DEMO MANUAL DC1626A LTC3838EFE Wide Input Range, High Efficiency Step-Down DC/DC Converter DESCRIPTION Demonstration circuit 1626A is a dual output 1.5V/15A and 1.2V/15A synchronous buck converter operating with a switching frequency of 300kHz over an input voltage range of 4.5V to 26V. The demo board comes in two versions. The -A version uses inductor DCR current sensing with an iron powder inductor for high efficiency. The -B version uses a 2.5mΩ sense resistor for accurate current sensing with a low DCR ferrite inductor. The fixed on-time valley current mode architecture of the LTC3838 allows for a fast load step response (see Figures 6 to 9). The load step response can be tested with the on-board load step circuit and a bench pulse generator. The demo board uses a high density, two sided drop-in layout. The entire converter, excluding the bulk output and input capacitors, fits within a compact 1.5" × 1.0" area on the board. The package style for the LTC3838EFE is a 38-lead TSSOP with an exposed ground pad. PERFORMANCE SUMMARY PARAMETER The main features of the board are listed below: • MODE jumper to program either DCM or FCM at light or no load • EXTVCC pin • PLLIN pin to synchronize the converter to an external clock • Remote sensing for VOUT1 • Optional resistors to tie the two phases together • Each rail has its own RUN pin, PGOOD pin and TRACK/SS pin Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. (TA = 25°C) CONDITION Minimum Input Voltage VALUE 4.5V Maximum Input Voltage 26V Output Voltage VOUT1 IOUT1 = 0A to 15A, VIN = 4.5V to 26V Output Voltage VOUT2 IOUT2 = 0A to 15A, VIN = 4.5V to 26V 1.5V ±2% VOUT1 Maximum Output Current, IOUT1 VIN = 4.5V to 26V, VOUT1 = 1.2V 15A VOUT2 Maximum Output Current, IOUT2 VIN = 4.5V to 26V, VOUT2 = 1.5V 15A Nominal Switching Frequency -A Efficiency See Figures 2 and 3 -B Efficiency See Figures 4 and 5 1.2V ±2% 300kHz VOUT1 = 1.2V, IOUT1 = 15A, VIN = 12V 89.1% Typical VOUT2 = 1.5V, IOUT2 = 15A, VIN = 12V 90.2% Typical VOUT1 = 1.2V, IOUT1 = 15A, VIN = 12V 85.9% VOUT2 = 1.5V, IOUT2 = 15A, VIN = 12V 88.2% dc1626afa 1 DEMO MANUAL DC1626A QUICK START PROCEDURE Demonstration circuit 1626A is easy to set up to evaluate the performance of the LTC3838EFE. Please refer to Figure 1 for proper measurement equipment setup and follow the procedure below. 1. With power off, connect the input supply, load and meters as shown in Figure 1. Preset the load to 0A and VIN supply to be 0V. Place jumpers in the following positions: JP4 RUN1 ON JP1 RUN2 ON JP3 MODE FCM 2. Adjust the input voltage to be between 4.5V to 26V. VOUT1 should 1.2V ±2%. VOUT2 should 1.5V ±2%. 3. Next, apply 15A load and recheck VOUT. 4. Once the DC regulation is confirmed, observe the output voltage ripple, load step response, efficiency and other parameters. Load Step Transient Testing Demonstration circuit 1626A provides a simple load step circuit consisting of a MOSFET and sense resistor for each rail. To apply a load step, follow the steps below. 1. Preset the amplitude of a pulse generator to 0.0V and the duty cycle to 5% or less. 2. Connect the scope to the VOUT BNC connectors for the rail under test with a coax cable. To monitor the load step current, connect the scope probe across the IOSTEP+/IOSTEP– turrets for that rail. 3. Connect the output of the pulse generator to the PULSE GEN turret for the rail under test and connect the return to one of the GND turrets. 4. With the converter running, slowly increase the amplitude of the pulse generator output to provide the desired load step pulse height. The scaling for the LOAD STEP signal is 10mV/A. Note 1. Use the BNC connectors labeled VOUT1 or VOUT2 to measure the output voltage ripple. Note 2. Do not apply the load from the VO1_SNS+ turret to the VO1_SNS– turret or from the VO2+ turret to the VO2– turret. These turrets are only intended to monitor the voltage across COUT1 and COUT5 respectively. Heavy load currents applied across these turrets may damage the converter. dc1626afa 2 DEMO MANUAL DC1626A QUICK START PROCEDURE Single Output/Dual Phase Operation • Tie VFB2 to INTVCC by stuffing 0Ω at R1. This will disable the error amp for phase 2 and internally tie the two ITH signals together. A single output/dual phase converter may be preferred for high output current applications. The benefits of single output/dual phase operation is lower ripple current through the input and output capacitors, faster load step response and simplified thermal design. To implement single output/ dual phase operation, make the following modifications: • Remove the ITH compensation network, VFB divider and TRACK/SS cap for phase 2. • Tie VRNG1 to VRNG2 by stuffing 0Ω at R4. • Tie RUN1 to RUN2 by stuffing 0Ω at R7. • Tie VOUT1 to VOUT2 by tying together the exposed copper pads on the VOUT shapes with pieces of heavy copper foil. • If the optional transient detect circuit is used, externally tie the DTR1 pin to the DTR2 pin. • Re-compensate if necessary. Vout2 V + * Iin A Iout2 + Vin supply - + Vin V - Vout2 load A + A + Vout1 load Iout1 - * Monitor the voltage across COUT3 and COUT7 for accurate efficiency measurements. + V Vout1 * Figure 1. Proper Measurement Equipment Setup dc1626afa 3 DEMO MANUAL DC1626A QUICK START PROCEDURE 95 100 90 1.5V 90 1.2V EFFICIENCY (%) EFFICIENCY (%) DCM 80 85 70 60 FCM 50 40 30 80 20 1.2V 1.5V 10 75 0 5 10 15 LOAD CURRENT (A) BOTH RAILS: QTOP = RJK0305DPB QBOTTOM = RJK0330DPB L = VISHAY IHLP4040DZ-01 0.56μH DCR = 1.7mΩ TYP, 1.8mΩ MAX 0 0.01 20 dc1626a F03 100 90 EFFICIENCY (%) 1.2V 85 DCM 80 1.5V 90 70 60 FCM 50 40 30 80 20 1.2V 1.5V 10 75 100 Figure 3. Efficiency Curves for the DC1626A-A (DCR Sense) in FCM and DCM. 95 EFFICIENCY (%) 1 10 LOAD CURRENT (A) BOTH RAILS: QTOP = RJK0305DPB QBOTTOM = RJK0330DPB L = VISHAY IHLP4040DZ-01 0.56μH DCR = 1.7mΩ TYP, 1.8mΩ MAX dc1626a F02 Figure 2. Efficiency Curves for the DC1626A-A (DCR Sense) in FCM 0.1 0 5 10 15 LOAD CURRENT (A) BOTH RAILS: QTOP = RJK0305DPB QBOTTOM = RJK0330DPB L = WURTH 7443330068 0.68μH DCR = 1.35mΩ ±10% RSENSE = 2.5mΩ 20 dc1626a F04 Figure 4. Efficiency Curves for the DC1626A-B (RSENSE) in FCM 0 0.01 0.1 1 10 LOAD CURRENT (A) BOTH RAILS: QTOP = RJK0305DPB QBOTTOM = RJK0330DPB L = WURTH 7443330068 0.68μH DCR = 1.35mΩ ±10% RSENSE = 2.5mΩ 100 dc1626a F05 Figure 5. Efficiency Curves for the DC1626A-B (RSENSE) in FCM and DCM dc1626afa 4 DEMO MANUAL DC1626A QUICK START PROCEDURE 1.2VO(AC) 50mV/DIV 109mV 1.5VO(AC) 50mV/DIV 15A LOAD STEP 5A/DIV 108mV 15A LOAD STEP 5A/DIV 5A 5A dc1626a F06 Figure 6. Load Step Response of the 1.2V Rail on the DC1626A-A (DCR Sense) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R 6.3V 1206, L = 0.56μH, fSW = 300kHz 1.2VO(AC) 50mV/DIV 114mV dc1626a F07 Figure 7. Load Step Response of the 1.5V Rail on the DC1626A-A (DCR Sense) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R 6.3V 1206, L = 0.56μH, fSW = 300kHz 1.5VO(AC) 50mV/DIV 15A LOAD STEP 5A/DIV 108mV 15A LOAD STEP 5A/DIV 5A dc1626a F08 Figure 8. Load Step Response of the 1.2V Rail on the DC1626A-B (RSENSE) At VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R 6.3V 1206, L = 0.68μH, fSW = 300kHz 5A dc1626a F09 Figure 9. Load Step Response of the 1.5V Rail on the DC1626A-B (RSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R 6.3V 1206, L = 0.68μH, fSW = 300kHz dc1626afa 5 DEMO MANUAL DC1626A PARTS LIST 1626A-A (DCR Sense) ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP, X7R 330pF 50V 0603 AVX 06035C331KAT2A Required Circuit Components 1 1 C12 2 5 C3, C16, C4, C10, C13 CAP, X5R 0.1μF 50V 0603 AVX 06035D104KAT2A 3 2 C5, C14 CAP, X5R 0.01μF 25V 0603 AAC 0603D103KAT2A 4 2 C6, C11 CAP, NPO 47pF 16V 0603 AVX 0603YA470KAT4A 5 1 C7 CAP, NPO 220pF 25V 0603 AVX 06033A221KAT2A 6 1 C8 CAP, X5R 4.7μF 16V 0805 AVX 0805YD475KAT2A 7 2 C9, C18 CAP, X5R 1μF 16V 0603 AVX 0603YD105KAT2A 8 2 CIN1, CIN2 CAP, 100μF 35V SIZE-F SUNCON 35HVH100M 9 3 CIN3, CIN4, CIN5 CAP, X5R 10μF 35V 1210 TAIYO YUDEN GMK325BJ106MN-T 10 4 COUT1, COUT2, COUT5, COUT6 CAP, 330μF 2.5V SIZE 7343 SANYO 2R5TPE330M9 11 4 COUT3, COUT4, COUT7, COUT8 CAP, X5R 100μF 6.3V 1206 MURATA GRM31CR60J107ME39L 12 2 D1, D2 DIODE, SCHOTTKY SOD-323 CENTRAL SEMI. CMDSH-4ETR 13 2 L1, L2 IND, 0.56μH VISHAY IHLP4040DZERR56M01 14 2 Q1, Q3 MOSFET, N-CHANNEL LFPAK RENESAS RJK0305DPB-00-J0 15 2 Q2, Q4 MOSFET, N-CHANNEL LFPAK RENESAS RJK0330DPB-00-J0 16 2 R12, R38 RES, 100k 1% 0603 VISHAY CRCW0603100KFKEA 17 1 R13 RES, 15k 1% 0603 VISHAY CRCW060315K0FKEA 18 4 R17, R23, R40, R46 RES, 10k 1% 0603 VISHAY CRCW060310K0FKEA 19 2 R18, R32 RES, 4.02k 1% 0603 VISHAY CRCW06034K02FKEA 20 2 R19, R34 RES, 11k 1% 0603 VISHAY CRCW06011K0FKEA 21 1 R21 RES, 40.2k 1%, 0603 VISHAY CRCW060340K2FKEA 22 2 R27, R25 RES, 2.2Ω 1% 0603 VISHAY CRCW06032R20FKEA 23 1 R28 RES, 137k 1% 0603 VISHAY CRCW0603137KFKEA 24 1 R31 RES, 17.4k 1% 0603 VISHAY CRCW06017K4FKEA 25 2 R42, R43 RES, 10Ω 1% 0603 VISHAY CRCW060310R0FKEA 26 9 R8, R11, R16, R35, R39, R48, R55, R20, R36, R30, R26 RES, 0Ω 0603 VISHAY CRCW06030000Z0EA 27 2 RS1, RS2 RES, 0.000Ω 1W 1% 2512 TEPRO RN5326 28 1 U1 LTC3838 38-LEAD TSSOP LINEAR TECH. LTC3838EFE Additional Circuit Components 1 0 C1, C2, C15, C17 CAP, 0603 OPTIONAL 2 0 CIN6-CIN8 CAP, 1210 OPTIONAL 3 0 COUT13-COUT16 CAP, 7343 OPTIONAL 4 0 Q5-Q8 MOSFET, N-CHANNEL LFPAK OPTIONAL 5 0 R1, R4, R7, R9, R47, R14, R15, R24, R29, R41, R45, R3, R6, R10, R37, R44, R49, R50 RES, 0603 OPTIONAL 6 2 Q9, Q10 MOSFET, N-CHANNEL DPAK VISHAY SUD50N03-12P-E3 7 2 R51, R52 RES, 10k 1% 0603 VISHAY CRCW060310K0FKEA 8 2 R53, R54 RES, 0.01Ω 1/2W 1% 2010 VISHAY WSL2010R0100FEA dc1626afa 6 DEMO MANUAL DC1626A PARTS LIST 1626A-A (DCR Sense) ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER STAND-OFF, NYLON 0.25" KEYSTONE 8831 (SNAP ON) Hardware/Components (For Demo Board Only) 1 4 STAND-OFF 2 23 E1-E12, E14-E25 TESTPOINT, TURRET 0.095" MILL-MAX 2501-2-00-80-00-00-07-0 3 6 J1-J6 JACK, BANANA KEYSTONE 575-4 4 2 J7, J8 CONN, BNC 5PINS CONNEX 112404 5 2 JP1, JP4 2MM SINGLE ROW HEADER, 3-PIN SAMTEC TMM-103-02-L-S 6 4 JP1-JP4 SHUNT SAMTEC 2SN-BK-G 7 2 JP2, JP3 2MM SINGLE ROW HEADER, 4-PIN SAMTEC TMM-104-02-L-S PART DESCRIPTION MANUFACTURER/PART NUMBER 1626A-B (RSENSE) ITEM QTY REFERENCE Required Circuit Components 1 1 C12 CAP, X7R 330pF 50V 0603 AVX 06035C331KAT2A 2 2 C3, C16 CAP, X7R 1000pF 16V 0603 AVX 0603YC102KAT2A 3 3 C4, C10, C13 CAP, X5R 0.1μF 50V 0603 AVX 06035D104KAT2A 4 2 C5, C14 CAP, X5R 0.01μF 25V 0603 AAC 0603D103KAT2A 5 2 C6, C11 CAP, NPO 47pF 16V 0603 AVX 0603YA470KAT4A 6 1 C7 CAP, NPO 220pF 25V 0603 AVX 06033A221KAT2A 7 1 C8 CAP, X5R 4.7μF 16V 0805 AVX 0805YD475KAT2A 8 2 C9, C18 CAP, X5R 1μF 16V 0603 AVX 0603YD105KAT2A 9 2 CIN1, CIN2 CAP, 100μF 35V SIZE-F SUNCON 35HVH100M 10 3 CIN3, CIN4, CIN5 CAP, X5R 10μF 35V 1210 TAIYO YUDEN GMK325BJ106MN-T 11 4 COUT1, COUT2, COUT5, COUT6 CAP, 330μF 2.5V SIZE 7343 SANYO 2R5TPE330M9 12 4 COUT3, COUT4, COUT7, COUT8 CAP, X5R 100μF 6.3V 1206 MURATA GRM31CR60J107ME39L 13 2 D1, D2 DIODE, SCHOTTKY SOD-323 CENTRAL SEMI. CMDSH-4ETR 14 2 L1, L2 IND, 0.68μH WURTH 7443330068 15 2 Q1, Q3 MOSFET, N-CHANNEL LFPAK RENESAS RJK0305DPB-00-J0 16 2 Q2, Q4 MOSFET, N-CHANNEL LFPAK RENESAS RJK0330DPB-00-J0 17 2 R12, R38 RES, 100k 1% 0603 VISHAY CRCW0603100KFKEA 18 1 R13 RES, 15k 1% 0603 VISHAY CRCW060315K0FKEA 19 4 R14, R15, R41, R45 RES, 10Ω 1% 0603 VISHAY CRCW060310R0FKEA 20 4 R17, R23, R40, R46 RES, 10k 1% 0603 VISHAY CRCW060310K0FKEA 21 1 R21 RES, 45.3k 1% 0603 VISHAY CRCW060345K3FKEA 22 2 R27, R25 RES, 2.2Ω 1% 0603 VISHAY CRCW06032R20FKEA 23 1 R28 RES, 137k 1% 0603 VISHAY CRCW0603137KFKEA 24 1 R31 RES, 20k 1% 0603 VISHAY CRCW060320K0FKEA 25 2 R42, R43 RES, 10Ω 1% 0603 VISHAY CRCW060310R0FKEA 26 9 R8, R11, R16, R35, R39, R48, R55, R24, R29 RES, 0Ω 0603 VISHAY CRCW06030000Z0EA 27 2 RS1, RS2 RES, SENSE 0.0025 2512 VISHAY WSL25122L500FEA 28 1 U1 LTC3838 38-LEAD TSSOP LINEAR TECH. LTC3838EFE dc1626afa 7 DEMO MANUAL DC1626A PARTS LIST 1626A-B (RSENSE) ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP, 0603 OPTIONAL Additional Circuit Components 1 0 C1, C2, C15, C17 2 0 CIN6-CIN8 CAP, 1210 OPTIONAL 3 0 COUT13-COUT16 CAP, 7343 OPTIONAL 4 0 Q5-Q8 MOSFET, N-CHANNEL LFPAK OPTIONAL 5 2 Q9, Q10 SUD50N03-12P-E3 VISHAY SUD50N03-12P-E3 6 0 R1, R4, R7, R9, R47, R18, R19, R20, R32, R34, R20, R36, R3, R6, R10, R37, R44, R49, R50, R30, R26 RES, 0603 OPTIONAL 7 2 R51, R52 RES, 10k 1% 0603 VISHAY CRCW060310K0FKEA 8 2 R53, R54 RES, 0.01Ω 1/2W 1% 2010 VISHAY WSL2010R0100FEA Hardware/Components (For Demo Board Only) 1 4 STAND-OFF STAND-OFF, NYLON 0.25" KEYSTONE, 8831 (SNAP ON) 2 23 E1-E12, E14-E25 TESTPOINT, TURRET 0.095" MILL-MAX 2501-2-00-80-00-00-07-0 3 6 J1-J6 JACK, BANANA KEYSTONE 575-4 4 2 J7, J8 CONN, BNC 5-PINS CONNEX 112404 5 2 JP1, JP4 2MM SINGLE ROW HEADER, 3-PIN SAMTEC TMM-103-02-L-S 6 4 JP1-JP4 SHUNT SAMTEC 2SN-BK-G 7 2 JP2, JP3 2MM SINGLE ROW HEADER, 4PIN SAMTEC TMM-104-02-L-S dc1626afa 8 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. A B C D OFF ON JP1 RUN2 RUN2 1 FCM OFF ON E19 E16 E15 R49 OPT C18 1uF EXTVCC R50 OPT VIN RUN1 C17 OPT R44 OPT R37 TRK/SS1 OPT -A (DCR SENSE) -B (RSENSE) ASSY 5 Vishay IHLP4040DZ-01 0.56uH WURTH 7443330068(0.68uH) L1,L2 2. INSTALL SHUNTS ON JUMPERS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. NOTES: UNLESS OTHERWISE SPECIFIED GND EXTVCC PGOOD1 RUN1 2 E10 E9 E8 3 2 R23 10K E14 TRK/SS1 CLKOUT PLLIN JP4 RUN1 R39 0 INTVCC C2 OPT R55 0 * * R31 R46 10K R40 10K 0.1uF 1000pF C16, C3 C15 OPT R24 * * C3 * S1- 17 16 15 14 13 12 11 18 C16 * 19 S1+ 9 8 7 10 VRNG2 6 5 4 3 2 1 INTVCC 4.02K OPT 33 34 35 36 37 28 29 30 22 23 24 25 26 DTR1 20 RUN1 21 PGOOD1 BOOST1 TG1 SW1 BG1 DRVCC1 27 VIN PGND INTVCC EXTVCC 31 11K OPT 4 0 OPT R36,R20 C13 0.1uF R47 OPT 0.000 Ohm 2512 0.0025 Ohm 2512 E23 E22 VOUT1 4 4 RJK0305DPB Q3 RJK0330DPB Q4 J7 1 RJK0330DPB Q2 OPT 0 3 0 OPT 17.4K 20K 4 SW1 4 40.2K 45.3K R21 1 L2 * R18 * CIN5 10uF 35V 1210 CIN3 10uF 35V 1210 L1 R32 * * S1- * R36 * R34 S1+ GND IOSTEP2- IOSTEP2+ CUSTOMER NOTICE E20 PULSE1 E25 E24 2 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. R51 10K E17 LOAD STEP 10mV / A 5% DUTY CYCLE MAX J8 COUT3 100uF 6.3V 1206 1 HZ MIKE S. SCALE = NONE APP ENG. PCB DES. APPROVALS VOUT2 330uF 2.5V 7343-D15T E12 E11 R52 10K J6 J5 E7 J4 J3 GND DATE 5-11-11 OPT 7343-D15T + COUT16 OPT 7343-D15T + COUT14 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only OPT 7343-D15T + COUT15 VOUT2 OPT 7343-D15T + COUT13 VOUT1 ONLY ADD FOOTPRINTS ON SOLDERMASK, DO NOT SHOW IN SCHEMATIC. OPTIONAL COUT MIKE S. APPROVED DATE: N/A SIZE LTC3838EFE 1 DEMO CIRCUIT 1626A Thursday, October 13, 2011 IC NO. SHEET 1 OF 1 2 REV. WIDE INPUT RANGE, HIGH EFFICIENCY DUAL STEP-DOWN DC-DC CONVERTER TECHNOLOGY E21 PULSE2 GND VOUT1 1.2V / 15A VO2- GND VOUT2 1.5V / 15A VO2+ VIN- GND VIN 4.5V - 26V VIN+ E18 VO1_SNS- TITLE: SCHEMATIC 1 E5 J2 J1 E3 E6 1 REVISION HISTORY DESCRIPTION PRODUCTION VO1_SNS+ + COUT1 Q10 SUD50N03-12P R54 0.01 2010 VOUT2 R43 10 330uF 2.5V 7343-D15T + COUT2 VOUT1 330uF 2.5V 7343-D15T 100uF 35V 35HV100M + CIN1 2 REV + COUT5 100uF 35V 35HV100M 330uF 2.5V 7343-D15T R42 10 __ ECO VIN +CIN2 + COUT6 CIN6 OPT 1210 COUT7 100uF 6.3V 1206 CIN7 (OPT) 1210 VOUT2 COUT4 100uF 6.3V 1206 COUT8 100uF 6.3V 1206 CIN8 (OPT) 1210 LOAD STEP CIRCUIT #2 * 2512 RS1 * * S2- 2512 RS2 2 R20 * R19 S2+ DCR SENSE FILTER / DIVIDER FOR PHASE 2 CIN4 10uF 35V 1210 DCR SENSE FILTER / DIVIDER FOR PHASE 1 OPT Q6 OPT Q5 OPT Q8 OPT Q7 Q9 SUD50N03-12P R53 0.01 2010 VOUT1 RJK0305DPB Q1 4 SW2 4 NOTE: EXTERNALLY TIE THE DTR1 PIN TO THE DTR2 PIN IF THE TRANSIENT DETECT CIRCUIT IS USED R29,R24 R30,R26 R31 IOSTEP1- IOSTEP1+ LOAD STEP 10mV / A 5% DUTY CYCLE MAX LOAD STEP CIRCUIT #1 INTVCC 4 4 R27 2.2 RUN2 VRNG2 CMDSH-3 D1 C8 4.7uF 16V 0805 R48 0 R41,R45, R14,R15, RS1, RS2 OPT 10 3 INTVCC D2 CMDSH-3 R7 OPT R4 OPT R1 OPT R38 100K INTVCC R350 C10 0.1uF C9 INTVCC 1uF R25 2.2 C4 0.1uF R12 100K RUN1 VRNG1 VFB2 OPTIONAL COMPONENTS FOR SINGLE OUTPUT, DUAL PHASE OPERATION INTVCC R160 DRVCC2 32 EXTVCC BG2 SW2 TG2 BOOST2 PGOOD2 RUN2 38 NOTE: TIE SGND PIN TO PGND PAD UNDERNEATH IC. SENSE1- SENSE1+ VOUTSENSE1- U1 LTC3838EFE VOUTSENSE1+ TRACK/SS1 ITH1 VRNG1 RT SGND CLKOUT MODE/PLLIN PHASEMD VRNG2 ITH2 TRACK/SS2 VFB2 SENSE2+ SENSE2- DTR2 R11 0 4 R32, R18 R34,R19 R45 S2+ S2- VRNG1 R41 * TRK/SS1 C12 330pF * * OPT TRK/SS2 C7 220pF R15 R14 R9 R28 137K C11 47pF R29 C14 0.01uF * R30 * C6 47pF FSW = 300kHz R26 * C5 0.01uF R13 VFB2 15K R21 VOUT2 R10 OPT TRK/SS2 C1 OPT INTVCC SYNC DCM 0 R6 OPT R3 OPT R17 10K 2 R8 VIN RUN2 3 90 DEG 60 DEG JP3 MODE E4 2 INTVCC 120 DEG JP2 PHASMD CLKOUT TRK/SS2 3 1 4 1 4 1 3 PGND 39 5 1 2 3 5 1 2 3 5 1 2 3 5 1 2 3 5 4 3 2 5 1 2 3 5 1 2 3 5 1 2 3 5 1 2 3 5 2 3 E2 5 4 3 2 E1 2 3 PGOOD2 A B C D DEMO MANUAL DC1626A SCHEMATIC DIAGRAM dc1626afa 9 DEMO MANUAL DC1626A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1626afa 10 Linear Technology Corporation LT 1011 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011