B-6
01/99
2N3957, 2N3958
N-Channel Dual Silicon Junction Field-Effect Transistor
Low and Medium Frequency
Differential Amplifiers
High Input Impedance
Amplifiers
Absolute maximum ratings at T
A
= 25C
Reverse Gate Source & Reverse Gate Drain Voltage
50 V
Gate Current
50 mA
Total Device Power Dissipation (each side)
250 mW
@ 85C Case Temperature (both sides)
500 mW
Power Derating (both sides)
4.3 mW/C
TO71 Package
See Section G for Outline Dimensions
Pin Configuration
1 Source, 2 Drain, 3 Gate, 5 Source,
6 Drain, 7 Gate
At 25C free air temperature:
2N3957
2N3958
Process NJ16
Static Electrical Characteristics
Min
Max
Min
Max
Unit
Test Conditions
Gate Source Breakdown Voltage
V
(BR)GSS
50
50
V
I
G
= 1 A, V
DS
= V
Gate Reverse Current
I
GSS
100
100
pA
V
GS
= 30V, V
DS
= V
500
500
nA
V
GS
= 30V, V
DS
= V
T
A
= 125C
Gate Operating Current
I
G
50
50
pA
V
DS
= 20V, I
D
= 200 A
250
250
nA
V
DS
= 20V, I
D
= 200 A
T
A
= 125C
Gate Source Voltage
V
GS
4.2
4.2
V
V
DS
= 20V, I
D
= 50 A
0.5
4
0.5
4
V
V
DS
= 20V, I
D
= 200 A
Gate Source Cutoff Voltage
V
GS(OFF)
1
4.5
1
4.5
V
V
DS
= 20V, I
D
= 1 nA
Gate Source Forward Voltage
V
GS(F)
2
2
V
V
DS
= , I
G
= 1 mA
Drain Saturation Current (Pulsed)
I
DSS
0.5
5
0.5
5
mA
V
DS
= 20V, V
GS
= V
Dynamic Electrical Characteristics
Common Source
g
fs
1000 3000 1000 3000
S
V
DS
= 20V, V
GS
= V
f = 1 kHz
Forward Transconductance
1000
1000
S
V
DS
= 20V, V
GS
= V
f = 200 MHz
Common Source Output Conductance
g
os
35
35
S
V
DS
= 20V, V
GS
= V
f = 1 kHz
Common Source Input Capacitance
C
iss
4
4
pF
V
DS
= 20V, V
GS
= V
f = 1 MHz
Drain Gate Capacitance
C
dgo
1.5
1.5
pF
V
DS
= 10V, I
S
= A
f = 1 MHz
Common Source
C
rss
1.2
1.2
pF
V
DS
= 20V, V
GS
= V
f = 1 MHz
Reverse Transfer Capacitance
Noise Figure
NF
0.5
0.5
dB
V
DS
= 20V, V
GS
= V
f = 100 Hz
R
G
= 10 M
Differential Gate Current
| I
G1
I
G2
|
10
10
nA
V
DS
= 20V, I
D
= 200 A
T
A
= 125C
Saturation Drain Current Ratio
I
DSS1
/ I
DSS2
0.9
1
0.85
1
V
DS
= 20V, V
GS
= V
Differential Gate Source Voltage
| V
GS1
V
GS2
|
20
25
mV
V
DS
= 20V, I
D
= 200 A
T
A
= 25C
Differential Gate Source
V
GS1
V
GS2
6
8
mV
V
DS
= 20V, I
D
= 200 A
to 55C
Voltage with Temperature
T
T
A
= 25C
7.5
10
mV
V
DS
= 20V, I
D
= 200 A
to 125C
Transconductance Ratio
g
fs1
/ g
fs2
0.9
1
0.85
1
V
DS
= 20V, I
D
= 200 A
f = 1 kHz
1000 N. Shiloh Road, Garland, TX 75042
(972) 487-1287
FAX
(972) 276-3375
www.interfet.com
Databook.fxp 1/14/99 11:30 AM Page B-6
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