AN103 - Siliconix

AN103 The FET Constant-Current Source/Limiter

www.DataSheet4U.com AN103 The FET Constant-Current Source/Limiter Introduction The combination of low associated operating voltage and high output impedance makes the FET attractive as a constant-current source. An adjustable-current source (Figure 1) may be built with a FET, a variable resistor, and a small battery. For optimum thermal stability, the FET .

Features

guaranteed peak operating voltage minimum of 100 V with a typical of 180 V. The J500 series features 50 V minimum with a typical of 100 V. The lower current devices in both series provide excellent current regulation down to as little as 1 V. Siliconix 10-Mar-97 Bias Resistor Selection All industry JFET part types exhibit a significant variation in IDSS and VGS(off) on min/max specifications and device-to-device variations. Using the simple source biasing current source as illustrated in Figure 1, the designer can graphically calculate the RS which best fits the desired drain current ID. Figu.