Fairchild FDS6982AS service manual

FDS6982AS

May 2008

FDS6982AS

Dual Notebook Power Supply N-Channel PowerTrench® SyncFET™

General Description

The FDS6982AS is designed to replace two single SO­8 MOSFETs and Schottky diode in synchronous
DC:DC power supplies that provide various peripheral
voltages for notebook computers and other battery
powered electronic devices. FDS6982AS contains two
unique 30V, N-channel, logic level, PowerTrench
MOSFETs designed to maximize power conversion
efficiency. The high-side switch (Q1) is designed with
specific emphasis on reducing switching losses while
the low-side switch (Q2) is optimized to reduce
conduction losses. Q2 also includes an integrated
Schottky diode using Fairchild’s monolithic SyncFET
technology.

Applications

• Notebook

D1

D1

D2

D2

G1

S2

G2

S1

= 25°C unless otherwise noted

A

SO-8

Absolute Maximum Ratings T

Features

• Q2: Optimized to minimize conduction losses

Includes SyncFET Schottky body diode

8.6A, 30V R

R

• Low gate charge (21nC typical)

• Q1: Optimized for low switching losses

6.3A, 30V R

R

• Low gate charge (11nC typical)

5
6
7
8

max= 13.5mΩ @ VGS = 10V

DS(on)

max= 16.5mΩ @ VGS = 4.5V

DS(on)

max= 28.0mΩ @ V

DS(on)

max= 35.0mΩ @ V

DS(on)

4

Q1

Q2

3
2
1

tmM

= 10V

GS

= 4.5V

GS

Symbol Parameter Q2 Q1 Units

V

Drain-Source Voltage 30 30 V

DSS

V

Gate-Source Voltage

GSS

ID Drain Current - Continuous (Note 1a) 8.6 6.3 A

- Pulsed 30 20

PD Power Dissipation for Dual Operation 2 W

Power Dissipation for Single Operation (Note 1a) 1.6

TJ, T

STG

Operating and Storage Junction Temperature Range –55 to +150

(Note 1b)

(Note 1c)

±20 ±20

1

0.9

V

°C

Thermal Characteristics

R

θJA

R

θJC

Thermal Resistance, Junction-to-Ambient
Thermal Resistance, Junction-to-Case

(Note 1a) 78

(Note 1) 40

°C/W
°C/W

Package Marking and Ordering Information

Device Marking Device Reel Size Tape width Quantity

FDS6982AS FDS6982AS 13” 12mm 2500 units

©2008 Fairchild Semiconductor Corpora tion

FDS6982AS Rev B1

FDS6982AS

Electrical Characteristics T

= 25°C unless otherwise noted

A

Symbol Parameter Test Conditions Type Min Typ Max Units

Off Characteristics

BV

Drain-Source Breakdown

DSS

Voltage

∆BVDSS
∆T

I

DSS

Breakdown Voltage
Temperature Coefficient

J

Zero Gate Voltage Drain

Current

I

Gate-Body Leakage

GSS

VGS = 0 V, ID = 1 mA

= 0 V, ID = 250 uA

V

GS

I

= 1 mA, Referenced to 25°C

D

= 250 µA, Referenced to 25°C

I

D

Q1
Q2
Q1

VDS = 24 V, VGS = 0 V Q2

Q1

V

= ±20 V, VDS = 0 V

GS

Q2
Q1

30
30

V

28
24

mV/°C

500

1

±100

Q2

On Characteristics (Note 2)

V

Gate Threshold Voltage VDS = VGS, ID = 1 mA

GS(th)

∆VGS(th)
∆TJ

R

DS(on)

Gate Threshold Voltage
Temperature Coefficient

Static Drain-Source

On-Resistance

I

On-State Drain Current VGS = 10 V, VDS = 5 V Q2

D(on)

V

= VGS, ID = 250 µA

DS

ID = 1 mA, Referenced to 25°C

I

= 250 uA, Referenced to 25°C

D

VGS = 10 V, ID = 8.6 A

= 10 V, ID = 8.6 A, TJ = 125°C

V

GS

V

= 4.5 V, ID = 7.5 A

GS

V

= 10 V, ID = 6.3 A

GS

= 10 V, ID = 6.3 A, TJ = 125°C

V

GS

= 4.5 V, ID = 5.6 A

V

GS

gFS Forward Transconductance VDS = 5 V, ID = 8.6 A

= 5 V, ID = 6.3 A

V

DS

Q2
Q1 1 1

1.4

1.9 3 3

Q2 –3.1

Q1 –4.3

Q2

11

Q1 20

30

Q1
Q2

20

32

Q1

13.5

20.0

16

16.5

13

28

26

33

25

35

A

S

19

mV/°C

mΩ

Dynamic Characteristics

C

Input Capacitance Q2

iss

C

Output Capacitance Q2

oss

C

Reverse Transfer Capacitance

rss

RG Gate Resistance VGS = 15mV, f = 1.0 MHz Q2

V

= 10 V, VGS = 0 V,

DS

f = 1.0 MHz

Q1

Q1
Q2
Q1

Q1

1250

610

410

180

130

85

1.4

2.2

pF

pF

pF

Switching Characteristics (Note 2)

t

Turn-On Delay Time

d(on)

tr Turn-On Rise Time

t

Turn-Off Delay Time

d(off)

tf Turn-Off Fall Time

t

Turn-On Delay Time

d(on)

tr Turn-On Rise Time

t

Turn-Off Delay Time

d(off)

tf Turn-Off Fall Time

= 15 V, ID = 1 A,

V

DD

= 10V, R

V

GS

V

= 15 V, ID = 1 A,

DD

= 4.5V, R

V

GS

GEN

GEN

= 6 Ω

= 6 Ω

Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1

9

10

18
20

6 7 12

14

27

24

44
39

11 3 20 6 ns

12

13

19

12

14

15

22
22
23
25
34
27

10 5 20

10

µA

nA

V

Ω

ns

ns

ns

ns

ns

ns

ns

FDS6982AS Rev B1

FDS6982AS

Electrical Characteristics (continued) T

Symbol

Parameter

Test Conditions

= 25°C unless otherwise noted

A

Type Min Typ Max Units

Switching Characteristics (Note 2)

Q

Qg

Qgs

Qgd

g

(TOT)

Total Gate Charge at Vgs=10V

Total Gate Charge at Vgs=5V

Gate–Source Charge

Gate–Drain Charge

Q2:
V

= 15 V, ID = 11.5A

DS

Q1:
V

= 15 V, ID = 6.3A

DS

Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1

21

11

12 6 16 9 nC

3.1

1.8

3.6

2.4

Drain–Source Diode Characteristics and Maximum Ratings

IS Maximum Continuous Drain-Source Diode Forward Current Q2

Q1

Trr Reverse Recovery Time

Qrr Reverse Recovery Charge

Trr Reverse Recovery Time

Qrr Reverse Recovery Charge

VSD Drain-Source Diode Forward

Voltage

I

= 11.5 A,

F

d

= 300 A/µs (Note 3)

iF/dt

I

= 6.3 A,

F

d

= 100 A/µs (Note 3)

iF/dt

VGS = 0 V, IS = 3 A (Note 2)
VGS = 0 V, IS = 6 A (Note 2)
VGS = 0 V, IS = 1.3 A (Note 2)

Notes:

1. R

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

θJA

the drain pins. R

is guaranteed by design while R

θJC

is determined by the user's board design.

θCA

Q2

Q1

Q2
Q2
Q1

3.0

19

12 nC

20

9 nC

0.5

0.6

0.8

30

nC

15

nC

nC

A

1.3
ns

ns

0.7

1.0

V

1.2

a) 78°C/W when

mounted on a

0.5in2 pad of 2
oz copper

Scale 1 : 1 on letter size paper

2. Pulse Test: Pulse Width < 300µs, Duty Cycle < 2.0%

3. See “SyncFET Schottky body diode characteristics” below.

4

5

b) 125°C/W when

mounted on a

0.02 in2 pad of
2 oz copper

c) 135°C/W when

mounted on a
minimum pad.

FDS6982AS Rev B1