VCR2N/4N/7N Vishay Siliconix JFET Voltage-Controlled Resistors PRODUCT SUMMARY Part Number VGS(off) Max (V) V(BR)GSS Min (V) rDS(on) Max () VCR2N −7 −25 60 VCR4N −7 −25 600 VCR7N −5 −25 8000 FEATURES BENEFITS APPLICATIONS D Continuous Voltage-Controlled Resistance D High Off-Isolation D High Input Impedance D Gain Ranging Capability/Wide Range Signal Attenuation D No Circuit Interaction D Simplified Drive D Variable Gain Amplifiers D Voltage Controlled Oscillator D AGC DESCRIPTION The VCR2N/4N/7N JFET voltage controlled resistors have an ac drain-source resistance that is controlled by a dc bias voltage (VGS) applied to their high impedance gate terminal. Minimum rDS occurs when VGS = 0 V. As VGS approaches the pinch-off voltage, rDS rapidly increases. This series of junction FETs is intended for applications where the drain-source voltage is a low-level ac signal with no dc component. Key to device performance is the predictable rDS change versus VGS bias where: r DS(@ V GS + 0) r DSbias [ Ť Ť V GS 1– V GS(off) These n-channel devices feature rDS(on) ranging from 20 to 8000 . All packages are hermetically sealed and may be processed per MIL-S-19500 (see Military Information). TO-206AA (TO-18) TO-206AF (TO-72) S S C 1 1 2 2 3 D 4 G and Case 3 D G Top View Top View VCR2N, VCR4N VCR7N For applications information see AN105. Document Number: 70293 S-41225—Rev. F, 28-Jun-04 www.vishay.com 1 VCR2N/4N/7N Vishay Siliconix ABSOLUTE MAXIMUM RATINGSa Gate-Source, Gate-Drain Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −25 V Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA Power Dissipationb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 mW Operating Junction Temperature Range . . . . . . . . . . . . . . . . . . . −55 to 175_C Lead Temperature (1/16” from case for 10 sec.) . . . . . . . . . . . . . . . . . . . 300_C Notes: a. TA = 25_C unless otherwise noted. b. Derate 2 mW/_C above 25_C. Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65 to 200_C SPECIFICATIONS (TA = 25_C UNLESS OTHERWISE NOTED) Limits VCR2N Parameter Symbol Test Conditions Typa V(BR)GSS IG = −1 A, VDS = 0 V −55 VGS(off) VDS = 10 V, ID = 1 A IGSS VGS = −15 V, VDS = 0 V Min VCR4N Max Min −7 −3.5 VCR7N Max Min −7 −2.5 Max Unit Static Gate-Source Breakdown Voltage Gate-Source Cutoff Voltage Gate Reverse Current −25 −3.5 −5 VGS = 0 V, ID = 10 mA Drain-Source On-Resistance −25 20 −0.2 200 −0.1 nA 600 VGS = 0 V, ID = 0.1 mA Gate-Source Forward Voltage V −5 60 VGS = 0 V, ID = 1 mA rDS(on) −25 4000 8000 VGS(F) VDS = 0 V, IG = 1 mA 0.7 V rds(on) VGS = 0 V, ID = 0 mA f = 1 kHz Drain-Gate Capacitance Cdg VGD = −10 V, IS = 0 mA f = 1 MHz 7.5 3 1.5 Source-Gate Capacitance Csg VGS = −10 V, ID = 0 mA f = 1 kHz 7.5 3 1.5 Dynamic Drain-Source On-Resistance 20 60 200 600 4000 8000 pF Notes: a. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing. NCB/NPA/NT TYPICAL CHARACTERISTICS (TA = 25_C UNLESS OTHERWISE NOTED) Output Characteristics (VCR2N) Output Characteristics (VCR4N) 30 1.0 VGS(off) = −4 V 25 20 −0.5 V −1.0 V 15 −1.5 V −2.0 V 10 −2.5 V 5 VGS = 0 V −2.0 V 0.8 ID − Drain Current (mA) ID − Drain Current (mA) −1.5 V VGS = 0 V −3.5 V −2.5 V −3.0 V 0.6 −4.0 V 0.4 0.2 VGS(off) = −4.2 V −3.0 V 0 0 0 0.2 0.4 0.6 VDS − Drain-Source Voltage (V) www.vishay.com 2 0.8 1 0 0.1 0.2 0.3 0.4 0.5 VDS − Drain-Source Voltage (V) Document Number: 70293 S-41225—Rev. F, 28-Jun-04 VCR2N/4N/7N Vishay Siliconix TYPICAL CHARACTERISTICS (TA = 25_C UNLESS OTHERWISE NOTED) Output Characteristics (VCR7N) 200 VGS(off) = −2.5 V ID − Drain Current (A) 160 VGS = 0 V −0.5 V 120 −1.0 V 80 −1.5 V 40 −2.0 V 0 0 0.2 0.4 0.6 0.8 1 VDS − Drain-Source Voltage (V) APPLICATIONS A simple application of a FET VCR is shown in Figure 1, the circuit for a voltage divider attenuator. The output voltage is: VOUT = R VIN rDS R + rDS It is assumed that the output voltage is not so large as to push the VCR out of the linear resistance region, and that the rDS is not shunted by the load. VIN VOUT − VGS VCR The lowest value which VOUT can assume is: VOUT(min) = + VIN rDS(on) R + rDS(on) Since rDS can be extremely large, the highest value is: FIGURE 1. Simple Attenuator Circuit VOUT(max) = VIN Document Number: 70293 S-41225—Rev. F, 28-Jun-04 www.vishay.com 3 Legal Disclaimer Notice Vishay Notice Specifications of the products displayed herein are subject to change without notice. Vishay Intertechnology, Inc., or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies. Information contained herein is intended to provide a product description only. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Vishay for any damages resulting from such improper use or sale. Document Number: 91000 Revision: 08-Apr-05 www.vishay.com 1