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LT8603 Quad Output Buck Converter and SEPIC Channel Demo Manual (DC2469A)

DC2469A features the LT8603 quad-output regulator, delivering 8V, 5V, 3.3V, and 1.8V outputs. The SEPIC channel allows regulated outputs to ride through automotive cold crank.

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Overview

The DC2469A demonstration circuit evaluates the LT8603, a low IQ quad-output power management IC. The board features three monolithic buck regulators and a boost channel configured as a SEPIC converter. Designed for a nominal 12V input, it provides regulated outputs of 8V, 5V, 3.3V, and 1.8V. The SEPIC configuration enables the system to maintain regulated outputs during automotive cold crank scenarios where input voltage drops significantly. The buck regulators operate at a 2MHz switching frequency with 180-degree phasing to minimize input ripple, while the SEPIC channel operates at 400kHz. Key features included in the design are cycle-by-cycle current limiting, independent channel enabling, and Burst Mode operation for high efficiency at light loads.

Use Cases

  • Automotive electronics power management
  • Cold crank ride-through systems
  • Industrial multi-rail power supplies
  • Transportation equipment power
  • Battery-powered high-efficiency systems

Topics

LT8603
LT8603EUJ
DC2469A
SEPIC converter
quad output regulator
monolithic buck converter
automotive power
cold crank ride-through
low IQ
Analog Devices

Referenced Parts

LTC6908CS6-1#PBF

Analog Devices

U2 IC, LTC6908CS6-1 TSOT-23-6 Analog Device, LTC6908CS6-1#PBF

BSZ067N06LS3G

Infineon

Q1 MOSFET-N Channel, PG-TSDSON-8 Infineon, BSZ067N06LS3 G

GRM155R61A225KE95D

Murata

C13, C19, C23 Cap, X7R 2.2μF 10V 10% 0402 Murata, GRM155R61A225KE95D

GRM155R71H104KE14J

Murata

C2, C3, C32 Cap, X7R 0.1μF 50V 10% 0402 Murata, GRM155R71H104KE14J

GRM21BR71C475KA73L

Murata

CVIN1, CVIN2 Cap, X7R 4.7μF 16V 10% 0805 Murata, GRM21BR71C475KA73L

GRM31CR61H106KA12L

Murata

CVIN4, CVIN5, CVIN6, CVIN7 Cap, X5R 10μF 50V 10% 1206 Murata, GRM31CR61H106KA12L

NPIM42P1R0MTRF

NIC Components

L4 Inductor, 1μH NPIM42P NIC Comp Corp, NPIM42P1R0MTRF

PMEG060V050EPD

Nexperia

D1 Schottky Rectifier, 60V, 5A, SOT1289 Nexperia, PMEG060V050EPD

2SN-BK-G

Samtec

XJP1, XJP2, XJP3, XJP4, XJP5 Shunt, 2mm Ctrs Samtec, 2SN-BK-G

16CE47BS

Sun Electronic Industries

C7 Cap, Alum 47μF 16V 20% Sun Elect Ind, 16CE47BS

50CE22BSS

Sun Electronic Industries

C1 Cap, Alum 22μF 50V 10% Sun Elect Ind, 50CE22BSS

CRCW06030000Z0EA

Vishay

R24, R27, R32, R33, R36, R37 Res, Jumper, Chip, 0Ω 0603 Vishay, CRCW06030000Z0EA

CRCW0603200KFKEA

Vishay

R9, R11, R13, R14, R19 Res, Chip 200k 0.1W 1% 0603 Vishay, CRCW0603200KFKEA

CRCW060324K9FKEA

Vishay

R2, R3, R4, R5 Res, Chip 24.9k 0.1W 1% 0603 Vishay, CRCW060324K9FKEA

CRCW08050000Z0EA

Vishay

L1, R34 Res, Jumper, Chip, 0Ω 0805 Vishay, CRCW08050000Z0EA

LT8603EUJ

Analog Devices

U1 IC, Buck Regulator QFN (40) (UJ) Analog Device, LT8603EUJ

XEL4030-152ME

Coilcraft

L3 Inductor, 1.5μH XEL4030 Coilcraft, XEL4030-152ME

XEL4030-332ME

Coilcraft

L2 Inductor, 3.3μH XEL4030 Coilcraft, XEL4030-332ME

PMEG6002EB

NXP

D2, D3 Schottky Rectifier, 0.2A, SOD523 NXP, PMEG6002EB

RL3720WT-R008-F

Susumu

R1 RES, CHIP, 0.008, 1W, 1%, 0815 Susumu, RL3720WT-R008-F

62000311121

Wurth Elektronik

JP1, JP2, JP3, JP4, JP5 Headers, 3 Pins 2mm Ctrs Wurth Elektronik, 62000311121

702931000

Wurth Elektronik

MH1 to MH4 STAND-OFF, NYLON 0.25" Tall (SNAP ON) Wurth Electronik, 702931000

742792150

Wurth Elektronik

FB1 BEAD, 4A 1206 Wurth Elektronik, 742792150

7448700015

Wurth Elektronik

L5 Inductor, 1.5μH Wurth Elektronik, 7448700015

PG-TSDSON-8

Infineon

30 1 Q1 MOSFET-N Channel, PG-TSDSON-8 Infineon, BSZ067N06LS3 G

SOD523

NXP

23 2 D2, D3 Schottky Rectifier, 0.2A, SOD523 NXP, PMEG6002EB

1.5A

Maxim

with 1.5A maximum output load current, and VOUT2 is

1.8A

Maxim

put VOUT3 is regulated at 1.8V with 1.8A maximum load

2.5A

Maxim

at 3.3V with 2.5A maximum output load current. The low