onsemi 1N5249B_T50R

Overview

1N5249B_T50R from ON Semiconductor is a 19 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 25°C with 23 Ω dynamic impedance at 19 mA test current and 0.1 μA maximum reverse leakage at 14.25 V. It serves as a precision voltage reference or overvoltage clamp in low-power analog circuits, power supply feedback loops, and sensor signal conditioning stages.

For engineers reviewing the 1N5249B_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include its 19 V nominal Zener voltage, tight 5% tolerance, DO-35 hermetic glass package, -65°C to +200°C operating junction temperature range, and TC of +0.085 %/°C - critical for stable biasing in industrial temperature environments.

Technical Context

This device operates in reverse breakdown mode with a specified Zener voltage (V_Z) of 18.05 V (min) to 19.95 V (max) at I_Z = 19 mA, measured under thermal equilibrium at lead temperature 30°C ±1°C. Its 23 Ω dynamic impedance (Z_Z) ensures stable regulation under varying load currents.

The 1N5249B_T50R exhibits a positive temperature coefficient of +0.085 %/°C, indicating increasing V_Z with rising temperature - a key factor when designing temperature-compensated references or selecting complementary devices for curvature correction.

Key Specifications

Pinout & Package

DO-35 glass package: axial-leaded, hermetically sealed, cathode indicated by color band. Dimensions per JEDEC DO-204AH: body length 4.56 mm, body diameter 1.91 mm, lead diameter 0.46 mm, overall length ≥25.40 mm (T50).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5249B_T50R, 1N5249BRLG offers identical performance in tape-and-reel form for automated manufacturing, whereas BZX55C18 provides a lower-cost alternative with relaxed regulation accuracy and impedance - requiring revalidation of loop stability and temperature drift in feedback paths.

Availability

1N5249B_T50R is available at Aetrix Electronics and suitable for industrial power supplies, sensor interface modules, and embedded microcontroller protection circuits requiring stable component supply and long-term parametric consistency.

Supply support for 1N5249B_T50R 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

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

The 1N52xxB series was designed as a general-purpose, high-reliability Zener reference family targeting cost-sensitive yet thermally demanding applications - emphasizing DO-35 hermeticity, wide temperature operation, and consistent batch-to-batch V_Z distribution.

FAQ

What is the exact Zener voltage range for 1N5249B_T50R at 25°C?

The 1N5249B_T50R has a guaranteed Zener voltage range of 18.05 V (minimum) to 19.95 V (maximum) when tested at I_Z = 19 mA and thermal equilibrium at lead temperature 30°C ±1°C, per ON Semiconductor's 1N5221B–1N5263B Rev. 3 datasheet. This 5% tolerance window is verified during production screening and applies to every unit shipped as 1N5249B_T50R.

Does 1N5249B_T50R support wave soldering, and what are its thermal limits?

Yes, the 1N5249B_T50R's DO-35 glass package is qualified for wave soldering with a maximum lead temperature of +230°C for 10 seconds at 1/16 inch from case. Its operating junction temperature spans -65°C to +200°C, and it derates linearly at 4.0 mW/°C above 50°C ambient - allowing full 500 mW operation up to 50°C, then reduced power at higher temperatures.

How does the +0.085 %/°C temperature coefficient of 1N5249B_T50R affect circuit design?

The +0.085 %/°C TC means the 1N5249B_T50R's Zener voltage increases by approximately 16 mV per °C rise (0.085% × 19 V). This must be included in thermal error budgets for precision references; however, it also enables active compensation - e.g., pairing with a negative-TC Zener like 1N5230B (-0.03 %/°C) to construct a near-zero TC reference string in analog front-ends.

Can 1N5249B_T50R be used as a forward-biased diode, and what is its V_F specification?

Yes, the 1N5249B_T50R functions as a standard silicon diode in forward bias. Its forward voltage is specified as ≤1.2 V at I_F = 200 mA, consistent with typical PN-junction behavior. This characteristic supports dual-use roles - such as polarity protection in series with a load or as part of a simple ESD protection network - though its primary design intent remains reverse-bias Zener regulation.

Is there a RoHS-compliant version of 1N5249B_T50R, and how is it marked?

Yes, the RoHS-compliant version is designated 1N5249BRLG - identical electrically and physically to 1N5249B_T50R but supplied in tape-and-reel packaging with "LG" suffix denoting lead-free and RoHS compliance. The DO-35 package itself contains no restricted substances, and both variants meet JESD204 and IPC/JEDEC standards for green electronics manufacturing.