Datasheet

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  
SCDS087G − APRIL 1999 − REVISED APRIL 2005
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
electrical characteristics
The electrical characteristics of the NMOS transistors used in the TVC devices are illustrated by TI SPICE
simulations. Figure 4 shows the test configuration for the TI SPICE simulations. The results, shown in
Figures 5 and 6, show the current through a pass transistor versus the voltage at the source for different
reference voltages. The plots of the dc characteristics clearly reveal that the device clamps at the desired
reference voltage for the varying device environments.
Figure 5 shows the V-I characteristics with low reference voltages and a reference-transistor drain-supply
voltage of 3.3 V. To further investigate the spread of the V-I characteristic curves, V
REF
was held at 2.5 V and
I
REF
was increased by raising V
DDREF
(see Figure 6). The result was a tighter grouping of the V-I curves.
V
DPASS
V
REF
R
DREF
GATE V
BIAS
V
DDREF
R
DPASS
V
DDPASS
V
SPASS
Figure 4. TI SPICE-Simulation Schematic and Voltage-Node Names