U421 CALOGIC | Alldatasheet

Document overview

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Technical content

U421 – U426

FEATURES

  • • 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 Herme tic Package -55oC to +150oC XU421-U426 Sorted Chips in Carriers -55oC to +150oC PIN CONFIGURATION CORPORATION S1C TO-78 4 5 BOTTOM VIEW 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) Device Dissipation (Each Side), T A = 25oC Total Device Dissipation, TA = 25oC 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 IG = -1µA, VDS = 0 BV G1G2 Gate-Gate Breakdown Voltage ±40 ±40 IG = -1µA, ID = 0, IS = 0 IGSS Gate Reverse Current (1) 1.0 3.0 pA T = +25oC VGS = -20V, VDS = 01.0 3.0 nA T = +125oC IG Gate Operating Current (1) .25 0.5 pA T = +25oC VDG = 10V, ID = 30µA.250 -500 T = +125oC VGS (off) Gate-Source Cutoff Voltage -0.4 -2.0 -0.4 -2.0 V VDS = 10V, ID = 1nA VGS Gate-Source Voltage -1.8 -2.9 VDG = 10V, ID = 30µA IDSS Saturation Drain Current 60 1000 60 1800 µA VDS = 10V, VGS = 0 DYNAMIC gfs Common-Source Forward Transconductance 300 1500 300 1500 VDS = 10V, VGS = 0 f = 1 kHz gos 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 gfs Common-Source Forward Transconductance 120 350 120 350 VDG = 10V, ID = 30µA f = 1kHz gos Common-Source Output Conductance 3.0 3.0 en 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 | VGS1 -VGS2 | Differential Gate-Source Voltage 10 15 25 mV VDG = 10V, ID = 30µA | VGS1 -VGS2 | ΔT Differential Gate-Source Voltage Change with Temperature (2) 10 25 40 V/ oC VDG = 10V, ID = 30µA, TA = -55oC, TB = 25oC, TC = 125oC C MRR Common Mode Rejection Ratio (3) 90 95 80 90 80 90 dB ID = 30µA, VDG = 10 to 20 V NOTES: 1. Approximately doubles for every 10oC increase in TA. 2. Measured at endpoints TA, TB and TC . 3. CMRR = 20log10 [ ] V DD = 10V. 4. Case lead not connected. VDD VGS1 -VGS2 ELECTRICAL CHARACTERISTICS (25oC Unless otherwise noted)