Fairchild FDS8978 service manual

FDS8978 N-Channel PowerTrench

30V, 7.5A, 18mΩ

®

MOSFET

FDS8978 Dual N-Channel PowerTrench

January 2011

Features

 r

 High performance trench technology for extremely low

 Low gate charge

 High power and current handling capability

 100% Rg Tested

 RoHS Compliant

= 18mΩ, V

DS(on)

= 21mΩ, V

DS(on)

r

DS(on)

SO-8

MOSFET Maximum Ratings T

Symbol Parameter Ratings Units

V

DSS

V

GS

I

D

E

AS

P

D

, T

T

J

STG

= 10V, ID = 7.5A

GS

= 4.5V, ID = 6.9A

GS

D2

D1

G2

S2

G1

Pin 1

Drain to Source Voltage 30 V

Gate to Source Voltage ±20 V

Drain Current

Continuous (T

Pulsed 49 A

Single Pulse Avalanche Energy (Note 1) 57 mJ

Power dissipation 1.6 W

Derate above 25

Operating and Storage Temperature -55 to 150

= 25oC, VGS = 10V, R

A

= 25oC, VGS = 4.5V, R

A

o

C13mW/

S1

= 25°C unless otherwise noted

A

θJA

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)

Applications

 DC/DC converters

D2

5

6

D2

D1

= 50oC/W)

= 50oC/W) 6.9 A

7

8

Q2

Q1

7.5 A

4

3

2

1

G2

S2

G1

S1

o

®

MOSFET

o

C

Thermal Characteristics

R

θJC

R

θJA

R

θJA

Thermal Resistance, Junction to Case (Note 2) 40

Thermal Resistance, Junction to Ambient (Note 2a) 78

Thermal Resistance, Junction to Ambient (Note 2c) 135

Package Marking and Ordering Information

Device Marking Device Package Reel Size Tape Width Quantity

FDS8978 FDS8978 SO-8 330mm 12mm 2500 units

1

o

C/W

o

C/W

o

C/W

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FDS8978 Dual N-Channel PowerTrench

Electrical Characteristics T

= 25°C unless otherwise noted

J

Symbol Parameter Test Conditions Min Typ Max Units

Off Characteristics

B

VDSS

I

DSS

I

GSS

Drain to Source Breakdown Voltage ID = 250µA, VGS = 0V 30 - - V

V

= 24V - - 1

Zero Gate Voltage Drain Current

DS

= 0V TJ = 150oC - - 250

V

GS

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

On Characteristics

V

GS(TH)

r

DS(on)

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

ID = 7.5A, VGS = 10V - 14 18

Drain to Source On Resistance

ID = 6.9A, VGS = 4.5V - 17 21

I

= 7.5A, VGS = 10V,

D

TJ = 150oC

- 22 29

Dynamic Characteristics

C

ISS

C

OSS

C

RSS

R

G

Q

g(TOT)

Q

g(5)

Q

gs

Q

gs2

Q

gd

Input Capacitance

Output Capacitance - 191 - pF

Reverse Transfer Capacitance - 11 2 - pF

VDS = 15V, VGS = 0V, f = 1MHz

- 907 1270 pF

Gate Resistance VGS = 0.5V, f = 1MHz - 1.2 4.0 Ω

Total Gate Charge at 10V VGS = 0V to 10V

Total Gate Charge at 5V VGS = 0V to 5V - 9 14 nC

VDD = 15V ID = 7.5A

- 17 26 nC

Gate to Source Gate Charge - 2.3 - nC

Gate Charge Threshold to Plateau - 1.5 - nC

Gate to Drain “Miller” Charge - 3.3 - nC

µA

mΩ

®

MOSFET

Switching Characteristics (V

t

ON

t

d(ON)

t

r

t

d(OFF)

t

f

t

OFF

Turn-On Time

Turn-On Delay Time - 7 10.5 ns

Rise Time - 37 55.5 ns

Turn-Off Delay Time - 48 72 ns

Fall Time - 24 36 ns

Turn-Off Time - 72 108 ns

GS

= 10V)

- 44 66 ns

VDD = 15V, ID = 7.5A VGS = 10V, RGS = 16Ω

Drain-Source Diode Characteristics

I

= 7.5A - - 1.25 V

V

SD

t

rr

Q

RR

Notes:

1: Starting TJ = 25°C, L = 1mH, IAS = 7.5A, VDD = 30V, VGS = 10V. 2: R

θJA

drain pins. R

a) 78°C/W when mounted on a 0.5 in

b) 125°C/W when mounted on a 0.02 in2 pad of 2 oz copper. c) 135°C/W when mounted on a minimun pad.

Source to Drain Diode Voltage

Reverse Recovery Time ISD = 7.5A, dISD/dt = 100A/µs - 19 25 ns

Reverse Recovered Charge ISD = 7.5A, dISD/dt = 100A/µs - 10 13 nC

is the sum of the junction-to-case and case-to-ambient thermal resistance where the case thermal reference is defined as the solder mounting surface of the

is guaranteed by design while R

θJC

2

pad of 2 oz copper.

is determined by the user’s board design.

θJA

SD

I

= 2.1A - - 1.0 V

SD

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FDS8978 Dual N-Channel PowerTrench

Typical Characteristics T

1.2

1.0

0.8

0.6

0.4

0.2

POWER DISSIPATION MULTIPLIER

0

0 25 50 75 100 150

TA, AMBIENT TEMPERATURE (oC)

Figure 1.

Normalized Power Dissipation vs

= 25°C unless otherwise noted

J

Ambient Temperature

2

1

θJA

Z

0.1

DUTY CYCLE-DESCENDING ORDER

D = 0.5

0.2

0.1

0.05

0.02

0.01

125

8

7

6

5

V

= 10V

GS

4

V

= 4.5V

3

, DRAIN CURRENT (A)

2

D

I

1

R

= 78oC/W

θJA

0

25 50 75 100 125 150

, AMBIENT TEMPERATURE (

T

A

Figure 2.

Maximum Continuous Drain Current vs

GS

Ambient Temperature

o

C)

®

MOSFET

NORMALIZED THERMAL

IMPEDANCE,

0.001

1000

, PEAK TRANSIENT POWER (W)

(PK)

P

0.01

100

10

0.5

SINGLE PULSE

R

= 135oC/W

θJA

-4

10

-3

10

Figure 3.

-2

10

t, RECTANGULAR PULSE DURATION (s)

-1

10

0

10

1

10

Normalized Maximum Transient Thermal Impedance

VGS = 10V

2

10

SINGLE PULSE

R

= 135oC/W

θJA

= 25oC

T

A

3

10

1

-4

10

-3

10

Figure 4.

-2

10

-1

10

t, PULSE WIDTH (s)

0

10

Single Pulse Maximum Power Dissipation

1

2

10

3

10

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Typical Characteristics T

= 25°C unless otherwise noted

J

FDS8978 Dual N-Channel PowerTrench

100

If R = 0 tAV = (L)(IAS)/(1.3*RATED BV

If R ≠ 0

= (L/R)ln[(IAS*R)/(1.3*RATED BV

t

AV

10

, AVALANCHE CURRENT (A)

AS

I

1

STARTING TJ = 150oC

0.01 0.1 1 10 100

tAV, TIME IN AVALANCHE (ms)

- VDD)

DSS

- VDD) +1]

DSS

STARTING TJ = 25oC

NOTE: Refer to Fairchild Application Notes AN7514 and AN7515

Figure 5.

Unclamped Inductive Switching

Capability

50

PULSE DURATION = 80µs DUTY CYCLE = 0.5%MAX

40

30

20

, DRAIN CURRENT (A)

10

D

I

VGS = 10V

VGS = 5V

VGS = 4.5V

VGS = 3.5V

VGS = 3V

50

PULSE DURATION = 80µs DUTY CYCLE = 0.5%MAX

40

V

= 5V

DS

30

20

, DRAIN CURRENT (A)

10

D

I

0

12345

50

40

30

20

, DRAIN TO SOURCE

ON RESISTANCE (mW)

DS(ON)

r

10

TJ = 25oC

TJ = 150oC

VGS, GATE TO SOURCE VOLTAGE (V)

Figure 6.

ID = 10.2A

ID = 1A

TJ = -55oC

Transfer Characteristics

PULSE DURATION = 80µs DUTY CYCLE = 0.5% MAX

®

MOSFET

0

0.0 0.2 0.4 0.6 0.8 1.0

VDS, DRAIN TO SOURCE VOLTAGE (V)

Figure 7. Saturation Characteristics

1.6 PULSE DURATION = 80µs

DUTY CYCLE = 0.5% MAX

1.4

1.2

ON RESISTANCE

1.0

NORMALIZED DRAIN TO SOURCE

0.8

-80 -40 0 40 80 120 160

Figure 9.

TJ, JUNCTION TEMPERATURE (oC)

Normalized Drain to Source On

Resistance vs Junction Temperature

VGS = 10V, ID = 10.2A

0

246810

Figure 8.

1.2

1.0

0.8

NORMALIZED GATE

THRESHOLD VOLTAGE

0.6

-80 -40 0 40 80 120 160

Figure 10.

, GATE TO SOURCE VOLTAGE (V)

V

GS

Drain to Source On Resistance vs Gate

Voltage and Drain Current

VGS = VDS, ID = 250µA

TJ, JUNCTION TEMPERATURE (oC)

Normalized Gate Threshold Voltage vs

Junction Temperature

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Fairchild FDS8978 service manual

Specifications and Main Features

Frequently Asked Questions

User Manual