onsemi BZX55C3V0_T50R

Overview

BZX55C3V0_T50R from Fairchild Semiconductor is a 3.0 V ±5% tolerance silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 85 Ω dynamic impedance at 5 mA test current and 4 μA reverse leakage at 1.0 V reverse voltage. It serves as a precision voltage reference or overvoltage clamp in low-power analog and power supply feedback circuits.

For engineers reviewing the BZX55C3V0_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, cathode identification via color band, and compatibility with through-hole PCB assembly for stable voltage regulation in cost-sensitive industrial controls.

Technical Context

The BZX55C3V0_T50R operates as a two-terminal voltage-reference device relying on controlled reverse-biased avalanche breakdown. Its 3.0 V nominal zener voltage is specified at 5 mA test current (IZ), with guaranteed min/max limits of 2.8 V and 3.2 V under standard conditions (Ta = 25°C).

Thermal performance is defined by a 4.0 mW/°C linear derating above 75°C lead temperature, and it supports operation across –65°C to +200°C junction and storage temperature range. Reverse leakage remains ≤4 μA at VR = 1.0 V, confirming tight low-voltage regulation capability.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode identified by a single black color band; leads are tinned copper alloy, suitable for wave or hand soldering. No polarity reversal - cathode must be connected to higher potential for zener operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4728A and BZX55C3V3_T50R, the BZX55C3V0_T50R offers the only 3.0 V option in the DO-35 form factor among Fairchild's BZX55C series, making it essential for designs requiring exact 3.0 V regulation with space-constrained through-hole layouts.

Availability

BZX55C3V0_T50R is available at Aetrix Electronics and suitable for industrial power supplies, embedded sensor interfaces, and legacy equipment repair requiring stable component supply with full traceability and long-lifecycle support.

Supply support for BZX55C3V0_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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.

The BZX55C series was developed as a general-purpose, cost-optimized Zener diode family targeting voltage reference and protection functions in consumer, industrial, and computing power systems.

FAQ

What is the exact zener voltage tolerance for BZX55C3V0_T50R?

The BZX55C3V0_T50R has a guaranteed zener voltage range of 2.8 V to 3.2 V at 5 mA test current and 25°C ambient, corresponding to a ±5% tolerance about the nominal 3.0 V rating. This tolerance is maintained across the full operating temperature range per the manufacturer's characterization data, and no additional binning or sorting is required to achieve this specification.

Can BZX55C3V0_T50R be used in surface-mount designs?

No - the BZX55C3V0_T50R uses a DO-35 glass axial package with radial leads intended for through-hole mounting. It is not compatible with SMT reflow or pick-and-place processes. For surface-mount equivalents, consider SOD-123 or SOD-323 packaged Zeners such as MMBZ5222BS, but note that voltage, impedance, and thermal characteristics differ significantly from the BZX55C3V0_T50R.

What is the maximum allowable reverse voltage before breakdown for BZX55C3V0_T50R?

The BZX55C3V0_T50R exhibits ≤4 μA reverse leakage current at VR = 1.0 V, and its sharp zener breakdown begins near 2.8 V. Therefore, the maximum recommended reverse voltage prior to entering regulation is 1.0 V - exceeding this risks premature conduction or increased leakage, especially at elevated temperatures. Always maintain VR < VZ(min) in non-regulating roles.

How does thermal derating affect BZX55C3V0_T50R's power handling?

BZX55C3V0_T50R's 500 mW power rating applies only when lead temperature (TL) is ≤75°C. Above that, power must be reduced linearly at 4.0 mW/°C. At TL = 100°C, for example, allowable power drops to 400 mW. Designers must calculate actual lead temperature under real PCB copper area and airflow conditions to avoid junction overheating and parametric shift.

Is BZX55C3V0_T50R suitable for automotive applications?

The BZX55C3V0_T50R supports an operating temperature range of –65°C to +200°C and meets JEDEC JESD22-A108 reliability standards per Fairchild's qualification. While not AEC-Q200 certified, its extended temperature capability and DO-35 hermeticity make it suitable for under-dash or engine-compartment-adjacent non-safety-critical subsystems - however, formal automotive qualification requires validation per AEC-Q200 Rev D by the end customer.