Diodes Incorporated 1N5237B-T

Overview

1N5237B-T from Diodes Incorporated is a 8.2V ±5% tolerance, 500mW surface-mount Zener diode in a hermetic DO-35 glass package, rated for 20mA test current and 8.0Ω dynamic impedance at I_ZT, used for precision voltage regulation and reference in low-power analog circuits.

For engineers reviewing the 1N5237B-T datasheet, 1N5237B-T pinout, 1N5237B-T application, or 1N5237B-T equivalent, key selection criteria include Zener voltage stability over temperature (+0.062%/°C), reverse leakage ≤3.0µA at 6.5V, and thermal resistance of 300°C/W in free-air conditions.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain a stable 8.2V reference under controlled current. Its glass-encapsulated DO-35 package ensures hermeticity and long-term parameter stability, with cathode band polarity marking and Sn96.5Ag3.5 lead finish compliant with RoHS 3.

It exhibits a positive temperature coefficient of +0.062%/°C, enabling predictable drift compensation in bias networks. Maximum power dissipation is 500mW at T_L ≤75°C with 9.5mm lead length; derating applies above that temperature per MIL-STD-202.

Key Specifications

Pinout & Package

Package: Hermetic DO-35 glass case with axial leads, cathode identified by a single black band. Dimensions: A ≤25.4mm, B ≤4.00mm, C ≤0.60mm, D ≤2.00mm (all mm). Weight ≈0.13g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMSZ5237B and 1N4738A, the 1N5237B-T offers hermetic DO-35 reliability and RoHS 3 compliance at 500mW, balancing precision, stability, and manufacturability for legacy-compatible low-power designs.

Availability

1N5237B-T is available at Aetrix Electronics and suitable for low-power voltage reference, overvoltage clamping, and current-source biasing applications requiring stable component supply and long-lifecycle support.

Supply support for 1N5237B-T 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, serving automotive, industrial, computing, and consumer markets with high-reliability components.

The 1N52xxB series belongs to Diodes' legacy Zener diode product line, designed specifically for general-purpose voltage regulation and reference in cost-sensitive, space-constrained, and thermally stable applications.

FAQ

Is the 1N5237B-T still in active production?

No - Diodes Incorporated has marked the 1N5237B-T as obsolete and discontinued per DS18006 Rev. 19. It remains available through authorized distributors and Aetrix Electronics' legacy inventory, with full traceability and documentation. Customers are advised to migrate to MMSZ5237B for new designs.

What is the maximum allowable reverse voltage before breakdown?

The 1N5237B-T begins controlled Zener breakdown at its nominal 8.2V, with guaranteed operation between 7.79V and 8.61V at 20mA. Applying >8.61V without current limiting risks thermal runaway; safe operation requires series resistance to limit I_Z within 500mW derating limits.

Can this diode be used in forward-bias mode?

Yes - it conducts with 1.1V forward voltage at 200mA, per datasheet specifications. However, its primary design intent is reverse-bias Zener regulation; forward use is limited to low-duty-cycle protection or indicator roles, not power rectification.

How does the +0.062%/°C temperature coefficient impact circuit accuracy?

This coefficient means V_Z increases by 0.062% per °C rise - e.g., +5.1mV/°C at 8.2V. Over a 50°C range (−25°C to +25°C), total drift is ~±0.25V. For high-accuracy systems, this must be modeled or compensated using complementary TC elements.