Can Zener diodes be used in parallel connection?

It is not recommended to use the Zener diodes in parallel connection. Even products with the same product name have variations in electrical characteristics such as Zener voltage. Therefore, there is a possibility that the current will concentrate in one of the Zener diodes, resulting in characteristic deterioration or destruction.

Assume that two Zener diodes DZ1 and DZ2 with different Zener voltages shown in Fig. 2 are connected in parallel as shown in Fig. 1. Apply the voltage Vin to reverse bias the pn junction of the Zener diode. The Zener voltage of DZ1 and DZ2 is VZ at this time.
There is a difference between the currents flowing through DZ1 and DZ2 when the Zener voltage is VZ, and as shown in Fig. 2, a higher current flow through DZ2. Do not connect Zener diodes in parallel because current might concentrate only on one diode.

Table-1　 Example of Zener voltage shown in a datasheet
Type Zener Voltage Vz (V)
Min Typ. Max Measure-ment
Current Iz (mA)
CMZB12 10.8 12 13.2 10
Fig. 1 Zener diode parallel circuit (not recommended)
Fig. 1 Zener diode parallel circuit (not recommended)
Fig. 2 V-I Curves of D<sub>Z1</sub> and D<sub>Z2</sub>
Fig. 2 V-I Curves of DZ1 and DZ2

Please also refer to the FAQ below.

FAQ：Is it OK to connect multiple diodes with the same part number in parallel?

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