DEMO MANUAL DC2846A LTC7804 Low IQ Synchronous Boost Controller DESCRIPTION Demonstration circuit DC2846A is a DC/DC synchronous boost converter featuring the LTC(R)7804 (MSE package), a spread spectrum or constant frequency current mode synchronous boost controller. The DC2846A generates a 24V output voltage and provides up to 6A of output current. The 500kHz constant switching frequency operation results in a small and efficient circuit. The main features of this board include: * Wide input voltage range: from 6V to 24V * Relatively high output power, up to 150W * Extremely low quiescent current, it's 15A at sleep mode and as low as 1A at shutdown * Onboard low power bias supply * Ability to select spread spectrum or fixed frequency * If VIN > VOUT, the DC2846A eliminates the usual boost topology losses by keeping the top MOSFET on continuously. The converter provides high output voltage accuracy (typically 2%) over a wide load range with no minimum load requirement. The DC2846A supports two ways of biasing step-up controllers: directly from the input voltage or output rail. The third possibility is connecting voltage source to EXTVCC terminal. The DC2846A extremely wide switching frequency range from 100kHz to 3MHz. It can be synchronized to the external clock anywhere inside this range. The spread spectrum operation is used for reducing the peak radiated and conducted noise to simplify compliance with electromagnetic interference (EMI) standards * Pulse-skipping mode, forced continuous operation or low ripple Burst Mode(R) operation at light loads The DC2846A has small circuit footprint. It is a high performance and cost-effective solution for telecom, automotive and Power over Ethernet applications. * Synchronization with external clock Design files for this circuit board are available. All registered trademarks and trademarks are the property of their respective owners. PERFORMANCE SUMMARY PARAMETER Specifications are at TA = 25C CONDITIONS VALUE UNITS Minimum Input Supply Voltage 6 V Maximum Input Supply Voltage 24 V 242% V Output Voltage Range VIN = 6V to 20V Typical Switching Frequency Typical Output Ripple (VOUT, 48V) Efficiency Typical (VOUT, 48V, VIN 12V) ILOAD = 3A 500 kHz 200 mV 95 % Rev. 0 1 DEMO MANUAL DC2846A QUICK START PROCEDURE Demonstration circuit 2846 is easy to set up to evaluate the performance of the LTC7804 controllers. Refer to Figure1 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 GND terminals. See Figure2 for proper scope probe technique. 1.Place jumper RUN (J2) in ON position, place jumper MODE (JP1) in PULSE SKIP position, place jumper FREQSET (JP4) into FIX FREQ position. 2. Place jumper VBIAS (JP3) in VIN position. 3. With power off, connect the input power supply to VIN and GND. Turn the input power source on and slowly increase the input voltage to 12V. Be careful not to exceed 24V. Figure1. Proper Measurement Equipment Setup Rev. 0 2 DEMO MANUAL DC2846A QUICK START PROCEDURE NOTE: Make sure that the input voltage VIN does not exceed 20V. If higher operating voltage is required, power components with higher voltage ratings should be used. 4.Check for the proper output voltage of 24V. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 5.Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. To synchronize DC2846A with external clock insert jumper FREQSET (JP4) in SYNC position and apply clock signals to terminal SYNC (E6). VIN CONVERTER EFFICIENCY DC2846SA yields 96% efficiency at 16V input voltage generating 24V at 6A, see Figure3. DC2846A able to deliver 6A output current down to 9V of input; however, output current should be reduced at lower voltage per Figure4. All efficiency measurements were conducted at room temperature, natural convection cooling with no air flow. DC2846A SPRED SPECTRUM The demo board DC2846AA shipped with fixed frequency operation. To employ the spread spectrum operation, insert the jumper PLLIN/SPREAD (JP4) in into SPREAD position. In this setting the switching frequency will change in 15% range relatively to the preset value. GND Figure2. Measuring Input or Output Ripple 97 7 20V 6 16V 95 12V 94 9V OUTPUT CURRENT (A) EFFICIENCY (%) 96 92 91 4 3 2 1 90 89 5 0 1 2 4 3 LOAD CURRENT (A) 5 6 DC2846A F03 Figure3. Efficiency vs Load for Different Input Voltage 0 6 6.5 7.5 7 8 INPUT VOLTAGE (V) 8.5 9 DC2846A F04 Figure4. Maximum Output Current vs Input Voltage Rev. 0 3 DEMO MANUAL DC2846A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP, 100pF, C0G, 25V, 10%, 0603 AVX, 06033A101KAT2A Required Circuit Components 1 1 C2 2 1 C3 CAP, 1500pF, X7R, 25V, 10%, 0603 AVX, 06033C152KAT2A 3 2 C4, C15 CAP, 0.1F, X5R, 25V, 10%, 0603 AVX, 06033D104KAT2A 4 1 C5 CAP, 1000pF, C0G, 25V, 10%, 0603 AVX, 06033A102KAT2A 5 1 C8 CAP, 4.7F, X5R, 25V, 10%, 0805 MURATA, GRM219R61E475KA73D 6 2 C19, C23 CAP, 1F, X5R, 50V, 10%, 0603 AVX, 06035D105KAT2A 7 2 CIN1, COUT5 CAP, 150F, ALUM ELECT, 35V, 20%, SMD SUN ELECT, 35HVH150M 8 9 CIN2, CIN3, CIN4, CIN5, COUT1, COUT2, COUT3, COUT4, COUT6 CAP, 10F, X5R, 50V, 10%, 1210 TDK, C3225X5R1H106K250AB 9 1 D1 DIODE, SCHOTTKY, 60V, 1A, SOD-123F DIODES, B160S1F-7 10 1 L1 IND, 2.8H, WE-HCI, FLAT WIRE, SMD WURTH, 7443551280 11 2 Q1,Q4 XSTR, MOSFET, N-CH, 40V, 98A, TDSON-8 INFINEON, BSC032N04LS 12 5 R2, R5, R6, R13, R16 RES, AEC-Q200, 0, 1/10W, 0603 VISHAY, CRCW06030000Z0EA 13 1 R4 RES, AEC-Q200, 16.9k, 1%, 1/10W, 0603 NIC, NRC06F1692TRF 14 1 R9 RES, 100, 1%, 1/10W, 0603 YAGEO, RC0603FR-07100RL 15 1 R10 RES, AEC-Q200, 232k, 1%, 1/10W, 0603 VISHAY, CRCW0603232KFKEA 16 1 R12 RES, AEC-Q200, 12.1k, 1%, 1/10W, 0603 VISHAY, CRCW0603100KFKEA 17 1 R14 RES, AEC-Q200, 100k, 1%, 1/10W,0603 VISHAY, CRCW0603100KFKEA 18 1 R18 RES, AEC-Q200, 76.8k, 1%, 1/10W, 0603 PANASONIC, ERJ3EKF7682V 19 1 R19 RES, AEC-Q200, 1M, 1%, 1/10W, 0603 VISHAY, CRCW06031M00FKEA 20 1 R20 RES, 200k, 1%, 1/10W, 0603 VISHAY, CRCW0603200KFKEA 21 1 R22 RES, AEC-Q200, 1k, 1%, 1/10W, 0603 VISHAY, CRCW06031K00FKEA 22 2 RSNS1, RSNS2 RES, SENSE, AEC-Q200, 0.005, 1%, 1/2W, 2010 VISHAY, WSL20105L000FEA 23 1 U1 IC, LOW IQ SYNC BOOST CONTROLLER, SSOP-16 ANALOG DEV INC, LTC7804EMSE#PBF Additional Demo Board Circuit Components 1 C7, C20, C21, C22 CAP, OPTION, 0603 OPT 2 COUT7 CAP, OPTION, ALUM ELECT, SMD OPT 3 Q2, Q3 XSTR, OPTION, MOSFET N-CH, PG-TDSON-8 OPT 4 R1, R3, R7, R8, R11, R15, R17 RES, OPTION, 0603 OPT MILL-MAX, 2501-2-00-80-00-00-07-0 Hardware: For Demo Board Only 1 10 E1, E2, E3, E4, E5, E6, E7, E8, E9, E10 TEST POINT, TURRET, 0.094", MTG HOLE 2 4 J1, J2, J3, J4 CONN, BANANA JACK, FEMALE, THT, NON-INSULATED, KEYSTONE, 575-4 SWAGE 3 2 JP1, JP4 CONN, HDR, MALE, 2 x 3, 2mm, VERT, STR, THT WURTH, 62000621121 4 2 JP2, JP3 CONN, HDR, MALE, 1 x 3, 2mm, STR, THT WURTH, 62000311121 Rev. 0 4 A B C D E9 E7 E8 OPT R17 100k R14 R21 0 JP1 6 4 3 5 2 MODE C15 0.1uF 1 EXTVCC R3 OPT R2 0 INTVCC E5 OFF ON 16.9k R4 100pF BURST MODE PULSE SKIP CCM 1500pF C3 C2 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 5 1. ALL RESISTORS AND CAPACITORS ARE 0603. R18 R15 TBD JP2 3 2 1 4 RUN R19 1M 1% VIN OPT R1 OPT VIN SS 4 SENSE1- RUN FREQ MODE VIN VOUT TRACK/SS ITH U1 JP3 3 2 1 VBIAS VBIAS C19 OPT EXTVCC 4 6 2 FIX FREQ. SYNC JP4 5 3 1 FREQ SET SPREAD 0 R16 3 THISCIRCUITISPROPRIETARYTOANALOGDEVICESINC.AND SUPPLIEDFORUSEWITHANALOGDEVICESINC.PARTS. ForADICustomerUseOnly ANALOGDEVICESINC.HASMADEABESTEFFORTTODESIGNA CIRCUITTHATMEETSCUSTOMERSUPPLIEDSPECIFICATIONS; HOWEVER,ITREMAINSTHECUSTOMER'SRESPONSIBILITYTO VERIFYPROPERANDRELIABLEOPERATIONINTHEACTUAL APPLICATION.COMPONENTSUBSTITUTIONANDPRINTED CIRCUITBOARDLAYOUTMAYSIGNIFICANTLYAFFECTCIRCUIT PERFORMANCEORRELIABILITY.CONTACTANALOGDEVICES INC.APPLICATIONSENGINEERINGFORASSISTANCE. i^ APPENG. R7 OPT SIZE: N/A 2 PROD 03/29/19 APPROVED i^ 10uF 50V 1210 + + + CIN1 150uF 35V VIN RSNS2 0.005 1% 2010 COUT5 150uF 35V GND E10 E6 E4 J4 J3 E3 CS- CS+ RSNS1 0.005 1% 2010 GND VOUT 24V/6A* VOUT 1630McCarthyBlvd. Milpitas,CA95035 GND SYNC GND GND VIN 6V-24V VIN SNS- E2 J2 COUT7 OPT J1 E1 Phone:14084321900 TITLE: DEMO CIRCUIT SCHEMATIC, www.analog.com CIN2 CIN3 CIN4 CIN5 R11 OPT R8 OPT 7443551370 L1 3.7uH 10uF 50V 1210 VOUT * FOLLOW DERATING CHART IN DEMO MANUAL. COUT1 COUT2 COUT3 COUT4 COUT6 3 REV 1 REVISION HISTORY DESCRIPTION DATE 1 SHEET 1 OF 1 710-DC2846A_REV03 SCHEMATIC NO. AND REVISION: DATE: Friday, March 29, 2019 PCABOM: 700-DC2846A_REV03 PCAASS'Y: 705-DC2846A_REV03 HIGH EFFICIENCY SYNCHRONOUS STEP-UP SUPPLY SCALE=NONE DC2846A SKU NO. IC NO. LTC7804EMSE \ - ECO APPROVALS C20 OPT R22 1k 1% 4 Q3 OPT 4 Q2 OPT 2 PCBDES. INTVCC 4 INTVCC C8 4.7uF Q4 0805 BSC032N04LS C4 0.1uF D1 BAS140W INTVCC 0 R13 4 Q1 BSC032N04LS CUSTOMER NOTICE VIN 8 13 10 11 14 16 15 12 1uF VBIAS VOUT PLLIN/SPREAD BG INTVCC EXTVCC BOOST SW TG VIN C23 LTC7804EMSE SENSE1+ R20 200k 1% 6 7 9 1 5 2 3 VFB R12 12.1k 1% R10 232k 1% C21 OPT C7 INTVCC C5 1000pF 86.6k 1% RUN R9 100 NOTE: UNLESS OTHERWISE SPECIFIED GND EXTVCC GND SS CS- SNS- CS+ R5 0 VIN R6 0 3 1 2 VOUT GND 17 5 6 7 8 1 2 3 5 6 7 8 1 2 3 5 6 7 8 3 2 1 5 6 7 8 3 2 1 4 1 2 5 A B C D DEMO MANUAL DC2846A SCHEMATIC DIAGRAM Rev. 0 5 DEMO MANUAL DC2846A ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. 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