Fairchild FDD8780, FDU8780 service manual

FDD8780/FDU8780
N-Channel PowerTrench® MOSFET

25V, 35A, 8.5mΩ

General Description

This N-Channel MOSFET has been designed specifically
to improve the overall efficiency of DC/DC converters using
either synchronous or conventional switching PWM
controllers. It has been optimized for low gate charge, low
r

and fast switching speed.

DS(on)

Features

 Max r

 Max r

 Low gate charge: Q

 Low gate resistance

= 8.5mΩ at V

DS(on)

= 12.0mΩ at V

DS(on)

= 10V, ID = 35A

GS

= 4.5V, ID = 35A

GS

= 21nC(Typ), VGS = 10V

g(10)

March 2006

E

E

R

F

D

A

E

L

FDD8780/FDU8780 N-Channel PowerTrench

I

M

P

L

E

M

E

N

T

A

T

I

O

N

Application

 Vcore DC-DC for Desktop Computers and Servers

 Avalanche rated and 100% tested

 RoHS Compliant

 VRM for Intermediate Bus Architecture

G

G

MOSFET Maximum Ratings T

DS

I-PAK

(TO-251AA)

= 25°C unless otherwise noted

C

D

S

Short Lead I-PAK

G

Symbol Parameter Ratings Units

V

DS

V

GS

Drain to Source Voltage 25 V

Gate to Source Voltage ±20 V

Drain Current -Continuous (Package Limited) 35

I

D

-Pulsed (Note 1) 224

E

AS

P

D

, T

T

J

STG

Single Pulse Avalanche Energy (Note 2) 73 mJ

Power Dissipation 50 W

Operating and Storage Temperature -55 to 175 °C

Thermal Characteristics

D

®

MOSFET

S

A -Continuous (Die Limited) 60

R

θJC

R

θJA

R

θJA

Thermal Resistance, Junction to Case TO-252,TO-251 3.0 °C/W

Thermal Resistance, Junction to Ambient TO-252,TO-251 100 °C/W

Thermal Resistance, Junction to Ambient TO-252,1in2 copper pad area 52 °C/W

Package Marking and Ordering Information

Device Marking Device Package Reel Size Tape Width Quantity

FDD8780 FDD8780 TO-252AA 13’’ 12mm 2500 units

FDU8780 FDU8780 TO-251AA N/A(Tube) N/A 75 units

FDU8780 FDU8780_F071 TO-251AA N/A(Tube) N/A 75 units

©2006 Fairchild Semiconductor Corporation
FDD8780/FDU8780 Rev. B

www.fairchildsemi.com1

Electrical Characteristics T

= 25°C unless otherwise noted

J

Symbol Parameter Test Conditions Min Typ Max Units

Off Characteristics

B

VDSS

∆B
∆T

I

DSS

I

GSS

VDSS

J

Drain to Source Breakdown Voltage ID = 250µA, VGS = 0V 25 V

Breakdown Voltage Temperature
Coefficient

Zero Gate Voltage Drain Current

ID = 250µA, referenced to
25

°C

VDS = 20V,
V

GS

= 0V

TJ = 150°C 250

12 mV/°C

1

Gate to Source Leakage Current VGS = ±20V ±100 nA

FDD8780/FDU8780 N-Channel PowerTrench

µA

On Characteristics

V

GS(th)

∆V
∆T

r

DS(on)

GS(th)

J

Gate to Source Threshold Voltage VGS = VDS, ID = 250µA 1.2 1.8 2.5 V

Gate to Source Threshold Voltage
Temperature Coefficient

Drain to Source On Resistance

Dynamic Characteristics

C

iss

C

oss

C

rss

R

g

Input Capacitance

Output Capacitance 265 355 pF

Reverse Transfer Capacitance 180 270 pF

Gate Resistance f = 1MHz 0.9 Ω

Switching Characteristics

t

d(on)

t

r

t

d(off)

t

f

Q

Q

Q

Q

g

g

gs

gd

Turn-On Delay Time

Rise Time 9 18 ns

Turn-Off Delay Time 43 69 ns

Fall Time 24 38 ns

Total Gate Charge V

Total Gate Charge V

Gate to Source Gate Charge 3.5 nC

Gate to Drain “Miller”Charge 4.7 nC

Drain-Source Diode Characteristics

V

SD

t

rr

Q

rr

Notes:
1: Pulse time < 300µs, Duty cycle = 2%.
2: Starting T

Source to Drain Diode Forward Voltage

Reverse Recovery Time IF = 35A, di/dt = 100A/µs 28 42 ns

Reverse Recovery Charge IF = 35A, di/dt = 100A/µs 20 30 nC

= 25oC, L = 0.3mH, IAS = 22A ,VDD = 23V, VGS = 10V.

J

ID = 250µA, referenced to
25

°C

-6.3 mV/°C

VGS = 10V, ID = 35A 6.5 8.5

VGS = 4.5V, ID = 35A 9.1 12.0

VGS = 10V, ID = 35A
TJ = 175°C

VDS = 13V, VGS = 0V,

10.4 15.0

1080 1440 pF

f = 1MHz

7 14 ns

VDD = 13V, ID = 35A
VGS = 10V, RGS = 17Ω

= 0V to 10V

GS

= 0V to 5V 11. 2 16 nC

GS

V

= 0V, IS = 35A 0.92 1.25

GS

V

= 0V, IS = 15A 0.84 1.0

GS

VDD = 13V
I

= 35A

D

Ig = 1.0mA

21 29 nC

mΩ

®

MOSFET

V

FDD8780/FDU8780 Rev. B

www.fairchildsemi.com2