SST421NL/423NL
Vishay Siliconix
Monolithic N-Channel JFET Duals
PRODUCT SUMMARY
Part Number
SST421NL
SST423NL
V
GS(off)
(V)
−0.4
to−2
−0.4
to
−2
V
(BR)GSS
Min (V)
−40
−40
g
fs
Min (mS)
0.3
0.3
jV
GS1
−
V
GS2
j
Max (mV)
10
25
FEATURES
D
D
D
D
D
D
D
Anti Latchup Capability
Monolithic Design
High Slew Rate
Low Offset/Drift Voltage
Low Gate Leakage: 0.6 pA
Low Noise
High CMRR: 102 dB
BENEFITS
D
D
D
D
D
D
D
External Substrate Bias—Avoids Latchup
Tight Differential Match vs. Current
Improved Op Amp Speed, Settling Time Accuracy
Minimum Input Error/Trimming Requirement
Insignificant Signal Loss/Error Voltage
High System Sensitivity
Minimum Error with Large Input Signals
APPLICATIONS
D
Ultralow Input Current
Differential Amps
D
High-Speed Comparators
D
Impedance Converters
DESCRIPTION
The SST421NL/423NL are monolithic dual n-channel JFETs
designed to provide very high input impedance for differential
amplification and impedance matching. Among its many
unique features, this series offers low operating gate current.
The SO-8 package provides ease of manufacturing, and the
symmetrical pinout prevents improper orientation. The SO-8
package is available with tape-and-reel options for
compatibility with automatic assembly methods.
Pins 4 and 8 on SST421NL/423NL part numbers enable the
substrate to be connected to a positive polarity, external bias
(V
DD
) to avoid latchup.
Similar versions of these part numbers are available in the
hermetically sealed TO-78 package. Full military processing
is available. See data sheets for part numbers U421/423.
Narrow Body SOIC
S
1
D
1
G
1
SUBSTRATE
1
2
3
4
Top View
Marking Codes:
SST421NL
−
(421NL)
SST423NL
−
(423NL)
8
7
6
5
SUBSTRATE
G
2
D
2
S
2
ABSOLUTE MAXIMUM RATINGS
Gate-Drain, Gate-Source Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−40
V
Gate-Gate Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
"40
V
Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA
Lead Temperature (
1
/
16
” from case for 10 sec.) . . . . . . . . . . . . . . . . . . 300
_C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
−65
to 200_C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . .
−55
to 150_C
Power Dissipation :
Per Side
a
. . . . . . . . . . . . . . . . . . . . . . . . 300 mW
Total
b
. . . . . . . . . . . . . . . . . . . . . . . . . . . 500 mW
Notes
a. Derate 2.4 mW/_C above 25_C
b. Derate 4 mW/_C above 25_C
Document Number: 72060
S-40391—Rev. B, 15-Mar-04
www.vishay.com
1
SST421NL/423NL
Vishay Siliconix
SPECIFICATIONS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Limits
SST421NL
SST423NL
Parameter
Static
Gate-Source
Breakdown Voltage
Gate-Gate
Breakdown Voltage
Gate-Source
Cutoff Voltage
Saturation Drain Current
Gate Reverse Current
Gate Operating Current
Drain-Source
On-Resistance
Gate-Source Voltage
Gate-Source
Forward Voltage
Symbol
Specific Test Conditions
Typ
a
Min
Max
Min
Max
Unit
V
(BR)GSS
V
(BR)G1
−
G2
V
GS(off)
I
DSS
I
GSS
I
G
r
DS(on)
V
GS
V
GS(F)
I
G
=
−1
mA,
V
DS
= 0 V
I
G
=
"1
mA,
I
D
= 0, I
S
= 0
V
DS
= 10 V, I
D
= 1 nA
V
DS
= 10 V, V
GS
= 0 V
V
GS
=
−20
V, V
DS
= 0 V
T
A
= 125_C
V
DG
= 10 V I
D
= 30
mA
V,
V
GS
= 0 V, I
D
= 10
mA
V
DG
= 10 V, I
D
= 30
mA
I
G
= 1 mA , V
DS
= 0 V
−60
"55
−1.2
400
−0.6
−0.3
−1.0
10
2000
−0.8
0.7
−40
"40
−0.4
60
−2
1000
−50
−50
−40
"40
−0.4
60
−2
1000
−50
−50
mA
pA
nA
pA
W
−1.8
−1.8
V
V
Dynamic
Common-Source Forward
Transconductance
Common-Source
Output Conductance
Common-Source Forward
Transconductance
Common-Source
Output Conductance
Common-Source
Input Capacitance
Common-Source
Reverse Transfer
Capacitance
Equivalent Input
Noise Voltage
g
fs
V
DS
= 10 V, V
GS
= 0 V f = 1 kHz
V
V,
g
os
g
fs
g
os
C
iss
V
DS
= 10 V, V
GS
= 0 V, f = 1 MHz
C
rss
e
n
V
DS
= 10 V, I
D
= 30
mA
, f = 10 Hz
0.7
30
1.5
1.5
nV⁄
√Hz
V
DS
= 10 V I
D
= 30
mA
, f = 1 kHz
V,
4
0.2
0.4
1.4
0.12
10
0.35
3
3
0.12
10
0.35
3
3
pF
mS
mS
mS
0.6
0.3
1.5
0.3
1.5
mS
Matching
Differential
Gate-Source Voltage
Gate-Source Voltage
Differential Change
with Temperature
Common Mode
Rejection Ratio
V
GS1
– V
GS2
D
V
GS1
– V
GS2
DT
CMRR
V
DG
= 10 V, I
D
= 30
mA
V
DG
= 10 V, I
D
= 30
mA
T
A
=
−55
to 125_C
V
DG
= 10 to 20 V, I
D
= 30
mA
102
90
10
10
80
25
40
mV
mV/_C
dB
NNT
Notes
a. Typical values are for DESIGN AID ONLY, not guaranteed or subject to production testing.
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Document Number: 72060
S-40391—Rev. B, 15-Mar-04
SST421NL/423NL
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Drain Current and Transconductance
vs. Gate-Source Cutoff Voltage
2
I
DSS
−
Saturation Drain Current (mA)
1
g
fs
−
Forward Transconductance (mS)
100 nA
10 nA
Gate Leakage Current
1.6
g
fs
1.2
I
DSS
0.8
I
D
= 100
mA
I
G
−
Gate Leakage
1 nA
100 pA
0.6
T
A
= 125_C
I
GSS
100
mA
30
mA
30
mA
0.8
0.4
10 pA
1 pA
0.1 pA
0
10
20
T
A
= 25_C
0.4
I
DSS
@ V
DS
= 10 V, V
GS
= 0 V
g
fs
@ V
DS
= 10 V, V
GS
= 0 V
f = 1 kHz
0.2
I
GSS
@ 25_C
0
−5
30
40
50
0
0
−1
−2
−3
−4
V
GS(off)
−
Gate-Source Cutoff Voltage (V)
V
DG
−
Drain-Gate Voltage (V)
0.5
Output Characteristics
V
GS(off)
=
−1
V
GS(off)
=
−1
V
1
Output Characteristics
V
GS(off)
=
−1.5
V
0.4
I
D
−
Drain Current (mA)
V
GS
= 0 V
−0.1
V
I
D
−
Drain Current (mA)
0.8
0.3
−0.2
V
−0.3
V
0.6
V
GS
= 0 V
−0.2
V
0.2
−0.4
V
−0.5
V
−0.6
V
−0.7
V
0.4
−0.4
V
0.2
−1.0
V
−0.6
V
−0.8
V
0.1
0
0
4
8
12
16
20
V
DS
−
Drain-Source Voltage (V)
0
0
4
8
12
16
20
V
DS
−
Drain-Source Voltage (V)
0.25
Output Characteristics
V
GS(off
)
=
−1
V
V
GS
= 0 V
−0.1
V
0.5
Output Characteristics
V
GS(off)
=
−1.5
V
0.2
I
D
−
Drain Current (mA)
I
D
−
Drain Current (mA)
−0.2
V
0.15
−0.3
V
−0.4
V
−0.5
V
0.5
−0.6
V
−0.7
V
0
0.2
0.4
0.6
0.8
1
0.4
VGS = 0 V
0.3
−0.2
V
0.1
0.2
−0.4
V
−0.6
V
0.1
−0.8
V
−1.0
V
0
V
DS
−
Drain-Source Voltage (V)
Document Number: 72060
S-40391—Rev. B, 15-Mar-04
0
0
0.2
0.4
0.6
0.8
1
V
DS
−
Drain-Source Voltage (V)
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SST421NL/423NL
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
0.5
Transfer Characteristics
V
GS(off)
=
−1
V
T
A
=
−55_C
25_C
(mV)
V
DS
= 10 V
100
Gate-Source Differential Voltage
vs. Drain Current
V
DG
= 10 V
T
A
= 25_C
U423
0.4
I
D
−
Drain Current (mA)
V
GS1
−
V
GS2
0.3
10
U421
0.2
125_C
0.1
0
0
−0.2
−0.4
−0.6
−0.8
−1
V
GS
−
Gate-Source Voltage (V)
1
10
100
I
D
−
Drain Current (mA)
1000
100
Voltage Differential with Temperature
vs. Drain Current
130
V
DG
= 10 V
DT
A
= 25 to 125_C
DT
A
=
−55
to 25_C
Common Mode Rejection Ratio
vs. Drain Current
DV
DG
D
V
GS1
−
V
GS2
(
m
V/
_C
)
120
CMRR = 20 log
CMRR (dB)
V
GS1
−
V
GS2
110
10
D
t
U423
DV
DG
= 10
−
20 V
5
−
10 V
100
U421
90
D
1
10
100
I
D
−
Drain Current (mA)
1000
80
10
100
I
D
−
Drain Current (mA)
5
r
DS(on)
−
Drain-Source On-Resistance (
Ω )
1000
100
Circuit Voltage Gain vs. Drain Current
A
V
+
g
fs
R
L
On-Resistance vs. Drain Current
80
A
V
−
Voltage Gain
1
)
R
L
g
os
Assume V
DD
= 15 V, V
DS
= 5 V
R
L
+
10 V
I
D
4
60
3
V
GS(off)
=
−1
V
40
V
GS(off)
=
−1
V
−1.5
V
2
−1.5
V
1
20
0
10
100
I
D
−
Drain Current (mA)
www.vishay.com
1000
0
0.01
0.1
I
D
−
Drain Current (mA)
Document Number: 72060
S-40391—Rev. B, 15-Mar-04
1
4
SST421NL/423NL
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Common-Source Input Capacitance
vs. Gate-Source Voltage
2
C rss
−
Reverse Feedback Capacitance (pF)
f = 1 MHz
C iss
−
Input Capacitance (pF)
1.6
V
DS
= 0 V
5V
1.2
10 V
0.8
1
f = 1 MHz
0.8
V
DS
= 0 V
0.6
10 V
0.4
5V
Common-Source Reverse Feedback
Capacitance vs. Gate-Source Voltage
0.4
0.2
0
0
−4
−8
−12
−16
−20
V
GS
−
Gate-Source Voltage (V)
1
0
0
−4
−8
−12
−16
−20
V
GS
−
Gate-Source Voltage (V)
Output Conductance vs. Drain Current
V
GS(off)
=
−1
V
V
DS
= 10 V
f = 1 kHz
50
Equivalent Input Noise Voltage vs. Frequency
V
DS
= 10 V
g
os
−
Output Conductance (µS)
0.8
T
A
=
−55_C
0.6
25_C
0.4
125_C
0.2
Hz
en
−
Noise Voltage nV /
40
30
I
D
= 30
mA
20
10
I
D
= 100
mA
0
10
100
I
D
−
Drain Current (mA)
1000
0
10
100
1k
f
−
Frequency (Hz)
10 k
100 k
1
Common-Source Forward Transconductance
vs. Drain Current
r
DS(on)
−
Drain-Source On-Resistance (
Ω )
V
GS(off)
=
−1
V
V
DS
= 10 V
f = 1 kHz
5
On-Resistance and Output Conductance
vs. Gate-Source Cutoff Voltage
r
DS
@ I
D
= 10
mA,
V
GS
= 0 V
g
os
@ V
DS
= 10 V, V
GS
= 0 V, f = 1 kHz
4
20
g
fs
−
Forward Transconductance (mS)
0.8
T
A
=
−55_C
0.6
25_C
0.4
125_C
16
g os
−
Output Conductance (
m
S)
3
r
DS
12
g
os
8
2
0.2
1
4
0
10
0
100
I
D
−
Drain Current (mA)
1000
0
−2
−3
−4
V
GS(off)
−
Gate-Source Cutoff Voltage (V)
−1
−5
0
Document Number: 72060
S-40391—Rev. B, 15-Mar-04
www.vishay.com
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