TEST CIRCUITS
VIN
IREF
VREF
VZ = VREF
IZ
Figure 1. Test Circuit for VZ=VREF
TYPICAL APPLICATIONS
AMS431L
VIN
VZ
R1
IREF
IZ
R2
VREF
VIN
VZ
IZ OFF
Figure 2. Test Circuit for VREF vs IZ.
Test circuit for IREF.
Figure 3. Test Circuit for Off-State Current
VIN
GND
R1
VREF
R2
VOUT
1) Set the VOUT according to the following equation:
VOUT = VREF⎜⎛1 + R1 ⎟⎞ + IREFR1
⎝ R2 ⎠
2) Choose the value of R as follows:
• The maximum limit for R should be such that the cathode current, IZ is greater than the minimum operating current (80µA) at VIN(min).
• The minimum limit for R should b such that IZ does not exceed 100mA under all load conditions, and the instantaneous turn-on value for IZ does not
exceed 150mA. Both of the following conditions must be met:
Rmin ≥ VIN(max) (to limit instantaneous turn - on IZ)
150mA
Rmin ≥ VIN(max) - VOUT (to limit IZ under normal operating conditions)
IOUT(min) + 100mA
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