Fairchild FDS6900AS service manual
May 2005
FDS6900AS
Dual N-Ch PowerTrench® SyncFET
General Description
™
Features
FDS6900AS
The FDS6900AS 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. FDS6900AS 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.
S1D2
D
S1D2
D
S1D2
D
G1
D
S
D1
S2
G
G2
S
S
SO-8
Pin 1
SO-
D1
Absolute Maximum Ratings T
= 25°C unless otherwise noted
A
• Q2: Optimized to minimize conduction losses
Includes SyncFET Schottky body diode
8.2A, 30V R
R
• Q1: Optimized for low switching losses
Low Gate Charge (11nC typical)
6.9A, 30V R
R
• 100% R
(Gate Resistance) Tested
G
= 22mΩ @ VGS = 10V
DS(on)
= 28mΩ @ VGS = 4.5V
DS(on)
= 27mΩ @ VGS = 10V
DS(on)
= 34mΩ @ VGS = 4.5V
DS(on)
81
Q1
Q2
Dual N-Channel SyncFet
72
63
54
Symbol Parameter Q2 Q1 Units
V
Drain-Source Voltage 30 30 V
DSS
V
Gate-Source Voltage
GSS
ID Drain Current - Continuous (Note 1a) 8.2 6.9 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 1) 40
(Note 1a) 78
°C/W
°C/W
Package Marking and Ordering Information
Device Marking Device Reel Size Tape width Quantity
FDS6900AS FDS6900AS 13” 12mm 2500 units
FDS6900AS FDS6900AS_NL (Note 4) 13” 12mm 2500 units
©2005 Fairchild Semiconductor Corporation
FDS6900AS Rev B(X)
A
FDS6900
Electrical Characteristics T
= 25°C unless otherwise noted
A
Symbol Parameter Test Conditions Type Min Typ Max Units
Off Characteristics
Q2
30
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
= 10 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
Q2
Q1
V
30
27
22
500
1
±100
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
I
= 10 mA, Referenced to 25°C
D
= 250 uA, Referenced to 25°C
I
D
VGS = 10 V, ID = 8.2 A
= 10 V, ID = 8.2 A, TJ = 125°C
V
GS
= 4.5 V, ID = 7.6 A
V
GS
= 10 V, ID = 6.9 A
V
GS
= 10 V, ID = 6.9 A, TJ = 125°C
V
GS
= 4.5 V, ID = 6.2 A
V
GS
gFS Forward Transconductance VDS = 5 V, ID = 8.2 A
= 5 V, ID = 6.9 A
V
DS
Q2
Q1 1 1
Q2
Q1
Q2 17
Q1 22
Q1
Q2
Q1
1.9
1.9 3 3
–3.2
–4.2
23
21
30
27
A
30
20
25
21
22
36
28
27
38
34
S
Dynamic Characteristics
C
Input Capacitance Q2
iss
C
Output Capacitance Q2
oss
C
Reverse Transfer Capacitance
rss
= 15 V, VGS = 0 V,
V
DS
f = 1.0 MHz
Q1
Q1
Q2
Q1
RG Gate Resistance Q2
Q1
570
600
180
150
70
70
2.8
2.2
pF
pF
pF
4.9
3.8
Switching Characteristics (Note 2)
t
Turn-On Delay Time
d(on)
tr Turn-On Rise Time
t
Turn -Off Dela y Time
d(off)
tf Turn-Off Fall Time
t
Turn-On Delay Time
d(on)
tr Turn-On Rise Time
t
Turn -Off Dela y 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
= 4.5 V, R
V
GS
GEN
= 6 Ω
GEN
= 6 Ω
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
10 9 19
18
5 4 10 8 ns
26
23
42
32
3 3 6
6
11
10
20
19
15 9 27
18
16
14
29
25
6 4 12 8 ns
S
mV/°C
µA
nA
V
mV/°C
mΩ
Ω
ns
ns
ns
ns
ns
ns
FDS6900AS Rev B (X)
A
FDS6900
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:
= 15 V, ID = 8.2A
V
DS
Q1:
= 15 V, ID = 6.9A
V
DS
Q2
Q1
Q2
Q1
Q2
Q1
Q2
Q1
10
11
5.8
6.1
1.6
1.7
2.1
2.2
15
15
8.2
8.5
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
= 8.2 A,
F
= 300 A/µs (Note 3)
d
iF/dt
I
= 6.9 A,
F
= 100 A/µs (Note 3)
d
iF/dt
VGS = 0 V, IS = 2.3 A (Note 2)
VGS = 0 V, IS = 5 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
2.3
1.3
15
6 nC
19
10 nC
0.6
0.7
0.7
0.7
1.0
1.2
S
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. FDS6900AS_NL is a lead free product. The FDS6900AS_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.
FDS6900AS Rev B (X)
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