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Texas Instruments TL431BCDBVT
- Part No.:
- TL431BCDBVT
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
TL431BCDBVT.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,852
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Product details
Overview
TL431BCDBVT from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.495 V nominal reference voltage with ±0.5% initial tolerance at 25°C, 0.2 Ω typical dynamic impedance, and operation across −40°C to 125°C. It serves as a high-stability replacement for Zener diodes in feedback loops of isolated DC/DC converters and industrial power supplies.
For engineers reviewing the TL431BCDBVT datasheet, TL431BCDBVT pinout, TL431BCDBVT application, or TL431BCDBVT equivalent, key selection criteria include its B-grade accuracy, Q-temp automotive-grade temperature range, low output noise, sink-current capability up to 100 mA, and compatibility with standard resistor-divider programming for adjustable outputs from 2.5 V to 36 V.
Technical Context
The TL431BCDBVT implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and NPN pass transistor. Its sharp turn-on characteristic and active output stage enable stable regulation without external compensation in most configurations.
It operates as a two-input comparator driving a cathode-sink output: the REF pin senses voltage relative to ANODE, and the device regulates by sinking current from CATHODE to ANODE when REF exceeds 2.495 V. Thermal drift is specified at 14 mV over −40°C to 125°C (Q-grade), and dynamic impedance remains ≤0.5 Ω up to 1 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.495 V nominal (2.483–2.507 V min/max), enabling precise feedback setpoints in power supply control loops |
| Initial Tolerance | ±0.5% at 25°C (B grade), reducing calibration burden in production test and improving system accuracy without trimming |
| Temp Range | −40°C to +125°C (Q grade), supporting under-hood automotive, industrial motor drives, and high-reliability server PSU designs |
| Dynamic Impedance | 0.2 Ω typical (≤0.5 Ω), ensuring minimal output voltage shift under load transients in closed-loop regulation |
| Sink Current Range | 1 mA to 100 mA, allowing direct interface with optocouplers, MOSFET gates, or discrete transistors in isolated feedback paths |
| Output Noise | Low broadband noise (typ. 220 nV/√Hz @ 1 kHz), critical for low-noise LDO references and precision ADC biasing |
| Ref Input Current | 2–4 µA typical, enabling high-impedance resistor-divider networks (e.g., 100 kΩ/10 kΩ) without significant error |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm), surface-mount, lead-free, RoHS-compliant. Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output node | Connects to high-side of feedback divider or optocoupler LED; sinks regulated current to ANODE |
| REF (Pin 2) | Reference input threshold | Senses voltage relative to ANODE; triggers regulation when ≥2.495 V; high-impedance (µA-level input) |
| ANODE (Pin 3) | Common return path | Typically tied to system ground or negative rail; forms reference point for REF and CATHODE voltage measurements |
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-voltage references |
| Thermal stability | 14 mV max deviation over −40°C to 125°C - ensures consistent regulation in wide-temperature industrial environments |
| Low dynamic impedance | 0.2 Ω typical - maintains tight output regulation during fast load steps in switching power supply feedback paths |
| Sharp turn-on | Active output stage enables clean, non-hysteretic regulation - avoids oscillation risks common with passive Zener solutions |
| High ESD robustness | ±2000 V HBM - supports reliable handling and assembly in standard manufacturing lines without special ESD controls |
Applications
| Rack Server Power Supply | Industrial AC/DC Converter |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in isolated 48 V–12 V DC/DC modules for datacenter servers. IC Role / Device Role / Timing Role: Precision shunt reference in optocoupler-based feedback loop, setting output voltage via resistor divider. Use Value: ±0.5% initial accuracy and 14 mV thermal drift ensure <±1% total output variation across full operating temperature, meeting strict server PSU specifications. |
Use Scenario: Output voltage regulation in 3 kW industrial AC/DC front-end power supplies. IC Role / Device Role / Timing Role: Shunt reference controlling PWM duty cycle through TL431-driven optocoupler interface. Use Value: 100 mA sink capability directly drives high-CTR optocouplers without buffer transistors, simplifying isolation design and improving transient response. |
| AC Inverter Drive | Servo Drive Control Module |
|
Use Scenario: DC bus voltage monitoring and overvoltage protection threshold in 3-phase motor inverters. IC Role / Device Role / Timing Role: Programmable voltage comparator reference, triggering shutdown when bus exceeds safe limit. Use Value: Adjustable trip point (e.g., 750 V via 300:1 divider) with stable 2.495 V core enables accurate, temperature-invariant overvoltage detection. |
Use Scenario: Feedback reference for analog current loop regulation in servo amplifier stages. IC Role / Device Role / Timing Role: Low-noise, low-drift reference source for DAC output buffering and op-amp offset calibration. Use Value: 220 nV/√Hz input noise and 0.2 Ω impedance minimize current-loop error and improve torque control resolution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BQDBVR | SOT-23-5 package (5-pin), same B-grade accuracy and Q-temp rating, but REF/ANODE/CATHODE pinout differs (Pin 1=NC, Pin 2=ANODE, Pin 3=NC, Pin 4=REF, Pin 5=CATHODE) | Requires PCB layout change due to different pin assignment and presence of two NC pins; not drop-in compatible | Select only if SOT-23-5 footprint is already standardized in design and pin reassignment is acceptable |
| TLVH431BQDBVR | Lower 1.24 V reference voltage, 1.5% initial tolerance, same Q-temp range and SOT-23-5 package; higher Iref (10 µA typ) | Better suited for low-voltage systems (<5 V output); less precise for 12 V+ rails; higher reference current increases divider power loss | Choose when designing sub-5 V isolated supplies where 1.24 V reference simplifies resistor ratios and reduces component count |
Compared with TL431BCDBVT, TL431BQDBVR requires board redesign due to incompatible pinout, while TLVH431BQDBVR trades accuracy and reference voltage for low-voltage flexibility - making TL431BCDBVT optimal for high-accuracy, mid-to-high-voltage industrial and server applications where SOT-23-3 space constraints apply.
Availability
TL431BCDBVT is available at Aetrix Electronics and suitable for rack server power supplies, industrial AC/DC converters, and servo drive control modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for TL431BCDBVT 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 power management ICs, with decades of expertise in precision reference and power control technologies.
The TL431 family was designed as a pin-compatible, high-accuracy replacement for Zener diodes in feedback regulation, targeting cost-sensitive yet performance-critical applications in power conversion, industrial automation, and computing infrastructure.
FAQ
What is the reference voltage tolerance of TL431BCDBVT at 25°C?
The TL431BCDBVT has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a 2.483 V to 2.507 V range around the nominal 2.495 V. This B-grade accuracy is confirmed in Section 6.11 of the TI SLVS543S datasheet and applies specifically to the TL431BCDBVT variant with Q-temp rating and SOT-23-3 packaging.
Does TL431BCDBVT support operation at −40°C to +125°C?
Yes, TL431BCDBVT is rated for operation from −40°C to +125°C (Q-grade specification). Its maximum reference voltage deviation over this full range is 14 mV, as documented in Section 6.13 of the TI datasheet. This makes TL431BCDBVT suitable for under-hood automotive, industrial motor drives, and high-ambient-temperature server applications.
What is the dynamic impedance of TL431BCDBVT and why does it matter?
TL431BCDBVT has a typical dynamic impedance of 0.2 Ω (≤0.5 Ω max), measured at ≤1 kHz with cathode current between 1 mA and 100 mA. This low value ensures minimal output voltage variation during load transients - critical for maintaining regulation stability in switching power supply feedback loops where TL431BCDBVT is commonly deployed.
Can TL431BCDBVT be used to set output voltages above 36 V?
No, TL431BCDBVT is specified for adjustable output voltages from Vref (≈2.5 V) up to 36 V only. The absolute maximum cathode voltage is 37 V (Section 6.1), and operation beyond 36 V violates recommended conditions. For higher-voltage applications, external level-shifting circuitry or alternative references must be used - TL431BCDBVT itself cannot safely regulate above 36 V.
How does the SOT-23-3 pinout of TL431BCDBVT differ from TL432 variants?
TL431BCDBVT uses the standard TL431 SOT-23-3 pinout: Pin 1 = CATHODE, Pin 2 = REF, Pin 3 = ANODE. TL432 variants (e.g., TL432BCDBVT) reverse this: Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF. Using TL432 in place of TL431BCDBVT without layout revision will result in incorrect or non-functional regulation due to misconnected REF and ANODE terminals.
TL431BCDBVT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.495V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
TL431BCDBVT FAQ
1.How can I place an order for TL431BCDBVT through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCDBVT 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 TL431BCDBVT reliable?
The price and inventory of TL431BCDBVT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCDBVT is usually 5 days.
3.What payment methods are accepted for TL431BCDBVT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCDBVT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCDBVT?
TL431BCDBVT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCDBVT 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 TL431BCDBVT?
For technical support, including TL431BCDBVT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCDBVT requirements.
6.How does Aetrix verify that TL431BCDBVT is sourced from the original manufacturer or authorized distributors?
All TL431BCDBVT 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 TL431BCDBVT meets industry standards.
7.What is the process for return or replacement of TL431BCDBVT?
All TL431BCDBVT units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCDBVT, 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 TL431BCDBVT part is unused and in its original packaging.
Return procedure for TL431BCDBVT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCDBVT Tags
-
TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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AN431AN-ATRG1
Diodes Incorporated
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LM4040CYM3-2.5-TR
Microchip Technology
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LM4040CYM3-4.1-TR
Microchip Technology
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LM4040EIM3-2.5/NOPB
Texas Instruments
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AZ431LBNTR-G1
Diodes Incorporated
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LM4040D20IDBZR
Texas Instruments
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LM4041DIM3-ADJ/NOPB
Texas Instruments
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LM4040DIM3X-2.5/NOPB
Texas Instruments
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LM4040DIM3-2.5/NOPB
Texas Instruments
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AZ431LANTR-G1
Diodes Incorporated
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