B-6
01/99
2N3957, 2N3958
N-Channel Dual Silicon Junction Field-Effect Transistor
Absolute maximum ratings at T = 25¡C
¥ Low and Medium Frequency
Differential Amplifiers
¥ High Input Impedance
Amplifiers
A
Reverse Gate Source & Reverse Gate Drain Voltage
– 50 V
50 mA
250 mW
500 mW
4.3 mW/°C
Gate Current
Total Device Power Dissipation (each side)
@ 85°C Case Temperature (both sides)
Power Derating (both sides)
At 25°C free air temperature:
Static Electrical Characteristics
2N3957
2N3958
Process NJ16
Test Conditions
I = – 1 µA, V = ØV
Min Max Min Max Unit
Gate Source Breakdown Voltage
V
– 50
– 50
V
– 100 pA
– 500 nA
– 50 pA
– 250 nA
(BR)GSS
G
DS
– 100
– 500
– 50
V
= – 30V, V = ØV
GS
DS
Gate Reverse Current
I
GSS
V
= – 30V, V = ØV
T = 125°C
A
GS
DS
V
= 20V, I = 200 µA
DS
D
Gate Operating Current
Gate Source Voltage
I
G
– 250
– 4.2
V
= 20V, I = 200 µA
T = 125°C
DS
D
A
– 4.2
V
V
V
= 20V, I = 50 µA
DS
D
V
GS
– 0.5 – 4 – 0.5 – 4
– 1 – 4.5 – 1 – 4.5
V
= 20V, I = 200 µA
DS
D
Gate Source Cutoff Voltage
V
V
V
= 20V, I = 1 nA
GS(OFF)
DS
D
Gate Source Forward Voltage
Drain Saturation Current (Pulsed)
V
2
5
2
5
V
V
= Ø, I = 1 mA
GS(F)
DS
G
I
0.5
0.5
mA
V
= 20V, V = ØV
DSS
DS
GS
Dynamic Electrical Characteristics
1000 3000 1000 3000 µS
V
= 20V, V = ØV
f = 1 kHz
Common Source
Forward Transconductance
DS
GS
g
g
fs
1000
1000
µS
µS
pF
pF
V
= 20V, V = ØV
f = 200 MHz
f = 1 kHz
DS
GS
Common Source Output Conductance
Common Source Input Capacitance
Drain Gate Capacitance
35
4
35
4
V
= 20V, V = ØV
os
DS
GS
C
V
= 20V, V = ØV
f = 1 MHz
f = 1 MHz
iss
DS
GS
C
1.5
1.5
V
= 10V, I = ØA
dgo
DS
S
Common Source
C
1.2
0.5
1.2
0.5
pF
V
= 20V, V = ØV
f = 1 MHz
f = 100 Hz
rss
DS
GS
Reverse Transfer Capacitance
V
= 20V, V = ØV
DS
GS
Noise Figure
NF
dB
nA
R = 10MΩ
G
Differential Gate Current
| I – I
|
10
1
10
1
V
= 20V, I = 200 µA
T = 125°C
G1
G2
DS
D
A
Saturation Drain Current Ratio
Differential Gate Source Voltage
I
/ I
0.9
0.9
0.85
0.85
V
= 20V, V = ØV
DSS1 DSS2
| V – V
DS
GS
|
GS2
20
25
mV
mV
V
= 20V, I = 200 µA
GS1
DS
D
T = 25°C
A
6
8
V
= 20V, I = 200 µA
DS
D
to – 55°C
∆V – V
Differential Gate Source
Voltage with Temperature
GS1 GS2
∆T
T = 25°C
A
7.5
1
10
1
mV
V
= 20V, I = 200 µA
DS
D
to 125°C
Transconductance Ratio
g
/ g
V
= 20V, I = 200 µA
f = 1 kHz
fs1 fs2
DS
D
TOÐ71 Package
See Section G for Outline Dimensions
Pin Configuration
1 Source, 2 Drain, 3 Gate, 5 Source,
6 Drain, 7 Gate
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