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Fairchild FDMF6705 Product Manual

Summary

This ultra-compact 6x6mm DrMOS module is an advanced power solution designed for high-efficiency, synchronous buck DC-DC conversion in space-constrained systems. Integrating MOSFETs, drivers, and diodes into one unit, it delivers up to 40A current handling with peak efficiencies exceeding 93%. Engineers utilize this component for critical applications, including desktop PCs, gaming motherboards, notebook computers, and blade servers requiring high-performance point-of-load regulation. The manual provides comprehensive technical specifications, detailed pin definitions, required PCB layout guidelines, and application circuits essential for integration.

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Page 1 Text Content

6705 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le

March 2012

FDMF6705 - Extra-Small, High-Performance, High- Frequency Dr MOS Module

Benefits Description The XS™ Dr MOS family is Fairchild’s next-generation,

 Ultra-Compact 6x6mm PQFN, 72% Space-Saving

fully optimized, ultra-compact, integrated MOSFET plus

Compared to Conventional Discrete Solutions

driver power stage solutions for high-current, high-

 Fully Optimized System Efficiency frequency, synchronous buck DC-DC applications. The

FDMF6705 integrates a driver IC, two power MOSFETs,

 Clean Switching Waveforms with Minimal Ringing

and a bootstrap Schottky diode into a thermally

 High-Current Handling enhanced, ultra-compact 6x6mm PQFN package.

Features With an integrated approach, the complete switching power stage is optimized with regards to driver and  Over 93% Peak-Efficiency MOSFET dynamic performance, system inductance, and Power MOSFET RDS(ON). XS™ Dr MOS uses

 High-Current Handling of 40A, at 12VIN

Fairchild's high-performance Power Trench® MOSFET

 High-Current Handling of 38A at 19VIN technology, which dramatically reduces switch ringing,

eliminating the need for a snubber circuit in most buck

 High-Performance PQFN Copper-Clip Package

converter applications.

 3-State 5V PWM Input Driver

A new driver IC with reduced dead times and

 Skip-Mode SMOD# (Low-Side Gate Turn Off) Input

propagation delays further enhances the performance of  Thermal Warning Flag for Over-Temperature this part. A thermal warning function has been included Condition to warn of a potential over-temperature situation. The FDMF6705 also incorporates features, such as Skip

 Driver Output Disable Function (DISB# Pin)

Mode (SMOD), for improved light-load efficiency along

 Internal Pull-Up and Pull-Down for SMOD# and with a 3-state PWM input for compatibility with a wide DISB# Inputs, Respectively range of PWM controllers.  Fairchild Power Trench® Technology MOSFETs for

Applications

Clean Voltage Waveforms and Reduced Ringing

 Fairchild Sync FET™ (Integrated Schottky Diode)  High-Performance Gaming Motherboards

Technology in the Low-Side MOSFET

 Notebook Computer V-Core and Non-V-Core

 Integrated Bootstrap Schottky Diode

 Compact Blade Server, V-Core and Non-V-Core

 Adaptive Gate Drive Timing for Shoot-through DC-DC Converters Protection

 Desktop Computer, V-Core and Non-V-Core

 Under-Voltage Lockout (UVLO)

DC-DC Converters

 Optimized for Switching Frequencies up to 1MHz

 Workstations

 Low-Profile SMD Package

 High-Current DC-DC Point-of-Load (POL)

 Fairchild Green Packaging and Ro HS Compliant Converters  Based on the Intel® 4.0 Dr MOS Standard  Small Form-Factor Voltage Regulator Modules

Ordering Information

Part Number Current Rating Package Top Mark

FDMF6705 40A 40-Lead, Clipbond PQFN Dr MOS, 6.0x6.0mm Package FDMF6705

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com FDMF6705 • Rev. 1.0.3

Page Summary Contents For Fairchild FDMF6705 Product Manual

Page 1 6705 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le March 2012 FDMF6705 - Extra-Small, High-Performance, High- Frequency Dr MOS Module Benefits Description The XS™ Dr MOS family is F...
Page 2 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Typical Application Circuit CVDRV CVIN VDRV VCIN VIN DISB# RBOOT DISB# CBOOT PWM Input PWM FDMF6705 PHASE SMOD# ON VSWH Open-Drain THWN...
Page 3 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Pin Configuration Figure 3. Bottom View Figure 4. Top View Pin Definitions Pin # Name Description When SMOD#=HIGH, the low-side driver ...
Page 4 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be opera...
Page 5 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Electrical Characteristics Typical values are VIN = 12V, VCIN = 5V, VDRV = 5V, and TA = +25°C unless otherwise noted. Symbol Parameter ...
Page 6 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Electrical Characteristics Typical values are VIN = 12V, VCIN = 5V, VDRV = 5V, and TA = +25°C unless otherwise noted. Symbol Parameter ...
Page 7 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le V IH_PWM IL_PWM GH to VSWH t D_TIMEOUT ( 250ns Timeout) t PD t PD PLGHL PHGLL t D_DEADOFF t D_DEADON Figure 5. PWM Timing Diagram © 201...
Page 8 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Typical Performance Characteristics rm al iz ed le er ss le ss le tp t c rr en t, (A Test Conditions: VIN=12V, VOUT=1.0V, VCIN=5V, VDRV...
Page 9 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Typical Performance Characteristics (Continued) ri ve ly rr t, IN (m rm al iz ed ri ve ly rr en rm al iz ed le er ss Test Conditions: V...
Page 10 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Typical Performance Characteristics (Continued) IS re sh ld lt ag re sh ld lt ag re sh ld lt ag Test Conditions: VIN=12V, VOUT=1.0V, VC...
Page 11 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Typical Performance Characteristics (Continued) Test Conditions: VIN=12V, VOUT=1.0V, VCIN=5V, VDRV=5V, LOUT=320n H, TA=25°C, and natura...
Page 12 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Functional Description The FDMF6705 is a driver-plus-FET module optimized 3-State PWM Input for the synchronous buck converter topology...
Page 13 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Adaptive Gate Drive Circuit The driver IC advanced design ensures minimum voltage at the VSWH pin. When the PWM signal goes MOSFET dead...
Page 14 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Skip Mode (SMOD) The SMOD function allows for higher converter Table 2. SMOD Logic efficiency under light-load conditions. During SMOD,...
Page 15 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Application Information Supply Capacitor Selection VCIN Filter For the supply inputs (VDRV & VCIN), a local ceramic The VDRV pin pr...
Page 16 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le PCB Layout Guidelines Figure 30 provides an example of a proper layout for the the boot capacitor (CBOOT) and Dr MOS BOOT pin. FDMF6705...
Page 17 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Bottom View Top View Figure 30. PCB Layout Example © 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com FDMF6705 • Rev. 1.0...
Page 18 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le Physical Dimensions PIN#1 0.10 INDICATOR TOP VIEW 0.60 SEE 0.35 DETAIL 'A' 0.50 TYP 2.10 2.10 LAND PATTERN RECOMMENDATION FRONT VIEW 0....
Page 19 - E xtra-S all H ig -P erfo rm an ce, H ig -F req en cy D r M le © 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com FDMF6705 • Rev. 1.0.3 19

Manual Details

Brand Fairchild
Pages 19
File Size 1.45 MB
Published June 16, 2026
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Frequently Asked Questions

What is the approximate size and package type of the FDMF6705?

It uses an ultra-compact 6x6mm PQFN package with 40 leads.

How does this DrMOS improve switching performance compared to discrete solutions?

It features Fairchild’s PowerTrench® MOSFET and SyncFET™ Schottky diode technology, which reduces switch ringing and eliminates the need for a snubber circuit in most converters.

What functions are included regarding efficiency and operation modes?

Features include Skip-Mode (SMOD) for improved light-load efficiency and a Thermal Warning Flag to alert potential over-temperature conditions.

Are there specific requirements for external components when using this module?

The IC bias supply (VCIN) requires a minimum 1µF ceramic capacitor, and the gate drive power (VDRV) also recommends at least 1µF of capacitance.