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

Nexperia USA Inc. BZX84-B51,215

Name: BZX84-B51,215
Brand: Nexperia USA Inc.
SKU: BZX84-B51,215
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX84-B51,215

Manufacturer:: Nexperia USA Inc.

Category:: Single Zener Diodes

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BZX84-B51,215.pdf

Description:: DIODE ZENER 51V 250MW TO236AB

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BZX84-B51,215 from Nexperia is a ±2 % tolerance Zener voltage regulator diode in SOT23 (TO-236AB) package, rated for 51 V nominal breakdown voltage at I_Z = 5 mA, with 250 mW total power dissipation and 40 W non-repetitive peak reverse power capability. It serves as a precision reference or overvoltage clamp in low-power analog signal conditioning and power rail stabilization circuits.

For engineers reviewing the BZX84-B51,215 datasheet, BZX84-B51,215 pinout, BZX84-B51,215 application, or BZX84-B51,215 equivalent, key selection considerations include its 51 V Zener voltage tolerance (±2 %), differential resistance of 400 Ω at I_Z = 5 mA, temperature coefficient of +0.05 mV/K, reverse current ≤0.2 μA at V_R = 38.8 V, and thermal resistance of 330 K/W junction-to-solder-point.

Technical Context

This device operates as a two-terminal shunt voltage regulator, maintaining stable output voltage across a load by conducting reverse current when input exceeds its specified Zener voltage. Its behavior is defined by sharp reverse breakdown at 51 V with low dynamic impedance (400 Ω typical) and minimal temperature drift (+0.05 mV/K).

The diode exhibits low forward voltage drop (≤0.9 V at 10 mA), supports surge handling up to 40 W for 100 μs pulses, and is characterized for operation from −55 °C to +150 °C ambient. Thermal performance relies on PCB copper area, with R_th(j-a) = 500 K/W in free air and R_th(j-sp) = 330 K/W to cathode solder point.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage V_Z	51 V nominal at I_Z = 5 mA; ±2 % tolerance ensures regulation within 49.98 V–52.02 V under standard test conditions
Differential Resistance r_dif	400 Ω max at I_Z = 5 mA; defines small-signal AC impedance affecting regulation stability under varying load
Reverse Current I_R	≤0.2 μA at V_R = 38.8 V; confirms low leakage below breakdown, critical for high-impedance bias networks
Temperature Coefficient S_Z	+0.05 mV/K at I_Z = 5 mA; indicates near-zero drift over temperature, enabling stable references in industrial environments
Total Power Dissipation P_tot	250 mW at T_amb ≤ 25 °C on FR4 PCB; sets maximum continuous DC power handling before thermal derating applies
Non-repetitive Peak Power P_ZSM	40 W for t_p = 100 μs; enables transient overvoltage suppression without failure during short-duration surges
Junction Temperature T_j	150 °C max; defines upper thermal limit for reliable long-term operation under sustained power stress

Pinout & Package

Package: SOT23 (TO-236AB), surface-mount plastic package with 3 leads; dimensions per Figure 11 (1.9 mm × 1.1 mm × 1.0 mm height); optimized for reflow and wave soldering per Figures 12–13.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode (A)	Connected to lower-potential side of regulated node; reverse-biased during Zener operation
2	Not Connected (n.c.)	Internal die pad with no electrical connection; must remain unconnected on PCB to avoid parasitic coupling
3	Cathode (K)	Connected to higher-potential side; carries reverse current during regulation; primary thermal path to PCB

Key Features

Feature	Design Value
±2 % Zener voltage tolerance	Enables tighter regulation than ±5 % variants (BZX84-C series), reducing need for post-regulation trimming in mid-precision applications
250 mW power rating in SOT23	Delivers usable regulation headroom in space-constrained designs where larger packages (e.g., DO-35) are impractical
40 W surge capability	Withstands common ESD and line-transient events without degradation, eliminating need for external TVS in many 51 V rail protection schemes
+0.05 mV/K temperature coefficient	Minimizes output drift over −55 °C to +150 °C, supporting stable references in automotive under-hood and industrial control environments
Low 0.2 μA reverse leakage at 38.8 V	Preserves accuracy in high-impedance divider networks and battery-powered sensor interfaces where quiescent current matters

Applications

Industrial Sensor Signal Conditioning

5 V Microcontroller Power Rail Clamp

Use Scenario: Stabilizing reference voltage for 12-bit ADC inputs measuring 4–20 mA loop signals in PLC analog input modules.

IC Role / Device Role / Timing Role: Shunt regulator providing 51 V reference for op-amp gain-setting resistors and isolated feedback dividers.

Use Value: ±2 % tolerance and +0.05 mV/K TC ensure <0.1 % full-scale error contribution over −25 °C to +70 °C operating range.

Use Scenario: Protecting 5 V supply pins of STM32F4 microcontrollers against accidental 12 V backfeed from connected peripherals.

IC Role / Device Role / Timing Role: Overvoltage clamp limiting rail excursion to 51 V during fault conditions, preventing latch-up or gate oxide damage.

Use Value: 40 W surge rating absorbs 100 μs transients exceeding 20 V without degradation, extending system field life.

Automotive Body Control Module Reference

Telecom Line Interface Protection

Use Scenario: Generating stable bias for CAN transceiver common-mode voltage circuitry in non-automotive-qualified BCM prototypes.

IC Role / Device Role / Timing Role: Precision Zener reference establishing 2.5 V virtual ground via resistor divider from 51 V source.

Use Value: 400 Ω differential resistance ensures <10 mV output shift under 100 μA load variation, meeting ISO 11898-2 common-mode stability requirements.

Use Scenario: Secondary clamping stage in PoE-powered Ethernet switch PHY interface, downstream of primary MOV protection.

IC Role / Device Role / Timing Role: Fast-acting shunt limiter suppressing residual surges above 38.8 V after primary protection has activated.

Use Value: 0.2 μA leakage at 38.8 V prevents false triggering of upstream current-limiting circuits during normal 48 V PoE operation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ON Semiconductor MMBZ5257BS-7-F	51 V, ±5 % tolerance, 225 mW P_tot, 300 Ω r_dif, −2.5 mV/K TC	Higher tempco causes ~12 mV drift over 100 °C span vs. BZX84-B51's ~5 mV	Select when cost sensitivity outweighs tempco and tolerance requirements; verify thermal design for lower P_tot
Vishay BZX84-C51-TP	51 V, ±5 % tolerance, 300 mW P_tot, 400 Ω r_dif, +0.05 mV/K TC	Wider tolerance increases worst-case regulation spread to ±2.55 V but higher P_tot allows greater continuous dissipation	Select when higher power margin is needed and ±5 % voltage uncertainty is acceptable in the application

Compared with MMBZ5257BS-7-F and BZX84-C51-TP, BZX84-B51,215 offers superior voltage accuracy (±2 % vs. ±5 %) and identical temperature stability, making it optimal for mid-precision references where tight initial tolerance matters more than absolute power headroom.

Availability

BZX84-B51,215 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, microcontroller power rail clamping, automotive body control module reference, and telecom line interface protection requiring stable component supply and consistent parametric performance across production batches.

Supply support for BZX84-B51,215 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 delivering high-performance logic, discrete, and MOSFET devices with focus on efficiency, reliability, and miniaturization for consumer, industrial, and automotive markets.

The BZX84 series belongs to Nexperia's precision Zener regulator portfolio, engineered for low-power voltage reference and overvoltage protection in space-constrained SMT designs where ±1 % to ±5 % tolerance grades meet diverse cost–performance trade-offs.

FAQ

What is the maximum continuous reverse current the BZX84-B51,215 can sustain at 25 °C ambient?

The device does not specify a maximum continuous reverse current independent of voltage. At its nominal 51 V Zener voltage and 250 mW power rating, the theoretical steady-state current is 4.9 mA (250 mW ÷ 51 V). However, actual operating current depends on circuit impedance and must stay within the 200 mA absolute maximum forward current limit per Table 5 - though Zener operation occurs in reverse bias, this rating constrains surge survivability and packaging integrity.

Can the BZX84-B51,215 be used in place of a BZX84-A51 for higher-precision applications?

No - the BZX84-A51 offers ±1 % tolerance (50.49–51.51 V), while the BZX84-B51 provides ±2 % (49.98–52.02 V). Substituting B into an A-design risks exceeding voltage error budgets in applications requiring <1 % regulation accuracy, such as precision DAC references or metrology front-ends. The differential resistance and temperature coefficient are nearly identical, but initial tolerance is the decisive differentiator.

How does the "n.c." pin (Pin 2) affect PCB layout and thermal design?

Pin 2 is internally unconnected and must remain floating on the PCB - no trace or copper pour should contact it. Doing so introduces parasitic capacitance and potential leakage paths that degrade reverse leakage specs. Thermally, it isolates the die from that lead; heat flows primarily through Pins 1 (anode) and 3 (cathode), with Pin 3 being the dominant thermal path to the board per R_th(j-sp) = 330 K/W specification.

Is the BZX84-B51,215 qualified for automotive applications per AEC-Q101?

No - per Section 13 Revision History and Legal Information, this revision explicitly states "Products changed to non-automotive qualification" and directs users to Nexperia's automotive-qualified −Q variants for AEC-Q101-compliant designs. The BZX84-B51,215 lacks automotive-grade screening, qualification testing, and guaranteed PPAP documentation required for under-hood or safety-critical vehicle systems.

BZX84-B51,215 Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: BZX84

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 51 V

Tolerance:: ±2%

Power - Max:: 250 mW

Impedance (Max) (Zzt):: 180 Ohms

Current - Reverse Leakage @ Vr:: 50 nA @ 35.7 V

Voltage - Forward (Vf) (Max) @ If:: 900 mV @ 10 mA

Operating Temperature:: -65°C ~ 150°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BZX84-B51,215 FAQ

1.How can I place an order for BZX84-B51,215 through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX84-B51,215 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 BZX84-B51,215 reliable?

The price and inventory of BZX84-B51,215 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84-B51,215 is usually 5 days.

3.What payment methods are accepted for BZX84-B51,215?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84-B51,215 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX84-B51,215?

BZX84-B51,215 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX84-B51,215 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 BZX84-B51,215?

For technical support, including BZX84-B51,215 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84-B51,215 requirements.

6.How does Aetrix verify that BZX84-B51,215 is sourced from the original manufacturer or authorized distributors?

All BZX84-B51,215 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 BZX84-B51,215 meets industry standards.

7.What is the process for return or replacement of BZX84-B51,215?

All BZX84-B51,215 units undergo pre-shipment inspection (PSI). If there is an issue with BZX84-B51,215, 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 BZX84-B51,215 part is unused and in its original packaging.

Return procedure for BZX84-B51,215:

1.Submit a request within 90 days.

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

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