Calogic XU421, XU426, U426, U421 Datasheet
N-Channel Dual JFET
U421 – U 426
FEATURES
••
Ultra Low Input Bias Current . . . . . . . 250 Fempto Amps
••
Low Operating Current
••
Tight M atching Cha racteristics
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 avail able in chip form for hybrid designs as well
as a hermetic TO-78 p acka ge.
ORDERING INFORMATION
Part Package Temperature Range
U421-U426 TO-78 Hermetic Package -55
o
C to +150oC
XU421-U426 Sorted Chips in Carriers -55
o
C to +150oC
PIN CONFIGU R ATIO N
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 (TA = 25oC unless otherwise noted)
Gate-to-Gat e V olta ge. . . . . . . . . . . . . . . . . . . . . . . . . . . . ±40V
Gate-Drain or Gate -So urce Voltage . . . . . . . . . . . . . . . . -40V
Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Device Dissipation (Each Side), T
A
= 25oC
(Der ate 3.2 mW/
o
C to 150oC). . . . . . . . . . . . . . 400mW
Total Device D issipat ion, T
A
= 25oC
(Der ate 6.0 mW/
o
C to 150oC). . . . . . . . . . . . . 750 mW
Storage Temperatur e Ra nge. . . . . . . . . . . . . -65
o
C to +150oC
ELECTRICAL CHARACTERISTICS (2 5oC unless oth erw ise 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
IG = -1µA, VDS = 0
BV
G1G2
Gate-Gate Breakdown Voltage
±40 ±40
IG = -1µA, ID = 0, IS = 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
= 30µA
.250 -500
T = +125
o
C
V
GS (off)
Gate-Source Cutoff Voltage
-0.4 -2.0 -0.4 -2.0
V
VDS = 10V, ID = 1nA
V
GS
Gate-Source Voltage
-1.8 -2.9
VDG = 10V, ID = 30µA
I
DSS
Saturation Drain Current
60 1000 60 1800 µA
VDS = 10V, VGS = 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
= 30µA
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 MΩ
SYMBOL CHARACTERISTIC
U421,4 U422,5 U423,6
UNIT TEST CONDITIONS
MIN TYP MAX MIN TYP MAX MIN TYP MAX
MATCH
| V
GS1-VGS2
| Differential Gate-Sou r ce Voltage
10 15 25 mV
VDG = 10V, ID = 30µA
| V
GS1-VGS2
|
∆T
Differential Gate-Source Voltage
Change with Temperature
(2)
10 25 40 V/ oC
V
DG
= 10V, ID = 30µA,
T
A
= -55oC, TB = 25oC,
T
C
= 125oC
C
MRR
Common Mode Rejection Ratio
(3)
90 95 80 90 80 90 dB
I
D
= 30µA, VDG = 10 to 20 V
NOTES:
1. Approximately doubles for every 10
o
C increase in TA.
2. Measured at endpoints T
A
, TB and TC.
3. CMRR = 20log
10
[
] VDD = 10V.
4. Case lead not connected.
V
DD
V
GS1-VGS2
ELECTRICAL CHARACTERISTIC S (25oC Unless otherwise noted)
Loading...