Fairchild FDS6986AS service manual
March 2005
FDS6986AS
FDS6986AS
Dual Notebook Power Supply N-Channel PowerTrench® SyncFET™
General Description
The FDS6986AS 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. FDS6986AS 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 lowside switch (Q2) is optimized to reduce conduction
losses. Q2 also includes an integrated Schottky diode
using Fairchild’s monolithic SyncFET technology.
D
2
D
/
S
2
1
D
/
S
1
D
D
1
D
D
1
D
G
SO-8
Pin 1
SO-8
S
1
S
2
S
G
2
G
S
1
S
/
D
2
Features
• Q2: Optimized to minimize conduction losses
Includes SyncFET Schottky body diode
7.9A, 30V R
R
• Q1: Optimized for low switching losses
Low gate charge (10 nC typical)
6.5A, 30V R
R
5
6
7
8
= 20 mΩ @ VGS = 10V
DS(on)
= 28 mΩ @ VGS = 4.5V
DS(on)
= 29 mΩ @ VGS = 10V
DS(on)
= 38 mΩ @ VGS = 4.5V
DS(on)
Q2
Q1
4
3
2
1
Absolute Maximum Ratings T
= 25°C unless otherwise noted
A
Symbol Parameter Q2 Q1 Units
V
Drain-Source Voltage 30 30 V
DSS
V
Gate-Source Voltage
GSS
ID Drain Current - Continuous (Note 1a) 7.9 6.5 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 ±16
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
FDS6986AS FDS6986AS 13” 12mm 2500 units
FDS6986AS FDS6986AS_NL (Note 4) 13” 12mm 2500 units
©2005 Fairchild Semiconductor Corporation
FDS6986AS Rev A(X)
A
FDS6986
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
= ±20 V, VDS = 0 V
V
GS
= ±16 V, VDS = 0 V
V
GS
Q2
Q1
30
30
V
31
23
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)
= VGS, ID = 250 µA
V
DS
= 1 mA, Referenced to 25°C
I
D
= 250 uA, Referenced to 25°C
I
D
VGS = 10 V, ID = 7.9 A
= 10 V, ID = 7.9 A, TJ = 125°C
V
GS
= 4.5 V, ID = 7 A
V
GS
= 10 V, ID = 6.5 A
V
GS
= 10 V, ID = 6.5 A, TJ = 125°C
V
GS
= 4.5 V, ID = 5.6 A
V
GS
gFS Forward Transconductance VDS = 5 V, ID = 7.9 A
= 5 V, ID = 6.5 A
V
DS
Q2
Q1 1 1
Q2
Q1
Q2 17
Q1 21
Q1
Q2
Q1
1.7
1.9 3 3
–3.2
–4.0
25
22
32
32
30
A
20
25
15
20
32
28
29
49
38
S
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
= 10 V, VGS = 0 V,
V
DS
f = 1.0 MHz
Q1
Q1
Q2
Q1
Q1
550
720
180
120
70
60
3.2
1.2
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
= 15 V, ID = 1 A,
V
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
19
6 4 12 8 ns
25
24
40
39
4 3 8 6 ns
11
10
20
20
15 9 26
18
15
13
26
23
6 3 12 6 ns
S
mV/°C
µA
nA
V
mV/°C
mΩ
Ω
ns
ns
ns
ns
ns
FDS6986AS Rev A (X)
Electrical Characteristics (continued) T
Symbol
Parameter
Test Conditions
= 25°C unless otherwise noted
A
Type Min Typ Max Units
Switching Characteristics (Note 2)
Q
Total Gate Charge, Vgs = 10V
g(TOT)
Qg Total Gate Charge, Vgs = 5V
Qgs Gate-Source Charge
Qgd Gate-Drain Charge
Q2:
= 15 V, ID = 7.9 A
V
DS
Q1:
= 15 V, ID = 6.5 A
V
DS
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
10
12
5.6
6.5 8 9
2.0
2.3
1.5
2.1
14
17
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
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
I
= 10 A,
F
= 300 A/µs (Note 3)
d
iF/dt
I
= 6.5 A,
F
= 100 A/µs (Note 3)
d
iF/dt
VGS = 0 V, IS = 2.3 A (Note 2)
VGS = 0 V, IS = 1.3 A (Note 2)
is determined by the user's board design.
θCA
Q2
Q1
Q2
Q1
3.0
1.3
15
6 nC
20
12 nC
0.6
0.8
0.7
1.2
nC
nC
nC
nC
A
ns
ns
V
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. FDS6986AS_NL is a lead free product. FDS6986AS_NL marking will appear on the reel label.
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.
FDS6986AS Rev A (X)
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