ZR431LDC Test Circuits Figure 1. Test Circuit for VZ = VREF Figure 2. Test Circuit for VZ > VREF Figure 3. Test Circuit for Off State Current Deviation of reference input voltage, VDEV, 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, VREF is defined as: V MAX V 1000000 V ppm ( /o ) C dev ref V ( 1 T T ) 2 ref The dynamic output impedance, RZ is defined as: V = V - V DEV MAX MIN VMIN V z R z I z When the device is programmed with two external resistors, R1 and R2 (Figure 2), the dynamic output impedance of the overall circuit, R’, is defined as: 1 R T1 Temperature T2 R R 1 ( ) z 2 R
