Fairchild FDMF6706C service manual

March 2012

FDMF6706C – Extra-Small, High-Performance, HighFrequency DrMOS Module

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

Benefits

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

Compared to Conventional Discrete Solutions

 Fully Optimized System Efficiency  Clean Switching Waveforms with Minimal Ringing  High-Current Handling

Features

 Over 93% Peak-Efficiency  High-Current Handling of 43A  High-Performance PQFN Copper Clip Package  3-State 5V PWM Input Driver  Shorter Propagation Delays than FDMF6704  Shorter Dead Times than FDMF6704  Skip-Mode SMOD# (Low-Side Gate Turn Off) Input  Thermal Warning Flag for Over-Temperature

Condition

 Driver Output Disable Function (DISB# Pin)  Internal Pull-Up and Pull-Down for SMOD# and

DISB# Inputs, Respectively

 Fairchild PowerTrench® Technology MOSFETs for

Clean Voltage Waveforms and Reduced Ringing

 Fairchild SyncFET™ (Integrated Schottky Diode)

Technology in the Low-Side MOSFET

 Integrated Bootstrap Schottky Diode  Adaptive Gate Drive Timing for Shoot-through

Protection

 Under-Voltage Lockout (UVLO)  Optimized for Switching Frequencies up to 1MHz  Low-Profile SMD Package  Fairchild Green Packaging and RoHS Compliant  Based on the Intel® 4.0 DrMOS Standard

Description

The XS™ DrMOS family is Fairchild’s next-generation, fully optimized, ultra-compact, integrated MOSFET plus driver power stage solutions for high-current, highfrequency, synchronous buck DC-DC applications. The FDMF6706C integrates a driver IC, two power MOSFETs, and a bootstrap Schottky diode into a thermally enhanced, ultra-compact 6x6mm PQFN package.

With an integrated approach, the complete switching power stage is optimized with regards to driver and MOSFET dynamic performance, system inductance, and Power MOSFET R Fairchild's high-performance PowerTrench® MOSFET technology, which dramatically reduces switch ringing, eliminating the need for a snubber circuit in most buck converter applications.

A new driver IC with reduced dead times and propagation delays further enhances the performance of this part. A thermal warning function has been included to warn of a potential over-temperature situation. The FDMF6706C also incorporates features, such as Skip Mode (SMOD), for improved light-load efficiency along with a 3-state 5V PWM input for compatibility with a wide range of PWM controllers.

. XS™ DrMOS uses

DS(ON)

Applications

High-Performance Gaming Motherboards

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

DC-DC Converters

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

DC-DC Converters

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

Converters

 Networking and Telecom Microprocessor Voltage

Regulators

 Small Form-Factor Voltage Regulator Modules

Ordering Information

Part

Number

FDMF6706C 40A 12V 1000kHz

Current

Rating

Input

Voltage

Switching

Frequency

Package Top Mark

40-Lead, Clipbond PQFN DrMOS,

6.0x6.0mm Package

FDMF6706C

Typical Application Circuit

A

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

V5V

C

VDRV

DISB#

PWM Input

OFF

ON

Open Drain Output

DrMOS Block Diagram

VCIN

UVLO

DISB#

PWM

SMOD#

THWN#

VDRV

VCIN

FDMF6706C

CGND

PGND

VIN

R

BOOT

PHASE

VSWH

BOOT

Figure 1. Typical Application Circuit

VDRV VIN

D

C

VIN

Boot

C

BOOT

VIN 3V ~ 15V

L

OUT

C

OUT

Q1 HS Power MOSFET

V

OUT

DISB#

PWM

THWN#

R

UP_PWM

R

DN_PWM

CGND

10µ

V

CIN

Temp. Sense

Input

State

3-

Logic

GH

Logic

Level Shift

Dead-Time

Control

GL

Logic

V

CIN

10µ

SMOD#

Figure 2. DrMOS Block Diagram

GH

30kΩ

PHASE

VSWH

V

DRV

GL

30kΩ

Q2 LS Power MOSFET

PGND

Pin Configuration

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

Figure 3. Bottom View Figure 4. Top View

Pin Definitions

Pin # Name Description

When SMOD#=HIGH, the low-side driver is the inverse of PWM input. When SMOD#=LOW,

1 SMOD#

2 VCIN IC bias supply. Minimum 1µF ceramic capacitor is recommended from this pin to CGND.

3 VDRV

4 BOOT

5, 37, 41 CGND IC ground. Ground return for driver IC.

6 GH For manufacturing test only. This pin must float. Must not be connected to any pin.

7 PHASE Switch node pin for bootstrap capacitor routing. Electrically shorted to VSWH pin.

8 NC

9 - 14, 42 VIN Power input. Output stage supply voltage.

15, 29 -

35, 43

16 – 28 PGND Power ground. Output stage ground. Source pin of low-side MOSFET.

36 GL For manufacturing test only. This pin must float. Must not be connected to any pin.

38 THWN#

39 DISB#

40 PWM PWM signal input. This pin accepts a 3-state 5V PWM signal from the controller.

VSWH

the low-side driver is disabled. This pin has a 10µA internal pull-up current source. Do not add a noise filter capacitor.

Power for gate driver. Minimum 1µF ceramic capacitor is recommended to be connected as close as possible from this pin to CGND.

Bootstrap supply input. Provides voltage supply to high-side MOSFET driver. Connect bootstrap capacitor from this pin to PHASE.

No connect. The pin is not electrically connected internally, but can be connected to VIN for convenience.

Switch node input. Provides return for high-side bootstrapped driver and acts as a sense point for the adaptive shoot-through protection.

Thermal warning flag, open collector output. When temperature exceeds the trip limit, the output is pulled LOW. THWN# does not disable the module.

Output disable. When LOW, this pin disables Power MOSFET switching (GH and GL are held LOW). This pin has a 10µA internal pull-down current source. Do not add a noise filter capacitor.

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.

Symbol Parameter Min. Max. Unit

VCIN, VDRV, DISB#, PWM, SMOD#, GL, THWN# to CGND Pins 6

VIN to PGND, CGND Pins 25

BOOT, GH to VSWH, PHASE Pins 6

VSWH, PHASE to PGND, CGND Pins 25

BOOT to PGND, CGND Pins 27

BOOT to VDRV 22

f

=300kHz 43

(1)

I

O(AV)

θ

T

JPCB

STG

=12V, VO=1.0V

VIN

Junction-to-PCB Thermal Resistance 3.5 °C/W

Operating and Storage Temperature Range -55 +150 °C

ESD Electrostatic Discharge Protection

SW

fSW=1MHz 40

Human Body Model, JESD22-A114 2000

Charged Device Model, JESD22-C101 2000

Note:

1. I

is rated using Fairchild’s DrMOS evaluation board, at TA = 25°C, with natural convection cooling. This rating

O(AV)

is limited by the peak DrMOS temperature, T

= 150°C, and varies depending on operating conditions and PCB

J

layout. This rating can be changed with different application settings.

V

A

V

Recommended Operating Conditions

The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings.

Symbol Parameter Min. Typ. Max. Unit

V

Control Circuit Supply Voltage 4.5 5.0 5.5 V

CIN

V

Gate Drive Circuit Supply Voltage 4.5 5.0 5.5 V

DRV

VIN Output Stage Supply Voltage

Note:

2. Operating at high V

can create excessive AC overshoots on the VSWH-to-GND and BOOT-to-GND nodes

IN

during MOSFET switching transients. For reliable DrMOS operation, VSWH-to-GND and BOOT-to-GND must

remain at or below the Absolute Maximum Ratings shown in the table above. Refer to the “Application Information” and “PCB Layout Guidelines” sections of this datasheet for additional information.

(2)

3.0 12.0 15.0 V

Electrical Characteristics

Typical values are VIN = 12V, V

Symbol Parameter Condition Min. Typ. Max. Unit

Basic Operation

IQ Quiescent Current IQ=I

UVLO UVLO Threshold V

UVLO

PWM Input

R

V

t

D_HOLD-OFF

V

HiZ_PWM

DISB# Input

V

t

PD_DISBL

t

PD_DISBH

SMOD# Input

V

IH_SMOD

V

t

PD_SLGLL

t

PD_SHGLH

Thermal Warning Flag

R

250ns Timeout Circuit

t

D_TIMEOUT

UVLO Hysteresis 0.4 V

_Hyst

Pull-Up Impedance 10 kΩ

UP_PWM

Pull-Down Impedance 10 kΩ

DN_PWM

PWM High Level Voltage

IH_PWM

3-State Rising Threshold

TRI_HI

3-State Falling Threshold

TRI_LO

PWM Low Level Voltage

IL_PWM

3-State Shutoff Time 160 200 ns

3-State Open Voltage 2.3 2.5 2.7 V

High-Level Input Voltage 2 V

IH_DISB

Low-Level Input Voltage 0.8 V

IL_DISB

I

Pull-Down Current 10 µA

PLD

Propagation Delay

High-Level Input Voltage 2 V

Low-Level Input Voltage 0.8 V

IL_SMOD

I

Pull-Up Current 10 µA

PLM

Propagation Delay

T

Activation Temperature 150 °C

ACT

T

Reset Temperature 135 °C

RST

Pull-Down Resistance I

THWN

Timeout Delay

= 5V, V

CIN

= 5V, and T

DRV

VCIN+IVDRV

Rising 2.9 3.1 3.3 V

CIN

= +25°C unless otherwise noted.

A

, PWM=LOW or HIGH or Float 2 mA

3.30 3.55 3.80

3.20 3.45 3.70

1.00 1.25 1.50

0.85 1.15 1.40

PWM=GND, Delay Between DISB# from HIGH to LOW to GL from HIGH to LOW

PWM=GND, Delay Between DISB# from LOW to HIGH to GL from LOW to HIGH

PWM=GND, Delay Between SMOD# from HIGH to LOW to GL from HIGH to LOW

PWM=GND, Delay Between SMOD# from LOW to HIGH to GL from LOW to HIGH

=5mA 30 Ω

PLD

SW=0V, Delay Between GH from HIGH to LOW and GL from LOW to HIGH

25 ns

10 ns

250 ns

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

V

Continued on the following page…

FDMF6706C - Extra-Small High-Performance, High-Frequency DrMOS Module

Electrical Characteristics

Typical values are VIN = 12V, V

Symbol Parameter Condition Min. Typ. Max. Unit

High-Side Driver

R

SOURCE_GH

R

SINK_GH

t

D_DEADON

t

PD_PLGHL

t

PD_PHGHH

t

PD_TSGHH

Low-Side Driver

R

SOURCE_GL

R

SINK_GL

t

D_DEADOFF

t

PD_PHGLL

t

PD_TSGLH

Boot Diode

Output Impedance, Sourcing Source Current=100mA 1 Ω

Output Impedance, Sinking Sink Current=100mA 0.8 Ω

Rise Time GH=10% to 90%, C

R_GH

Fall Time GH=90% to 10%, C

F_GH

LS to HS Deadband Time

PWM LOW Propagation Delay

PWM HIGH Propagation Delay (SMOD Held LOW)

Exiting 3-State Propagation Delay

Output Impedance, Sourcing Source Current=100mA 1 Ω

Output Impedance, Sinking Sink Current=100mA 0.5 Ω

Rise Time GL=10% to 90%, C

R_GL

Fall Time GL=90% to 10%, C

F_GL

HS to LS Deadband Time

PWM-HIGH Propagation Delay

Exiting 3-State Propagation Delay

VF Forward-Voltage Drop IF=10mA 0.35 V

VR Breakdown Voltage IR=1mA 22 V

= 5V, V

CIN

= 5V, and T

DRV

= +25°C unless otherwise noted.

A

=1.1nF 12 ns

LOAD

=1.1nF 11 ns

LOAD

GL going LOW to GH going HIGH, 2V GL to 10 % GH

PWM going LOW to GH going LOW, V

IL_PWM

to 90% GH

PWM going HIGH to GH going HIGH, V

to 10% GH (SMOD=LOW)

IH_PWM

PWM (from 3-State) going HIGH to GH going HIGH, V

IH_PWM

to 10% GH

=2.7nF 12 ns

LOAD

=2.7nF 8 ns

LOAD

SW going LOW to GL going HIGH,

2.2V SW to 10% GL

PWM going HIGH to GL going LOW, V

IH_PWM

to 90% GL

PWM (from 3-State) going LOW to GL going HIGH, V

IL_PWM

to 10% GL

10 ns

16 30 ns

30 ns

12 ns

9 25 ns

20 ns