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Texas Instruments LM431BIZ/NOPB
- Part No.:
- LM431BIZ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
LM431BIZ/NOPB.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,278
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Product details
Overview
LM431BIZ/NOPB from Texas Instruments is a precision adjustable shunt voltage regulator in TO-92 package, featuring 2.50 V nominal reference voltage (±10 mV tolerance), 50 ppm/°C average temperature coefficient, 0.5 Ω dynamic output impedance, and operation from 2.5 V to 36 V output range. It serves as a programmable Zener replacement in feedback loops of linear and switching power supplies.
For engineers reviewing the LM431BIZ/NOPB datasheet, LM431BIZ/NOPB pinout, LM431BIZ/NOPB application, or LM431BIZ/NOPB equivalent, this device is selected for precision voltage monitoring, current source/sink design, overvoltage protection, and low-noise shunt regulation where stable 2.5 V reference and thermal compensation across –40°C to +85°C are required.
Technical Context
The LM431BIZ/NOPB implements a bandgap-referenced error amplifier driving an NPN pass transistor in a 3-terminal shunt topology. Its internal reference is trimmed for ±1% initial accuracy (B-grade) and compensated across the full industrial temperature range (–40°C to +85°C).
It operates in closed-loop mode with external resistor divider (R1/R2) setting output voltage via VO = VREF × (1 + R1/R2), requiring minimum cathode current of 1 mA and supporting up to 100 mA shunt current. The device exhibits fast turn-on response and low-output noise due to its monolithic construction and optimized internal compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.50 V (typ), ±10 mV max deviation at 25°C - sets precise output threshold for feedback networks |
| Temperature Coefficient | 50 ppm/°C avg - ensures ≤1.75 mV drift over –40°C to +85°C for stable regulation |
| Dynamic Output Impedance | 0.5 Ω (typ) - maintains tight output voltage under dynamic load transients |
| Cathode Voltage Range | 2.5 V to 36 V - supports wide-range programmable outputs without external components |
| Min Cathode Current | 1 mA - defines lowest operating point for reliable regulation in low-power designs |
| Max Cathode Current | 100 mA - determines maximum shunt power dissipation (2.5 W at 36 V) |
| Reference Input Current | 2–4 μA (typ) - enables high-impedance feedback dividers with minimal loading error |
Pinout & Package
LM431BIZ/NOPB uses a 3-pin TO-92 package (LP drawing), body size 4.30 mm × 4.30 mm, with through-hole mounting and RoHS-compliant CU SN lead finish. Thermal resistance RθJA = 162.4 °C/W enables operation up to 85°C ambient with appropriate PCB copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Output / Shunt Current Sink | Main regulated node; connects to supply rail and load; carries total shunt current |
| Anode (Pin 3) | Ground Reference | Return path for reference and cathode currents; must be low-impedance ground connection |
| Reference (Pin 2) | Feedback Input | Senses divided output voltage; high-impedance input (μA-level bias) for precision resistor networks |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Voltage | Programmable from 2.5 V to 36 V using two external resistors - eliminates need for multiple fixed Zeners |
| Temperature Compensation | Guaranteed stability over –40°C to +85°C - removes external thermal correction circuitry |
| Low Dynamic Output Impedance | 0.5 Ω typical - sustains <10 mV output variation during 50 mA load steps |
| Fast Turn-On Response | Sub-microsecond activation - enables use in crowbar and overvoltage latch circuits |
| Low-Output Noise | Typical 20 μVRMS (10 Hz–10 kHz) - suitable for precision analog references and sensor excitation |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring & Protection |
|---|---|
Use Scenario: Secondary-side voltage sensing in isolated flyback converters with optocoupler feedback. IC Role / Device Role / Timing Role: Adjustable shunt regulator providing precise 2.5 V reference to drive optocoupler LED. Use Value: Enables ±1% output regulation across line/load/temperature without secondary-side LDO or TL431 clone. |
Use Scenario: Overvoltage detection in 12 V automotive accessory rails with latch-off capability. IC Role / Device Role / Timing Role: Precision comparator with hysteresis (via resistor network) triggering SCR crowbar. Use Value: Accurate 13.8 V trip point (±0.14 V) with <10 μs response, replacing discrete Zener+transistor solutions. |
| Current Source/Sink Circuits | Zener Diode Replacement |
Use Scenario: Constant-current LED driver for industrial status indicators with 20 mA setpoint. IC Role / Device Role / Timing Role: Shunt-regulated current sink using cathode-to-load configuration. Use Value: Delivers stable 20 mA over 5–24 V supply range with <2% variation across temperature. |
Use Scenario: Replacing 3.3 V Zener diode in microcontroller reset circuit with improved stability. IC Role / Device Role / Timing Role: Programmable shunt reference configured for 3.3 V output via R1/R2 divider. Use Value: Reduces voltage drift from >100 ppm/°C (Zener) to 50 ppm/°C while lowering dynamic impedance by 10×. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBZR | SO-8 package, 2.495 V reference (±0.5%), lower tempco (30 ppm/°C), higher min cathode current (1 mA vs 1 mA same), same TO-92 pinout not applicable | Preferred for surface-mount designs requiring tighter initial accuracy and better thermal performance; unsuitable for through-hole layouts | Select when PCB space allows SMT and ±0.5% reference accuracy is mandatory; requires layout change from TO-92 |
| AS431AT-E1 | TO-92 package, 2.50 V reference (±1%), 70 ppm/°C tempco, 1.5 mA min cathode current, 100 mA max cathode current | Compatible footprint but higher minimum current increases quiescent loss in ultra-low-power systems | Choose for cost-sensitive industrial applications where 70 ppm/°C drift is acceptable and supply can sustain ≥1.5 mA idle current |
Compared with TL431BIDBZR and AS431AT-E1, LM431BIZ/NOPB offers optimal balance of through-hole compatibility, 50 ppm/°C stability, and 1 mA minimum operating current-making it ideal for legacy designs, prototyping, and cost-constrained industrial power monitors where TO-92 mechanical robustness is valued.
Availability
LM431BIZ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, automotive voltage monitors, and embedded current-source circuits requiring stable component supply with long-term lifecycle support.
Supply support for LM431BIZ/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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets since 1930.
LM431BIZ/NOPB belongs to TI's precision shunt regulator product line, designed specifically for cost-effective, thermally stable voltage reference and regulation in space-constrained and high-reliability applications.
FAQ
What is the reference voltage tolerance of LM431BIZ/NOPB at 25°C?
The LM431BIZ/NOPB has a reference voltage (VREF) of 2.50 V with a maximum deviation of ±10 mV at 25°C, corresponding to ±0.4% initial accuracy. This B-grade tolerance is confirmed in Section 6.5 of the SNVS020H datasheet under "Electrical Characteristics" for LM431B devices, and applies directly to the LM431BIZ/NOPB variant in TO-92 packaging.
Can LM431BIZ/NOPB replace a standard 3.3 V Zener diode in a microcontroller reset circuit?
Yes, LM431BIZ/NOPB can directly replace a 3.3 V Zener diode by configuring R1 and R2 to set VO = 3.3 V using VO = VREF × (1 + R1/R2). With its 50 ppm/°C tempco and 0.5 Ω dynamic impedance, LM431BIZ/NOPB delivers significantly better stability and transient response than typical Zeners-reducing reset threshold drift by >50% over temperature.
What is the minimum cathode current required for regulation in LM431BIZ/NOPB?
The LM431BIZ/NOPB requires a minimum cathode current (IZ(MIN)) of 1 mA to maintain regulation, as specified in Section 6.5 of the SNVS020H datasheet. Below this threshold, the device exits regulation and output voltage collapses. This value is consistent across all LM431B variants, including LM431BIZ/NOPB in TO-92 package.
Does LM431BIZ/NOPB support operation at –40°C?
Yes, LM431BIZ/NOPB is rated for industrial temperature operation from –40°C to +85°C, as indicated by the "I" suffix in its full part number family and confirmed in Section 6.3 ("Recommended Operating Conditions") of the SNVS020H datasheet. Its temperature-compensated bandgap reference ensures stable 2.50 V output across this full range.
How does the dynamic output impedance of LM431BIZ/NOPB affect load regulation?
The LM431BIZ/NOPB has a typical dynamic output impedance (rZ) of 0.5 Ω, meaning a 50 mA load step causes only ~25 mV output deviation. This low impedance directly improves load regulation-enabling stable voltage control in current-sink and feedback applications where traditional Zeners exhibit >10 Ω impedance and >500 mV droop under similar conditions.
LM431BIZ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Series:
- -
- Packaging:
- Box
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
LM431BIZ/NOPB FAQ
1.How can I place an order for LM431BIZ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431BIZ/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 LM431BIZ/NOPB reliable?
The price and inventory of LM431BIZ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431BIZ/NOPB is usually 5 days.
3.What payment methods are accepted for LM431BIZ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431BIZ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431BIZ/NOPB?
LM431BIZ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431BIZ/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 LM431BIZ/NOPB?
For technical support, including LM431BIZ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431BIZ/NOPB requirements.
6.How does Aetrix verify that LM431BIZ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM431BIZ/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 LM431BIZ/NOPB meets industry standards.
7.What is the process for return or replacement of LM431BIZ/NOPB?
All LM431BIZ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM431BIZ/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 LM431BIZ/NOPB part is unused and in its original packaging.
Return procedure for LM431BIZ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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