onsemi 1N5937BG

Overview

1N5937BG from onsemi is a 3 W, ±5% tolerance Zener diode in DO-41 package with nominal Zener voltage of 33 V, maximum Zener impedance of 11.4 Ω at 33 mA test current, and surge rating of 98 W for 1 ms. It regulates voltage in low-power DC supply rails, reference circuits, and overvoltage protection in industrial power supplies.

For engineers reviewing the 1N5937BG datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, cathode/anode polarity mapping, Pb-free compliance status, and direct alternatives for voltage reference design and replacement sourcing.

Technical Context

This device uses silicon-oxide passivated junction technology to achieve stable Zener breakdown with low leakage (≤0.25 μA at 25.1 V) and high ESD robustness (Class 3, >16 kV HBM). Its axial-leaded DO-41 package enables through-hole mounting with lead temperature tolerance up to 260°C for 10 seconds.

The 1N5937BG operates across −65°C to +200°C junction temperature range and exhibits a positive temperature coefficient above ~5 V - confirmed at +0.065 %/°C typical for 33 V units per Figure 6. Steady-state power dissipation is rated at 3 W at 75°C lead temperature, derating linearly by 24 mW/°C above that point.

Key Specifications

Pinout & Package

DO-41 package with axial leads: Cathode identified by color band; Anode is unmarked lead. Mounting position is unrestricted. Lead temperature tolerance: 260°C at 1/16″ from case for 10 s.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener voltage regulation applications.

Compared with 1N5937BG, the 1N5937BRLG offers identical performance in automated manufacturing contexts, while BZX85C33 trades power capability and regulation tightness for lower cost in non-demanding applications - making 1N5937BG optimal for robust, medium-power voltage stabilization where thermal margin and impedance matter.

Availability

1N5937BG is available at Aetrix Electronics and suitable for industrial power supplies, programmable logic controller (PLC) I/O protection, and test equipment voltage calibration requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for 1N5937BG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 1N5937BG belongs to the 1N5913B Series of 3 W Zener regulators designed for high-reliability voltage reference and overvoltage protection in demanding industrial and automotive environments.

FAQ

What is the Zener voltage tolerance of the 1N5937BG?

The 1N5937BG has a ±5% tolerance on its nominal Zener voltage of 33 V, meaning the actual measured voltage at 33 mA test current falls between 31.35 V and 34.65 V. This tolerance is guaranteed per onsemi's Electrical Characteristics table and applies under standard test conditions (TL = 30°C, 90-second measurement duration). The "B" suffix in the part number explicitly denotes this ±5% tolerance grade.

Can the 1N5937BG be used in surface-mount designs?

No - the 1N5937BG is packaged exclusively in the axial-leaded DO-41 (Case 59) format and is intended for through-hole mounting. It lacks surface-mount terminations or land patterns. For SMT-compatible alternatives with similar 33 V regulation, consider the MMBZ5256BLT1G (SOT-23, 500 mW) or NZ9F33VST5G (SOD-923, 300 mW), though neither matches the 3 W power rating or low impedance of the 1N5937BG.

What is the maximum allowable lead temperature during soldering for the 1N5937BG?

The maximum lead temperature for soldering the 1N5937BG is 260°C, applied at a distance of 1/16″ from the case for no longer than 10 seconds. This specification ensures junction integrity is preserved during hand or wave soldering. Exceeding this limit risks internal bond degradation or passivation layer damage, potentially increasing leakage or shifting Zener voltage unpredictably.

How does the 1N5937BG perform under pulsed surge conditions?

The 1N5937BG is rated for 98 W non-repetitive surge power at 1 ms pulse width, as shown in Figure 3 of the onsemi datasheet. This capability allows it to safely clamp short-duration transients - such as EFT bursts or inductive kickback - without failure. However, repetitive surges must respect thermal limits derived from Figure 2's transient thermal resistance curves to avoid cumulative junction overheating.

Is the 1N5937BG suitable for automotive under-hood applications?

Yes - the 1N5937BG is qualified for operation from −65°C to +200°C junction temperature, covering extended automotive under-hood thermal ranges. Its silicon-oxide passivated junction and robust DO-41 mechanical construction support reliability in high-vibration, high-temperature environments. However, system-level qualification (e.g., AEC-Q200) is not claimed by onsemi for this part, so design-in requires independent validation per vehicle OEM requirements.