My Inquiry
My Account
onsemi MMBZ5253B
- Part No.:
- MMBZ5253B
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5253B.pdf
- Description:
- DIODE ZENER 25V 350MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,042
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MMBZ5253B from Fairchild Semiconductor is a 25 V, 5% tolerance surface-mount Zener diode in SOT-23 package, rated for 350 mW power dissipation, with 35 Ω dynamic impedance at 1 mA test current and maximum 0.25 µA reverse leakage at 19 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMBZ5253B datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance, dynamic impedance at specified test current, power rating under ambient thermal conditions, reverse leakage at rated VR, and SOT-23 terminal compatibility with high-density PCB layouts.
Technical Context
The MMBZ5253B operates as a silicon planar Zener diode optimized for stable voltage reference and clamping in bias networks, feedback loops, and ESD-sensitive signal paths. Its 25 V nominal breakdown voltage is specified at IZ = 1 mA, with tight 5% tolerance and temperature coefficient of approximately +0.08%/°C near 25 °C.
Designed for operation up to +150 °C junction temperature, it maintains regulated output under low-current conditions (IZK = 0.25 mA) with ZZK = 5.0 Ω, enabling reliable performance in battery-powered sensors and portable instrumentation where quiescent current and thermal stability are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 25 V ±5% at IZ = 1 mA - defines precise clamping threshold for 24 V rail supervision and analog reference buffering |
| Dynamic Impedance (ZZ) | 35 Ω at IZ = 1 mA - determines regulation error under load transients in feedback divider networks |
| Reverse Leakage (IR) | 0.25 µA max at VR = 19 V - ensures minimal parasitic current draw in high-impedance bias chains |
| Power Dissipation (PD) | 350 mW at TA = 25 °C - sets maximum continuous power handling before thermal derating begins |
| Forward Voltage (VF) | ≤0.9 V at IF = 10 mA - supports use as low-drop rectifier or polarity protection diode in dual-role designs |
| Junction Temperature (TJ) | +150 °C max - enables deployment in automotive cabin modules and industrial controllers without forced cooling |
Pinout & Package
MMBZ5253B is housed in a standard SOT-23 plastic surface-mount package with three terminals: anode (Pin 1), cathode (Pin 2), and no-connect (Pin 3). Pin 3 is internally unconnected and must remain floating per manufacturer specification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connected to lower-potential node in reverse-biased Zener configuration; forward conduction path when used as rectifier |
| Pin 2 | Cathode | Connected to higher-potential node; Zener breakdown occurs between Pin 2 and Pin 1 when reverse biased |
| Pin 3 | No Connect (NC) | Internally isolated; must not be soldered or tied to any net to avoid parametric shift or failure |
Key Features
| Feature | Design Value |
|---|---|
| 5% Zener voltage tolerance | Enables accurate voltage thresholding in comparator reference inputs without external trimming |
| SOT-23 footprint | Supports automated placement and reflow in space-constrained consumer and IoT PCBs |
| 350 mW power rating | Permits direct integration into 3.3 V/5 V logic supply rails without external series resistor derating |
| 0.25 µA IR at 19 V | Minimizes loading on high-impedance sensor outputs and op-amp feedback nodes |
Applications
| Industrial Sensor Signal Conditioning | USB Port Overvoltage Protection |
|---|---|
Use Scenario: Stabilizing reference voltage for 12-bit ADC front-end in temperature/humidity transmitters operating from 3.3 V supply. IC Role / Device Role / Timing Role: Zener reference diode providing 25 V clamp for op-amp input protection and 2.5 V reference divider bias point. Use Value: Maintains ±0.5% reference accuracy across –40 °C to +85 °C ambient due to low TC and tight VZ tolerance. | Use Scenario: Protecting USB 2.0 data lines (D+/D–) and VBUS against ESD and transient overvoltage events in portable docking stations. IC Role / Device Role / Timing Role: Low-capacitance Zener clamp placed between signal line and ground to shunt >8 kV HBM ESD pulses. Use Value: Limits voltage excursion to ≤27 V during transients while adding <0.5 pF parasitic capacitance to preserve signal integrity. |
| Low-Power Microcontroller Reset Circuit | Automotive Cabin Control Panel Bias Network |
Use Scenario: Generating clean reset threshold for ARM Cortex-M0+ MCU powered from 5 V LDO in smart home hubs. IC Role / Device Role / Timing Role: Zener-based voltage monitor feeding RC delay network to microcontroller reset pin. Use Value: Delivers deterministic 4.75 V reset assertion with <10 µs response time and zero external components beyond capacitor. | Use Scenario: Providing stable bias current for LED backlight drivers and touch controller references in vehicle infotainment displays. IC Role / Device Role / Timing Role: Precision Zener element in constant-current source topology regulating LED string current. Use Value: Ensures ±2% current regulation over 12 V battery variation (9–16 V) and –40 °C to +105 °C temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C24 | 24 V nominal VZ, same 5% tolerance and SOT-23 package; 27 Ω ZZ at 5 mA (vs. 35 Ω at 1 mA for MMBZ5253B) | Lower clamping voltage suits 24 V system monitoring but requires recalculation of divider ratios | Select when tighter regulation at higher test current is preferred and 1 V lower Zener voltage is acceptable |
| 1N5253B | Same 25 V VZ and 5% tolerance, but DO-35 through-hole package; 35 Ω ZZ at 1 mA, identical IR spec | Requires manual assembly or wave-solder process; unsuitable for fully SMT production | Choose only for legacy repair, prototyping, or mixed-technology boards where SMT density is not required |
Compared with BZX84-C24 and 1N5253B, the MMBZ5253B offers optimal balance of SMT compatibility, 25 V clamping precision, and low-leakage performance for modern compact electronics-making it preferred for new designs targeting automated manufacturing and thermal efficiency.
Availability
MMBZ5253B is available at Aetrix Electronics and suitable for industrial sensor interfaces, USB peripheral protection, and automotive cabin control systems requiring stable component supply and long-term lifecycle support.
Supply support for MMBZ5253B 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.
The MMBZ52xxB series belongs to Fairchild's precision Zener diode product line, engineered for stable voltage reference and transient suppression in space- and power-constrained applications.
FAQ
What is the Zener voltage tolerance of the MMBZ5253B?
The MMBZ5253B has a Zener voltage tolerance of ±5% at 25 °C, meaning its actual breakdown voltage falls within 23.75 V to 26.25 V when tested at IZ = 1 mA. This tolerance is guaranteed across the full operating temperature range and is critical for maintaining accuracy in voltage reference and overvoltage detection circuits using the MMBZ5253B.
Can the MMBZ5253B be used in place of a 24 V Zener diode?
No-the MMBZ5253B is specifically rated for 25 V nominal Zener voltage and is not a drop-in replacement for 24 V parts like BZX84-C24. Substituting it in a 24 V design would raise the clamping threshold by 1 V, potentially compromising circuit protection margins or reference accuracy unless recalculating all associated resistive dividers and thresholds for the MMBZ5253B.
What is the maximum reverse leakage current for the MMBZ5253B?
The MMBZ5253B specifies a maximum reverse leakage current (IR) of 0.25 µA at VR = 19 V and TA = 25 °C. This ultra-low leakage ensures minimal loading on high-impedance nodes such as op-amp inputs, ADC reference dividers, and microcontroller wake-up comparators where the MMBZ5253B is deployed.
Is Pin 3 of the MMBZ5253B electrically connected?
No-Pin 3 of the MMBZ5253B is designated NC (No Connect) and is internally unconnected. It must remain unconnected on the PCB; soldering or routing to any net may cause unpredictable electrical behavior or parametric shift, as confirmed in the Fairchild MMBZ5221B–MMBZ5257B datasheet Rev. A2 for the MMBZ5253B.
What is the forward voltage specification for the MMBZ5253B?
The MMBZ5253B has a maximum forward voltage (VF) of 0.9 V at IF = 10 mA, consistent across the entire MMBZ5200 series. This specification allows the MMBZ5253B to serve dual roles-as a Zener clamp in reverse bias and as a low-VF rectifier or polarity protection diode in forward bias-without requiring separate discrete components.
MMBZ5253B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 25 V
- Tolerance:
- ±5%
- Power - Max:
- 350 mW
- Impedance (Max) (Zzt):
- 35 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 19 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
MMBZ5253B FAQ
1.How can I place an order for MMBZ5253B through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5253B 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 MMBZ5253B reliable?
The price and inventory of MMBZ5253B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5253B is usually 5 days.
3.What payment methods are accepted for MMBZ5253B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5253B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5253B?
MMBZ5253B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5253B 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 MMBZ5253B?
For technical support, including MMBZ5253B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5253B requirements.
6.How does Aetrix verify that MMBZ5253B is sourced from the original manufacturer or authorized distributors?
All MMBZ5253B 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 MMBZ5253B meets industry standards.
7.What is the process for return or replacement of MMBZ5253B?
All MMBZ5253B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5253B, 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 MMBZ5253B part is unused and in its original packaging.
Return procedure for MMBZ5253B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5253B Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
