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

onsemi SZMMSZ5221BT1G

Name: SZMMSZ5221BT1G
Brand: onsemi
SKU: SZMMSZ5221BT1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SZMMSZ5221BT1G

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: SOD-123

Datasheet:: SZMMSZ5221BT1G.pdf

Description:: DIODE ZENER 2.4V 500MW SOD123

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Product details

Overview

SZMMSZ5221BT1G from onsemi is a 2.4 V ±5% Zener diode in SOD−123 package, rated for 500 mW power dissipation at 75°C ambient, with 1200 Ω maximum dynamic impedance at 20 mA test current and 0.25 μA leakage at 100 V reverse bias. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.

For engineers reviewing the SZMMSZ5221BT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 2.4 V nominal Zener voltage, ±5% tolerance, thermal equilibrium–specified V_Z, 150°C max junction temperature, and AEC−Q101 qualification for automotive use.

Technical Context

This device operates as a two-terminal voltage regulator diode, conducting in reverse breakdown to maintain stable voltage across its terminals when biased above V_Z. Its Zener voltage is specified under thermal equilibrium conditions (T_L = 30°C ±1°C), ensuring repeatable calibration independent of transient self-heating.

It features Class 3 ESD robustness (>16 kV HBM), Pb−free construction, and UL 94 V−0 flammability rating. The SOD−123 package supports automated assembly and delivers 340°C/W junction-to-ambient thermal resistance on FR−5 board.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	2.4 V nominal, 2.28–2.52 V range at I_ZT = 20 mA - defines stable regulation point for low-voltage reference designs
Power Dissipation (P_D)	500 mW on FR−5 board at T_L = 75°C - sets maximum continuous power handling before thermal derating applies
Zener Impedance (Z_ZT)	1200 Ω max at I_ZT = 20 mA - indicates voltage regulation stability under load variation
Leakage Current (I_R)	0.25 μA max at V_R = 100 V - ensures minimal standby current in high-impedance bias networks
Junction Temperature Range	−55°C to +150°C - enables operation in under-hood automotive and industrial environments
ESD Rating	Class 3 (>16 kV) per HBM - provides robustness against handling and system-level electrostatic discharge events
AEC−Q101 Qualified	Yes - confirms suitability for automotive electronics requiring qualified reliability and traceable manufacturing controls

Pinout & Package

SOD−123 surface-mount plastic package (Case 425, Style 1), dimensions 1.60 × 2.69 × 1.16 mm, cathode indicated by polarity band. Designed for high-density PCB layouts and reflow-compatible assembly.

Pin/Terminal	Circuit Role	Design Meaning
1 (Cathode)	Reverse-biased terminal during Zener operation	Connected to higher potential node to enable breakdown conduction; polarity band identifies this terminal
2 (Anode)	Forward-biased terminal during Zener operation	Connected to lower potential node; forward voltage ≤0.95 V at 10 mA enables use as clamp or level shifter

Key Features

Feature	Design Value
500 mW power rating on FR−5 board	Enables reliable voltage regulation in space-constrained, low-power analog circuits without active cooling
±5% Zener voltage tolerance	Supports cost-sensitive applications where tight voltage accuracy is not required but repeatability matters
Thermal equilibrium–specified V_Z	Ensures consistent Zener voltage measurement across production lots and operating conditions
AEC−Q101 qualification and PPAP capability	Meets automotive supply chain requirements for documentation, traceability, and process control
ESD robustness >16 kV (HBM)	Reduces need for external protection in handheld, sensor, and interface circuits exposed to user handling

Applications

Automotive Sensor Biasing	Industrial Analog Signal Clamping
Use Scenario: Providing stable 2.4 V reference for MEMS pressure sensor bridge excitation in engine control modules. IC Role / Device Role / Timing Role: Zener diode acting as precision shunt voltage reference, regulating bias voltage despite battery voltage fluctuations (9–16 V). Use Value: Maintains sensor output linearity and offset stability over −40°C to +125°C ambient, leveraging AEC−Q101 qualification and 150°C junction rating.	Use Scenario: Clamping op-amp input to prevent damage from transient overvoltage in 4–20 mA loop receivers. IC Role / Device Role / Timing Role: Two-terminal shunt protector limiting input voltage to ≤2.52 V, protecting downstream amplifier inputs. Use Value: Low leakage (0.25 μA @ 100 V) avoids loading high-impedance feedback networks; SOD−123 footprint minimizes PCB area.
Consumer Battery Monitoring	Medical Instrument Reference
Use Scenario: Monitoring Li-ion cell voltage via resistive divider with 2.4 V Zener clamp to protect ADC input. IC Role / Device Role / Timing Role: Overvoltage clamp placed across ADC input to absorb surge energy exceeding full-scale range. Use Value: 1200 Ω Z_ZT ensures predictable clamping voltage shift under fault current; Pb−free and RoHS-compliant construction meets consumer safety standards.	Use Scenario: Generating stable 2.4 V reference for precision thermistor readout in portable patient monitors. IC Role / Device Role / Timing Role: Shunt voltage reference establishing known bias point for ratiometric analog front-end measurements. Use Value: Thermal equilibrium specification guarantees <±0.1% V_Z drift between calibration and field operation, critical for clinical-grade accuracy.

Automotive Sensor Biasing

Industrial Analog Signal Clamping

Use Scenario: Providing stable 2.4 V reference for MEMS pressure sensor bridge excitation in engine control modules.

IC Role / Device Role / Timing Role: Zener diode acting as precision shunt voltage reference, regulating bias voltage despite battery voltage fluctuations (9–16 V).

Use Value: Maintains sensor output linearity and offset stability over −40°C to +125°C ambient, leveraging AEC−Q101 qualification and 150°C junction rating.

Use Scenario: Clamping op-amp input to prevent damage from transient overvoltage in 4–20 mA loop receivers.

IC Role / Device Role / Timing Role: Two-terminal shunt protector limiting input voltage to ≤2.52 V, protecting downstream amplifier inputs.

Use Value: Low leakage (0.25 μA @ 100 V) avoids loading high-impedance feedback networks; SOD−123 footprint minimizes PCB area.

Consumer Battery Monitoring

Medical Instrument Reference

Use Scenario: Monitoring Li-ion cell voltage via resistive divider with 2.4 V Zener clamp to protect ADC input.

IC Role / Device Role / Timing Role: Overvoltage clamp placed across ADC input to absorb surge energy exceeding full-scale range.

Use Value: 1200 Ω Z_ZT ensures predictable clamping voltage shift under fault current; Pb−free and RoHS-compliant construction meets consumer safety standards.

Use Scenario: Generating stable 2.4 V reference for precision thermistor readout in portable patient monitors.

IC Role / Device Role / Timing Role: Shunt voltage reference establishing known bias point for ratiometric analog front-end measurements.

Use Value: Thermal equilibrium specification guarantees <±0.1% V_Z drift between calibration and field operation, critical for clinical-grade accuracy.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMSZ5221BT1G	No SZ prefix; not AEC−Q101 qualified; identical electrical specs and SOD−123 package	Intended for commercial/industrial use only; lacks automotive change control and PPAP documentation	Select when automotive qualification is unnecessary and cost sensitivity is higher
BZX84-C2V4LT1G	Same 2.4 V ±5%, SOT−23 package (larger footprint), 350 mW rating, 600 Ω Z_ZT at 5 mA	Better regulation at low current but lower power headroom; less suitable for sustained 20 mA operation	Select when lower dynamic impedance at light loads is prioritized over power capacity and automotive compliance

Compared with SZMMSZ5221BT1G, MMSZ5221BT1G offers identical regulation performance without automotive qualification overhead, while BZX84-C2V4LT1G trades higher Z_ZT stability at 20 mA for improved low-current regulation in SOT−23-making SZMMSZ5221BT1G optimal for automotive or high-reliability 20 mA reference applications.

Availability

SZMMSZ5221BT1G is available at Aetrix Electronics and suitable for automotive sensor biasing, industrial signal clamping, and medical instrument reference designs requiring stable component supply, long-term lifecycle support, and AEC−Q101 compliance.

Supply support for SZMMSZ5221BT1G 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

onsemi (Semiconductor Components Industries, LLC) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

SZMMSZ5221BT1G belongs to the SZMMSZ52xxxT1G series of AEC−Q101-qualified Zener diodes designed specifically for automotive electronics requiring enhanced reliability, traceability, and thermal stability in harsh environments.

FAQ

What is the nominal Zener voltage and tolerance of SZMMSZ5221BT1G?

The SZMMSZ5221BT1G has a nominal Zener voltage of 2.4 V with a ±5% tolerance, meaning its actual breakdown voltage falls between 2.28 V and 2.52 V when measured at I_ZT = 20 mA under thermal equilibrium conditions (T_L = 30°C ±1°C). This tolerance is confirmed in the onsemi datasheet's 5% tolerance electrical characteristics table.

Is SZMMSZ5221BT1G qualified for automotive applications?

Yes, SZMMSZ5221BT1G is AEC−Q101 qualified and PPAP capable, as explicitly stated in the onsemi datasheet under "Features". The "SZ" prefix denotes devices manufactured under automotive-specific site and process controls, making SZMMSZ5221BT1G suitable for under-hood and safety-critical vehicle systems.

What is the maximum power dissipation of SZMMSZ5221BT1G and how does it derate with temperature?

SZMMSZ5221BT1G is rated for 500 mW total power dissipation on FR−5 board at lead temperature (T_L) = 75°C. Above 75°C, it derates linearly at 6.7 mW/°C. This derating curve is defined in the Maximum Ratings table and validated per JEDEC JESD51 thermal test methods.

What package type and dimensions does SZMMSZ5221BT1G use?

SZMMSZ5221BT1G uses the SOD−123 surface-mount package (Case 425, Style 1), with mechanical dimensions of 1.60 mm × 2.69 mm × 1.16 mm. The cathode is marked by a polarity band, and the package is void-free, transfer-molded, and UL 94 V−0 rated, as documented in the Mechanical Characteristics section.

How does the Zener impedance of SZMMSZ5221BT1G affect its voltage regulation performance?

SZMMSZ5221BT1G has a maximum Zener impedance (Z_ZT) of 1200 Ω at I_ZT = 20 mA, which determines how much its regulated voltage changes with load current variation. Lower Z_ZT yields tighter regulation; this value is measured using 1 kHz AC signal at 10% of DC test current, per datasheet Note 5.

SZMMSZ5221BT1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: SZMMSZ52xxxT1G

Package/Case:: SOD-123

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 2.4 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 30 Ohms

Current - Reverse Leakage @ Vr:: 100 µA @ 1 V

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

Operating Temperature:: -55°C ~ 150°C

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOD-123

SZMMSZ5221BT1G FAQ

1.How can I place an order for SZMMSZ5221BT1G through Aetrix?

Please submit a Request for Quotation (RFQ) for SZMMSZ5221BT1G 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 SZMMSZ5221BT1G reliable?

The price and inventory of SZMMSZ5221BT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZMMSZ5221BT1G is usually 5 days.

3.What payment methods are accepted for SZMMSZ5221BT1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZMMSZ5221BT1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SZMMSZ5221BT1G?

SZMMSZ5221BT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SZMMSZ5221BT1G 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 SZMMSZ5221BT1G?

For technical support, including SZMMSZ5221BT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZMMSZ5221BT1G requirements.

6.How does Aetrix verify that SZMMSZ5221BT1G is sourced from the original manufacturer or authorized distributors?

All SZMMSZ5221BT1G 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 SZMMSZ5221BT1G meets industry standards.

7.What is the process for return or replacement of SZMMSZ5221BT1G?

All SZMMSZ5221BT1G units undergo pre-shipment inspection (PSI). If there is an issue with SZMMSZ5221BT1G, 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 SZMMSZ5221BT1G part is unused and in its original packaging.

Return procedure for SZMMSZ5221BT1G:

1.Submit a request within 90 days.

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

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