English
Language : 

U421 Datasheet, PDF (1/1 Pages) Calogic, LLC – N-Channel Dual JFET
U421
HIGH INPUT IMPEDANCE
MONOLITHIC DUAL
N-CHANNEL JFET
Linear Systems replaces discontinued Siliconix U421
The U421 is a high input impedance Monolithic Dual N-Channel JFET
The U421 monolithic dual n-channel JFET is designed
to provide very high input impedance for differential
amplification and impedance matching. Among its
many unique features, this series offers operating gate
current specified at -250 fA. The U421 is a direct
replacement for discontinued Siliconix U421.
FEATURES
HIGH INPUT IMPEDANCE
HIGH GAIN
LOW POWER OPERATION
ABSOLUTE MAXIMUM RATINGS
@ 25°C (unless otherwise noted)
IG = 0.25pA MAX
gfs = 120µmho MIN
VGS(OFF) = 2V MAX
The hermetically sealed TO-71 & TO-78 packages are
Maximum Temperatures
well suited for military applications. The 8 Pin P-DIP
and 8 Pin SOIC provide ease of manufacturing, and the
symmetrical pinout prevents improper orientation.
Storage Temperature
‐65°C to +150°C
Operating Junction Temperature
+150°C
Maximum Voltage and Current for Each Transistor – Note 1
(See Packaging Information).
‐VGSS
Gate Voltage to Drain or Source
40V
‐VDSO
Drain to Source Voltage
40V
‐IG(f)
Gate Forward Current
10mA
U421 Applications:
Maximum Power Dissipation
Device Dissipation @ Free Air – Total
400mW @ +125°C
ƒ Ultra Low Input Current Differential Amps
ƒ High-Speed Comparators
ƒ Impedance Converters
MATCHING CHARACTERISTICS @ 25°C UNLESS OTHERWISE NOTED
SYMBOL
CHARACTERISTICS VALUE UNITS CONDITIONS
|∆V GS1‐2 /∆T|max.
DRIFT VS.
TEMPERATURE
10 µV/°C VDG=10V, ID=30µA
TA=‐55°C to +125°C
| V GS1‐2 | max.
OFFSET VOLTAGE 10
mV VDG=10V, ID=30µA
ELECTRICAL CHARACTERISTICS @ 25°C (unless otherwise noted)
SYMBOL
CHARACTERISTICS
MIN.
TYP.
MAX.
UNITS
CONDITIONS
BVGSS
Breakdown Voltage
40
60
‐‐
V
VDS = 0
IG =1nA
Click BVGGO
Gate‐To‐Gate Breakdown
40
TRANSCONDUCTANCE
YfSS
Full Conduction
300
YfS
Typical Operation
120
DRAIN CURRENT
IDSS
Full Conduction
60
To Buy ‐‐
‐‐
‐‐
1500
200
350
V
µmho
µmho
IG = 1µA
VDS = 10V
VDG = 10V
ID = 0
IS= 0
VGS = 0V f = 1kHz
ID = 30µA f = 1kHz
‐‐
1000
µA
VDS = 10V
VGS = 0V
GATE VOLTAGE
VGS(off)
VGS
Pinchoff voltage
Operating Range
‐‐
‐‐
2.0
V
‐‐
‐‐
1.8
V
VDS = 10V
VDG = 10V
ID = 1nA
ID = 30µA
GATE CURRENT
IGmax.
Operating
‐‐
‐‐
.25
pA
VDG = 10V
ID = 30µA
‐IGmax.
High Temperature
‐‐
‐‐
250
pA
TA = +125°C
IGSSmax.
At Full Conduction
‐‐
‐‐
1.0
pA
VDS = 0V
VGS = 20V
‐IGSSmax.
High Temperature
‐‐
‐‐
1.0
nA
TA = +125°C
OUTPUT CONDUCTANCE
YOSS
Full Conduction
‐‐
‐‐
10
µmho
YOS
Operating
‐‐
0.1
3.0
µmho
VDS = 10V
VDG = 10V
VGS = 0V
ID = 30µA
COMMON MODE REJECTION
CMR
‐20 log | ∆V GS1‐2/ ∆VDS|
‐‐
90
‐‐
dB
∆VDS = 10 to 20V ID = 30µA
‐20 log | ∆V GS1‐2/ ∆VDS|
‐‐
90
‐‐
dB
∆VDS = 5 to 10V ID = 30µA
NOISE
VDG = 10V ID = 30µA RG = 10MΩ
NF
Figure
‐‐
‐‐
1
dB
f = 10Hz
en
Voltage
‐‐
20
70
nV/√Hz
VDG = 10V ID = 30µA f = 10Hz
CAPACITANCE
‐‐
10
‐‐
VDG = 10V ID = 30µA f = 1KHz
CISS
Input
‐‐
‐‐
3.0
pF
VDS= 10V VGS = 0 f = 1MHz
CRSS
Reverse Transfer
‐‐
‐‐
1.5
pF
Note 1 – These ratings are limiting values above which the serviceability of any semiconductor may be impaired
Available Packages:
TO-71 / TO-78 (Top View)
P-DIP / SOIC (Top View)
U421 in TO-71 & TO-78
U421 in PDIP & SOIC
U421 available as bare die
Please contact Micross for full package and die dimensions
Email: chipcomponents@micross.com
Information furnished by Linear Integrated Systems and Micross Components is believed to be accurate and reliable. However, no responsibility is assumed for its use; nor for any infringement of patents or
other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Linear Integrated Systems.