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
= 25¡C
Reverse Gate Source & Reverse Gate Drain Voltage – 50 V
Gate Current 50 mA
Total Device Power Dissipation (each side) 250 mW
@ 85°C Case Temperature (both sides) 500 mW
Power Derating (both sides) 4.3 mW/°C
TOÐ71 Package
See Section G for Outline Dimensions
Pin Configuration
1 Source, 2 Drain, 3 Gate, 5 Source,
6 Drain, 7 Gate
At 25°C 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 µA, V
DS
= ØV
Gate Reverse Current I
GSS
– 100 – 100 pA V
GS
= – 30V, V
DS
= ØV
– 500 – 500 nA V
GS
= – 30V, V
DS
= ØV T
A
= 125°C
Gate Operating Current I
G
– 50 – 50 pA V
DS
= 20V, I
D
= 200 µA
– 250 – 250 nA V
DS
= 20V, I
D
= 200 µA T
A
= 125°C
Gate Source Voltage V
GS
– 4.2 – 4.2 V V
DS
= 20V, I
D
= 50 µA
– 0.5 – 4 – 0.5 – 4 V V
DS
= 20V, I
D
= 200 µA
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)
22
DS
= Ø, I
G
= 1 mA
Drain Saturation Current (Pulsed) I
DSS
0.5 5 0.5 5 mA V
DS
= 20V, V
GS
= ØV
Dynamic Electrical Characteristics
Common Source
g
fs
1000 3000 1000 3000 µS V
DS
= 20V, V
GS
= ØV f = 1 kHz
Forward Transconductance
1000 1000 µS V
DS
= 20V, V
GS
= ØV f = 200 MHz
Common Source Output Conductance g
os
35 35 µS V
DS
= 20V, V
GS
= ØV f = 1 kHz
Common Source Input Capacitance C
iss
44pF
DS
= 20V, V
GS
= ØV f = 1 MHz
Drain Gate Capacitance C
dgo
1.5 1.5 pF V
DS
= 10V, I
S
= ØA f = 1 MHz
Common Source
C
rss
1.2 1.2 pF V
DS
= 20V, V
GS
= ØV f = 1 MHz
Reverse Transfer Capacitance
Noise Figure NF 0.5 0.5 dB
V
DS
= 20V, V
GS
= ØV
f = 100 Hz
R
G
= 10 MΩ
Differential Gate Current | I
G1
– I
G2
|10 10nAV
DS
= 20V, I
D
= 200 µA T
A
= 125°C
Saturation Drain Current Ratio I
DSS1
/ I
DSS2
0.9 1 0.85 1 V
DS
= 20V, V
GS
= ØV
Differential Gate Source Voltage | V
GS1
– V
GS2
| 20 25 mV V
DS
= 20V, I
D
= 200 µA
T
A
= 25°C
Differential Gate Source
∆V
GS1
– V
GS2
68mVV
DS
= 20V, I
D
= 200 µA
to – 55°C
Voltage with Temperature
∆T
T
A
= 25°C
7.5 10 mV V
DS
= 20V, I
D
= 200 µA
to 125°C
Transconductance Ratio g
fs1
/ g
fs2
0.9 1 0.85 1 V
DS
= 20V, I
D
= 200 µA 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