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onsemi BZX84C33LT3
- Part No.:
- BZX84C33LT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX84C33LT3.pdf
- Description:
- DIODE ZENER 33V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:7,900
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Product details
Overview
BZX84C33LT3 from onsemi is a 33 V, ±5% tolerance Zener diode in SOT-23 package, rated for 225 mW power dissipation at 25°C on FR-5 board, with 325 Ω dynamic impedance at 20 mA test current and 55 µA maximum reverse leakage at 24.8 V. It serves as a precision voltage reference or overvoltage clamp in low-power portable electronics.
For engineers reviewing the BZX84C33LT3 datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (33 V), tolerance (±5%), thermal resistance (556 °C/W), ESD rating (>16 kV HBM), and SOT-23 footprint compatibility with high-density PCB layouts.
Technical Context
This device operates in reverse-biased breakdown mode to maintain stable voltage across its cathode-anode terminals. Its Zener voltage is specified at three test currents (2 mA, 1 mA, and 10 mA), with temperature coefficient of +23.1 mV/°C - indicating positive drift above 6 V threshold.
The SOT-23 package features pin 1 (anode), pin 2 (no connection), and pin 3 (cathode), with void-free thermosetting plastic case rated UL 94 V-0 and maximum soldering temperature of 260°C for 10 seconds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage | 33 V nominal, 31–35 V range at 5 mA - defines clamping/reference level in regulation circuits |
| Power Dissipation | 225 mW on FR-5 board at 25°C - sets max continuous DC power before thermal derating begins |
| Zener Impedance | 325 Ω at 10 mA - determines AC voltage variation under dynamic load changes |
| Reverse Leakage | 55 µA max at 24.8 V - impacts quiescent current in battery-powered hold-up or sensing paths |
| Temperature Coefficient | +23.1 mV/°C - quantifies voltage drift per degree Celsius rise above 25°C ambient |
| Capacitance | 70 pF at 0 V, 1 MHz - affects high-frequency noise filtering and signal integrity in RF-adjacent nodes |
| ESD Rating | Class 3 (>16 kV HBM) - enables direct interface with exposed I/O without external protection |
Pinout & Package
SOT-23 surface-mount package (Case 318, Style 8), 3-terminal configuration with no internal connection on pin 2; polarity indicated by cathode band on package body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential node; reverse bias applied between pin 3 and pin 1 |
| 2 | No Connection | Internally unconnected; must remain floating - no PCB trace or pad required |
| 3 | Cathode | Connected to higher-potential node; Zener breakdown occurs when voltage at pin 3 exceeds pin 1 by ≥33 V |
Key Features
| Feature | Design Value |
|---|---|
| Pb-Free Compliant Packaging | RoHS-compliant SOT-23 construction meets global environmental compliance requirements without performance trade-offs |
| High-Density Mounting | Small outline (2.8 × 1.2 × 0.95 mm) enables placement in space-constrained mobile and wearable PCBs |
| Automated Assembly Optimized | Transfer-molded thermoset plastic case ensures reliable pick-and-place and reflow soldering yield |
| Stable High-Voltage Regulation | 33 V Zener point with tight ±5% tolerance supports accurate voltage monitoring in 3.3 V–5 V system rails |
| Robust ESD Immunity | Class 3 Human Body Model rating (>16 kV) eliminates need for discrete ESD protection in many I/O applications |
Applications
| USB Port Protection | Smartphone Power Monitoring |
|---|---|
Use Scenario: Clamping transient surges on USB D+ and D− lines during hot-plug events. IC Role / Device Role / Timing Role: Zener voltage regulator acting as shunt protector to limit line voltage to safe levels. Use Value: Prevents damage to USB transceivers by clamping spikes above 33 V while maintaining signal integrity below threshold. | Use Scenario: Monitoring battery voltage in lithium-ion powered handheld devices using resistive divider feedback. IC Role / Device Role / Timing Role: Precision voltage reference providing stable 33 V reference for ADC input scaling. Use Value: Enables accurate state-of-charge estimation with <±1% error over temperature due to known TC and tight tolerance. |
| IoT Sensor Node Voltage Clamp | Industrial PLC Input Conditioning |
Use Scenario: Protecting analog sensor inputs (e.g., temperature, humidity) from ESD and overvoltage events. IC Role / Device Role / Timing Role: Bidirectional transient suppressor leveraging Zener and forward diode characteristics. Use Value: Absorbs >16 kV HBM strikes without degradation, preserving sensor accuracy and long-term reliability. | Use Scenario: Level-shifting and clamping 24 V industrial control signals to 3.3 V microcontroller inputs. IC Role / Device Role / Timing Role: Interface protection device limiting input voltage to prevent MCU GPIO latch-up. Use Value: Maintains functional safety margin with 33 V standoff while allowing fast response to fault conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBZ5265BLT1 | 33 V nominal, ±5%, but rated 350 mW on FR-4 - higher power handling, different thermal profile | Preferred where board layout allows larger thermal relief or higher ambient temperatures exist | Select when >225 mW dissipation is needed; verify SOT-23 pinout match and derating curves |
| BZX84C33ET1G | Same electrical specs, but in Pb-free SOT-23 with "G" suffix - identical Zener parameters and package dimensions | Drop-in replacement where RoHS compliance is mandatory and tape/reel format aligns | Choose for new designs requiring documented Pb-free status; same footprint and performance as BZX84C33LT3 |
Compared with BZX84C33LT3, MMBZ5265BLT1 offers higher power capability but requires thermal redesign, while BZX84C33ET1G provides identical regulation performance with guaranteed Pb-free compliance - making it ideal for compliance-driven production ramp.
Availability
BZX84C33LT3 is available at Aetrix Electronics and suitable for USB protection, smartphone power monitoring, IoT sensor clamping, and industrial PLC input conditioning requiring stable component supply and consistent parametric performance.
Supply support for BZX84C33LT3 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 (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The BZX84C33LT3 belongs to the BZX84CxxxLT1 Zener regulator family, designed specifically for compact, high-reliability voltage reference and overvoltage protection in portable and space-constrained electronic systems.
FAQ
What is the Zener voltage tolerance of the BZX84C33LT3?
The BZX84C33LT3 has a nominal Zener voltage of 33 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 31 V and 35 V when tested at 5 mA. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official datasheet, and applies across the full operating temperature range of −65°C to +150°C.
Does the BZX84C33LT3 have a connected pin 2?
No, pin 2 of the BZX84C33LT3 is internally not connected (NC). The device uses only pins 1 (anode) and 3 (cathode) for operation. Pin 2 must remain unconnected on the PCB - no trace, via, or copper pour should be attached to it, as confirmed in the Package Dimensions diagram (page 7) and Electrical Characteristics notes.
What is the maximum reverse leakage current for the BZX84C33LT3?
The BZX84C33LT3 specifies a maximum reverse leakage current of 55 µA at VR = 24.8 V, measured at TA = 25°C. This value is listed in the Electrical Characteristics table under "Max Reverse Leakage Current" for the BZX84C33LT1 series. Leakage remains below this limit up to the rated junction temperature of +150°C.
Can the BZX84C33LT3 be used in place of the BZX84C33ET1G?
Yes, the BZX84C33LT3 and BZX84C33ET1G share identical Zener voltage, tolerance, impedance, leakage, and package dimensions. The only difference is the "G" suffix denoting guaranteed Pb-free construction in the latter. Both are SOT-23, pin-compatible, and electrically interchangeable - though BZX84C33ET1G is preferred where RoHS compliance documentation is required.
What is the thermal resistance junction-to-ambient for the BZX84C33LT3?
The BZX84C33LT3 has a thermal resistance of 556 °C/W when mounted on an FR-5 board, as specified in the Maximum Ratings table. This value assumes standard 1.0 × 0.75 × 0.62 inch board size and defines how much temperature rise occurs per milliwatt of dissipated power - critical for calculating safe operating area in continuous regulation applications.
BZX84C33LT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- BZX84CxxxLT1
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±6%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 23.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
BZX84C33LT3 FAQ
1.How can I place an order for BZX84C33LT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84C33LT3 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 BZX84C33LT3 reliable?
The price and inventory of BZX84C33LT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84C33LT3 is usually 5 days.
3.What payment methods are accepted for BZX84C33LT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84C33LT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84C33LT3?
BZX84C33LT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84C33LT3 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 BZX84C33LT3?
For technical support, including BZX84C33LT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84C33LT3 requirements.
6.How does Aetrix verify that BZX84C33LT3 is sourced from the original manufacturer or authorized distributors?
All BZX84C33LT3 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 BZX84C33LT3 meets industry standards.
7.What is the process for return or replacement of BZX84C33LT3?
All BZX84C33LT3 units undergo pre-shipment inspection (PSI). If there is an issue with BZX84C33LT3, 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 BZX84C33LT3 part is unused and in its original packaging.
Return procedure for BZX84C33LT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84C33LT3 Tags
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