Taiwan Semiconductor Corporation BZY55B11

Overview

BZY55B11 from Taiwan Semiconductor is a surface-mount Zener diode engineered for precision voltage regulation and reference applications, with a nominal Zener voltage of 11.00 V (±2%), 5 mA test current, 20 Ω dynamic impedance at IZT, 500 mW power dissipation, and operation across –55°C to +150°C junction temperature. It serves as a stable voltage reference in DC/DC converters and low-voltage adapter circuits.

For engineers reviewing the BZY55B11 datasheet, BZY55B11 pinout, BZY55B11 application, or BZY55B11 equivalent, key selection criteria include its ±2% VZ tolerance, 20 Ω Zener impedance at 5 mA, 0805 ceramic package footprint, cathode-band polarity marking, and suitability for space-constrained board-level stabilization where thermal resistance (RθJA = 300°C/W) and moisture sensitivity level 1 compliance are critical.

Technical Context

The BZY55B11 operates as a single-die, silicon planar Zener diode optimized for stable reverse-breakdown behavior under DC and pulsed conditions (10 ms pulse test). Its breakdown mechanism is controlled by avalanche multiplication above ~6 V, consistent with its 11 V nominal rating and 20 Ω Zener impedance at IZT.

It exhibits a leakage current ≤0.1 µA at VR = 8.2 V and forward voltage of 1.5 V at IF = 10 mA, enabling bidirectional circuit analysis in clamp/reference designs. The device meets JESD201 Class 1A whisker resistance and UL 94HB flammability requirements for high-reliability PCB assembly.

Key Specifications

Pinout & Package

Package: 0805 ceramic surface-mount case with cathode indicated by a visible band on one end; dimensions 2.00 ± 0.20 mm × 1.25 ± 0.20 mm × 0.75 ± 0.10 mm; weight ≈ 5.99 mg.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5240B and 1N4740A, the BZY55B11 offers tighter ±2% tolerance and 0805 SMD compatibility at 500 mW - making it optimal for production-grade, space-constrained, precision-regulated rails where traceability and JEDEC-compliant assembly are required.

Availability

BZY55B11 is available at Aetrix Electronics and suitable for low-voltage stabilizers, on-board DC/DC converters, and adapter designs requiring stable component supply, RoHS compliance, and moisture-insensitive SMD packaging.

Supply support for BZY55B11 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, rectifiers, Zener diodes, and TVS components for industrial and consumer markets.

The BZY55 series is part of TSC's precision Zener portfolio designed specifically for surface-mount voltage reference and shunt regulation in space-constrained, high-volume applications demanding tight tolerances and J-STD-020 compliance.

FAQ

What is the Zener voltage tolerance for BZY55B11?

The BZY55B11 has a Zener voltage tolerance of ±2%, with a specified range of 10.78 V to 11.22 V at 5 mA test current. This tight tolerance is confirmed in the Electrical Specifications table of the official Taiwan Semiconductor datasheet (Version D2301) and enables high-accuracy voltage referencing without calibration. The BZY55B11 maintains this tolerance across its qualified operating temperature range.

What is the maximum power dissipation of BZY55B11?

The BZY55B11 has a maximum power dissipation (PD) of 500 mW at TA = 25°C, as stated in the Absolute Maximum Ratings section. Derating is required above 25°C ambient, following the admissible power dissipation curve in the datasheet, with a junction-to-ambient thermal resistance (RθJA) of 300°C/W. This rating applies to the 0805 ceramic package under standard PCB copper area conditions.

Does BZY55B11 have moisture sensitivity level (MSL) classification?

Yes, the BZY55B11 is rated at Moisture Sensitivity Level 1 per J-STD-020, meaning it can be stored indefinitely at ≤30°C/60% RH without baking prior to reflow soldering. This eliminates floor-life restrictions and simplifies SMT line integration - a key advantage over MSL2+ Zener diodes that require dry-packaging and time-bound assembly.

What is the Zener impedance of BZY55B11 and why does it matter?

The BZY55B11 has a Zener impedance (ZZT) of 20 Ω at IZT = 5 mA. This value reflects the dynamic resistance in the breakdown region and directly impacts regulation accuracy under varying load currents - lower ZZT means less output voltage deviation. At 20 Ω, the BZY55B11 provides superior regulation stability compared to higher-impedance alternatives like the 1N4740A (20 Ω typical but ±5% VZ).

Is BZY55B11 RoHS compliant and lead-free?

Yes, the BZY55B11 is RoHS compliant and lead-free, as explicitly stated in the Features section of the Taiwan Semiconductor datasheet. It meets EU Directive 2011/65/EU requirements and contains no restricted substances above threshold limits. The device uses lead-free terminations and halogen-free molding compound, supporting environmentally compliant manufacturing and end-of-life recycling.