onsemi 1N5350BRLG 5W Zener Diode: Datasheet, Specifications, and Application Circuits

The 1N5350BRLG from onsemi is a robust 5W Zener diode designed for voltage regulation and protection in a wide array of electronic circuits. As part of the popular 1N53xxB series, this component is renowned for its reliability and ability to handle higher power levels compared to standard Zener diodes. This article delves into its key specifications, datasheet insights, and typical application circuits.

Key Specifications and Datasheet Overview

The 1N5350BRLG is a silicon planar power Zener diode hermetically sealed in a solid DO-201AD package, which is ideal for heat dissipation. Its primary electrical characteristics are its Zener voltage (Vz) and its power rating.

Zener Voltage (Vz): 16V (at a test current Izt of 110 mA). The voltage tolerance is ±5%.

Maximum Power Dissipation (Ptot): 5.0 Watts at a case temperature (Tc) of 75°C.

Test Current (Izt): 110 mA.

Maximum Zener Impedance (Zzt): 4 Ω (at Izt).

Reverse Leakage Current: Typically < 5 µA (at 12V, 25°C).

Operating Temperature Range: -65°C to +200°C.

A critical parameter from the datasheet is the derating curve. Above 50°C, the maximum power dissipation must be reduced linearly, reaching 0 Watts at 200°C. For stable, long-term operation, ensuring adequate heatsinking is paramount to keep the junction temperature within safe limits.

Application Circuits

The high power rating of the 1N5350BRLG makes it suitable for applications beyond simple voltage reference tasks, often serving in surge suppression and voltage clamping roles.

1. Basic Voltage Regulator:

This is the most straightforward application. The Zener diode is placed in reverse bias across the load. A series current-limiting resistor (Rs) is essential to control the current flow through the diode and drop the excess voltage from the input supply (Vin). The value of Rs must be carefully chosen to ensure the Zener current (Iz) remains between its minimum knee current (Izk) and its maximum allowable current, calculated as Izmax = Ptot / Vz.

2. Overvoltage Protection / Clamp Circuit:

In this configuration, the 1N5350BRLG is used to protect a sensitive load from voltage spikes. The diode is connected between the voltage rail and ground. Under normal operating conditions (where Vin < Vz), the Zener is in a high-impedance state (reverse leakage) and does not conduct. If a voltage spike occurs and Vin exceeds the 16V breakdown voltage, the Zener diode conducts heavily, clamping the voltage to approximately 16V and shunting the harmful transient current to ground, thereby protecting the downstream components.

3. Crowbar Circuit:

For more aggressive protection, the Zener diode can be used to trigger a "crowbar" circuit. The Zener is connected to the gate of an SCR (Silicon Controlled Rectifier). When the input voltage exceeds Vz, the Zener conducts, providing current to the SCR's gate, which triggers it into a latched, low-impedance state. This effectively short-circuits the power supply to ground, blowing a fuse or tripping a circuit breaker and completely disconnecting the load from the dangerous overvoltage.

Conclusion

The onsemi 1N5350BRLG is a high-power, reliable voltage regulator essential for designs requiring robust overvoltage protection and stable voltage references at power levels up to 5W. Its hermetic package ensures performance in demanding environments. Understanding its specifications and proper heatsinking requirements is key to implementing effective and durable circuits.

ICGOODFIND: A reliable component for robust 5W voltage regulation and transient protection.

Keywords: Zener Diode, Voltage Regulation, Overvoltage Protection, 5W Power Dissipation, Circuit Clamping