onsemi 1SMB5936BT3G Zener Diode: Datasheet, Specifications, and Application Notes

The 1SMB5936BT3G from onsemi is a high-power, surface-mount Zener diode designed for voltage regulation and transient suppression in a wide array of electronic circuits. Part of the popular 1SMB series, this component is engineered to dissipate significantly higher power than standard Zeners, making it an ideal solution for robust circuit protection and voltage clamping.

Key Specifications and Datasheet Overview

The 1SMB5936BT3G is a 15.6V Zener diode with a tight tolerance of ±5%. Its most striking feature is its ability to handle a peak pulse power dissipation of 600W at a specified waveform of 10/1000μs. This high surge capability is crucial for protecting sensitive components from voltage spikes and transients, such as those caused by electrostatic discharge (ESD) or inductive load switching.

Key electrical characteristics include:

Nominal Zener Voltage (Vz): 15.6V @ Izt = 91mA

Maximum Reverse Leakage Current (IR): 5μA @ Vr = 11.8V

Maximum Zener Impedance (ZZT): 1.5Ω @ Izt = 91mA

Forward Voltage (VF): 3.5V @ IF = 10A

The device is housed in a DO-214AA (SMB) surface-mount package, which offers a good balance between compact size and efficient thermal performance. The package is halogen-free and RoHS compliant, adhering to modern environmental standards.

Primary Applications and Circuit Notes

The primary function of the 1SMB5936BT3G is transient voltage suppression (TVS). However, its stable Zener characteristic also makes it suitable for general voltage regulation in power supplies.

1. Overvoltage/ESD Protection:

It is commonly placed in parallel across data lines, power rails, or I/O ports to clamp any voltage spike exceeding its breakdown voltage (Vz) to a safe level, thereby shunting harmful current away from integrated circuits (ICs).

2. Voltage Clamping:

In circuits involving relays, motors, or solenoids, the sudden collapse of their magnetic fields can generate large voltage spikes. The 1SMB5936BT3G acts as a clamp, absorbing this energy and protecting the driving transistor or MOSFET.

3. Basic Voltage Regulation:

While not as efficient as a dedicated voltage regulator IC for primary power regulation, it can serve as a simple shunt regulator for low-current reference voltages or for stabilizing voltage in non-critical, low-power applications.

Important Design Considerations:

Power Dissipation: The 600W rating is for a very short, single pulse. For continuous operation, the average power dissipation must not exceed 3.0W (at TL = 75°C). Proper PCB layout with sufficient copper pour is essential for heat sinking.

Current Limiting: When used as a shunt regulator, a series current-limiting resistor is mandatory to set the operating current and prevent excessive power dissipation that would destroy the diode.

Voltage Derating: Designers should consider the positive temperature coefficient of the Zener voltage, which causes Vz to increase with junction temperature.

ICGOODFIND Summary

The onsemi 1SMB5936BT3G is a highly reliable and robust 15.6V Zener diode excelling in transient voltage suppression and power regulation. Its exceptional 600W peak pulse power rating in a compact SMB package makes it a superior choice for safeguarding modern electronics against overvoltage events in automotive, industrial, and consumer applications. Careful attention to thermal management and current limiting is key to leveraging its full performance.

Keywords: Zener Diode, Transient Voltage Suppression, 600W Peak Power, Voltage Regulation, Surface Mount