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EVAL-LT8391D-AZ: 6V to 45V Synchronous 4-Switch Buck-Boost LED Driver

High-efficiency synchronous 4-switch buck-boost LED driver evaluation board for the LT8391D, supporting 6V-45V input and up to 50V LED output at 1.5A.

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Overview

The EVAL-LT8391D-AZ evaluation circuit is a 4-switch synchronous buck-boost LED driver featuring the LT8391D. It is designed to drive a single string of LEDs at up to 1.5A with an output voltage up to 50V from an input range of 6V to 45V. The board operates at 400kHz and includes low EMI features such as an optimized layout, spread spectrum frequency modulation (SSFM), and an input EMI filter. It supports both external PWM dimming and analog dimming via the CTRL pin. The design utilizes AEC-Q101 qualified MOSFETs and AEC-Q200 qualified ceramic capacitors, making it suitable for automotive environments. Protection features include input undervoltage lockout (UVLO) and protection against open and short LED conditions.

Use Cases

  • Automotive LED lighting
  • High-power LED strings
  • Battery-powered LED drivers
  • Chassis-ground return lighting systems
  • Variable input voltage lighting

Topics

LT8391D
Buck-Boost LED Driver
EVAL-LT8391D-AZ
AEC-Q101
SSFM
PWM Dimming
Analog Devices
EMI Filter
High-side sensing
Synchronous Driver

Referenced Parts

XAL6060-103MEB

Coilcraft

IND., 10μH, SHIELDED PWR, 20%, 7A, 29.82mΩ, 6.56mm × 6.36mm, AEC-Q200

BLM31KN471SZ1L

Murata

IND., 470Ω AT 100MHz, FERRITE BEAD, 25%, 4A, 20mΩ, 1206, AEC-Q200

BUK9M19-60EX

Nexperia

XSTR., MOSFET, N-CH, 60V, 38A, LFPAK33, AEC-Q101

EEEFT1H470AP

Panasonic

CAP., 47μF, ALUM ELECT, 50V, 20%, 6.3mm × 5.8mm SMD, RADIAL, AEC-Q200

MPZ2012S102ATD25

TDK

IND., 1k AT 100MHz, FERRITE BEAD, 25%, 1.5A, 150mΩ, 0805, AEC-Q200

XEL5050-332MEB

Coilcraft

IND., 3.3μH, SHIELDED, 20%, 10.6A, 14.6mΩ, 5.48mm × 5.28mm, AEC-Q200

60800213421

Wurth Elektronik

CONN., SHUNT, FEMALE, 2 POS, 2mm

62000421121

Wurth Elektronik

CONN., HDR, MALE, 2×2, 2mm, VERT, STR, THT

AEC-Q200

Murata

9 1 C21 CAP., 6800pF, X7R, 50V, 10%, 0402, AEC-Q200 MURATA, GCM155R71H682KA55D

AEC-Q200

Murata

29 1 C16 CAP., 0.1μF, X7R, 100V, 10%, 0805, AEC-Q200 MURATA, GCM21BR72A104KA37L

AEC-Q200

Murata

4 1 C12 CAP., 1μF, X7S, 100V, 10%, 0805, AEC-Q200 MURATA, GCM21BC72A105KE36L

AEC-Q200

Murata

26 4 C2-C5 CAP., 10μF, X5R, 50V, 10%, 1206, AEC-Q200 MURATA, GRT31CR61H106KE01L

AEC-Q200

Murata

2 1 C9 CAP., 1μF, X7R, 50V, 10%, 0805, AEC-Q200 MURATA, GCM21BR71H105KA03L

AEC-Q200

Murata

1 2 C7, C8 CAP., 10μF, X5R, 50V,10%, 1206, AEC-Q200 MURATA, GRT31CR61H106KE01L

AEC-Q200

Murata

30 2 FB1, FB2 IND., 470Ω AT 100MHz, FERRITE BEAD, 25%, 4A, 20mΩ, 1206, AEC-Q200 MURATA, BLM31KN471SZ1L

AEC-Q200

Murata

5 3 C13, C17, C20 CAP., 0.1μF, X7R, 16V, 10%, 0402, AEC-Q200 MURATA, GCM155R71C104KA55D

AEC-Q200

Murata

25 1 C1 CAP., 0.1μF, X7R, 50V, 10%, 0402, AEC-Q200 MURATA, GCM155R71H104KE02D

AEC-Q200

Panasonic

19 2 R9, R10 RES., 0Ω, 1/10W, 0402, AEC-Q200 PANASONIC, ERJ2GE0R00X

AEC-Q200

Panasonic

27 1 C6 CAP., 47μF, ALUM ELECT, 50V, 20%, 6.3mm × 5.8mm SMD, RADIAL, AEC-Q200 PANASONIC, EEEFT1H470AP

AEC-Q200

Panasonic

22 1 R18 RES., 2.2k, 1%, 1/10W, 0402, AEC-Q200 PANASONIC, ERJ2RKF2201X

AEC-Q200

TDK

31 2 FB4, FB5 IND., 1k AT 100MHz, FERRITE BEAD, 25%, 1.5A, 150mΩ, 0805, AEC-Q200 TDK, MPZ2012S102ATD25

AEC-Q200

Taiyo Yuden

6 1 C14 CAP., 4.7μF, X5R, 6.3V, 20%, 0402, AEC-Q200 TAIYO YUDEN, JMK105BBJ475MVHF

AEC-Q200

Taiyo Yuden

7 1 C18 CAP., 2.2μF, X5R, 6.3V, 20%, 0402, AEC-Q200 TAIYO YUDEN, JMK105BJ225MVHF

AEC-Q200

Taiyo Yuden

8 1 C19 CAP., 0.47μF, X7R, 6.3V, 10%, 0402, AEC-Q200 TAIYO YUDEN, JMK105B7474KVHF

AEC-Q200

Vishay

14 2 R3, R17 RES., 100k, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW0402100KFKED

AEC-Q200

Vishay

16 4 R5, R7, R11, R14 RES., 2Ω, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW04022R00FKED

AEC-Q200

Vishay

20 1 R15 RES., 1M, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW04021M00FKED

AEC-Q200

Vishay

12 1 R1 RES., 383k, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW0402383KFKED

AEC-Q200

Vishay

18 2 R8, R13 RES., 100k, 5%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW0402100KJNED

AEC-Q200

Vishay

21 1 R16 RES., 17.4k, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW040217K4FKED

AEC-Q200

Vishay

13 1 R2 RES., 165k, 1%, 1/16W, 0402, AEC-Q200 VISHAY, CRCW0402165KFKED

AEC-Q200

Vishay

23 1 R20 RES., 0Ω, 1/4W, 1206, AEC-Q200 VISHAY, CRCW12060000Z0EA

2mm

Wurth Elektronik

38 1 XJP1 CONN., SHUNT, FEMALE, 2 POS, 2mm WURTH ELEKTRONIK, 60800213421

EVAL-LT8391D-AZ: 6V to 45V Synchronous 4-Switch Buck-Boost LED Driver | Design Resources