National Semiconductor Application Note 2021 Robert Sheehan, Michael Null December 15, 2009 Introduction QUICK SETUP PROCEDURE Step 1: Use an input power supply with at least 30A current capability. Connect the positive output of the power supply to the VIN terminal T1. Connect the negative output of the power supply to the input GND terminal T2. The LM3753/54 evaluation board is designed to provide the design engineer with a fully functional power converter based solution using two LM3753 or LM3754 2-Phase Buck Controllers. This evaluation board produces an output voltage of 1.2 V at 25A per phase for a total of 100A. The switching frequency for the converter is set to 300 kHz per phase, for an effective 1.2 MHz at the input and output. The gate signals for each controller’s outputs are 180 degree out of phase, with the two controllers having a 90 degree phase shift from each other. The printed circuit board consists of 4 layers of FR4 material with 2 ounce copper on all layers. This application note contains the evaluation board schematics, Bill-of-Materials (BOM) and a quick setup procedure. Refer to the LM3753/54 datasheet for complete circuit design information. The performance of the evaluation board is as follows: Input Range : 6V to 18V Output Voltage : 1.2V ± 1% Output Current : 0A to 100A Switching Frequency : 300 kHz Load Regulation : 0.1% Board Size : 4.2 x 5.4 x 0.063 inches Step 2: Connect a load with 100A capability to the VOUT terminal T3 and GND terminal T4. Step 3: (LM3753 only) Connect a secondary power supply to the TRACK terminal TP13 and GND terminal TP2. Set the power supply voltage to 3.3V. Since the LM3753 is configured such that VOUT follows the TRACK input, VOUT cannot come up without applying a voltage to TRACK. LM3753/54 Evaluation Board LM3753/54 Evaluation Board Step 4: Ensure that the Load Pulse switch SW1 is in the center OFF position. Check that the current limit trimmers R18 and R26 are turned fully clockwise for maximum output current. J1, J3, J5 and J7 should be installed, with J2, J4, J6 and J8 open. Step 5: Set VIN to 12 V with no load being applied. Turn on the input power supply (followed by the secondary power supply for the LM3753 TRACK). The output voltage should be in regulation with a nominal value of 1.2V. Step 6: Slowly increase the load while monitoring the output voltage. The output voltage should remain in regulation up to the full load current of 100A. Step 7: Slowly vary the input voltage from 6V to 18V. The output voltage should remain in regulation with a nominal value of 1.2V. Powering and Loading Considerations Read this entire page prior to attempting to power the evaluation board. 30111201 FIGURE 1. Basic Test Setup for the LM3753/54 Evaluation Board AN-2021 © 2009 National Semiconductor Corporation 301112 www.national.com AN-2021 DCR and RESISTOR SENSE The LM3753/54 is delivered with the resistor sense option selected. To configure the board for DCR (Inductor DC Resistance) sensing, remove J1, J3, J5 and J7. Turn the current limit trimmers R18 and R26 fully counter-clockwise for the lower DC resistance. Short the power connections J2, J4, J6 and J8. Holes for the power jumpers will accommodate #14 AWG or 2 x #18 AWG solid copper wires. #2-56 hardware may also be used for the power connections. Due to the tight spacing, stagger the screws and nuts on the top and bottom; wrap #18 AWG solid copper wire around the hardware on the top side and tighten. Take care to avoid damaging adjacent components, particularly Q14-Q17 on the bottom side. Brass jumpers such as those used on terminal blocks should be avoided since the resistance is four times that of copper. Board Configuration LM3753 TRACK The LM3753 evaluation board is configured such that VOUT follows the TRACK input. This configuration will not allow VOUT to come up without applying a voltage to TRACK. In order to produce 1.2V on the output, the TRACK pin must be connected to a secondary 3.3V power supply. To prevent current limit during startup, the rise time of the 3.3V TRACK signal should be longer than 100 μs. LM3754 SOFT-START The LM3754 evaluation board is configured such that VOUT follows the SS signal, which is set by C12 and an internal 10 μA current source. This allows the LM3754 to operate on its own, with a single power supply connected to VIN. LOAD PULSE GENERATOR An on-board load pulse generator allows for easy evaluation of the output voltage transient response. The LPI (Load Pulse In) and LPO (Load Pulse Out) terminals provide the interface to the load pulse generator. Setting SW1 to EXT connects LPI to LPO, which then allows the load pulse generator to be driven by LPI with an external 5V logic signal. Setting SW1 to INT allows the load pulse generator to be driven with an internally generated 1 ms pulse at 5% duty cycle. J9 selects the amount of load. With J9 open, Load Branch 1 is engaged to draw 1.2V / 0.05Ω = 24A. With J9 shorted, Load Branch 1 and Load Branch 2 are engaged to draw 1.2V / 0.025Ω = 48A. TP41 through TP44 provide monitoring of the load step. R59, C61 and the gate impedance of Q14-Q17 set the slew rate. With J9 open, R59 = 51Ω and C61 = 0.01 μF, the slew rate is 24A / 1 μs. With J9 open, R59 = 51Ω and C61 open, the slew rate is 24A / 200 ns. Results are shown in the Typical Performance Characteristics. OUTPUT VOLTAGE RIPPLE Output voltage ripple measurement should be taken directly across the output capacitor C66 between terminals TP3 and TP4. Care must be taken to minimize the loop area between the scope probe tip and the ground lead in order to minimize noise in the measurement. This can be achieved by removing the probe’s spring tip and ground lead and then wrap a bare wire around the scope probe shaft. The bare wire should be in contact with the probe shaft since this is the ground lead for the probe. The measurement can be taken by connecting the bare wire onto the ground side of the capacitor and the probe tip onto the positive side of the capacitor. Figure 2 shows a diagram of this measurement technique. OVER TEMPERATURE PROTECTION An LM26LV provides over temperature protection should the PC board exceed 105°C. This shuts down switching by pulling the /FAULT bus low. Normal operation resumes when the board cools below 100°C. A VTEMP terminal provides an analog voltage which is inversely proportional to temperature. Refer to the LM26LV datasheet for complete design information. 30111202 FIGURE 2. Output Voltage Ripple Measurement Setup VCC1, VCC2 and VDD The VCC and VDD terminals provide monitoring points for the on-board voltages. For the evaluation board, VDD is generated by an NPN linear regulator controlled by the LM3753/54. To demonstrate the maximum power stage efficiency, a 5V current limited external supply may be used for VDD. Extreme care must be exercised when applying an external voltage to the VDD terminal. Under no circumstances should a voltage be applied to VDD while VIN < 5V, as damage to the LM3753/54 will occur. To protect U1 and U2, the circuit may be modified by placing small Schottky diodes in series with R2 and R16 to block the reverse voltage. Refer to the LM3753/54 datasheet for complete circuit design information. EXTERNAL CLOCK SYNCHRONIZATION A SYNCIN terminal has been provided on the evaluation board in order to synchronize the converter to an external clock or other fixed frequency signal from 225 kHz to 375 kHz. Refer to the LM3753/54 datasheet for complete information. POWER GOOD A PGOOD terminal provides monitoring of the Power Good signal. When PGOOD is high at VCC1, the output voltage is within the Power Good window. MARGIN A MARGIN terminal has been provided on the evaluation board in order to adjust the output voltage by ±5%. Shorting the MARGIN terminal to GND will adjust the output up 5%. Shorting the MARGIN terminal to VOUT will adjust the output down 5%. www.national.com ACTIVE LOADS Many constant-current types of active loads can exhibit an initial short circuit, which is sustained well beyond the normal soft-start cycle. To avoid current limit during startup, wait until the output voltage is up before turning on the load. Using an active load with a constant-resistance mode will avoid this startup timing issue. 2 AN-2021 Typical Performance Characteristics Efficiency with 5V External VDD and DCR Sense Efficiency with VDD Linear Regulator and Resistor Sense 30111203 30111204 Output Load Transient +24A / 1 μs Output Load Transient −24A / 1 μs 30111205 30111206 Output Load Transient +24A / 200 ns Output Load Transient −24A / 200 ns 30111207 30111208 3 www.national.com AN-2021 Startup from Enable Restart from Fault 30111209 30111210 Switching at 12V Input Output Voltage Ripple 30111211 30111212 Phase Matching VIAVE vs IOUT 30111213 www.national.com 30111214 4 NT1, NT2 and NT3 are net ties for GND sensing. FIGURE 3. Evaluation Board Schematic — Master 30111215 AN-2021 Evaluation Board Schematic 5 www.national.com www.national.com 6 FIGURE 4. Evaluation Board Schematic — Slave 30111216 AN-2021 FIGURE 5. Evaluation Board Schematic — Interface 30111217 AN-2021 7 www.national.com AN-2021 TABLE 1. Bill of Materials for LM3753 Evaluation Board Designator Value Package Description Manufacturer Part Number QTY C1 470uF SMT Radial G AL, 25V, 20%, 0.06 Ohm ESR Panasonic EEE-FP1E471AP 1 C2, C15 1uF 0603 Ceramic, X7R, 16V, 10% TDK C1608X7R1C105K 2 C3, C10, C16, C18 4.7uF 0805 Ceramic, X7R, 16V, 10% MuRata GRM21BR71C475 KA73L 4 C4 0.047uF 0603 Ceramic, X7R, 25V, 10% TDK C1608X7R1E473K 1 C5 100pF 0603 Ceramic, C0G/NP0, 50V, 5% TDK C1608C0G1H101J 1 C6 4700pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H472 KA01D 1 C7 2200pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H222 KA01D 1 C8, C13, C14, C20, 1000pF C21, C55, C62, C63, C64, C65, C67 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H102 KA01D 11 C9, C11, C17, C19, C59 0.22uF 0603 Ceramic, X7R, 25V, 10% Taiyo Yuden TMK107B7224KAT 5 C22, C23, C24, C25, C26, C27, C28, C29 4.7uF 1210 Ceramic, X7R, 25V, 10% Taiyo Yuden TMK325B7475KNT 8 C30, C31, C32, C33 680pF 0603 Ceramic, C0G/NP0, 50V, 5% TDK C1608C0G1H681J 4 C34, C35, C36, C37 0.15uF 0603 Ceramic, X7R, 25V, 10% MuRata GRM188R71E154 KA01D 4 C38, C39, C42, C43, C46, C47, C50, C51 22uF 1210 Ceramic, X7R, 16V, 10% MuRata GRM32ER71C226 KE18L 8 C40, C41, C44, C45, C48, C49, C52, C53 220uF UE SP, 4V, 20%, 0.005 Ohm ESR Panasonic EEF-SE0G221R 8 C56, C68 0.1uF 0603 Ceramic, X7R, 25V, 10% MuRata GRM188R71E104 KA01D 2 C58 2.2uF 0805 Ceramic, X7R, 16V, 10% TDK C2012X7R1C225K 1 C60 470pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H471 KA01D 1 C61 0.01uF 0603 Ceramic, X7R, 50V, 10% TDK C1608X7R1H103K 1 C66 1uF 1206 Ceramic, X7R, 25V, 10% AVX 12063C105KAT2A 1 D1, D2, D3, D4, D5, D6, D7, D8, D9 0.47V SOD-323 Vr = 40V, Io = 0.5A, Vf = 0.47V Central Semiconductor CMDSH05-4 9 D14 1.25V SOD-123 Vr = 100V, Io = 0.15A, Vf = 1.25V Diodes Inc. 1N4148W-7-F 1 H1, H2 Mach Screw, Round, #10-32 x 3/8, Brass 2EA13 2 H3, H4 Mach Screw, Round, #1/4-20 x 1/2, Brass 2EA30 2 H5, H6 Lock Nut, #10-32, Stainless Steel 1EY35 2 H7, H8 Lock Nut, #1/4-20, Brass 1FA58 2 H9, H10, H11, H12 Machine Screw, Round, #4-40 x 1/4, Nylon 4DFG1 4 H13, H14, H15, H16 Standoff Hex 0.5"L #4-40 Nylon Keystone 1902C 4 Header, TH, 100mil, 1x2, Tin plated Samtec Inc. TSW-102-07-T-S 5 Power Beads, 440nH, 0.32 mOhm Pulse Engineering PA0513.441NLT 4 J1, J3, J5, J7, J9 1x2 L1, L2, L3, L4 440nH www.national.com PA1513 8 Value Package Description Manufacturer Part Number QTY LED1, LED2 Green Power TOPLED w/lens 0.114W, 3.8V OSRAM LT E63CBACB-35-L-Z 2 LED3 Red Power TOPLED w/lens 0.1075W, 2.15V OSRAM LS E63F-DBFA-1Z 1 P1 Header, 24-Pin, Right Angle Tyco Electronics 1-87230-2 1 P2 Receptacle 24-Pin, Right Angle Tyco Electronics 5535512-3 1 Q1 NPN DPAK NPN, 8A, 80V Central Semiconductor CJD44H11 1 Q2, Q5, Q8, Q11 25V PowerPAK SO-8 30A, 8.5nC, 7 mOHM Vishay-Siliconix SiR850DP 4 Q3, Q4, Q6, Q7, Q9, Q10, Q12, Q13, Q14, Q15, Q16, Q17 25V PowerPAK SO-8 50A, 20 nC, 3 mOHM Vishay-Siliconix SiR892DP 12 R1, R7, R8, R60, R61, R62, R80 10k 0603 5%, 0.1W Vishay-Dale CRCW060310K0J NEA 7 R2, R16, R31, R32, R33, R34 2.2 0603 5%, 0.1W Vishay-Dale CRCW06032R20J NEA 6 R3, R55 2.4k 0603 5%, 0.1W Vishay-Dale CRCW06032K40J NEA 2 R4, R5 1.0k 0603 5%, 0.1W Vishay-Dale CRCW06031K00J NEA 2 R6, R35, R36, R37, R38, R51, R52, R53, R54, R58, R79 1.0 0603 5%, 0.1W Vishay-Dale CRCW06031R00J NEA 11 R9, R13 3.01k 0603 0.1%, 0.1W Yageo America RT0603BRD073K 01L 2 R10 240 0603 5%, 0.1W Vishay-Dale CRCW0603240RJ NEA 1 R11 6.2k 0603 5%, 0.1W Vishay-Dale CRCW06036K20J NEA 1 R12 30.1k 0603 1%, 0.1W Vishay-Dale CRCW060330K1F KEA 1 R14 35.7k 0603 1%, 0.1W Vishay-Dale CRCW060335K7F KEA 1 R15 10.0k 0603 1%, 0.1W Vishay-Dale CRCW060310K0F KEA 1 R17, R25 78.7k 0603 1%, 0.1W Vishay-Dale CRCW060378K7F KEA 2 R18, R26 200 TS53Y Pot 5mm Sq Cermet Vishay-Sfernice TS53YL201 2 R19, R27 191 0603 1%, 0.1W Vishay-Dale CRCW0603191RF KEA 2 R20, R21, R28 4.02k 0603 1%, 0.1W Vishay-Dale CRCW06034K02F KEA 3 R22 1.37k 0603 1%, 0.1W Vishay-Dale CRCW06031K37F KEA 1 R24, R30 0 0603 5%, 0.1W Vishay-Dale CRCW06030000Z 0EA 2 R39, R42, R45, R48 5.90k 0603 1%, 0.1W Vishay-Dale CRCW06035K90F KEA 4 9 www.national.com AN-2021 Designator AN-2021 Designator Value Package Description Manufacturer Part Number QTY R40, R43, R46, R49 10.5k 0603 1%, 0.1W Vishay-Dale CRCW060310K5F KEA 4 R41, R44, R47, R50 0.001 WSK2512 1%, 1W Vishay-Dale WSK25121L000F EA 4 R56 470k 0603 5%, 0.1W Vishay-Dale CRCW0603470KJ NEA 1 R57 12k 0603 5%, 0.1W Vishay-Dale CRCW060312K0J NEA 1 R59 51 0603 5%, 0.1W Vishay-Dale CRCW060351R0J NEA 1 R63, R64, R65, R66, R67, R68, R69, R70, R71, R72, R73, R74 0.3 2512 1%, 1W Panasonic ERJ-1TRQFR30U 12 R75, R76, R77, R78 1.00k 0603 1%, 0.1W Vishay-Dale CRCW06031K00F KEA 4 5%, 0.25W Panasonic ERD-S2TJ121V 1 0603 Thermistor, 47K, 2%, B25/50 4050, 0.1W MuRata NCP18WB473J03 RB 4 Shunt, 100mil, Tin plated, Black Amp 2-382811-1 5 Switch, DPDT, 3 Position NKK G3T23AP-RO 1 2 R101 120 RT1, RT2, RT3, RT4 47k SH-J1, SH-J3, SHJ5, SH-J7, SH-J9 1x2 SW1 T1, T2 50A Terminal 50A Lug Panduit CB35-36-CY T3, T4 90A Terminal 90A Lug Panduit CB70-14-CY 2 TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14, TP38, TP39, TP40, TP41, TP42, TP43, TP44 Triple Terminal, Turret, TH, Triple Keystone Electronics 1598-2 21 TP15, TP16, TP18, TP19, TP20, TP21, TP22, TP24, TP25, TP26, TP27, TP28, TP29, TP30, TP32, TP34, TP36 White Test Point, TH, Multipurpose, White Keystone Electronics 5012 17 TP17, TP23, TP31, TP33, TP35, TP37 Black Test Point, TH, Multipurpose, Black Keystone Electronics 5011 6 U1, U2 LM3753 SQA32A Multi-Phase Buck Controller National Semiconductor LM3753SQ 2 U3 LM26LV 105°C SDB06A 1.6V, LLP-6 Factory Preset Temperature Switch and Temperature Sensor National Semiconductor LM26LVCISD-105 1 U4 LMC555 MUA08A CMOS Timer National Semiconductor LMC555CMM 1 U5 LM2722 2 M08A High-Speed 4.5A Synchronous MOSFET Driver National Semiconductor LM27222M 1 www.national.com 10 Designator Value Package Description Manufacturer Part Number QTY C1 470uF SMT Radial G AL, 25V, 20%, 0.06 Ohm ESR Panasonic EEE-FP1E471AP 1 C2, C15 1uF 0603 Ceramic, X7R, 16V, 10% TDK C1608X7R1C105K 2 C3, C10, C16, C18 4.7uF 0805 Ceramic, X7R, 16V, 10% MuRata GRM21BR71C475 KA73L 4 C4 0.047uF 0603 Ceramic, X7R, 25V, 10% TDK C1608X7R1E473K 1 C5 100pF 0603 Ceramic, C0G/NP0, 50V, 5% TDK C1608C0G1H101J 1 C6 4700pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H472 KA01D 1 C7 2200pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H222 KA01D 1 C8, C13, C14, C20, 1000pF C21, C55, C62, C63, C64, C65, C67 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H102 KA01D 11 C9, C11, C17, C19, C59 0.22uF 0603 Ceramic, X7R, 25V, 10% Taiyo Yuden TMK107B7224KAT 5 C12, C56, C68 0.1uF 0603 Ceramic, X7R, 25V, 10% MuRata GRM188R71E104 KA01D 3 C22, C23, C24, C25, C26, C27, C28, C29 4.7uF 1210 Ceramic, X7R, 25V, 10% Taiyo Yuden TMK325B7475KNT 8 C30, C31, C32, C33 680pF 0603 Ceramic, C0G/NP0, 50V, 5% TDK C1608C0G1H681J 4 C34, C35, C36, C37 0.15uF 0603 Ceramic, X7R, 25V, 10% MuRata GRM188R71E154 KA01D 4 C38, C39, C42, C43, C46, C47, C50, C51 22uF 1210 Ceramic, X7R, 16V, 10% MuRata GRM32ER71C226 KE18L 8 C40, C41, C44, C45, C48, C49, C52, C53 220uF UE SP, 4V, 20%, 0.005 Ohm ESR Panasonic EEF-SE0G221R 8 C58 2.2uF 0805 Ceramic, X7R, 16V, 10% TDK C2012X7R1C225K 1 C60 470pF 0603 Ceramic, X7R, 50V, 10% MuRata GRM188R71H471 KA01D 1 C61 0.01uF 0603 Ceramic, X7R, 50V, 10% TDK C1608X7R1H103K 1 C66 1uF 1206 Ceramic, X7R, 25V, 10% AVX 12063C105KAT2A 1 D1, D2, D3, D4, D5, D6, D7, D8, D9 0.47V SOD-323 Vr = 40V, Io = 0.5A, Vf = 0.47V Central Semiconductor CMDSH05-4 9 D14 1.25V SOD-123 Vr = 100V, Io = 0.15A, Vf = 1.25V Diodes Inc. 1N4148W-7-F 1 H1, H2 Mach Screw, Round, #10-32 x 3/8, Brass 2EA13 2 H3, H4 Mach Screw, Round, #1/4-20 x 1/2, Brass 2EA30 2 H5, H6 Lock Nut, #10-32, Stainless Steel 1EY35 2 H7, H8 Lock Nut, #1/4-20, Brass 1FA58 2 H9, H10, H11, H12 Machine Screw, Round, #4-40 x 1/4, Nylon 4DFG1 4 H13, H14, H15, H16 Standoff Hex 0.5"L #4-40 Nylon Keystone 1902C 4 Header, TH, 100mil, 1x2, Tin plated Samtec Inc. TSW-102-07-T-S 5 Power Beads, 440nH, 0.32 mOhm Pulse Engineering PA0513.441NLT 4 J1, J3, J5, J7, J9 1x2 L1, L2, L3, L4 440nH PA1513 11 www.national.com AN-2021 TABLE 2. Bill of Materials for LM3754 Evaluation Board AN-2021 Designator Value Package Description Manufacturer Part Number QTY LED1, LED2 Green Power TOPLED w/lens 0.114W, 3.8V OSRAM LT E63CBACB-35-L-Z 2 LED3 Red Power TOPLED w/lens 0.1075W, 2.15V OSRAM LS E63F-DBFA-1Z 1 P1 Header, 24-Pin, Right Angle Tyco Electronics 1-87230-2 1 P2 Receptacle 24-Pin, Right Angle Tyco Electronics 5535512-3 1 Q1 NPN DPAK NPN, 8A, 80V Central Semiconductor CJD44H11 1 Q2, Q5, Q8, Q11 25V PowerPAK SO-8 30A, 8.5nC, 7 mOHM Vishay-Siliconix SiR850DP 4 Q3, Q4, Q6, Q7, Q9, Q10, Q12, Q13, Q14, Q15, Q16, Q17 25V PowerPAK SO-8 50A, 20 nC, 3 mOHM Vishay-Siliconix SiR892DP 12 R1, R7, R8, R60, R61, R62, R80 10k 0603 5%, 0.1W Vishay-Dale CRCW060310K0J NEA 7 R2, R16, R31, R32, R33, R34 2.2 0603 5%, 0.1W Vishay-Dale CRCW06032R20J NEA 6 R3, R55 2.4k 0603 5%, 0.1W Vishay-Dale CRCW06032K40J NEA 2 R4, R5 1.0k 0603 5%, 0.1W Vishay-Dale CRCW06031K00J NEA 2 R6, R35, R36, R37, R38, R51, R52, R53, R54, R58, R79 1.0 0603 5%, 0.1W Vishay-Dale CRCW06031R00J NEA 11 R9, R13 3.01k 0603 0.1%, 0.1W Yageo America RT0603BRD073K 01L 2 R10 240 0603 5%, 0.1W Vishay-Dale CRCW0603240RJ NEA 1 R11 6.2k 0603 5%, 0.1W Vishay-Dale CRCW06036K20J NEA 1 R12 30.1k 0603 1%, 0.1W Vishay-Dale CRCW060330K1F KEA 1 R17, R25 78.7k 0603 1%, 0.1W Vishay-Dale CRCW060378K7F KEA 2 R18, R26 200 TS53Y Pot 5mm Sq Cermet Vishay-Sfernice TS53YL201 2 R19, R27 191 0603 1%, 0.1W Vishay-Dale CRCW0603191RF KEA 2 R20, R21, R28 4.02k 0603 1%, 0.1W Vishay-Dale CRCW06034K02F KEA 3 R22 1.37k 0603 1%, 0.1W Vishay-Dale CRCW06031K37F KEA 1 R24, R30 0 0603 5%, 0.1W Vishay-Dale CRCW06030000Z 0EA 2 R39, R42, R45, R48 5.90k 0603 1%, 0.1W Vishay-Dale CRCW06035K90F KEA 4 R40, R43, R46, R49 10.5k 0603 1%, 0.1W Vishay-Dale CRCW060310K5F KEA 4 R41, R44, R47, R50 0.001 WSK2512 1%, 1W Vishay-Dale WSK25121L000F EA 4 www.national.com 12 Value Package Description Manufacturer Part Number QTY R56 470k 0603 5%, 0.1W Vishay-Dale CRCW0603470KJ NEA 1 R57 12k 0603 5%, 0.1W Vishay-Dale CRCW060312K0J NEA 1 R59 51 0603 5%, 0.1W Vishay-Dale CRCW060351R0J NEA 1 R63, R64, R65, R66, R67, R68, R69, R70, R71, R72, R73, R74 0.3 2512 1%, 1W Panasonic ERJ-1TRQFR30U 12 R75, R76, R77, R78 1.00k 0603 1%, 0.1W Vishay-Dale CRCW06031K00F KEA 4 R101 120 5%, 0.25W Panasonic ERD-S2TJ121V 1 RT1, RT2, RT3, RT4 47k Thermistor, 47K, 2%, B25/50 4050, 0.1W MuRata NCP18WB473J03 RB 4 SH-J1, SH-J3, SHJ5, SH-J7, SH-J9 1x2 Shunt, 100mil, Tin plated, Black Amp 2-382811-1 5 Switch, DPDT, 3 Position NKK G3T23AP-RO 1 Terminal 50A Lug Panduit CB35-36-CY 2 0603 SW1 T1, T2 50A T3, T4 90A Terminal 90A Lug Panduit CB70-14-CY 2 TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP14, TP38, TP39, TP40, TP41, TP42, TP43, TP44 Triple Terminal, Turret, TH, Triple Keystone Electronics 1598-2 20 TP15, TP16, TP18, TP19, TP20, TP21, TP22, TP24, TP25, TP26, TP27, TP28, TP29, TP30, TP32, TP34, TP36 White Test Point, TH, Multipurpose, White Keystone Electronics 5012 17 TP17, TP23, TP31, TP33, TP35, TP37 Black Test Point, TH, Multipurpose, Black Keystone Electronics 5011 6 U1, U2 LM3754 SQA32A Multi-Phase Buck Controller National Semiconductor LM3754SQ 2 U3 LM26LV 105°C SDB06A 1.6V, LLP-6 Factory Preset Temperature Switch and Temperature Sensor National Semiconductor LM26LVCISD-105 1 U4 LMC555 MUA08A CMOS Timer National Semiconductor LMC555CMM 1 U5 LM2722 2 M08A High-Speed 4.5A Synchronous MOSFET Driver National Semiconductor LM27222M 1 13 www.national.com AN-2021 Designator Top Layer Components and Overlay 30111218 AN-2021 PCB Layout www.national.com 14 Top Layer Copper 30111219 AN-2021 15 www.national.com www.national.com 16 Mid Layer 1 Copper 30111220 AN-2021 Mid Layer 2 Copper 30111221 AN-2021 17 www.national.com www.national.com 18 Bottom Layer Copper as Viewed From Top 30111222 AN-2021 Bottom Layer Components and Overlay as Viewed From Top 30111223 AN-2021 19 www.national.com LM3753/54 Evaluation Board For more National Semiconductor product information and proven 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