My Inquiry
My Account
Texas Instruments LM431BCM3X/NOPB
- Part No.:
- LM431BCM3X/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM431BCM3X/NOPB.pdf
- Description:
- IC VREF SHUNT ADJ 1% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:134,451
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM431BCM3X/NOPB from Texas Instruments is a 3-terminal adjustable precision shunt regulator with 2.5 V reference voltage, ±17 mV reference deviation over temperature, 0.5 Ω dynamic output impedance, 1 mA minimum cathode current, and 100 mA maximum cathode current. It operates as a programmable Zener replacement in linear power supply feedback loops and voltage monitoring circuits.
For engineers reviewing the LM431BCM3X/NOPB datasheet, LM431BCM3X/NOPB pinout, LM431BCM3X/NOPB application, or LM431BCM3X/NOPB equivalent, this page delivers verified electrical specs, SOT-23-3 package mapping, thermal derating guidance, and validated alternative options for precision shunt regulation design.
Technical Context
The LM431BCM3X/NOPB implements a bandgap-referenced error amplifier driving an NPN output stage to maintain precise cathode-to-reference voltage at 2.485–2.51 V across 0°C to 70°C. Its internal architecture enables stable closed-loop operation with external resistor dividers while supporting open-loop comparator use via independent reference biasing.
It requires no external compensation in standard shunt configurations but exhibits oscillation risk under specific capacitive loading and feedback network conditions-stability boundaries are defined per Figure 2 of the datasheet. Thermal hysteresis (typical <10 mV after cycling) arises from package mechanical stress, not circuit topology.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (VREF) | 2.485–2.51 V at 25°C; sets minimum programmable output voltage threshold |
| Reference voltage deviation | ±17 mV over full 0°C to 70°C range; defines worst-case output setpoint drift |
| Dynamic output impedance | 0.5 Ω typical at DC; ensures low AC output impedance for ripple rejection in feedback paths |
| Min/max cathode current | 1–100 mA operating range; determines external series resistor sizing and power dissipation limits |
| Temperature coefficient | Average 50 ppm/°C; quantifies reference voltage drift per degree Celsius change |
| OFF-state cathode current | 0.3–1 μA at 36 V cathode voltage; enables ultra-low quiescent current in disable states |
| ESD rating (HBM) | ±2500 V; informs handling requirements during PCB assembly and test |
Pinout & Package
SOT-23-3 package (2.92 mm × 1.30 mm body), surface-mount, single-row 3-pin configuration with gull-wing leads. Thermal resistance RθJA = 267.7 °C/W; derate linearly above 25°C at 2.2 mW/°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode | Output terminal / shunt current sink | Connects to regulated voltage node; carries total load + shunt current; voltage referenced to Anode |
| Anode | Ground reference / current return path | Typically tied to system ground; completes shunt current path; defines cathode voltage polarity |
| Reference | Feedback input / precision voltage sense | Connected to resistor divider midpoint; controls regulation point; draws only 2–4 μA input current |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage range | 2.5 V to 36 V via two external resistors; eliminates need for multiple fixed-voltage Zeners |
| Fast turn-on response | Sub-microsecond activation enables use in transient-sensitive protection circuits like crowbar triggers |
| Low-output noise | Typical 20 μVRMS (unspecified bandwidth); supports clean references in ADC/DAC systems |
| Temperature-compensated reference | Stable 2.485–2.51 V over 0°C to 70°C; removes need for external thermal compensation networks |
| Space-saving SOT-23 package | 2.92 mm × 1.30 mm footprint; suitable for high-density power management on compact PCBs |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring & Protection |
|---|---|
|
Use Scenario: Secondary-side feedback loop in isolated flyback or forward converters. IC Role / Device Role / Timing Role: Adjustable shunt regulator providing precise error signal to optocoupler input. Use Value: Enables ±1% output voltage regulation without transformer auxiliary winding or secondary LDO. |
Use Scenario: Overvoltage lockout circuit triggering shutdown when rail exceeds safe threshold. IC Role / Device Role / Timing Role: Precision comparator with programmable trip point using internal reference. Use Value: Delivers accurate 5.0 V or 12.0 V threshold detection with <10 mV hysteresis-induced error. |
| Current Source/Sink Circuits | Zener Diode Replacement |
|
Use Scenario: Constant-current LED driver or sensor biasing network. IC Role / Device Role / Timing Role: Shunt-regulated current source where load connects between cathode and supply. Use Value: Provides 10–100 mA stable current with <0.5% variation across temperature and line voltage. |
Use Scenario: Replacing 3.3 V, 5.1 V, or 12 V Zener diodes in legacy analog designs. IC Role / Device Role / Timing Role: Programmable precision shunt element with superior tempco and impedance vs. discrete Zener. Use Value: Reduces BOM count by enabling single part to replace >10 fixed-voltage Zener variants. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBZR | Same 2.5 V reference, ±2% initial tolerance (vs. LM431BCM3X/NOPB's ±1%), higher 2.0 Ω dynamic impedance | Lower precision; less suitable for <1% output regulation but widely available and lower cost | Select TL431CDBZR when ±2% output accuracy suffices and cost sensitivity outweighs thermal stability needs |
| AS431ARTDT-33 | 2.5 V reference, ±0.5% initial tolerance, 0.3 Ω dynamic impedance, -40°C to 105°C operation | Broadened temperature range and tighter tolerance enable automotive-grade designs | Choose AS431ARTDT-33 for extended temperature operation or where <0.5% initial accuracy is mandatory |
Compared with TL431CDBZR and AS431ARTDT-33, the LM431BCM3X/NOPB offers optimal balance of commercial-grade precision (±1%), low dynamic impedance (0.5 Ω), and SOT-23 footprint-making it ideal for space-constrained industrial power supplies requiring stable 0.5–1% regulation.
Availability
LM431BCM3X/NOPB is available at Aetrix Electronics and suitable for switch-mode power supply feedback, voltage monitoring, current source/sink circuits, and Zener diode replacement applications requiring stable component supply and consistent parametric performance.
Supply support for LM431BCM3X/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in power management ICs.
The LM431 product line delivers precision shunt regulation for feedback, monitoring, and reference applications-designed to replace discrete Zener diodes while improving accuracy, thermal stability, and design flexibility.
FAQ
What is the reference voltage tolerance of LM431BCM3X/NOPB?
The LM431BCM3X/NOPB has a reference voltage (VREF) of 2.485–2.51 V at 25°C, corresponding to ±1% initial tolerance. This tolerance remains stable across its 0°C to 70°C operating temperature range, with total deviation limited to ±17 mV over that interval as specified in Section 6.5 of the SNVS020H datasheet.
Can LM431BCM3X/NOPB be used in place of a standard Zener diode?
Yes, the LM431BCM3X/NOPB functions as a direct, high-performance replacement for Zener diodes in applications requiring better temperature stability, lower dynamic impedance, or adjustable output voltage. Unlike fixed Zeners, it achieves programmable regulation from 2.5 V to 36 V using two external resistors-and maintains 50 ppm/°C tempco versus typical Zener drift of 100–500 ppm/°C.
What is the minimum cathode current required for regulation in LM431BCM3X/NOPB?
The LM431BCM3X/NOPB requires a minimum cathode current (IZ(MIN)) of 1 mA to maintain regulation, as confirmed in Section 6.5 of the datasheet. Below this threshold, the device exits regulation and cathode voltage drops below the programmed setpoint. Designers must size the external series resistor to ensure IZ ≥ 1 mA under worst-case conditions (minimum input voltage, maximum load current).
Does LM431BCM3X/NOPB require an external capacitor for stability?
No, the LM431BCM3X/NOPB does not require an external capacitor for basic shunt regulation stability. However, Section 9.2.1.3 and Figure 2 of the datasheet define stability boundaries: capacitive loading on the cathode or reference pins can induce oscillation. TI recommends placing any bypass or filter capacitors physically close to the cathode pin and avoiding excessive capacitance unless compensated per stability curves.
What package type and marking does LM431BCM3X/NOPB use?
The LM431BCM3X/NOPB uses the SOT-23-3 package (2.92 mm × 1.30 mm) with gull-wing leads and is marked "N1D" on the top surface. This matches the DBZ package designation in TI's packaging documentation and distinguishes it from SOIC-8 (D) and TO-92 (LP) variants of the same LM431 family.
LM431BCM3X/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 37 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- 50ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
LM431BCM3X/NOPB FAQ
1.How can I place an order for LM431BCM3X/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431BCM3X/NOPB 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 LM431BCM3X/NOPB reliable?
The price and inventory of LM431BCM3X/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431BCM3X/NOPB is usually 5 days.
3.What payment methods are accepted for LM431BCM3X/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431BCM3X/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431BCM3X/NOPB?
LM431BCM3X/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431BCM3X/NOPB 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 LM431BCM3X/NOPB?
For technical support, including LM431BCM3X/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431BCM3X/NOPB requirements.
6.How does Aetrix verify that LM431BCM3X/NOPB is sourced from the original manufacturer or authorized distributors?
All LM431BCM3X/NOPB 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 LM431BCM3X/NOPB meets industry standards.
7.What is the process for return or replacement of LM431BCM3X/NOPB?
All LM431BCM3X/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM431BCM3X/NOPB, 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 LM431BCM3X/NOPB part is unused and in its original packaging.
Return procedure for LM431BCM3X/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM431BCM3X/NOPB Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
Tech Hub
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…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
