2N3958
Vishay Siliconix
Document Number: 70256
S-04031—Rev. B, 04-Jun-01 www.vishay.com
8-1
Monolithic N-Channel JFET Dual
PRODUCT SUMMARY
VGS(off) (V) V(BR)GSS Min (V) gfs Min (mS) IG Max (pA) jVGS1 – VGS2j Max (mV)
–1.0 to –4.5 –50 1 –50 25
FEATURES BENEFITS APPLICATIONS
DMonolithic Design
DHigh Slew Rate
DLow Offset/Drift Voltage
DLow Gate Leakage: 5 pA
DLow Noise: 9 nV⁄√Hz
DHigh CMRR: 100 dB
DTight Differential Match vs. Current
DImproved Op Amp Speed, Settling Time
Accuracy
DMinimum Input Error/Trimming Requirement
DInsignificant Signal Loss/Error Voltage
DHigh System Sensitivity
DMinimum Error with Large Input Signal
DWideband Differential Amps
DHigh-Speed,
Temp-Compensated,
Single-Ended Input Amps
DHigh Speed Comparators
DImpedance Converters
DESCRIPTION
The low cost 2N3958 JFET dual is designed for
high-performance differential amplification for a wide range of
precision test instrumentation applications. This series
features tightly matched specs, low gate leakage for accuracy,
and wide dynamic range with IG guaranteed at VDG = 20 V.
The hermetically-sealed TO-71 package is available with full
military processing (see Military Information and the
2N5545/5546/5547JANTX/JANTXV data sheet).
For similar products see 2N5196/5197/5198/5199, the
low-noise U/SST401 series, the high-gain 2N5911/5912, and
the low-leakage U421/423 data sheets.
TO-71
Top View
G1
S1
D1
G2
D2
S2
1
2
3
6
5
4
ABSOLUTE MAXIMUM RATINGS
Gate-Drain, Gate-Source Voltage –50 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate Current 50 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 Sidea250 mW. . . . . . . . . . . . . . . . . . . . . . . .
Totalb500 mW. . . . . . . . . . . . . . . . . . . . . . . . . . .
Notes
a. Derate 2 mW/_C above 85_C
b. Derate 4 mW/_C above 85_C
2N3958
Vishay Siliconix
www.vishay.com
8-2 Document Number: 70256
S-04031—Rev. B, 04-Jun-01
SPECIFICATIONS (TA = 25_C UNLESS OTHERWISE NOTED)
Limits
Parameter Symbol Test Conditions Min TypaMax Unit
Static
Gate-Source Breakdown Voltage V(BR)GSS IG = –1 mA, VDS = 0 V –50 –57
Gate-Source Cutoff Voltage VGS(off) VDS = 20 V, ID = 1 nA –1.0 –2–4.5 V
Saturation Drain CurrentbIDSS VDS = 20 V, VGS = 0 V 0.5 3 5 mA
VGS = –30 V, VDS = 0 V –10 –100 pA
Gate Reverse Current IGSS TA = 150_C–20 –500 nA
VDG = 20 V, ID = 200 mA–5–50 pA
Gate Operating Current IGTA =125_C–0.8 –250 nA
VDG = 20 V, ID = 200 mA–0.5 –1.5 –4
Gate-Source Voltage VGS ID = 50 mA–4.2 V
Gate-Source Forward Voltage VGS(F) IG = 1 mA, VDS = 0 V 2
Dynamic
Common-Source
Forward T ransconductance gfs VDS = 20 V, VGS = 0 V 1 2.5 3 mS
Common-Source Output Conductance gos f = 1 kHz 2 35 mS
Common-Source Input Capacitance Ciss 3 4
Common-Source
Reverse Transfer Capacitance Crss
VDS = 20 V, VGS = 0 V
f = 1 MHz 1 1.2 pF
Drain-Gate Capacitance Cdg VDG = 10 V, IS = 0 , f = 1 MHz 1.5
Equivalent Input Noise Voltage enVDS = 20 V, VGS = 0 V, f = 1 kHz 9nV⁄
√Hz
Noise Figure NF VDS = 20 V, VGS = 0 V
f = 100 Hz, RG = 10 MW0.5 dB
Matching
Differential Gate-Source Voltage |VGS1–VGS2|VDG = 20 V, ID = 200 mA15 25 mV
Gate-Source Voltage Differential Change with
Temperature D|VGS1–VGS2|
DTVDG = 20 V, ID = 200 mA
TA = –55 to 125_C20 100 mV/_C
Saturation Drain Current Ratio IDSS1
IDSS2 VDS = 20 V, VGS = 0 V 0.85 0.97 1
T ransconductance Ratio gfs1
gfs2 V
DS
= 20 V, I
D
= 200
m
A 0.85 0.97 1
Differential Output Conductance |gos1–gos2|
VDS = 20 V, ID = 200
m
A
f = 1 kHz 0.1 mS
Differential Gate Current |IG1–IG2|VDG = 20 V, ID = 200 mA
TA = 125_C0.1 10 nA
Common Mode Rejection RatiocCMRR VDG = 10 to 20 V, ID = 200 mA100 dB
Notes
a. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing. NQP
b. Pulse test: PW v300 ms duty cycle v3%.
c. This parameter not registered with JEDEC.
2N3958
Vishay Siliconix
Document Number: 70256
S-04031—Rev. B, 04-Jun-01 www.vishay.com
8-3
TYPICAL CHARACTERISTICS (TA = 25_C UNLESS OTHERWISE NOTED)
5
0–5–4–3–2–1
4
2
1
00302010 40 50
3
2.6
2.2
1
3
Drain Current and Transconductance
vs. Gate-Source Cutoff Voltage Gate Leakage Current
VGS(off) – Gate-Source Cutoff Voltage (V) VDG – Drain-Gate Voltage (V)
– Gate Leakage
IG
0.1 pA
10 pA
1 pA
IDSS @ VDS = 15 V, VGS = 0 V
gfs @ VDG = 15 V, VGS = 0 V
f = 1 kHz
gfs
IDSS
IGSS @ 125_C
IGSS @ 25_C
TA = 125_C
TA = 25_C
200 mA
100 pA
1 nA
10 nA
100 nA
5
012168420
4
3
2
1
0
Output Characteristics Output Characteristics
VDS – Drain-Source Voltage (V) VDS – Drain-Source Voltage (V)
– Drain Current (mA)
ID
– Drain Current (mA)
ID
–0.2 V
–0.4 V
–0.6 V
–0.3 V
–0.8 V
–1.0 V
–1.2 V
–1.4 V
VGS(off) = –2 V
VGS = 0 V
5
4
3
2
1
0
VGS = 0 V
VGS(off) = –3 V
2
0 0.6 0.80.40.2 1
1.6
1.2
0.8
0.4
0
Output Characteristics Output Characteristics
VDS – Drain-Source Voltage (V) VDS – Drain-Source Voltage (V)
– Drain Current (mA)
ID
– Drain Current (mA)
ID
VGS(off) = –2 V
VGS = 0 V
2.5
2.0
1.5
1.0
0.5
00 0.6 0.80.40.2 1
VGS = 0 V
VGS(off) = –3 V –0.3 V
–0.9 V
–0.6 V
–2.1 V
–1.5 V
–1.2 V
–2.4 V
–1.8 V
1.8
1.4
IG @ ID = 200 mA
50 mA
–0.2 V
–0.4 V
–0.6 V
–0.8 V
–1.0 V
–1.2 V
–1.4 V
–1.6 V
012168420
50 mA
–0.9 V
–0.6 V
–2.1 V
–1.5 V
–1.2 V
–1.8 V
–2.4 V
IDSS – Saturation Drain Current (mA)
gfs – Forward Transconductance (mS)
2N3958
Vishay Siliconix
www.vishay.com
8-4 Document Number: 70256
S-04031—Rev. B, 04-Jun-01
TYPICAL CHARACTERISTICS (TA = 25_C UNLESS OTHERWISE NOTED)
0.01 0.1 1
10
1
0–1.5–1.0–0.5 –2.0 –2.5
4
3
2
1
0
0.01 0.1 1
130
120
80
110
100
90
0.01 0.1 1
100
10
1
100
5
0.1 10.01
100
80
60
40
20
0
Transfer Characteristics Gate-Source Differential Voltage
vs. Drain Current
Voltage Differential with Temperature
vs. Drain Current Common Mode Rejection Ratio
vs. Drain Current
CMRR (dB)
AV– Voltage Gain
VGS – Gate-Source Voltage (V) ID – Drain Current (mA)
ID – Drain Current (mA) ID – Drain Current (mA)
ID – Drain Current (mA)
TA = –55_C
125_C
VGS(off) = –2 V
VDG = 20 V
VDG = 20 V
TA = 25_C
5 – 10 V
VGS(off) = –3 V
– Drain Current (mA)
ID
Circuit Voltage Gain vs. Drain Current On-Resistance vs. Drain Current
ID – Drain Current (mA)
0.01 0.1 1
1 k
800
600
400
200
0
VGS(off) = –2 V
AV+gfs RL
1)RLgos
RL+10 V
ID
Assume VDD = 15 V, VDS = 5 V
VDS = 20 V
–2 V
–3 V
25_C
DVDG = 10 – 20 V
(mV)
VGS1 VGS2
–
V/ _C
()
t
D
Dm
VGS1 VGS2
–
VGS1 VGS2
–
DVDG
CMRR = 20 log D
rDS(on) – Drain-Source On-Resistance ( Ω )
DTA = 25 to 125_C
DTA = –55 to 25_C
2N3958
Vishay Siliconix
Document Number: 70256
S-04031—Rev. B, 04-Jun-01 www.vishay.com
8-5
TYPICAL CHARACTERISTICS (TA = 25_C UNLESS OTHERWISE NOTED)
10 100 1 k 100 k10 k
10
0–12 –16 –20–8–4
8
6
4
2
0
VGS – Gate-Source Voltage (V)
Common-Source Input Capacitance
vs. Gate-Source Voltage
– Input Capacitance (pF)Ciss
VDS = 0 V
5 V
20 V
f = 1 MHz 5
0–12 –20–16–8–4
4
3
2
1
0
Common-Source Reverse Feedback
Capacitance vs. Gate-Source Voltage
– Reverse Feedback Capacitance (pF)Crss
VGS – Gate-Source Voltage (V)
VDS = 0 V
5 V
15 V
f = 1 MHz
16
12
8
4
0
20 Equivalent Input Noise Voltage vs. Frequency
f – Frequency (Hz)
VDS = 20 V
ID @ 200 mA
VGS = 0 V
2.5
2.0
1.5
1.0
0.5
00.01 0.1 1
Output Conductance vs. Drain Current
ID – Drain Current (mA)
TA = –55_C
125_C
0.01 0.1 1
2.5
2.0
1.5
1.0
0.5
0
Common-Source Forward Transconductance
vs. Drain Current
ID – Drain Current (mA)
TA = –55_C
125_C
1 k
0–3–5–4–2–1
800
600
400
200
0
10
8
6
4
2
On-Resistance and Output Conductance
vs. Gate-Source Cutoff Voltage
VGS(off) – Gate-Source Cutoff Voltage (V)
rDS @ ID = 100 mA, VGS = 0 V
gos @ VDS = 20 V, VGS = 0 V, f = 1 kHz
rDS
gos
25_C
25_C
VGS(off) = –2 V VDS = 20 V
f = 1 kHz
VGS(off) = –2 V VDS = 20 V
f = 1 kHz
15 V
20 V
S)gos– Output Conductance ( m
0
en – Noise Voltage nV / Hz
gos – Output Conductance (µS)
rDS(on) – Drain-Source On-Resistance ( Ω )
gfs – Forward Transconductance (mS)
