Single Zener Diodes
Single Zener Diodes are semiconductor devices designed to work under a specific reverse voltage, used to provide voltage stabilization and protection functions. Unlike ordinary diodes, it can work normally in the reverse breakdown state without damage, and keeps the voltage basically constant by controlling the current when it changes in a large range.
1. What is the Working Principle of Single Zener Diodes?
Based on the reverse breakdown characteristics of the PN junction: when the reverse voltage is lower than the breakdown point, the resistance is extremely high and the leakage current is extremely small; once the voltage reaches the critical breakdown value (i.e. Zener voltage), the current increases sharply, the resistance drops sharply, and the voltage stabilizes near the breakdown value, thereby achieving voltage stabilization.
2. What are the Main Parameters of Single Zener Diodes?
Stable Voltage (Uz): The stable voltage value generated at both ends under rated current, which varies slightly with current and temperature (such as 2CW51 type Uzmin is 3.0V, Uzmax is 3.6V).
Reverse Leakage Current (Iz): The minimum current to maintain the voltage stabilization effect. If it is lower than this value, the voltage stabilization performance deteriorates, and if it is higher, the power consumption needs to be controlled.
Dynamic Resistance (Rz): The ratio of voltage change to current change. The larger the working current, the smaller Rz (e.g., Rz is 18Ω at 5mA for 2CW7C, and drops to 2Ω at 20mA).
Rated Power Consumption (Pz): Determined by the temperature rise of the chip, which is the product of Uz and the maximum allowable current Izm (e.g., Pz of 2CW51 is 60mW).
Temperature Coefficient (α): The relative change in voltage caused by a temperature change of 1°C, which affects stability.
3. What are Single Zener Diodes Used for?
In practical applications, Single Zener Diodes are often used as voltage reference components or regulators, such as clamping voltage in ESD protection interfaces, or achieving higher stable voltages through series connection; their nonlinear I-V characteristics (dynamic resistance Rdyn=∆V/∆I) ensure that the voltage fluctuation rate is extremely small (e.g., when Rdyn=10Ω and ∆I=10mA, ∆V is only 10mV).