ZMM5239B-7 Discrete Semiconductor Products

Diodes - Zener - Single

The ZMM5239B-7 is a single zener diode that is typically used for voltage regulation and surge absorption. This unique device comprises of a heavily doped PN junction. Such junctions are characterized by their wide reverse break-down region. This ensures the ZMM5239B-7 is able to handle large transient voltage spikes in order to filter out electromagnetic interference.

Zener diodes are also used as voltage references in order to maintain a preset, constant voltage output. By changing the current that passes across the diode, the voltage can be adjusted, thanks to the inherent voltage-regulation property of the zener state. This feature of "zener action" is why these devices are so valuable in electronic circuits.

The typical application field of this diode mostly comprises of power supply circuits and power line protection for telecommunications equipment and even industrial control applications. Due to their good reverse-breakdown parameters, ZMM5239B-7 diodes are highly suitable to keep voltage surges and transients within safe limits. In most designs, the diode should be reverse biased to ensure it is in its enhanced diode mode, thereby enabling it to conduct current during forward operation.

Working Principle

The ZMM5239B-7 is composed of a PN junction, which enables the diode to operate in reverse current. In reverse bias operation, these diodes are characterized by their total breakdown voltage which is of the order of 5 volts. Under normal operation, the PN junction consists of an anode and cathode, each equipped with a potential barrier. When a reverse bias is applied on the junction (i.e. the negative terminal of the supply is connected to the anode and the positive terminal of the supply to the cathode), it becomes depleted of charge carriers. This is due to the electric field that is generated, forcing the majority carriers away from the junction.

When a critical reverse voltage is reached, the depletion layer extends to its maximum extent and just after the potential barrier is reversed. This point of voltage, where the potential barrier reverses, is known as the "zener knee". It is marked as the peak operating voltage of the diode. When the voltage across the junction exceeds the peak knee voltage, a large amount of current starts to flow through the diode. In other words, the diode\'s breakdown voltage is exceeded, and this current is called as "zener current" which continues to flow until the voltage is reduced below its peak value.

The ZMM5239B-7 diode is not suitable to be connected across a load, since it can be destroyed if used in this configuration. To operate it safely, the diode must be connected in reverse bias, between ground potential and the positive voltage source. In addition, an appropriate current limiting resistor should be used to protect the diode from damaging current surges. This diode also provides an area for absorptive operation. Therefore, it can be used for power factor correction, surge limiting, and voltage regulation.

The ZMM5239B-7 zener diode is an important component for many different types of applications because it is able to provide a stable, regulated voltage under the most demanding conditions. With its compact size and high packaging density, it is ideal for board-level applications, allowing engineers to integrate the device into potentially space-restricted designs. Along with its abundant uses and reliable performance, this diode offers a great value of money.