QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568 DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR LTC3407 DESCRIPTION Demonstration circuit 568 is a Dual Synchronous, 600mA, 1.5MHz Step-Down DC/DC Regulator featuring the LTC®3407. The DC568 has an input voltage range of 2.5V to 5.5V, and either output is capable of delivering up to 600mA of output current. In Burst Mode operation, the LTC3407 requires only 40 uA of quiescent current, and the DC568 provides higher efficiency at light load currents. In Pulse Skip mode, the DC568 provides lower output ripple voltage at light load currents. In either mode, the DC568 can provide up to 96% efficiency on either channel and consumes less than 1uA in shutdown. The LTC3407 comes in a small 10-Pin MS10E package, which has an exposed pad on the bottom-side of the IC for better thermal performance. These features, plus the nominal operating frequency of 1.5MHz (allowing the exclusive use of low profile surface mount components), make the DC568 demo board an ideal circuit for use in battery-powered, hand-held applications. Design files for this circuit board are available. Call the LTC factory. LTC and Burst Mode is registered trademark of Linear Technology Corporation. Table 1. Performance Summary (T A = 25°C) PARAMETER Minimum Input Voltage CONDITION VALUE 2.5V Maximum Input Voltage 5.5V 1.2V ±2% Output Voltage VOUT1 VIN = 2.5V to 5.5V, IOUT1 = 0A to 600 mA 1.5V ±2% 1.8V ±2% Typical Output Ripple VOUT1 VIN = 5V, IOUT1 = 600 mA (20 MHz BW) 20mVP–P Line ±1% Load ±1% Output Voltage VOUT2 VIN = 2.5V to 5.5V, IOUT2 = 0A to 600 mA 2.5V ±2% Typical Output Ripple VOUT2 VIN = 5V, IOUT2 = 600 mA (20 MHz BW) 20mVP–P Line ±1% Load ±1% Output Regulation Output Regulation Nominal Switching Frequency 1.5 MHz QUICK START PROCEDURE Demonstration circuit 568 is easy to set up to evaluate the performance of the LTC3407. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the probe tip 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568 DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR directly across the VIN or VOUT and GND terminals. See Figure 2 for proper scope probe technique. 1. Connect the input power supply to the VIN and GND terminals on the left-side of the board. Do not hot-plug VIN or increase VIN over the rated maximum supply voltage of 5.5V, or the part may be damaged. Connect the loads between the VOUT and GND terminals on the right-side of the board. Refer to figure 1 for the proper measurement equipment setup. 2. Before proceeding to operation, insert jumpers JP1 and JP2 into the OFF positions, jumper JP3 into the VOUT1 voltage position of choice (1.2V, 1.5V, and 1.8V), and jumper JP4 into the desired mode of operation: Pulse Skip or Burst Mode. 3. Apply 3.3V at VIN. Measure both VOUTs; they should read 0V. If desired, one can measure the shutdown supply current at this point. The supply current will be approximately 33 uA in shutdown, with roughly 32 uA due to the optional 100k• pullup resistor of the Power-On Reset (POR) feature. This resistor can be removed, and the actual shutdown supply current can be measured, if the POR feature is not required. 4. Turn on VOUT1 and VOUT2 by changing jumpers JP1 and JP2 from the OFF position(s) to the ON position(s). Vary the input voltage from 2.5V to 5.5V and adjust each load current from 0 to 600mA. Both output voltages should be regulating. 5. Set the load current of both outputs between 200 mA and 600 mA, and measure both output ripple voltages; they should measure less than 20 mVAC each. Also, observe the voltage waveform at the switch node (pin 3) of each regulator. The switching frequencies should be between 1.2 MHz and 1.8 MHz (T = 0.833 us and 0.555 us), and each switch node waveform should be rectangular in shape. 6. To change the mode of operation, change jumpers JP1 and JP2 from the ON position(s) to the OFF position(s). Then change jumper JP4 to the alternative position. Re-insert jumpers JP1 and JP2 into the ON position(s). Observe the voltage waveform at both switch nodes. When finished, insert jumpers JP1 and JP2 to the OFF position(s) and disconnect the power. 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568 DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568 DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR 4 5 4 3 2 1 REVISION HISTORY ECO REV DESCRIPTION 3 D ON OFF R1 4.7M 5% C1 604K 10pF 1 FBK1 GND R8 R9 604K 402K 301K LTC3407EMS VIN 1.8V 1.5V R5 1.2V E4 1 C L2 SW2 7 VOUT2 E3 2.2uH FBK2 10 C2 R6 10pF 887K 2.5V @ 600mA COUT2 C4 10uF OPTIONAL 6.3V GND R7 BURST MODE E6 280K 2 3 JP3 5% R10 4.7M 5% B 4.7M POR 8 MODE/SYNC R4 OFF 6 COUT1 10uF 6.3V GND C3 CH.2 RUN2 9 4 SW1 5 2.2uH OPTIONAL 2 RUN1 ON R3 100K L1 VOUT1 E2 R2 U1 3 JP2 2 JP1 2 1 CH.1 E5 1.2V/1.5V/1.8V @ 600mA D VIN 3 CIN 10uF 6.3V 1 + 3 E1 C JP4 1 B POR PULSE SKIP E7 CONTRACT NO. APPROVALS DRAWN MEI DATE 02/19/03 CHECKED A APPROVED ENGINEER DESIGNER Wednesday, June 11, 2003 5 APPROVED 02/19/03 VIN VIN 2.5V-5.5V C5 47uF 10V GND DATE PROTO 4 3 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 TITLE A SCH, LTC3407EMS DUAL DC/DC CONVERTER SIZE CAGE CODE DWG NO FILENAME: 568A-3.DSN SCALE: 2 REV DC568A 3 SHEET 1 1 OF 1 Linear Technology Corporation LTC3407EMS Item 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 Qty 3 2 0 1 7 3 1 2 3 1 2 1 1 1 1 1 Ref COUT1,COUT2,CIN C2,C1 C3,C4 C5 E1,E2,E3,E4,E5,E6,E7 JP1,JP2,JP4 JP3 L1,L2 R1,R3,R10 R2 R4,R5 R6 R7 R8 R9 U1 DC568A Rev 3 6/17/2005 Parts List Desc CAP, X5R 10uF 6.3V 20% 0805 CAP, NPO 10pF 50V 10% 0402 CAP, 0805 CAP, TANT 47uF 10V 20% 6032 TURRETS HEADER, 3P 2mm HEADER, 3X2 2mm IND, 2.2uH RES, 4.7M OHMS 5% 1/16W 0402 RES, 100K OHMS 1% 1/16W 0402 RES, 604K OHMS 1% 1/16W 0402 RES, 887K OHMS 1% 1/16W 0402 RES, 280K OHMS 1% 1/16W 0402 RES, 402K OHMS 1% 1/16W 0402 RES, 301K OHMS 1% 1/16W 0402 IC, LTC3407EMS 1 of 1 Part Number TAIYO YUDEN JMK212BJ106MG AVX 04025A100KAT TBD AVX TAJW476M010R MILL-MAX 2501-2 COMM CON 2802S-03-G1 COMM CON 2202S-06G1 TAIYO YUDEN LQLBC25182R2M AAC CR05-475JM AAC CR05-1003FM AAC CR05-6043FM AAC CR05-8873FM AAC CR05-2803FM AAC CR05-4023FM AAC CR05-3013FM LINEAR TECH. LTC3407EMS