In electronic circuit design, the Zener Diode is an indispensable component, playing a crucial role in circuits due to its unique voltage regulation characteristics. Among the various models of Zener Diodes, the ZM4739A stands out as a favored choice among engineers and technicians for its high performance and wide applicability. This article will delve into the performance parameters of the ZM4739A Zener Diode and its applications in circuits.

Slkor Voltage Regulator Diode ZM4739A product photo

I. Overview of the ZM4739A Zener Diode

The ZM4739A is a high-performance Zener Diode with a nominal regulation value of 9.1V, boasting an accuracy of up to ±5% and a power rating of 1W. This Zener Diode features characteristics such as low reverse current and low impedance, enabling it to provide stable voltage output in various circuits, ensuring the stable operation of the circuit.

Slkor Voltage Regulator Diode ZM4739A specification

II. Key Performance Parameters of the ZM4739A Zener Diode

Nominal Regulation Value: 9.1V. This is the constant voltage value that the ZM4739A Zener Diode can maintain under normal operating conditions. Due to manufacturing tolerances and environmental factors, the actual regulation value may fluctuate around this nominal value, but the fluctuation range is strictly controlled within ±5%.

Accuracy: ±5%. This refers to the regulation accuracy of the ZM4739A Zener Diode, indicating the maximum deviation between its actual regulation value and the nominal value. This high precision feature allows the ZM4739A to provide stable and reliable voltage output in circuits with stringent requirements.

Power Rating: 1W. This is the maximum power that the ZM4739A Zener Diode can withstand under normal operating conditions. Exceeding this power rating may lead to diode damage or performance degradation. Therefore, it is necessary to ensure that the current and voltage passing through the Zener Diode in the circuit are within its rated range during circuit design.

Reverse Current (Ir): 10μA @ 7V. This refers to the magnitude of the reverse current flowing through the ZM4739A Zener Diode when it has not reached the breakdown voltage (in this case, 9.1V). This parameter reflects the performance of the Zener Diode in reverse operation, which has significant implications for circuit stability and power consumption.

Impedance (Zzt): 5Ω. This is the dynamic impedance of the ZM4739A Zener Diode, reflecting its ability to respond to changes in current during operation. A lower impedance means that the Zener Diode can respond to current changes more quickly, maintaining stable output voltage.

Parameters of Slkor Voltage Regulator Diode ZM4739A

III.Usage Precautions:

When using the ZM4739A Zener Diode, ensure that the input voltage does not exceed its rated power and voltage range.

When designing circuits, fully consider the temperature coefficient and power consumption characteristics of the Zener Diode to ensure circuit stability and reliability under different temperature and load conditions.

During soldering and installation, take care to avoid mechanical or thermal damage to the Zener Diode.

Before use, inspect the appearance and pins of the Zener Diode to ensure there are no damages or short circuits.

IV.Why Add a Current-Limiting Resistor to a Zener Diode?

There are several reasons for adding a current-limiting resistor to a Zener Diode:

Protecting the Zener Diode: When a Zener Diode operates in reverse breakdown mode, although the voltage across its terminals remains constant, there is still a limited current passing through its internal PN junction. This current (known as the Zener current) is restricted. If the current flowing through the Zener Diode is too large, it can cause excessive internal heating and potentially damage the Zener Diode. Therefore, a current-limiting resistor is needed in series with the Zener Diode to limit the current flowing through it and protect its normal operation.

Adjusting the Output Voltage: The resistance value of the current-limiting resistor affects the current flowing through the Zener Diode, thereby influencing its output voltage. By adjusting the resistance value of the current-limiting resistor, the output voltage of the Zener Diode can be adjusted within a certain range to meet the requirements of different circuits.

Stabilizing the Output Voltage: Although a Zener Diode can provide a stable output voltage, its output voltage is still affected by fluctuations in the input voltage. When the input voltage fluctuates, the current flowing through the Zener Diode also changes, affecting its output voltage. By placing a current-limiting resistor in series with the Zener Diode, the impact of input voltage fluctuations on the output voltage can be reduced, improving the stability of the output voltage.

Preventing Current Surges: In certain situations, such as circuit startup or when the power is turned on, large current surges may occur. These current surges can damage the Zener Diode or other circuit components. By adding a current-limiting resistor in series with the Zener Diode, the magnitude of these current surges can be limited, protecting the circuit components' safety.

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.