitor, C4 between pin 6 VDD and pin 4 GND due to V = L*di/dt. All external capacitors of the TDA6108JF / 08AJF application must be grounded to the small signal GND The value of C3, C4 and R4 depend on the layout of the CRT-board. During a flashtest can be checked which values give the lowest voltage peaks between pin 6 VDD and pin 4 GND. These voltage peaks can be measured with a digital oscilloscope with probes and grounding as close as possible to pin 6 VDD and pin 4 GND. A special provision can be made on the probe to be close to the pins. It is very important that the grounding wire of the probe is short for not picking up spikes in the GND. 10. 11. 12. 13. External protection components, diodes and resistors Flash resistor, RFLASH 1kΩ / 0.5W low ohmic • Limits flashover current peaks => Always needed in surge resistor (high • When the value is larger than 1kΩ, the application voltage resistor). bandwidth will be reduced. RFLASH must be • When the value is smaller than 1kΩ, capable of handling larger than 5A flash current peaks can large peak voltages be expected. from a flashover Diode, D1, D2 and D3 BAV21 or equivalent. D1, D2 and D3 clamp the output to the VDD => Always needed in supply during a flashover. D1 must have a fast application transient response, low shunt capacitance and capable of handling large peak currents from a flashover. Resistor, R1, R2 and R3 Limits flashover current peaks on the CRT100Ω / 0.25W => Always needed in board application Resistor, R5 1.5kΩ / 0.5W surge Limits flashover current peaks on the CRTresistor (high voltage board resistor). R5 must be capable of handling large peak voltages from a flashover 20 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers 14. 15. 16. 17. 18. 19. 20. 21. 22. Application Note AN10227-01 Optimal PCB-layout to have optimal robustness If D1, D2 and D3 are needed, <5mm the cathodes of D1, D2 and D3 must be close to C1 in the layout. See Figure 9 below. C1 must be as close as <5mm possible to pin 6 VDD and pin 4 GND of the video amplifier. See Figure 9 below. Distance of G2, G1, R, G and > 3 mm B copper tracks to adjacent tracks G2 CRT pins must have 2 slots cut on the PCB to increase the distance from the adjacent R and B pins. No copper track in between CRT pins. No sharp edges on the copper track. Large signal GND and (if > 2mm used) EHT info track distance must be 2mm from all other tracks. CRT wire between aquadag layer and CRT-board must be as short as possible. CRT wire between aquadag layer and CRT-board must not be too thin. 21 A small discharge loop. The track between diodes and capacitor must be short to avoid high voltages V = L*di/dt generated during a flashover. Prevent that large flashover voltage / current peaks can directly flow through the small signal GND. Prevent arcing during flash over. Prevent arcing during flash over. Prevent arcing during flash over. Prevent arcing during flash over. Prevent arcing during flash over. A small discharge loop during flashover. Low impedance discharge loop during flashover. Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 Figure 9 shows the optimal CRT PCB-layout for good flashover robustness. Figure 9: Optimal CRT PCB-layout with TDA6108JF/08AJF 22 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 5. THE TDA6107JF / 07AJF AND TDA6108JF / 08AJF REFERENCE / DEMO BOARD The TDA6107JF / 07AJF reference board is shown in Figure 11 and Figure 12. The TDA6108JF / 08AJF has its own reference / demo board and is shown in Figure 14 and Figure 15. These boards are meant for evaluation and demonstration purposes. R1 1E2 C5 220pF - 2n7 500V TDA6107(A)JF 1 2 3 4 5 6 7 8 9 C4 4u7 - 10u 250V KB KG KR R4 1k5 5 4 3 2 R5 1k5 1 R6 47E - 100E C6 220pF - 2n7 500V ff GND 4 5 6 AQUA Vdd EHT R3 1k5 X1 Blue Green Red GND Iom X2 1 2 3 G2 G1 G3 f f C3 100nF 250V C2 2n7 500V R7 1k R2 1k5 Vg2 Aqua C1 1n 2kV Figure 10: Application diagram of the TDA6107JF / 07AJF reference / demo board When the TDA6107JF / 07AJF is used with 1k5 flash resistor (R3, R4, R5), the external flash diodes are not needed. If the TDA6107JF / 07AJF is used with 1k flash resistors, external flash diodes + 100Ω resistors must be used. See for a detailed description section 4.1. For the TDA6107JF / 07AJF with external flash protection, the TDA6108JF / 08AJF reference / demo must be used. G1 is connected to the small signal GND via a 1k flash resistor. 23 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TDA6107JF / 07AJF reference / demo board (layout side) Figure 11: TDA6107JF / 07AJF reference / demo board layout This reference / demo board has an option to use the aquadag ground for the EHT info. This can be done by leaving out the jumper wire above connector X2. Then the aquadag ground is isolated from the large signal ground (heater and VG2 decoupling capacitor). 24 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TDA6107JF / 07AJF reference / demo board (component side) Figure 12: Components TDA6107JF / 07AJF reference / demo board On this TDA6107JF / 07AJF reference / demo board a 15.2 K/W heatsink is mounted, however a smaller heatsink of 21.5K/W would be sufficient for the TDA6107JF / 07AJF. See section: 3.2 25 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 Application diagram of the TDA6108JF / 08AJF reference / demo board: R1 1E2 C5 220pF - 2n7 500V C4 10uF 250V X1 5 4 3 2 Blue Green Red GND 1 Iom R8 D1 100E BAV21 R3 1k R9 100E R4 1k R10 100E D2 BAV21 D3 BAV21 R5 1k ff GND 4 5 6 AQUA Vdd R6 47E - 100E C6 220pF - 2n7 500V TDA6108(A)JF 1 2 3 4 5 6 7 8 9 X2 1 2 3 KB KG KR EHT G2 G1 G3 f f C3 100nF 250V C2 2n7 500V R7 1k R2 1k5 Vg2 C1 1n 2kV Figure 13: Application diagram of the TDA6108JF / 08AJF reference / demo board External flash diodes must always be used with the TDA6108JF / 08AJF. G1 is connected to the small signal GND via a 1k flash resistor. 26 Aqua Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TDA6108JF / 08AJF reference / demo board (layout side) Figure 14: TDA6108JF / 08AJF reference / demo board layout This reference / demo board has an option to use the aquadag ground for the EHT info. This can be done by leaving out the jumper wire above connector X2. Then the aquadag ground is isolated from the large signal ground (heater and VG2 decoupling capacitor). 27 Philips Semiconductors TDA6107JF/07AJF/08JF/08AJF Triple video output amplifiers Application Note AN10227-01 TDA6108JF / 08AJF reference / demo board (component side) Figure 15: Components TDA6108JF / 08AJF reference / demo board On this TDA6108JF / 08AJF reference / demo board a 12 K/W heatsink is mounted, which is sufficient for the TDA6108JF / 08AJF. See section: 3.2. 28 Philips Semiconductors – a worldwide company Contact information For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825 For sales offices addresses send e-mail to: [email protected]. © Koninklijke Philips Electronics N.V. 2002 SCB74 All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights.