In the complex world of electronic devices, stable voltage output is crucial to ensure proper circuit operation. Voltage regulator diodes, especially the ZM4746A model, have become invaluable aids to circuit designers due to their unique stabilizing characteristics. This article delves into the characteristics of the ZM4746A and discusses its practical applications in circuit design.

Slkor Voltage Regulator Diode ZM4746A product photo

I. Key Characteristics of ZM4746A Voltage Regulator Diode

Nominal Voltage (Vz): The nominal stabilizing value of the ZM4746A is 18V, meaning it can maintain an output voltage stable at around 18V under normal operating conditions.

Accuracy: This voltage regulator diode has an accuracy of ±5%, indicating that the fluctuation range of the output voltage is between 18V ± 0.9V. This high precision stabilizing characteristic ensures circuit stability and reliability.

Power: The ZM4746A has a power rating of 1W, meaning it can withstand a certain current and voltage load, meeting the requirements of most electronic devices.

Reverse Current (Ir): Before reaching the breakdown voltage, the reverse current of the ZM4746A is only 5μA @ 13.7V. This feature helps reduce circuit power consumption and improve efficiency.

Impedance (Zzt): The impedance of the ZM4746A is 20Ω, and this relatively low impedance enables it to quickly respond to current changes in the circuit, thereby maintaining stable output voltage.

Slkor Voltage Regulator Diode ZM4746A specification

Parameters of Slkor Voltage Regulator Diode ZM4746A

II. Applications of ZM4746A Voltage Regulator Diode

Power Circuits: In power circuits, the ZM4746A can serve as a reference voltage source, providing a stable 18V voltage output to other circuits. By adjusting the value of the current-limiting resistor in the circuit, precise adjustment of the output voltage can be achieved.

Amplifier Circuits: In amplifier circuits, the ZM4746A can be used to stabilize bias voltage or operating point voltage, ensuring amplifier stability and linearity.

Sensor Circuits: Sensors typically require a stable reference voltage to improve measurement accuracy. The ZM4746A can provide a stable 18V reference voltage for sensors, thereby enhancing sensor performance.

Digital Circuits: In digital circuits, the ZM4746A can serve as a voltage stabilizer, providing stable power supply voltage to logic gate circuits, ensuring the correct operation of digital circuits.

III. Precautions for Use

Power Voltage: Ensure that the power voltage input to the ZM4746A does not exceed its maximum rated voltage and power to prevent device damage.

Temperature and Power Dissipation: When designing circuits, consider the temperature coefficient and power dissipation characteristics of the ZM4746A. Additional heat dissipation measures may be required under high temperature or high load conditions.

Installation and Soldering: During soldering and installation, avoid causing mechanical or thermal damage to the ZM4746A. Use appropriate soldering tools and parameters to ensure soldering quality.

Inspection and Testing: Before use, check the appearance and pins of the ZM4746A to ensure there is no damage or short circuit. Verify its stabilizing performance through testing to ensure it meets requirements.

In which region does the voltage regulator diode operate?

When a voltage regulator diode operates normally, it primarily operates in the reverse breakdown region. Below is a detailed explanation of the operating regions of the voltage regulator diode:

Reverse Breakdown Region:

Voltage regulator diodes utilize the reverse breakdown state of the PN junction to achieve voltage regulation. In this state, although the current varies over a wide range, the voltage across the diode remains stable at or near the breakdown voltage.

When the reverse voltage is less than the breakdown voltage (Vz) of the voltage regulator diode, the reverse current is very small. When the reverse voltage reaches Vz, the voltage regulator diode undergoes breakdown, and the reverse current increases sharply. This breakdown is reversible, meaning that once the applied reverse voltage is removed, the diode's breakdown immediately recovers.

Principle of Regulation:

The principle of voltage regulation of the voltage regulator diode relies on its operation in the breakdown region, where the voltage hardly varies with the current. By adjusting the reverse voltage, the voltage across the diode can be maintained within a stable range.

Main Parameters:

● Uz (Stable Voltage): Refers to the stable voltage value generated across the diode when it passes the rated current. This value may vary slightly with different operating currents and temperatures.

● Iz (Reverse Leakage Current): Refers to the current passing through the diode when it generates a stable voltage. Below this value, although the diode can still regulate, the effectiveness of regulation deteriorates; above this value, as long as it does not exceed the rated power dissipation, it is permissible.

● Rz (Dynamic Resistance): Refers to the ratio of the voltage change across the diode to the current change. This ratio varies with different operating currents.

● Pz (Rated Power Dissipation): Determined by the allowable temperature rise of the chip, its value is the product of the stable voltage Vz and the maximum allowable current Izm.

About Slkor：
Slkor has research and development offices in Busan, South Korea, Beijing, China, and Suzhou, China. Most of the wafer manufacturing and packaging and testing are carried out within China. The company employs and collaborates with individuals and organizations worldwide, with a laboratory for product performance and reliability testing and a central warehouse located at its headquarters in Shenzhen. Slkor has filed for over a hundred invention patents, offers more than 2,000 product models, and serves over ten thousand customers globally. Its products are exported to countries and regions including Europe, the Americas, Southeast Asia, and the Middle East, making it one of the rapidly growing semiconductor companies in recent years. With well-established management systems and streamlined workflows, Slkor has rapidly enhanced the brand awareness and reputation of its "SLKOR" brand through its outstanding quality and standardized services. Its product range includes three major series: diodes, transistors, and power devices, with recent introductions of new products such as Hall elements and analog devices, expanding its presence in sensors, Risc-v microcontrollers, and other product categories.