IL
Input
Fig 1 – Test Circuit for V
z
=V
ref
DC TEST CIRCUITS
Fig 2 – Test Circuit for V
z
>V
ref
Input V
I
Z
zoff
Fig 3 – Test Circuit for Off
State current
ZR431
4-194
NOTES
Deviation of reference input voltage, V
dev,
is defined as the maximum variation of the reference
input voltage over the full temperature range.
The average temperature coefficient of the reference input voltage, V
ref
is defined as:
V
ref
ppm
°C
V
dev
x 1000000
V
ref
T1 T2
The dynamic output impedance, Rz, is defined as:
R
Z
V
Z
I
Z
When the device is programmed with two external
resistors, R1 and R2, (fig 2) , the dynamic output
impedance of the overall circuit, R’, is defined as:
R’
R
z
1
R1
R2
Vmax
Vmin
Vdev = Vmax - Vmin
78
