CALOGIC XU425

N-Channel Dual JFET
CORPORATION
U421 – U426
FEATURES
• Ultra Low Input Bias Current . . . . . . . 250 Fempto Amps
• Low Operating Current
• Tight Matching Characteristics
APPLICATIONS
Low Leakage FET Input Op Amps
• Ultra
• 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 -55oC to +150oC
XU421-U426 Sorted Chips in Carriers -55oC to +150oC
PIN CONFIGURATION
TO-78
1
2
3
4
5
6
7
SOURCE 1
DRAIN 1
GATE 1
CASE/BODY
SOURCE 2
DRAIN 2
GATE 2
4 5
3
2
6
7
1
BOTTOM VIEW
CJ4
C
G2
D2
S2
G1
D1
S1
U421 – U426
CORPORATION
ABSOLUTE MAXIMUM RATINGS (TA = 25oC unless otherwise noted)
Total Device Dissipation, TA = 25oC
(Derate 6.0 mW/ oC to 150oC) . . . . . . . . . . . . . 750 mW
Storage Temperature Range . . . . . . . . . . . . . -65oC to +150oC
Gate-to-Gate Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . ±40V
Gate-Drain or Gate-Source Voltage . . . . . . . . . . . . . . . . -40V
Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA
Device Dissipation (Each Side), TA = 25oC
(Derate 3.2 mW/ oC to 150oC) . . . . . . . . . . . . . . 400mW
ELECTRICAL
(25oC Unless
otherwise noted)
noted)
ELECTRICAL CHARACTERISTICS
CHARACTERISTICS (25oC
unless otherwise
SYMBOL
U421-3
CHARACTERISTIC
U424-6
MIN
TYP MAX
MIN
TYP
-60
-40
-60
UNIT
MAX
TEST CONDITIONS
STATIC
BVGSS
Gate-Source Breakdown Voltage
-40
BVG1G2
Gate-Gate Breakdown Voltage
±40
±40
(1)
IGSS
Gate Reverse Current
IG
Gate Operating Current
VGS (off)
Gate-Source Cutoff Voltage
(1)
VGS
Gate-Source Voltage
IDSS
Saturation Drain Current
V
IG = -1µA, VDS = 0
IG = -1µA, ID = 0, IS = 0
1.0
3.0
pA
T = +25oC
1.0
3.0
nA
T = +125 oC
.25
0.5
.250
-500
-0.4
-2.0
-0.4
-2.0
60
1000
60
1800
300
1500
300
1500
-1.8
pA
V
-2.9
µA
T = +25oC
T = +125 oC
VGS = -20V,
VDS = 0
VDG = 10V,
ID = 30µA
VDS = 10V, ID = 1nA
VDG = 10V, ID = 30µA
VDS = 10V, VGS = 0
DYNAMIC
gfs
Common-Source Forward Transconductance
gos
Common-Source Output Conductance
10
10
Ciss
Common-Source Input Capacitance
3.0
3.0
Crss
Common-Source Reverse Transfer Capacitance
1.5
1.5
gfs
Common-Source Forward Transconductance
gos
Common-Source Output Conductance
en
Equivalent Short Circuit Input
NF
SYMBOL
120
350
120
CHARACTERISTIC
70
20
70
nV/ Hz
10
1.0
U421,4
f = 1kHz
3.0
10
Noise Figure
f = 1MHz
pF
350
3.0
20
f = 1 kHz
VDS = 10V,
VGS = 0
1.0
U422,5
dB
U423,6
MIN TYP MAX MIN TYP MAX MIN TYP MAX
UNIT
VDG = 10V,
ID = 30µA
f = 10Hz
f = 1kHz
f = 10 Hz
RG = 10 MΩ
TEST CONDITIONS
MATCH
| VGS1-VGS2 | Differential Gate-Source Voltage
10
15
25
mV
| VGS1-VGS2 | Differential Gate-Source Voltage
Change with Temperature (2)
∆T
10
25
40
V/ oC
CMRR
Common Mode Rejection Ratio (3)
90
NOTES:
1. Approximately doubles for every 10oC increase in TA.
2. Measured at endpoints TA, TB and TC.
95
80
90
3. CMRR = 20log 10
80
V
90
[VGS1DD
-VGS2 ]
4. Case lead not connected.
dB
VDD = 10V.
VDG = 10V, ID = 30µA
VDG = 10V, ID = 30µA,
TA = -55oC, TB = 25oC,
TC = 125oC
ID = 30µA, VDG = 10 to 20 V