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Электронный компонент: U421

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N-Channel Dual JFET
U421 U426
FEATURES

Ultra Low Input Bias Current . . . . . . . 250 Fempto Amps

Low Operating Current

Tight Matching Characteristics
APPLICATIONS

Ultra Low Leakage FET Input Op Amps

Electrometer

Infrared Detectors

pH Meters
DESCRIPTION
The Calogic U421 Series are Dual N-Channel JFETs on a
monolithic structure designed specifically for very high input
impedance for differential amplification and impedance
matching. This series features ultra low input bias current
(250 fempto amps, U421) while offering high gain at low
operating currents and tight matching characteristics. These
devices are available in chip form for hybrid designs as well
as a hermetic TO-78 package.
ORDERING INFORMATION
Part
Package
Temperature Range
U421-U426
TO-78 Hermetic Package -55
o
C to +150
o
C
XU421-U426 Sorted Chips in Carriers
-55
o
C to +150
o
C
PIN CONFIGURATION
CORPORATION
S2
G1
D2
D1
G2
S1
C
TO-78
1
2
3
4 5
BOTTOM VIEW
1
2
3
4
5
6
7
7
6
SOURCE 1
DRAIN 1
GATE 1
CASE/BODY
SOURCE 2
DRAIN 2
GATE 2
CJ4
U421 U426
CORPORATION
ABSOLUTE MAXIMUM RATINGS (T
A
= 25
o
C unless otherwise noted)
Gate-to-Gate Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . .
40V
Gate-Drain or Gate-Source Voltage . . . . . . . . . . . . . . . . -40V
Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Device Dissipation (Each Side), T
A
= 25
o
C
(Derate 3.2 mW/
o
C to 150
o
C) . . . . . . . . . . . . . . 400mW
Total Device Dissipation, T
A
= 25
o
C
(Derate 6.0 mW/
o
C to 150
o
C) . . . . . . . . . . . . . 750 mW
Storage Temperature Range . . . . . . . . . . . . . -65
o
C to +150
o
C
ELECTRICAL CHARACTERISTICS (25oC unless otherwise noted)
SYMBOL
CHARACTERISTIC
U421-3
U424-6
UNIT
TEST CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
STATIC
BV
GSS
Gate-Source Breakdown Voltage
-40
-60
-40
-60
V
I
G
= -1
A, V
DS
= 0
BV
G1G2
Gate-Gate
Breakdown
Voltage
40
40
I
G
= -1
A, I
D
= 0, I
S
= 0
I
GSS
Gate
Reverse
Current
(1)
1.0
3.0
pA
T = +25
o
C
V
GS
= -20V,
V
DS
= 0
1.0
3.0
nA
T = +125
o
C
I
G
Gate
Operating
Current
(1)
.25
0.5
pA
T = +25
o
C
V
DG
= 10V,
I
D
= 30
A
.250
-500
T = +125
o
C
V
GS (off)
Gate-Source
Cutoff
Voltage
-0.4
-2.0
-0.4
-2.0
V
V
DS
= 10V, I
D
= 1nA
V
GS
Gate-Source
Voltage
-1.8
-2.9
V
DG
= 10V, I
D
= 30
A
I
DSS
Saturation
Drain
Current
60
1000
60
1800
A
V
DS
= 10V, V
GS
= 0
DYNAMIC
g
fs
Common-Source
Forward
Transconductance
300
1500
300
1500
V
DS
= 10V,
V
GS
= 0
f = 1 kHz
g
os
Common-Source Output Conductance
10
10
C
iss
Common-Source Input Capacitance
3.0
3.0
pF
f = 1MHz
C
rss
Common-Source Reverse Transfer Capacitance
1.5
1.5
g
fs
Common-Source
Forward
Transconductance
120
350
120
350
V
DG
= 10V,
I
D
= 30
A
f = 1kHz
g
os
Common-Source Output Conductance
3.0
3.0
e
n
Equivalent Short Circuit Input
20
70
20
70
nV/ Hz
f = 10Hz
10
10
f = 1kHz
NF
Noise Figure
1.0
1.0
dB
f = 10 Hz
R
G
= 10 M
SYMBOL
CHARACTERISTIC
U421,4
U422,5
U423,6
UNIT
TEST CONDITIONS
MIN TYP MAX MIN TYP MAX MIN TYP MAX
MATCH
| V
GS1
-V
GS2
| Differential Gate-Source Voltage
10
15
25
mV
V
DG
= 10V, I
D
= 30
A
| V
GS1
-V
GS2
|
T
Differential Gate-Source Voltage
Change with Temperature
(2)
10
25
40
V/
o
C
V
DG
= 10V, I
D
= 30
A,
T
A
= -55
o
C, T
B
= 25
o
C,
T
C
= 125
o
C
C
MRR
Common Mode Rejection Ratio
(3)
90
95
80
90
80
90
dB
I
D
= 30
A, V
DG
= 10 to 20 V
NOTES:
1. Approximately doubles for every 10
o
C increase in T
A
.
2. Measured at endpoints T
A
, T
B
and T
C
.
3. CMRR = 20log
10
[
]
V
DD
= 10V.
4. Case lead not connected.
V
DD
V
GS1
-V
GS2
ELECTRICAL CHARACTERISTICS (25
o
C Unless otherwise noted)