DESCRIPTION The demo circuit 7A is a dual current mode PWM step-down DC/DC converter featuring LT 99. The demo circuit is designed for V and.v outputs from a 7V to 60V input. The current capability of each channel is up to A when running individually and A when both are sourcing the same current without special heat sinking. Individual soft-start, current limit, comparator, input voltage for each output as well as frequency division and synchronous and clock output functions simplify the complex design of dual-output power converters Both converters are synchronized to either a common external clock input or a resistor programmable 0kHz to MHz internal oscillator. At all frequencies, a 80 phase shift between channels is maintained, reducing voltage ripple. Programmable frequency allows optimization between efficiency and external component size. Each output can be independently disabled using its own SHDN pin and be placed in a low quiescent current shutdown mode. The LT99 data sheet gives complete description of the device, operation and application information. The data DEMO MANUAL DC7A LT99A Monolithic Dual Tracking A Step-Down Switching Regulator sheet must be read in conjunction with this quick start guide for demo circuit 7A. Design files for this circuit board are available at http://www.linear.com/demo EFFICIEY (%) 00 9 90 8 80 7 70 6 V OUT = V V OUT =.V 60 0. 0.6 0.9...8...7.0 LOAD CURRENT FOR SIGNAL CHANNEL (A) DC7a F0 Figure. Single Channel Efficiency at V IN = V, f = 00kHz L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMAE SUMMARY Specifi cations are at T A = C. PARAMETER CONDITIONS VALUE Minimum Input Voltage 7V Maximum Input Voltage 60V (For Transient. Continuous Operation if D and D Are Replaced with Higher Voltage Rated Schottky Diodes) Output Voltage V OUT V IN = 7~ 60V.0V ±% Output Voltage V OUT V IN = 7~ 60V.V ±% Switching Frequency 00kHz ±0% Maximum Output Current I OUT V IN = 7~ 60V A Individually, A Both Running Maximum Output Current I OUT V IN = 7~ 60V A Individually, A Both Running Voltage Ripple V OUT V IN = V, I OUT = A <0mV Voltage Ripple V OUT V IN = V, I OUT = A <0mV
DEMO MANUAL DC7A DESCRIPTION 00 9 90 0.9 0.8 V OUT = V/A, V OUT NO LOAD V OUT =.V/A, V OUT NO LOAD 0.9 0.8 EFFICIEY (%) 8 80 7 70 6 T J PIN VOLTAGE (V) 0.7 0.6 0. T J PIN VOLTAGE (V) 0.7 0.6 0. 60 0. 0. 0.6 0.8.0...6.8.0 LOAD CURRENT FOR BOTH CHANNELS (A) 0. 0 0 0 0 V IN (V) 0. 0 0 0 0 V IN (V) DC7a F0 DC7a F0 DC7a F0 Figure. Dual Channel Efficiency at V IN = V, f = 00kHz Figure. DC7A T J Pin Voltage When Channels Running Individually at A Load (T A = C) Figure. DC7A T J Pin Voltage When Both Channels Sourcing A Current at Meantime (T A = C) QUICK START PROCEDURE Demo circuit 7A is easy to set up to evaluate the performance of the LT99. Refer to Figure 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 directly across the VIN or VOUT and terminals. See Figure 6 for proper scope probe technique.. Place JP on the SINGLE position.. With power off, connect the input power supply to VIN and. (Connect another input power supply to VIN and if DUAL is selected.). Turn on the power at the input. NOTE. Make sure that the input voltage does not exceed 60V (Due to part selection on D and D, 60V is for transient purpose. Continuous operation can be available after D and D are replaced with higher voltage rated schottky diodes).. Check for the proper output voltages. NOTE. If there is no output, temporarily disconnect the load to make sure that the load is not set too high.. Once the proper output voltages are established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. ADDITIONAL NOTES If an EMI filter is desirable on VIN, it can be feasibly installed on the back of the board in the optional circuit area. However, a trace cut is required for the insertion of the optional circuit. See Figure 7 for the cut line.
DEMO MANUAL DC7A QUICK START PROCEDURE Figure. DC7A Proper Equipment Setup VIN Figure 6. Measuring Input or Output Ripple Figure 7. Cut Line for the EMI Filter Installation
DEMO MANUAL DC7A PARTS LIST ITEM QTY REFEREE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components C, C, C, C CAP,.μF 0% X7R AVX CKATA C, C CAP, 0.7μF 0% V X7R MURATA GRM88R7E7KAD C7, C8 CAP, 00μF 0% 0V XR TAIYO YUDEN LMKABJ07MM-T C0, C CAP, 00 pf 0% V NPO AVX 00A0KATA C, C CAP, 00 0.μF 0% 6V X7R TDK C00X7RC0K 6 C, C CAP, 00 680pF 0% V X7R AVX 00C68KATA 7 C6, C7 CAP, 00 pf 0% V NPO AVX 00A0KAT 8 C CAP, 00 0nF 0% 6V X7R MURATA GRMR7C0KA0D 9 D, D DIODE, SCHOTTKY BARRIER SOD ON SEMICONDUCTOR MMSD70TG 0 D, D DIODE, SCHOTTKY RECTIFIER SMB DIODES I. B60B L IND, μh NIC NPIM0B0MTRF L IND, 0μH NIC NPIM0B00MTRF R, R RES, kω /6W NIC NRC06F00TRF R RES, 00.kΩ /6W VISHAY CRCW00KFKED R6 RES, 00.9kΩ /6W VISHAY CRCW00K9FKED 6 R7, R8 RES, 00 00kΩ % /6W VISHAY CRCW0000KJNED 7 R9, R0 RES, 00 8.06kΩ /6W VISHAY CRCW008K06FKED 8 R, R RES, 00 00kΩ /6W VISHAY CRCW0000KFKED 9 R, R RES, 00 0kΩ /6W NIC NRC0F00TRF 0 R RES, 00 7.kΩ /6W VISHAY CRCW007KFKED R6 RES, 00 0kΩ /6W VISHAY CRCW000K0FKED R7 RES, 00 0.kΩ /6W VISHAY CRCW000KFKED U IC, STEP-DOWN REGULATOR LINEAR TECHNOLOGY LT99EFE Additional Demo Board Circuit Components C, C CAP, μf 0% OSCON SUON 00CEBS 0 C6, C9 CAP, 080 0μF 0% 6V XR ION MURATA GRMBR6C06KEL ION 0 C8 CAP, uf 0% OSCON ION SANYO 00CEBS ION 0 C9 CAP, 0.0μF 0% X7R ION AVX C0KAT ION 0 C0 CAP,.μF 0% X7R ION AVX CKATA ION 6 0 C CAP, 00 0nF 0% 6V X7R ION MURATA GRMR7C0KA0D ION 7 0 D, D6 DIODE, SCHOTTKY BARRIER SOD ION ON SEMICONDUCTOR MMSD70TG ION 8 0 D7, D8 DIODE, ION 9 0 R8 RES, 0Ω JUMPER ION VISHAY CRCW0000Z0EA ION 0 0 FB FERRITE BEAD ION TAIYO YUDEN FBMJ6HS800 ION 0 L IND, μh ION VISHAY IHLP00DZ-0 ION Hardware/Components (For Demo Board Only) JP HEADER, -PIN SAMTEC TMM-0-0-L-S 8 TP, TP, TP TO TP8, TP6, TP7 TURRET MILL-MAX 0--00-80-00-00-07-0 9 TP, TP, TP9 TO TP TURRET MILL-MAX 08--00-80-00-00-07-0 JP SHUNT, mm SAMTEC SN-BK-G
DEMO MANUAL DC7A SCHEMATIC DIAGRAM INPUT MODE SINGLE REVISION HISTORY ECO REV DESCRIPTION DATE APPROVED PRODUCTION 0-7- EDWIN L. VOUT CASCADE DUAL JP [] VIN D VIN D VIN 7V - 60V TP TP + C uf C.uF C.uF R k VIN VOUT VOUT VIN D7 D6 MMSD70TG C 0.7uF D MMSD70TG U LT99EFE 8 SW BST SW 0 L 0uH D MMSD70TG R k C.uF C.uF TP6 + C uf VIN 7V - 60V VIN 6 SHDN BST SHDN VIN 6 SHDN TP D B60B uh L D B60B C 0.7uF D8 D MMSD70TG TP7 TP SHDN 8 C C IND IND VOUT VOUT VOUT VOUT 6 VOUT VOUT V/A * TP C6 C7 9 FB FB C8 C9 TP6 * 0uF 00uF R C0 C R6 00uF 0uF 6V 0V.K CMPI.9K 0V 6V 8 R7 pf pf R8 CMPI 080 00K CMPO 00K 080 7 CMPO CMPO SS TP7 TP9 TP C 0.uF C 680pF R9 8.06K R 00K R 0k 0 7 SS ILIM VC RT/SY DIV SS ILIM VC CLKOUT TJ 6 9 8 7 R 0k R0 8.06K R 00K C 680pF C 0.uF TP8 TP0 TP CMPO SS C6 pf C7 pf 0 9 R8 9 SY TP CLKOUT TP 7 C R R6 TEMP 0nF TP 7.k 0k B B C R7 0.k (00kHz) 0nF 9 P VIN VIN FB BEAD L uh C9 0.0uF C0.uF C8 + uf NOTES: UNLESS OTHERWISE SPECIFIED, TECHNOLOGY JW A A [] SEE QUICK START GUIDE FOR DETAILS ON JP SETTING AND INPUT VOLTAGE IMPLEMENTATION ORDER. EDWIN L. DUAL MONOLITHIC STEP-DOWN. ALL CAPACITORS ARE 00. CONVERTER ALL RESISTORS ARE 00. * SEE QUICK START GUIDE FOR DETAILS ON CURRENT CAPABILITY. LT99EFE DEMO CIRCUIT 7A Tuesday, January 7, 0 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.
DEMO MANUAL DC7A 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 0 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, ILUDING 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, IIDENTAL, 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 60 McCarthy Blvd. Milpitas, CA 90 Copyright 00, Linear Technology Corporation 6 LT 0 PRINTED IN USA Linear Technology Corporation 60 McCarthy Blvd., Milpitas, CA 90-77 (08) -900 FAX: (08) -007 www.linear.com LINEAR TECHNOLOGY CORPORATION 0