DEMO MANUAL DC2257A LTM8005 38VIN, 38VOUT Boost Module LED Driver with 40V Switch DESCRIPTION Demonstration circuit 2257A features the LTM(R)8005 - a 38VIN, 38VOUT boost Module(R) LED driver that can disconnect the output to protect against faults and provides spread spectrum switching to simplify emissions compliance. DC2257A is an LED driver with an input range for normal operation from 6V to 27V. OVLO becomes active for inputs above 29V and the maximum input voltage is 38V. The LED current is 1.2A and the base switching frequency is 350kHz. The efficiency is 92% when the input is 12V with a 35V LED load. 35V is the maximum LED voltage. The demo circuit requires application of an external voltage to the PWM terminal for operation. The external voltage can be a DC level or an appropriate PWM dimming signal. Common frequencies for PWM dimming are 100Hz or higher. Analog dimming is achieved using the CTRL inputs. DC2257A allows adjustments to output voltage, output current, input current, switching frequency, frequency modulation rate including disable, feedback loop compensation, EN/UVLO threshold, OVLO threshold, softstart period, and fault latch-off or hiccup. In most cases, adjustment is made by modifying the appropriate resistor or capacitor component(s). DC2257A provides outputs for input and output current monitoring and fault status for short and open LEDs. The demo circuit is designed to be easily reconfigured to buck mode, buck-boost mode and SEPIC topologies. There are placeholders to mount optional LC input filter components. The LTM8005 data sheet must be read in conjunction with this demo manual to properly use or modify DC2257A. Design files for this circuit board are available at http://www.linear.com/demo/DC2257A L, LT, LTC, LTM, Linear Technology, the Linear logo and Module are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. BOARD PHOTO dc2257af 1 DEMO MANUAL DC2257A PERFORMANCE SUMMARY PARAMETER Specifications are at TA = 25C CONDITIONS MIN TYP 6V Minimum Input Voltage, VPVIN 27V Maximum Input Voltage - Switching, VPVIN Maximum Input Voltage - Not Switching, VPVIN MAX VOVLO 1.25 38V 35V Maximum LED Voltage, VLED LED Current, ILED R5 = 100k, R6 = 73.2k 1.2A Input Turn-On Voltage, VPVIN(EN) R7 = 19.1k, R8 = 1M, R9 = 93.1k, VPVIN Rising 5.9V Input Turn-Off Voltage, VPVIN(UVLO) R7 = 19.1k, R8 =1M, R9 = 93.1k, VPVIN Falling 4.9V Input OVLO Turn-Off Voltage, VPVIN(OVLO_TURN-OFF) R7 = 19.1k, R8 = 1M, R9 = 93.1k, VPVIN Rising 29.1V Input OVLO Turn-On Voltage, VPVIN(OVLO_TURN-ON) R7 = 19.1k, R8 = 1M, R9 = 93.1k, VPVIN Falling 28.4V Efficiency VPVIN = 12V, VLED = 35V, ILED = 1.2A 92% Switching Frequency R1 = 23.2k, Spread Spectrum = OFF 350kHz Input Current Limit RS1 = 0.008 7.5A Peak QUICK START PROCEDURE To use DC2257A to evaluate the performance of the LTM8005, refer to Figure 1 for the proper measurement equipment setup and then follow the procedure below. supply voltage does not exceed the forward voltage of the LED string. OVLO becomes active to inhibit switching for an input voltage of greater than 29V. NOTE: PWM must be pulled high to work. If PWM is not used, connect the PWM terminal to a 2V to 5V source or connect the PWM pin to VREF on the PCB using R18. 4. Connect an input to the PWM terminal. If PWM is not used, connect PWM to a 2V to 5V DC source or to VREF on the PCB using resistor R18. PWM must be pulled high to work. For PWM dimming, connect a 100Hz or higher PWM signal to the PWM terminal. 1. Connect a string of LEDs with a forward voltage of 35V or less, but greater than the PVIN voltage, to the LED+ and GND terminals on the PCB as shown in Figure 1. 2. Connect the EN/UVLO terminal to ground with a clipon lead. 3. With the power off, connect the input power supply to the PVIN and GND terminals within the voltage range specified on the PCB. Make sure that the input power 2 5. Turn the PVIN power supply on. 6. Release the EN/UVLO to GND connection. 7. Observe the LED string running at the programmed LED current; or, observe the reduction of brightness in the LED string with PWM dimming. dc2257af DEMO MANUAL DC2257A QUICK START PROCEDURE Figure 1. Proper Measurement Equipment Setup dc2257af 3 DEMO MANUAL DC2257A QUICK START PROCEDURE Output Current Noise Spectrum 50 40 AMPLITUDE (dBV) 30 20 10 0 -10 -20 DETECTOR = PEAK-HOLD RBW = 9kHz CT-1 CURRENT TRANSFORMER SPREAD SPECTRUM = OFF -30 -40 -50 0 5 10 15 20 FREQUENCY (MHz) 25 30 DC2257A F02 Figure 2. Output Current Noise Spectrum with Spread Spectrum = OFF, VIN = 12V, POUT = 42W, CT-1 Current Transformer 50 40 AMPLITUDE (dBV) 30 20 10 0 -10 -20 DETECTOR = PEAK-HOLD RBW = 9kHz CT-1 CURRENT TRANSFORMER SPREAD SPECTRUM = ON -30 -40 -50 0 5 10 15 20 FREQUENCY (MHz) 25 30 DC2257A F02 Figure 3. Output Current Noise Spectrum with Spread Spectrum = ON, VIN = 12V, POUT = 42W, CT-1 Current Transformer 4 dc2257af DEMO MANUAL DC2257A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 CAP., X7R, 1F, 50V, 10%, 0805 MURATA, GRM21BR71H105KA12L 2 5 C2, C3, C4, C7, C8 CAP., X7R, 4.7F, 50V, 10%, 1210 MURATA, GRM32ER71H475KA88L 3 1 C5 CAP., X7R, 0.022F, 16V, 10%, 0603 MURATA, GRM188R71C223KA01D 4 1 C6 CAP., X7R, 0.1F, 25V, 10%, 0603 AVX, 06033C104KAT2A 5 1 L1 INDUCTOR, 10H COILCRAFT, XAL8080-103ME 6 1 R1 RES, CHIP, 23.2k, 1/10W, 1%, 0603 VISHAY, CRCW060323K2FKEA 7 1 R2 RES, CHIP, 12.4k, 1/10W, 1%, 0603 VISHAY, CRCW060312K4FKEA 8 1 R3 RES, CHIP, 1.5k, 1/10W, 5%, 0603 VISHAY, CRCW06031K50JNEA 9 1 R4 RES, CHIP, 374k, 1/10W, 1%, 0603 VISHAY, CRCW0603374KFKEA 10 1 R5 RES, CHIP, 100k, 1/10W, 1%, 0603 VISHAY, CRCW0603100KFKEA 11 1 R6 RES, CHIP, 73.2k, 1/10W, 1%, 0603 VISHAY, CRCW060373K2FKEA 12 1 U1 I.C., MODULE LED DRIVER, 80-BGA LINEAR TECH, LTM8005EY#PBF AVX, 06033C104KAT2A Optional Demo Circuit Components 1 1 C13 CAP., X7R, 0.1F, 25V, 10%, 0603 2 0 C11, C19, C27 (OPT) CAP., 0603 3 0 C9, C10, C12, C15-C18, C22-C26 (OPT) CAP., 1210 4 1 C14 CAP., X7R, 6.8nF, 16V, 10%, 0603 5 0 C21 (OPT) CAP., ALUM, OPT, 10mm DIA. 6 1 D1 DIODE, SMA 7 0 L2 (OPT) INDUCTOR, OPT, 8mm x 8mm 8 0 M1 (OPT) MOSFET, SOT23 9 0 Q1 (OPT) TRANS, SOT23 10 1 RS1 RES, CHIP, .008, 1W, 1%, 2512 AVX, 0603YC682KAT2A FAIRCHILD SEMI.,ES1A VISHAY, WSL25128L000FEA 11 0 RS2 (OPT) RES, 2010 12 1 R7 RES, CHIP, 19.1k, 1/10W, 1%, 0603 VISHAY, CRCW060319K1FKEA 13 1 R8 RES, CHIP, 1M, 1/10W, 1%, 0603 VISHAY, CRCW06031M00FKEA 14 1 R9 RES, CHIP, 93.1k, 1/10W, 1%, 0603 VISHAY, CRCW060393K1FKEA 15 0 R10, R12-R15, R18, R19, R21-R27, R30 (OPT) RES, 0603 16 1 R11 RES, CHIP, 0, 1/10W, 1%, 0603 VISHAY, CRCW06030000Z0EA 17 1 R16 RES, CHIP, 0, 1/4W, 1%, 1206 VISHAY, CRCW12060000Z0EAHP 18 0 R20 (OPT) RES, 1206 19 3 R17, R28, R29 RES, CHIP, 100k, 1/10W, 5%, 0603 VISHAY, CRCW0603100KJNEA 1 19 E1-E19 TESTPOINT, TURRET, .094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0 2 1 JP1 HEADER 3-PIN 0.079 SINGLE ROW WURTH, 620 003 111 21 3 1 XJP1 SHUNT, .079" CENTER WURTH, 608 002 134 21 Hardware dc2257af 5 GND GND ISMON PWM CTRL2 CTRL1 GND E8 E7 E6 E5 E10 E9 E4 VIN E3 6V - 27V 38V MAX. 29V OVLO R16 0 Ohm 1206 E2 PVIN 6V - 27V 38V MAX. 29V OVLO E1 R6 73.2k 1% C1 1uF 50V 0805 C12 (OPT) 1210 PVIN 1 2 3 C2 4.7uF 50V 1210 CTRL2 VIN EN/UVLO SPREAD SPECTRUM ON OFF JP1 C13 0.1uF PWM C3 4.7uF 50V 1210 R17 100k CTRL1 VREF C9 (OPT) 1210 R5 100k 1% C14 6.8nF OVLO J8 J1 J7 K7 K6 J6 F1 G1 R7 19.1k 1% RAMP ISMON PWM CTRL2 CTRL1 VREF VIN EN/UVLO C6 0.1uF (OPT) R22 R11 0 Ohm R9 93.1k 1% R12 (OPT) G2 EN/UVLO SS K4 R8 1M 1% VOUT K5 IVINP H1 OVLO RT 0.008 1% 2512 RS1 F2 IVINN L1 10uH R1 23.2k 1% 350kHz VC OPENLED SHORTLED IVINCOMP FB AUX LED+ LED+ LED+ ISN ISN ISN VOUT VOUT VOUT VOUT VOUT VOUT DA DA DA DA DA DA K3 H8 H7 H2 K2 J2 G6 G7 G8 F6 F7 F8 A7 A8 B7 B8 C7 C8 A5 A6 B5 B6 C5 C6 C5 22nF R3 1.5k 1% R4 374k SW C4 4.7uF 50V 1210 C11 (OPT) FB ISN 1. ALL RESISTORS 5%, 0603. 2. ALL CAPACITORS 0603. C8 4.7uF 50V 1210 R28 100k 12.4k 1% R2 C7 4.7uF 50V 1210 R29 100k C10 (OPT) 1210 VOUT NOTE: UNLESS OTHERWISE SPECIFIED. XAL8080-103ME COILCRAFT U1 LTM8005EY IVINN A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4 SW SW SW SW SW SW SW SW SW SW SW SW GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND 6 D1 D2 D3 D4 D5 D6 D7 D8 E1 E2 E3 E4 E5 E6 E7 E8 F3 F4 F5 G3 G4 G5 H3 H4 H5 H6 J3 J4 J5 K1 K8 PVIN V_EXT E18 GND E19 /OPENLED E15 IVINCOMP E16 SHORTLED E17 OPENLED E13 GND E14 GND E12 LED+ 1.2A 35V LED MAX. D1 ES1A C19 (OPT) E11 VOUT DEMO MANUAL DC2257A SCHEMATIC DIAGRAM dc2257af 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. PWM CTRL1 VIN C27 (OPT) EN/UVLO (OPT) 1206 R20 C22 (OPT) 1210 PVIN (OPT) R18 R10 (OPT) VOUT C23 (OPT) 1210 VREF R15 (OPT) R13 (OPT) PVIN L2 (OPT) 8mm x 8mm C21 (OPT) 10mm Dia. SMD R14 (OPT) VOUT + PVIN FB ISN R19 (OPT) VOUT (OPT) R24 (OPT) R23 (OPT) 2010 RS2 OVLO M1 (OPT) SOT23 VREF SW Q1 (OPT) SOT23 /OPENLED (OPT) 1210 (OPT) 1210 C26 (OPT) 1210 C25 C24 IVINN VOUT R27 (OPT) R25 (OPT) (OPT) 1210 (OPT) 1210 C18 (OPT) 1210 C17 (OPT) 1210 C16 C15 (OPT) R21 PVIN R30 (OPT) R26 (OPT) VOUT DEMO MANUAL DC2257A SCHEMATIC DIAGRAM dc2257af 7 DEMO MANUAL DC2257A 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 (c) 2004, Linear Technology Corporation 8 dc2257af Linear Technology Corporation LT 1016 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com (c) LINEAR TECHNOLOGY CORPORATION 2016