DEMO MANUAL DC2123A LT3790 60V Four-Switch Synchronous Buck-Boost Controller DESCRIPTION The DC2123A is a 60V four-switch synchronous buck-boost controller that demonstrates the high power capability of the LT®3790. The output is 24V and the maximum output current is 5A. The switching frequency is 200kHz and efficiency is as high as 98% for a 24V input. The LT3790 is capable of high power operation. DC2123A can be altered for either lower input voltage operation with the same output power or for increased output power with higher minimum input voltage. VIN can be reduced to 8VIN minimum and still deliver 120W output by changing RS1 to 2mΩ, RIN1 to 1.5mΩ, and R3 (UVLO) to 88.7k. If VIN remains always above 20V, IOUT can be increased to 12A+ (for 290W output) with the above changes, and an additional change of ROUT to 4mΩ. The operating input voltage range of DC2123A is from 12V to 57V. The output voltage, EN/UVLO, and OVLO are all programmed by resistor dividers. EN/UVLO is set so the circuit will turn off when the input voltage falls below 11.9V and will turn on when the input voltage rises above 13.4V. OVLO is set to engage for input voltages above 57V. Current sense resistors program input and output current limits and also determine the monitoring voltages that indicate input and output current. IVINMON provides a 60mV/1A voltage that is used to monitor the input current. Input current limit occurs at 16.7A and is set by RIN1. ISMON provides a 160mV/1A voltage that is used to monitor the output current. The output current limit is 7.5A and is set by RS2. The demo circuit features MOSFETs that compliment the 5V gate drive of the LT3790 to achieve high efficiency. 60V MOSFETs are used on the input side of the four-switch topology while 40V MOSFETs are used on the output side. Ceramic capacitors are used at both the circuit input and output because of their small size and high ripple current capability. In addition to ceramic capacitors, there is an aluminum polymer capacitor on the output that assures feedback loop stability, even at low temperatures. The input has an aluminum electrolytic capacitor in addition to ceramic capacitors. A two-stage L-C input filter can easily be added for electro-magnetic compatibility. The pcb has large copper planes and extensive vias for thermal performance. The CLKOUT output and the SYNC input can be used to synchronize switching between two or more DC2123A circuits. A resistor from SYNC to ground must be removed prior to using the SYNC input. SHORT and C/10 are open-collector status flag outputs and are pulled up to the INTVCC pin voltage. A resistor shorts the CCM pin to C/10 and causes the circuit to change to discontinuous conduction mode (DCM) when C/10 is active at light load currents. CCM can also be connected with a resistor to INTVCC instead of C/10 for continuous conduction mode (CCM) operation over the entire load range. The CTRL input is pulled up to the VREF pin through a 0Ω resistor to set the output current limit to its maximum, and an external voltage on CTRL can be used to lower the current limit if the resistor is removed. A capacitor at the SS pin programs soft-start and additionally SS is pulled up to the VREF pin through a 100k resistor. The switching frequency is adjustable with a resistor. The demo circuit is designed to be easily reconfigured to many other applications, including the example schematics in the data sheet. Consult the factory for assistance. High power operation, four-switch buck-boost topology, fault protection and full monitoring make the LT3790 attractive for high power voltage regulator circuits and also circuits that require output current regulation such as battery chargers. The LT3790EFE is available in a thermally enhanced 38-lead TSSOP package. The LT3790 data sheet must be read in conjunction with this demo manual to properly use or modify demo circuit DC2123A. Design files for this circuit board are available at http://www.linear.com/demo/DC2123A 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. dc2123af 1 DEMO MANUAL DC2123A PERFORMANCE SUMMARY Specifications are at TA = 25°C PARAMETER CONDITIONS Minimum Input Voltage, VPVIN VOUT = 24V IOUT ≤ 4.5A Maximum Input Voltage, VPVIN VOUT = 24V IOUT ≤ 5A Maximum Output Current 13.3V < VPVIN < 57V, CTRL = VREF VPVIN = 12V, CTRL = VREF Input EN Voltage, VPVIN(EN) R3 = 56.2k, R4 = 499k, VPVIN Rising 13.4 V Input UVLO Voltage, VPVIN(UVLO) R3 = 56.2k, R4 = 499k, VPVIN Falling 11.9 V Input OVLO Turn-Off Voltage, VPVIN(OVLO turn-off) R11 = 27.4k, R1 = 499k, VPVIN Rising 57.6 V Input OVLO Turn-On Voltage, VPVIN(OVLO turn-on) R11 = 27.4k, R1 = 499k, VPVIN Falling 56.2 V Output Voltage VOUT R19 = 71.5k, R34 = 1.37k, R20 = 3.83k Efficiency VPVIN = 24V, IOUT = 5A 98 % Switching Frequency R18 = 147k 200 kHz Input Current Limit RIN1 = 0.003Ω 16.7 A Output Current Limit RS2 = 0.008Ω 7.5 A MIN TYP MAX UNITS 12 V 57 V 5 4.5 A A 23.5 24.5 V QUICK START PROCEDURE It is easy to set up demonstration circuit DC2123A to evaluate the performance of the LT3790. Refer to Figure 1 for the proper measurement equipment setup and follow the procedure below: NOTE: Make sure that the voltage applied to PVIN does not exceed the absolute maximum voltage rating of 60V for the LT3790. 1.Connect the EN/UVLO terminal to ground with a clip-on lead. Connect the power supply (with power off), load, and meters as shown. 2 2.After all connections are made, turn on the input power and verify that the input voltage is between 12V and 57V. 3.Remove the clip-on lead from EN/UVLO. Verify that the output voltage is 24V. NOTE: If the output voltage is low, temporarily disconnect the load to make sure that it is not set too high. 4.Once the proper output voltage is established, adjust the input voltage and load within the operating ranges and observe the output voltage regulation, ripple voltage, efficiency and other parameters. dc2123af DEMO MANUAL DC2123A QUICK START PROCEDURE Figure 1. Proper Measurement Equipment Setup for DC2123A 100 VIN = 24V VIN = 12V EFFICIENCY (%) 95 90 85 80 0 1 3 2 LOAD CURRENT (A) 4 5 dc2123a F02 Figure 2. Efficiency dc2123af 3 DEMO MANUAL DC2123A QUICK START PROCEDURE VIN = 14V VIN = 24V VIN = 54V Figure 3. Output Voltage Ripple at 5A Output Current, VOUT = 24V, 25MHz Bandwidth VIN = 14V VIN = 24V VIN = 54V Figure 4. Output Voltage Load Transient Response, VOUT = 24V, IOUT = 2.5A to 5A to 2.5A, 25MHz Bandwidth 4 dc2123af DEMO MANUAL DC2123A QUICK START PROCEDURE 30 25 VOUT (V) 20 15 10 5 0 0 1 2 3 4 5 IOUT (A) 6 7 8 dc2009a F05 Figure 5. VOUT in Current Limit, VIN = 24V DIFFERENCES BETWEEN LT3790 AND LT3791-1 The LT3790 is an improved version of the LT3791-1 and is recommended for use in new designs. Some external component values may change, but otherwise, the LT3790 is functionally equivalent to the LT3791-1. The differences between the two products are: 1.The LT3790 has a 60mV (typical) full-scale V(ISP-ISN) current sense voltage, compared to 100mV (typical) for the LT3791-1. This change allows lower power current sense resistors to be used for most applications. 2.The LT3790 CTRL pin linear range is from 0V to 1.1V, and has a turn-off threshold of 50mV(typical), compared to a 200mV to 1.1V linear range and 175mV (typical) turn-off threshold for the LT3791-1. These changes make it easier to parallel two or more LT3790 ICs for higher power levels. 3.The LT3790 C/10 pin pulls low when the V(ISP-ISN) voltage is less than 1/10 full scale, compared to the LT3791-1, where C/10 pulls low when both V(ISP-ISN) is less than 1/10 full scale and VFB is greater than 1.15V(typical). Since the C/10 pin is used to allow DCM mode for some applications, this change ensures that negative current does not occur at light loads for a broader range of applications. dc2123af 5 DEMO MANUAL DC2123A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Electrical Components 1 1 CC1 Cap., X7R 0.01µF 25V 10% 0603 AVX 06033C103KAT2A 2 1 CC2 Cap., NPO 1000pF 25V 10% 0603 AVX 06033A102KAT1A 3 1 CSS1 Cap., X7R 33nF 25V 10% 0603 AVX 06033C333KAT1A 4 1 C1 Cap., X5R 0.47µF 16V 20% 0402 TDK C1005X5R1C474MT 5 3 C2, C12, C13 Cap., X5R 0.1µF 16V 10% 0402 TDK C1005X5R1C104KT 6 1 C3 Cap., X5R 1µF 100V 10% 1206 Taiyo Yuden HMK316BJ105KL-T 7 1 C4 Cap., X5R 4.7µF 10V 10% 0603 Taiyo Yuden LMK107BJ475KA 8 2 C6, C7 Cap., X7S 4.7µF 100V 10% 1210 TDK C3225X7S2A475K200AB 9 1 C10 Cap., Alum. Elect. 47µF 80V ± 20% United Chemi-Con EMZA800ADA470MJA0G 10 2 C14, C15 Cap., X5R 4.7µF 50V 20% 1210 Taiyo Yuden UMK325BJ475MM-T 11 2 C20, C30 Cap., Hybrid Cond. Polymer 220µF 35V 20% SUN Electronic Industries 35HVP220M 12 1 C29 Cap., X7R 0.033µF 16V 10% 0402 TDK C1005X7R1C333K 13 2 D1, D2 Schottky Barrier 100V SOD323 (SC-90) NXP Semi. BAT46WJ 14 1 L1 Inductor, 10µH SER2900 Coilcraft SER2918H-103KL 15 2 M1, M2 Mosfet-N Channel, 60V/25A LFPAK Renesas RJK0651DPB-00-J5 16 2 M3, M4 Mosfet-N Channel, 40V/35A LFPAK Renesas RJK0451DPB-00-J5 17 1 RC1 Res., Chip 15k 0.06W 5% 0402 Vishay CRCW040215K0JNED 18 1 RIN1 Res., 0.003 1W 1% 2512 Vishay WSL25123L000FEA 19 1 RS1 Res., 0.004 1/2W 1% 2010 Vishay WSL20104L000FEA 20 1 RS2 Res., 0.008 1W 1% 2512 Panasonic ERJ-M1WSF8M0U 21 2 R1, R4 Res., Chip 499k 0.06W 1% 0603 Vishay CRCW0603499KFKEA 22 1 R3 Res., Chip 56.2k 0.06W 1% 0402 Vishay CRCW040256K2FKED 23 1 R5 Res., Chip 51 0.06W 5% 0402 NIC NRC04F51R0TRF 24 2 R6, R10 Res., Chip 200k 0.06W 5% 0603 Vishay CRCW0603200KJNEA 25 1 R11 Res., Chip 27.4k 0.06W 1% 0402 Vishay CRCW040227K4FKED 26 1 R16 Res., Chip 200k 0.06W 5% 0402 Vishay CRCW0402200KJNED 27 1 R17 Res., Chip 100k 0.06W 5% 0402 Vishay CRCW0402100KJNED 28 1 R18 Res., Chip 147k 0.06W 1% 0402 Vishay CRCW0402147KFKED 29 1 R19 Res., Chip 71.5k 0.06W 1% 0603 Vishay CRCW060371K5FKEA 30 1 R20 Res., Chip 3.83k 0.06W 1% 0402 Vishay CRCW04023K83FKED 31 1 U1 I.C., 60V Buck-Boost Volt. Reg. Linear Tech. Corp. LT3790EFE#PBF 6 dc2123af DEMO MANUAL DC2123A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Optional Electrical Components 1 0 C5, C8, C9, C16, C17, C18 (Opt) Cap., 1210 2 0 C11, C19 (Opt) OPTIONAL 3 0 C21, C22, C28 Cap., 0603 4 0 C23 OPTIONAL 5 0 C24, C25, C26, C27 (Opt) OPTIONAL 6 0 D3, D4 (Opt) Schottky Diode, SMB 7 0 D5, D6 (Opt) Diode, SOD-123 8 0 D7 (Opt) Diode, SOD-523 9 0 L2, L3 (Opt) OPTIONAL 10 0 M5, M6, M7, M8, M12 (Opt) OPTIONAL 11 0 M9, M10, M11 (Opt) OPTIONAL 12 0 R2, R23, R24, R26-R32 Res., 0603 OPTIONAL 13 1 R7 Res.,Chip 0Ω 1206 14 0 R8, R9, R25 Res., 0402 OPTIONAL 15 3 R12, R14, R22 Res., Chip 0Ω 0402 Vishay CRCW04020000Z0ED 16 2 R13, R21 Res., Chip 0Ω 0603 Vishay CRCW06030000Z0EA 17 1 R34 Res., Chip 1.37k 0.06W 1% 0603 Panasonic ERJ-3EKF1371V 1 4 E1, E2, E19, E20 Connector, Banana Jack Keystone 575-4 2 13 E3, E5, E6, E7, E8, E9, E10, E11, E12, E13, E14, E21, E22 Turret, Testpoint Mill Max 2308-2-00-80-00-00-07-0 3 5 E4, E15, E16, E17, E24 Turret, Testpoint Mill Max 2501-2-00-80-00-00-07-0 4 0 E18 (Opt) OPTIONAL 5 0 E23 (Opt) OPTIONAL 6 4 MH1-MH4 Standoff Nylon 0.50" Yageo RC1206FR-070RL Hardware Keystone, 8833 (Snap-On) dc2123af 7 E10 E9 E8 E7 E6 E5 E4 E3 GND GND GND GND R6 200k 5% 0603 INTVCC VIN R13 0 Ohm 0603 TP2 TP1 TP6 R10 200k 5% 0603 R8 (Opt) TP5 R1 499k 0603 PVIN VREF INTVCC *C/10 *SHORT R3 56.2k R2 (Opt) 0603 ALL RESISTORS 0402 1%. ALL CAPACITORS 0603. NOTE: UNLESS OTHERWISE SPECIFIED. E17 E16 E15 E14 E11 ISMON E12 CLKOUT E13 SYNC IVINMON C/10 SHORT CTRL OVLO EN/UVLO GND VIN 12V - 57V E2 R16 100k 5% R17 200k 5% SS 2 C29 0.033µF 0402 32 34 33 7 8 4 5 6 1 38 VREF CSS1 33nF R14 0 Ohm C2 0.1µF 0402 R12 0 Ohm R11 27.4k R9 (Opt) 9 R4 499K 0603 R18 147k 200kHz SS CCM SYNC CLKOUT ISMON 0402 0.47µF C1 0.003 1% 2512 R5 51 5% U1 LT3790EFE IVINMON C/10 SHORT VREF CTRL OVLO EN/UVLO RT 35 GND RIN1 36 CC1 0.01µF RC1 15k 5% VC PVIN 10 IVINP 11 IVINN TEST1 29 E1 CC2 1000pF TP4 TP3 PWM PWMOUT ISN ISP FB TG2 SW2 BG2 SNSN SNSP BG1 SW1 TG1 BST2 BST1 SW1 16 SW2 TG2 FB 21 24 37 PWMOUT PWM 31 3 26 25 BG2 RS1 0.004 1% 2010 SNSP 19 28 27 BG1 0 Ohm 0603 R21 M2 RJK0651DPB TG1 18 C4 4.7µF 10V M1 RJK0651DPB INTVCC 14 22 15 13 C3 1µF 100V 1206 INTVCC R7 0 Ohm 1206 VIN 12 SGND SGND 30 39 PGND PGND 8 20 17 PVIN 12V - 57V INTVCC D2 BAT46WJ C6 4.7uF 100V 1210 D3 (Opt) SMB 2 3 1 C13 0.1µF L1 0402 10µH SER2918H-103KL C12 0.1µF 0402 D1 BAT46WJ C5 (Opt) 1210 D4 (Opt) SMB C15 4.7µF 50V 1210 C9 (Opt) 1210 M4 RJK0451DPB ISP C14 4.7µF 50V 1210 C8 (Opt) 1210 M3 RJK0451DPB C7 4.7uF 100V 1210 C16 (Opt) 1210 80V C10 + 47µF (Opt) C21 2512 0.008 RS2 C17 (Opt) 1210 R22 0 Ohm C18 (Opt) 1210 (Opt) 12.5mm Dia. Thru‐Hole + C11 IVINN R20 3.83k R19 71.5k 0603 R34 1.37k 0603 + C20 (Opt) 220µF 12.5mm Dia. 35V Thru‐Hole + C19 VOUT E20 E19 220µF 35V + C30 OUT GND *SHORT SS VREF *C/10 PWMOUT FB BG2 SW2 TG2 SNSP BG1 SW1 TG1 ISP PWM INTVCC VOUT 24V 5A E18 (Opt) DEMO MANUAL DC2123A SCHEMATIC DIAGRAM dc2123af PWM 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. D5 C24 4.7µF 100V 1210 (Opt) (Opt) SOD-123 D6 (Opt) SOD-123 PWM C23 + 47µF 80V (Opt) PVIN E21 VIN M9 (Opt) SOT-23 FB L2 4.7µH R25 (Opt) R26 (Opt) 0603 VREF ISP R24 D7 (Opt) SOD-523 *SHORT M6 (Opt) LFPAK L3 4.7µH SNSP SW1 SW1 M5 (Opt) LFPAK 7443551470 C27 Wurth Electronik 4.7µF (Opt) 100V 1210 (Opt) PVIN R28 (Opt) 0603 (Opt) 0603 R23 (Opt) 0603 C26 4.7µF 100V 1210 (Opt) C22 (Opt) R27 (Opt) 0603 BG1 *C/10 7443551470 C25 Wurth Electronik 4.7µF (Opt) 100V 1210 (Opt) ISP IVINN TG1 IVINN PVIN C28 (Opt) R32 (Opt) 0603 SS M10 (Opt) SOT-23 R31 (Opt) 0603 VREF BG2 TG2 R29 (Opt) 0603 R30 (Opt) 0603 PWMOUT SNSP SW2 SW2 ISP M7 (Opt) LFPAK M8 (Opt) LFPAK M11 (Opt) SOT-23 INTVCC M12 (Opt) LFPAK INTVCC *SHORT SS VREF *C/10 PWMOUT FB BG2 SW2 TG2 SNSP BG1 SW1 TG1 ISP PWM E24 (Opt) E23 GND LED- E22 INTVCC DEMO MANUAL DC2123A SCHEMATIC DIAGRAM 10mm Dia. Surface Mount dc2123af 9 DEMO MANUAL DC2123A 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 10 Linear Technology Corporation dc2123af LT 1214 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2014