The JFE2140 functionality is identical to standard
N-channel depletion JFET devices. The gate-to-source (VGS) voltage,
drain-to-source voltage (VDS) and drain-to-source current
(IDS) determine the region of operation.
- For VGS < VGSC: JFE2140
conduction channel is closed; IDS is only determined by junction
leakage current.
- For VGS >
VGSC: Two modes of operation can exist depending on
VDS. When VDS is less than the linear (saturation)
region threshold (see Figure 9-2), the
device operates in the linear region, meaning that the device behaves as a
resistor connected from drain-to-source with minimal variation from any changes
in VGS. When VDS is greater than the linear (saturation)
region threshold, IDS has a strong dependance on VGS,
where the relationship is described by the parameter gm.