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Dual Output DC/DC Converter Solutions for Xilinx FPGA Based Systems

Design solutions for Xilinx FPGA power supplies using LTC3407, LTC3736, and LTC3708 regulators to provide dual outputs with tracking and sequencing capabilities.

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Overview

This design document outlines high-efficiency dual-output DC/DC converter solutions tailored for Xilinx FPGA families, including Virtex-II Pro, Virtex-II, and Spartan-3. It details three primary solutions based on load requirements: the LTC3407 for 600mA applications, the LTC3736 for 5A loads using 2-phase operation to minimize input ripple, and the LTC3708 for high-current 15A systems. The document addresses critical FPGA power design challenges such as core and I/O voltage requirements, supply sequencing, and ratiometric or coincident voltage tracking. Full schematics are provided featuring components from Murata, Taiyo Yuden, Vishay, Renesas, and Sanyo.

Use Cases

  • Powering Xilinx FPGA core and I/O rails
  • High-efficiency buck regulation for multi-rail systems
  • Supply sequencing and tracking in digital systems
  • Point-of-load regulation for high-current FPGA applications
  • Reducing input capacitor RMS current in dual-output designs

Topics

LTC3407
LTC3736
LTC3708
Xilinx FPGA Power
DC/DC Converter
Dual Output Regulator
Voltage Tracking
Supply Sequencing
Synchronous Step-Down
2-Phase Controller
Spartan-3
Virtex-II Pro

Referenced Parts

4TPD330M

Sanyo

COUT1: SANYO POSCAP 4TPD330M

CMDSH-3

Central Semiconductor

CMDSH-3

LQH32CN2R2M33

Murata

AN95 F01 C1, C2, C3: TAIYO YUDEN JMK316BJ106ML L1, L2: MURATA LQH32CN2R2M33

LTC3407

Linear Technology

New dual output DC/DC regulators from Linear Technology, the LTC3407

LTC3708

Linear Technology

The LTC3708-based dual output supply is an ideal choice

LTC3736

Linear Technology

The LTC3736 is a 2-phase dual synchronous step down DC/DC controller.

ETQP3H

Panasonic

L1, L2: PANASONIC ETQP3H

HAT2165

Renesas

M3, M4: RENESAS HAT2165

HAT2168

Renesas

M1, M2: RENESAS HAT2168

2R5TPD470M

Sanyo

COUT2: SANYO POSCAP 2R5TPD470M

JMK316BJ106ML

Taiyo Yuden

C1, C2, C3: TAIYO YUDEN JMK316BJ106ML

IHLP2525CZ-01

Vishay Dale

L1 1.5μH IHLP2525CZ-01

Si7540DP

Vishay Siliconix

Q2A Si7540DP Q2B Si7540DP Q1A Si7540DP Q1B Si7540DP

B340A

Diodes Incorporated

D1 B340A D2 B340A

JMK316BJ106ML

Taiyo Yuden

AN95 F01 C1, C2, C3: TAIYO YUDEN JMK316BJ106ML L1, L2: MURATA LQH32CN2R2M33