DEMO MANUAL DC2117A. LTC3895EFE High Input Voltage Synchronous Buck Converter DESCRIPTION PERFORMANCE SUMMARY

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1 DEMO MANUAL DC7A DESCRIPTION LTC89EFE High Input Voltage Synchronous Buck Converter Demonstration circuit 7A is a single output high voltage nonisolated synchronous step-down converter that drives all N-channel MOSFET power stage. It features the LTC89EFE, a high voltage step-down DC/DC controller housed in a TSSOP-8 package with several pins removed for high voltage spacing. This DC7A operates over an input voltage range from V to 0V, while the LTC 89 can operate up to 0V. This demo board produces a V output voltage with up to a A output current, and is configured with a sense resistor for over current protection and has optional DCR sensing. To prevent high on-chip power dissipation in high input voltage applications, the LTC89 includes an NDRV pin which drives the gate of an optional external N-channel MOSFET acting as a low dropout linear regulator to supply IC power and is an option on this board. An internal charge pump allows for 00% duty cycle operation in dropout, a useful feature when powered from a battery during discharge. The LTC89 s powerful Ω N-channel MOSFET gate drivers can be adjusted from V to 0V to enable the use of logic- or standard-level MOSFETs to maximize efficiency. The EXTV CC pin permits the LTC89 to be powered from the output of the switching regulator or other available source, reducing power dissipation and improving efficiency. A mode selector allows the DC7A to operate in forced continuous operation, pulse-skipping or low ripple Burst Mode operation during light loads. Additional features include a power good output signal, a PLLIN, PHASEMD and CLKOUT for multiphase operation. The LTC89 data sheet gives a complete description of the part, operation and application information and must be read in conjunction with this demo board manual. Design files for this circuit board are available at L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY Specifications are at T A = C Table. PARAMETER CONDITIONS UNITS Input Voltage Range DC Up to 0V PK Transient V ~ 0V Output Voltage V OUT V IN = ~0V, I OUT = 0~A, JP: FCM V ± % (.76V ~.V) Maximum Output Current I OUT(MAX) V IN = ~0V A Default Operating Frequency (Typical) 0kHz External Clock Sync Frequency Range 7kHz to 80kHz Typical Full Load Efficiency (See Figure ) V IN = 8V, V OUT = V, I OUT = A, f SW = 0kHz 9.9% *Important Note: 60V or higher voltage can result in an electric shock if care is not taken. Also, hot plugging the circuit to a power supply that has more than 0V present at its output can produce a high voltage transient exceeding the absolute maximum input voltage which can damage the DC7A board. dc7afa

2 DEMO MANUAL DC7A QUICK START PROCEDURE Demonstration circuit DC7A is easy to set up to evaluate the performance of the LTC89EFE. 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 V IN or V OUT and terminals or directly across relevant capacitor. See Figure for proper scope probe technique.. Place jumpers in the following positions: JP JP JP JP8 ON FCM ON OFF. With power off, connect the input power supply to V IN and.. Turn on the power at the input. NOTE. Make sure that the input voltage is higher than V and does not exceed 0V.. Check the output voltage. The output voltage should be between.76v and.v. Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, output voltage ripple, efficiency and other parameters. NOTE. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. Figure. Proper Measurement Equipment Setup dc7afa

3 DEMO MANUAL DC7A QUICK START PROCEDURE + C OUT V OUT Figure. Measuring Input or Output Ripple Across Terminals or Directly Across Ceramic Capacitor FREQUENCY SYNCHRONIZATION AND MODE SELECTION Demonstration circuit 7A s mode selector allows the converter to run in forced continuous operation, pulseskipping operation, Burst Mode operation or Burst Mode operation with adjustable clamp level by changing the position of JP. To synchronize the DC7A to an external clock, apply the sync signal to the PLLIN turret. Depending upon the JP setting, the DC7A will operate in different modes. See Table for the detailed description. Table. Mode Selection and Synchronized Operation Options CONFIGURATION JP MODE WITH SYNC SIGNAL SUPPLIED TO PLLIN Forced Continuous Operation FCM FCM Pulse-Skipping Operation PS PS Burst Mode Operation with Adjustable Clamp Level BURST ADJ FCM Burst Mode Operation with Default Clamp BURST DEFAULT FCM 00% DUTY Demonstration circuit 7A features 00% duty cycle operation in dropout. Set the JP to ON position to activate this feature. Set JP to OFF position disables the internal charge pump and enables boost refresh, allowing for 99% duty cycle operation in dropout. dc7afa

4 DEMO MANUAL DC7A IONAL INDUCTOR DCR CURRENT SENSING Demonstration circuit 7A provides an optional circuit for inductor DCR current sensing. Inductor DCR current sensing uses the DCR of the inductor to sense the inductor current instead of discrete sense resistors. The advantages of DCR sensing are lower cost, reduced board space and higher efficiency, but the disadvantage is a less accurate current limit. If DCR sensing is used, be sure to select an inductor current with a sufficiently high saturation current or use an iron powder type material. Refer to Table for optional inductor DCR current sensing setup and to the data sheet for more details. Table. Optional Inductor DCR Current Sensing CONFIGURATION RS R R8 C6 R7 R8 R9 R0 Current Sense Ref Sch Ref Sch Ref Sch OPEN OPEN OPEN OPEN OPEN Resistor (Default) Inductor DCR Current Sensing 0Ω Copper OPEN OPEN Calculated Value from Data Sheet 0Ω 0Ω LOW QUIESCENT CURRENT APPLICATIONS AND MEASUREMENT The typical quiescent current (I Q ) of the LTC89 controller is 0µA in sleep mode as specified in the LTC89 data sheet. However, the input current of the DC7A board can be higher than this value because of additional circuit outside of the IC. To reduce the total input current, large value FB divider resistors should be used. In addition, some jumpers and resistors should be configured accordingly. Refer to Table for the low input quiescent current setup. Table. Low Input Quiescent Current Configuration Reference Designator R R R JP JP JP JP8 Function OVLO PGOOD INTV CC Jumper MODE Selector 00% DUTY BIAS Supply Stuffing Option OPEN 0Ω OPEN OPEN BURST ADJ or BURST DEFAULT OFF OFF dc7afa

5 DEMO MANUAL DC7A EXTV CC BIAS SUPPLY By default, the DC7A EXTV CC turret is tied to the V V OUT to save IC power loss. To power the EXTV CC from onboard bias supply:. Leave the JP7 OPEN. This step disconnects the EXTV CC from V OUT.. Keep the JP8 at the ON position. The onboard BIAS supply output voltage is V. Alternatively, EXTV CC can also be powered by an external power supply:. Leave the JP7 OPEN.. Keep the JP8 at the OFF position.. Apply a DC voltage (<V) between the EXTV CC and turret, after the input voltage is established. Ensure that EXTV CC V IN EFFICIENCY (%) V IN = 8V V IN = 0V V IN = 7V I OUT (A) DC7a F0 Figure. DC7A V OUT Typical Efficiency vs Load Current dc7afa

6 DEMO MANUAL DC7A EXTV CC BIAS SUPPLY 0MHz BW V OUT 00mV/DIV 00µs/DIV DC7a F0 Figure. DC7A V OUT.A ~.A Load Transient at V IN = 8V 0MHz BW V OUT 00mV/DIV 00µs/DIV DC7a F0 Figure. DC7A V OUT.A ~.A Load Transient at V IN = 0V 6 dc7afa

7 DEMO MANUAL DC7A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components CIN CAP, 00μF 0% 00V ELEC NIC NRB-XS0M00V6x0TBF CIN, CIN, CIN, CIN, C CAP, 8 0.7μF 0% 00V X7R MURATA GRMDR7E7KW0L CIN6, CIN7 CAP, 0 0.μF 0% 00V X7R MURATA GRMDR7D0KW0L COUT CAP, 0 μf 0% 6V X7R TDK CX7RC6K COUT, COUT CAP, 7 0μF 0% 6V AVX TPSD7M06R0 6 C, C, C CAP, μF 0% V X7R TDK C608X7RE0K 7 C CAP, 060 nf 0% 0V X7R AVX 060C0KATA 8 C6 CAP, pF 0% 0V X7R AVX 060C7KATA 9 C7 CAP, 060 μf 0% 6V X7R TDK C608X7RC0M 0 C9 CAP, 060 0pF 0% 0V X7R AVX 060C00KATA C0 CAP, pF % 0V NPO AVX 060A0JATA C CAP, μF 0% 00V VISHAY VJ06YMXCAC C CAP, 060.7μF 0% 6V XR TDK C608XRC7M080AC C CAP, 0.7μF 0% 6V X7R AVX 0YC7KATA L IND, μh % WURTH ELEKTRONIK L IND, 70μH COILCRAFT MSS08T-7KLB 7 L IND,.0μH VISHAY IHLP-66BZERR0M 8 Q, Q, Q XSTR, N-CHANNEL DMOS FET INFINEON BSC0NNSG 9 RS RES, 0.006Ω % /W VISHAY WSL6L000FEA8 0 R RES, 060 9k % /0W VISHAY CRCW0609KFKEA R RES, 060.7k % /0W VISHAY CRCW060K7FKEA 8 R8, R0, R, R, R7, R8, R9, R RES, 060 0Ω JUMPER VISHAY CRCW Z0EA R9 RES, 060 0M % /0W VISHAY CRCW0600M0JNEA R RES, 060.Ω % /0W VISHAY CRCW060R0JNEA R RES, 060 0k % /0W VISHAY CRCW0600K0FKEA 6 R RES, 060 0k % /0W VISHAY CRCW0600K0JNEA 7 R RES, 060 0k % /0W VISHAY CRCW0600KFKEA 8 R6, R7, R RES, k % /0W VISHAY CRCW06000KJNEA 9 R8 RES, k % 0.W VISHAY CRCW0609K9FKEA 0 R RES, k % /0W VISHAY CRCW0600KFKEA R6 RES, k % /0W VISHAY CRCW06080K6FKEA R0, R6 RES, 060 0Ω % /0W VISHAY CRCW0600R0FKEA R RES, 060 M % /0W VISHAY CRCW060M00FKEA R RES, k % /0W VISHAY CRCW06067KFKEA R RES, k % /0W VISHAY CRCW06096KFKEA 6 U IC, SYNCHRONOUS BUCK CONVERTER LINEAR TECH. LTC89EFE 7 U IC, SYNCHRONOUS STEP-DOWN LINEAR TECH LTC69EMSE REGULATOR dc7afa 7

8 DEMO MANUAL DC7A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Additional Demo Board Circuit Components 0 CIN8 CAP, 8 ION ION 0 COUT CAP, 7 ION ION 0 C, C, C8, C6 CAP, 060 ION ION 0 D, D DIODE, ION ION 0 L ALTERNATE IND, μh % WURTH ELEKTRONIK L IND, μh ION COILCRAFT SER9H-KL ION 7 0 Q XSTR, POWER ION 8 0 Q XSTR, NMOS ION ION 9 0 Q6, Q7 XSTR, IMOS POWER -TRANSISTOR INFINEON IPD0N0N G ION ION 0 0 Q, Q XSTR, ION ION 0 R, R, R, R6, R7, R, R9, R0, R, RES, 060 ION ION R7, R8, R9, R0 0 R RES, 06 ION ION Hardware E, E, E, E, E6, E7, E8, E9, E0, E, E TURRET MILL-MAX JP, JP, JP8 HEADER, -PIN, mm SULLINS NRPN0PAEN-RC JP HEADER, -PIN mm SULLINS NRPN0PAEN-RC JP, JP6, JP7 HEADER, -PIN, mm SULLINS NRPN0PAEN-RC JP HEADER, DOUBLE ROW mm mm SULLINS NRPN0PAEN-RC 6 J, J, J, J JACK, BANANA KEYSTONE XJP, XJP, XJP, XJP, XJP SHUNT, mm SAMTEC SN-BK-G 8 XJP6, XJP7, XJP8, XJP6, XJP7, XJP8 STANDOFF, SNAP ON KEYSTONE_88 8 dc7afa

9 DEMO MANUAL DC7A SCHEMATIC DIAGRAM REVISION HISTORY ECO REV DESCRIPTION DATE APPROVED PROTO 0/8/ W_ PROD 06/6/ W_ PROD - Parts addition 0/0/6 W_ NC FREQ DRVSET DRVUV BOOST SW TG 0 C C JP7 U R9 D R0 C 0 R 0.7uF LTC69EMSE % M TG 00V % 8 L 70uH EXTVCC SW MSS0BT C R.7uF VBIAS 67k 6V % ON Q6 VFB 9 TG RUN R OFF R SW SW JP8 96k VPRG 7 D C 0.uF SW SW BG D D 60 McCarthy Blvd. CUSTOMER NOTICE APPROVALS Milpitas, CA 90 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A Phone: (08) CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; TECHNOLOGY Fax: (08)-007 HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL `\ LTC Confidential-For Customer Use Only APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. TITLE: CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT W _A SCHEMATIC PERFORMANCE OR RELIABILITY. CONTACT LINEAR HIGH INPUT VOLTAGE SYNCHRONOUS TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. BUCK CONVERTER SIZE LTC89EFE IC NO. REV. N/A DEMO CIRCUIT 7A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE DATE: SHEET OF Tuesday, May, CLKOUT PGOOD E8 E R7 R7 0 PLLIN E9 R + R 0.k % C6 R 0 R 0 + R 00K R0 R6 80.6k % R 0 R9 R0 R8 0 J E EXTVCC Q7 + R9 SW TG SENSE+ A A R 9k % U RUN LTC89EFE R.7k % ON R C C 0.uF R 8 OFF R9 OVLO PHASE MD 0M R R0 VPRG ILIM 7 JP 0 E RUN PHASMD 6 80 SENSE+ C R SENSE+ C 90 R6 C R7 nf SENSE- E 0.uF SENSE- JP E R8 0 SS RUN L SS J.0uH EXTVCC VFB VOSP R CIN7 CIN6 CIN CIN CIN CIN + CIN C7 0K % C6 700pF ITH EXTVCC R 0.uF 0.uF 0.7uF 0.7uF 0.7uF 0.7uF 00uF C9 0pF V - 0V E C8. 00V 00V 00V V 00V 00V 00V MODE uf MODE R R C0 00pF MODE J FCM 0k 0k % P.S. 0 - JP CIN8 C BURST ADJ. E6 R6 B uF B CPUMP_EN 00V Q 00V VOSP 00k 7 8 BURST DEFAULT Q BSC0NNSG CLKOUT NDRV 8 Q JP E7 JP6 BSC0NNSG R6 R7 0 VOUT 00k L uh % 00% DUTY C J PLLIN DRVCC 6 RS VOUT VOUT ON Q 7600 R8.7uF COUT COUT COUT COUT BSC0NNSG 9.9k uf 0uF 0uF PGOOD Q OFF V, A % 6V 6V 6V 7 R JP BG BG SENSE- E0 OVLO BG FBO VPRG 6 ISET SS NC NC NC NC 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. dc7afa 9

10 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, 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 60 McCarthy Blvd. Milpitas, CA 90 Copyright 00, Linear Technology Corporation 0 dc7afa LT 066 REV A PRINTED IN USA Linear Technology Corporation 60 McCarthy Blvd., Milpitas, CA (08) -900 FAX: (08) LINEAR TECHNOLOGY CORPORATION 06