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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Nexperia USA Inc. PZU51B2AX

Name: PZU51B2AX
Brand: Nexperia USA Inc.
SKU: PZU51B2AX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PZU51B2AX

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

Package:: -

Datasheet:: PZU51B2AX.pdf

Description:: PZU51B2A/SOD323/SOD2

Quantity:: RFQ Add To RFQ list

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Inventory:9,576

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Product details

Overview

PZU51B2AX from Nexperia is a precision Zener voltage regulator diode in SOD323 (SC-76) package, designed for stable 51 V reference and overvoltage clamping in low-power analog circuits. It delivers ±2 % tolerance (B2 series), 40 W non-repetitive peak reverse power dissipation, and 320 mW total power dissipation at 25 °C ambient, with typical differential resistance of 400 Ω at I_Z = 2 mA and reverse current ≤180 nA at V_R = 36 V.

For engineers reviewing the PZU51B2AX datasheet, PZU51B2AX pinout, PZU51B2AX application, or PZU51B2AX equivalent, this device is selected for high-accuracy voltage referencing in sensor signal conditioning, industrial power supply feedback loops, and ESD-protected interface rails where tight regulation and low leakage are critical.

Technical Context

This Zener operates in reverse breakdown mode with a nominal working voltage of 51 V at I_Z = 2 mA, exhibiting a temperature coefficient of +0.4 mV/K - indicating positive thermal drift optimized for stable biasing across temperature. Its differential resistance remains below 400 Ω under rated test conditions, ensuring minimal output voltage variation with load current changes.

The device uses a planar silicon process in a hermetically sealed plastic SOD323 package, supporting surface-mount reflow and wave soldering per JEDEC standards. Thermal resistance from junction to ambient is 390 K/W on standard FR4 PCB, enabling reliable operation up to 150 °C junction temperature under defined mounting conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Working Voltage (V_Z)	51 V nominal at I_Z = 2 mA; defines precise clamping/reference point in feedback or protection circuits
Tolerance	±2 % (B2 series); enables tighter regulation than ±5 % variants, reducing system calibration burden
Differential Resistance (r_dif)	≤400 Ω at I_Z = 2 mA; ensures <100 mV output shift per 0.25 mA load change in reference applications
Reverse Current (I_R)	≤180 nA at V_R = 36 V; minimizes standby power loss and leakage-induced offset in high-impedance nodes
Non-repetitive Peak Power (P_ZSM)	40 W at t_p = 100 µs; supports transient surge suppression without failure in short-duration overvoltage events
Total Power Dissipation (P_tot)	320 mW at T_amb ≤ 25 °C on FR4 PCB; sets continuous DC power limit for thermal design in compact layouts
Junction Temperature (T_j)	−55 °C to +150 °C; allows deployment in extended industrial environments without derating below −40 °C

Pinout & Package

Package: SOD323 (SC-76), surface-mounted plastic case measuring 1.7 mm × 1.25 mm × 0.95 mm with 1.3 mm lead pitch and cathode-marked top surface.

Pin/Terminal	Circuit Role	Design Meaning
1	Cathode	Connected to regulated output or voltage reference node; marking bar identifies this terminal
2	Anode	Connected to ground or lower-potential rail; reverse-biased configuration enables Zener operation

Key Features

Feature	Design Value
±2 % voltage tolerance (B2)	Reduces post-production trimming needs in precision voltage references and analog front-ends
Low reverse leakage (≤180 nA)	Preserves accuracy in high-impedance sensing paths and battery-powered monitoring circuits
Optimized fast switching & noise reduction	Intentional minor leakage rise improves transient response and reduces broadband noise in regulation loops
SOD323 footprint compatibility	Enables drop-in replacement in space-constrained designs using industry-standard 0805-equivalent layout
JEDEC-compliant reflow profile support	Validated for standard Pb-free reflow (J-STD-020), simplifying manufacturing integration

Applications

Industrial Sensor Signal Conditioning

Programmable Logic Controller (PLC) Input Protection

Use Scenario: Stabilizing reference voltage for 4–20 mA transmitter analog-to-digital conversion stages.

IC Role / Device Role / Timing Role: Zener diode providing fixed 51 V reference for op-amp biasing and ADC full-scale calibration.

Use Value: ±2 % tolerance and low 180 nA leakage ensure <0.1 % full-scale error contribution across −40 °C to +85 °C operating range.

Use Scenario: Clamping input transients on 24 V DC digital I/O channels exposed to inductive kickback.

IC Role / Device Role / Timing Role: Reverse-biased Zener acting as overvoltage protector upstream of optocoupler input circuitry.

Use Value: 40 W non-repetitive surge rating absorbs 100 µs spikes up to 80 V without degradation, preserving channel integrity.

Medical Instrumentation Reference Supply

Automotive Body Control Module (BCM) Interface Rail

Use Scenario: Generating stable bias for low-noise instrumentation amplifiers in portable ECG front-ends.

IC Role / Device Role / Timing Role: Precision shunt regulator establishing clean 51 V auxiliary rail for analog signal chain components.

Use Value: Optimized leakage/noise trade-off per AN90031 reduces RMS noise floor by >3 dB versus standard ±5 % Zeners.

Use Scenario: Protecting LIN bus transceiver inputs against load dump surges in 12 V vehicle subsystems.

IC Role / Device Role / Timing Role: Standby Zener clamp limiting voltage excursion to 51 V during ISO 7637-2 Pulse 1/2a events.

Use Value: SOD323 package enables placement directly at connector entry point, minimizing parasitic inductance and improving clamping speed.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C51	±5 % tolerance, higher r_dif (≤600 Ω), 300 mW P_tot, SOT23 package	Lower accuracy and larger footprint; suitable only where cost outweighs precision	Select when board space permits SOT23 and ±5 % regulation suffices for non-critical rails
MMSZ5257B	±5 % tolerance, 500 mW P_tot, 350 Ω r_dif, SOD123 package	Higher power rating but looser tolerance and larger body (2.7 mm × 1.6 mm)	Choose for higher continuous dissipation needs where 51 V reference stability is secondary to thermal margin

Compared with BZX84-C51 and MMSZ5257B, PZU51B2AX provides superior voltage accuracy (±2 % vs. ±5 %), smaller SOD323 footprint, and purpose-tuned leakage/noise behavior-making it optimal for high-fidelity analog references and compact transient protection where precision matters.

Availability

PZU51B2AX is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, PLC input protection, medical instrumentation reference supplies, and automotive BCM interface rails requiring stable component supply with guaranteed long-term continuity.

Supply support for PZU51B2AX 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, serving automotive, industrial, and consumer markets with robust, scalable solutions.

PZUxBA series belongs to Nexperia's general-purpose Zener regulator portfolio, engineered for precision voltage referencing and overvoltage clamping in space-constrained, thermally demanding applications across industrial and medical electronics.

FAQ

What is the maximum continuous reverse current the PZU51B2AX can sustain at 51 V?

The device does not specify a maximum continuous reverse current; instead, its safe operating limit is defined by total power dissipation (320 mW at 25 °C ambient). At 51 V, this corresponds to ~6.3 mA average Zener current on FR4 PCB. Exceeding this requires thermal derating per the R_th(j-a) = 390 K/W curve.

Does PZU51B2AX support lead-free reflow soldering?

Yes - PZU51B2AX is qualified for Pb-free reflow per J-STD-020, with peak temperature up to 260 °C. The SOD323 package and internal construction meet standard JEDEC moisture sensitivity level 1 requirements, eliminating pre-bake necessity for most assembly lines.

How does the B2 tolerance grade differ electrically from B1 or B3 in the same voltage bin?

Within the PZU51BA family, B1, B2, and B3 all denote ±2 % tolerance, differing only in marking code (e.g., PZU51B2AX uses "X" marking per Table 4). No electrical performance distinction exists between these sub-series - they share identical V_Z, r_dif, I_R, and thermal specs.

Can PZU51B2AX be used in series or parallel configurations for higher voltage or current handling?

No - Zener diodes must not be paralleled due to mismatched breakdown characteristics causing current hogging and thermal runaway. For higher voltage, use cascaded single devices with balancing resistors; for higher current, select a higher-power Zener (e.g., PZU51B2A in SOD123) or active regulation instead.

PZU51B2AX Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: -

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: -

Tolerance:: -

Power - Max:: -

Impedance (Max) (Zzt):: -

Current - Reverse Leakage @ Vr:: -

Voltage - Forward (Vf) (Max) @ If:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

PZU51B2AX FAQ

1.How can I place an order for PZU51B2AX through Aetrix?

Please submit a Request for Quotation (RFQ) for PZU51B2AX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PZU51B2AX reliable?

The price and inventory of PZU51B2AX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PZU51B2AX is usually 5 days.

3.What payment methods are accepted for PZU51B2AX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PZU51B2AX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PZU51B2AX?

PZU51B2AX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PZU51B2AX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PZU51B2AX?

For technical support, including PZU51B2AX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PZU51B2AX requirements.

6.How does Aetrix verify that PZU51B2AX is sourced from the original manufacturer or authorized distributors?

All PZU51B2AX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PZU51B2AX meets industry standards.

7.What is the process for return or replacement of PZU51B2AX?

All PZU51B2AX units undergo pre-shipment inspection (PSI). If there is an issue with PZU51B2AX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PZU51B2AX part is unused and in its original packaging.

Return procedure for PZU51B2AX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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