MIC9131 Evaluation Board Micrel MIC9131 Evaluation Board High Voltage, High Speed Telecom DC to DC Controller General Description Requirements This evaluation board provides a platform for evaluating the MIC9131 Telecom power supply controller IC in a resonant reset forward converter topology. The evaluation board schematic is shown in Figure 1. Please refer to the MIC9131 data sheet for a detailed explanation of the control IC. The evaluation board requires a DC input power source. The source must be able to supply at least 0.4A at 36VIN to get maximum power from the output. The output may be loaded with a resistive or active load. The active load may be set for constant current or constant resistance mode. Specifications Precautions Recommended Operating Input Voltage ........... 36V to 72V Output Voltage ............................................................. 3.3V Maximum Output Voltage ............................................. 3.6V Maximum Output Current ............................................. 3.5A Output Switching Frequency ..................... 570kHz (typical) Peak voltages in the input section may reach 200V. Care should be taken to prevent damage to persons or equipment during circuit evaluation. The evaluation board does not have input reverse polarity protection. Applying a negative voltage at the VIN terminal (with respect to ground) may permanently damage the components on the board. The maximum input voltage is limited to 80 volts to prevent overvoltage stress on the components. Do not exceed 3.6V on the output. Increasing the output voltage will increase the peak reset voltage and peak secondary side gate drive voltage. Components may be damaged if the peak reset voltage exceeds the VDS of the primary side MOSFET or the VGS of the secondary side MOSFETs. Schematic T1 Coiltronics CIX04-15459 D3 MBR0540 10VBIAS 1 D9 0W C9 1mF 25V N=3 L1 3.8mH CDRH104R Q3 Si4800DY N=4 6 D4 B330 8, 9 C10 C16 C6 open 330mF 0.1mF 6.3V Q2 Si4884DY +VIN 36V to 72V 2 R1 1Meg C14 open VOUT = 3.5V@3A 10, 11 R12 open 1N=28 Lpri=120mH D2 ESID R10 100W U2 PS2703-1 4 C2 1mF 100V C12 open 4 R2 37.4k C1 1nF R15 20k 10VBIAS 13 UVLO LINE 1 6 COMP VCC 2 FB 10 EN OUT 16 SYNC ISNS 14 VBIAS 8 CPWR 3 RSET 9 BIAS SS 12 PGND 15 AGND 11 3 3 C3 open U3 TLV431AI 5 gate drive R14 0W Q1 IRFR9N20 200V 0.38W R11 16.5k C7 680pF 2 R7 806W 10VBIAS R13 10k VBIAS R18 8.25k R16 3.24k R17 10.5k R6 0.75W 1W OSC R5 562k R8 7.32k 4 C13 0.1mF 7 5 FB D5 ES1D U1 MIC9131 R3 20k FB C11 330pF 630V L2 47mH CDRH6D38 1 VBIAS 4 D6-A BAW56 D6-B BAW56 C15 330pF gate drive R4 5.76k C5 0.1mF C8 47pF C4 10nF Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com January 2002 1 MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel Getting Started Input Undervoltage Lockout 1) Connect an input voltage source to VIN and GND terminals. An ammeter may be placed between the source and VIN terminal to monitor input current. Connect a load to the 3.3V output and GND terminals. An ammeter may be used at the output as well. Resistors R1 and R2 set the input undervoltage lockout feature (see Figure 1). The gate drive is disabled if pin 13 of the MIC9131 is less than a nominal 1.22V. The UVLO threshold of the circuit is set using the R1/R2 voltage divider. The formula to calculate the turn-on voltage is: 3) Apply 48 volts at the input. The output voltage should be 3.3V. 4) The switching waveform (VDS of the primary side FET, Q1) may be monitored by placing an oscilloscope probe on the tab of Q1. R2 = 1.22 × R1 VIN – 1.22 Where VIN is the desired input voltage when the MIC9131 starts switching. The UVLO pin features 140mV (typical) of hysteresis to prevent startup oscillations due to noise/ripple or high impedance on the VIN supply. The turn-off input voltage (as VIN decreases) is calculated below: VIN (off) = 10.8 × R1 + R2 R2 For the evaluation board the turn-on voltage is typically 34V and the turn-off voltage is typically 30V. MIC9131 Evaluation Board 2 January 2002 MIC9131 Evaluation Board Micrel Bill of Materials Item U1 U2 U3 C1 C2 C3 C4 C5,C13 C6, C9 C7 C8 C10, C14 C11 C12 C15 C16 D4 or D2, D5 or D3 or D6 or L1 L2 Q1 or or Q2 Q3 R1 R2 R3, R15 R4 R5 R6 R7 R8 R9, R14 R10 R11 R12 R13 R16 R17 R18 T1 Part Number MIC9131BM PS2703-1 TLV431AIDBVR VJ0805Y102KXAAB VJ1206Y105KXBAB. Manufacturer Micrel Semiconductor1 NEC2 TI Vishay-Vitramon3 Vishay-Vitramon3 VJ0805Y103KXAAB VJ0805Y104KXAAB GRM42-6 X7R 105K 25 VJ0805Y681KXAAB VJ0805Y470KXAAB Vishay-Vitramon3 Vishay-Vitramon3 MuRata4 Vishay-Vitramon3 Vishay-Vitramon3 GRM31BR32J331CKY01L MuRata4 VJ0805Y331KXAAB 594D337X06R3D2T B340A SK34A US1D US1D B0540W MBRX0540 BAW56 BAW56WCT CDRH104R-3R8NC CDRH6D38-470NC FQD9N25TF IRFR9N20D H5N2504DS Si4884DY Si4800DY CRCW08051004FRT1 CRCW08053742FRT1 CRCW08052002FRT1 CRCW08055761FRT1 CRCW08055623FRT1 LR-2512-R75-F CRCW08058060FRT1 CRCW08057321FRT1 CRCW080500R0FRT1 CRCW08051000FRT1 CRCW08051651FRT1 Vishay-Vitramon3 Vishay3 Diodes Inc.5 Micro Commercial Component6 Diodes Inc.5 Micro Commercial Component6 Diodes Inc.5 Micro Commercial Component6 Micro Commercial Component6 Diodes Inc.5 Sumida Inc,7 Sumida Inc,7 Fairchild Semiconductor8 International Rectifier9 Hitachi10 Vishay-Siliconix3 Vishay-Siliconix3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 IRC11 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 CRCW08051002FRT1 CRCW08053241FRT1 CRCW08051052FRT1 CRCW08058251FRT1 CTX04-15459-A Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Vishay-Dale3 Cooper Electronics12 1. Micrel Semiconductor, tel.: 408-944-0800 7. 8. 9. 10. 11. 12. 2. NEC, tel.: 408-243-2111 3. Vishay, tel.: 206-452-5664 4. MuRata, tel.: 800-831-9172 5. Diodes Inc. tel.: 805-446-4800 Description MIC9131 controller Opto-Isolator Voltage Reference 1nF, 50V, X7R 1µF, 100V, X7R open 10nF, 50V, X7R 0.1µF, 50V, X7R 1µF, 25V, X7R size 1206 680pF, 50V, NPO, 5% 47pF, 50V, NPO, 5% open 330pF, 630V, X7R size 1206 open 330pF, 50V, NPO, 5% 330µF, 6.3V, ESR=0.06Ω 40V, 3A, Schottky Qty 1 1 1 1 1 1 1 2 2 1 1 2 1 1 1 1 1 200V, 1A ultrafast 2 40V, 500mA, Schottky 40V, 500mA, Schottky signal diode signal diode 3.8µH 47µH 250V, 0.38Ω, D-pak 200V, 0.38Ω, D-pak 1 1 1 1 1 1 1 30V N-channel MOSFET 30V N-channel MOSFET 1Meg 37.4K 20K 5.76K 562K 0.75Ω, 1% 806Ω 7.32K 0Ω 100Ω 16.5K open 10K 3.24K 10.5K 8.25K Lpri=120µH, 400kHz 1 1 1 1 2 1 1 1 1 1 2 1 1 1 1 1 1 1 1 Sumida Inc., tel.: 510-668-0660 Fairchild Semidconductor, tel.: 408-822-2185 International Rectifier, tel.: 925-455-8888 Hitachi, tel.: 408-432-3300 IRC, tel.: 650-962-5300 Cooper Electronics, tel.: 561-752-5036 6. Micro Commercial Components, tel.: 800-346-3371 January 2002 3 MIC9131 Evaluation Board MIC9131 Evaluation Board Micrel PCB Layout Information Top-Side Silk Screen Bottom-Side Silk Screen Top-Side Copper Bottom-Side Copper MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2002 Micrel Incorporated MIC9131 Evaluation Board 4 January 2002