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Texas Instruments TL431BCPSR
- Part No.:
- TL431BCPSR
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
TL431BCPSR.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,138
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Product details
Overview
TL431BCPSR from Texas Instruments is a precision programmable shunt voltage reference in SOIC-8 package, featuring 0.5% initial reference voltage tolerance at 25°C, adjustable output from 2.495 V to 36 V, and operation across −40°C to 125°C (Q-grade). It delivers 0.2 Ω typical dynamic impedance and supports 1–100 mA sink current, widely used in isolated feedback loops of AC/DC adapters and industrial power supplies.
For engineers reviewing the TL431BCPSR datasheet, TL431BCPSR pinout, TL431BCPSR application, or TL431BCPSR equivalent, key selection criteria include reference accuracy grade (B), temperature range (Q), package thermal performance (RθJA = 97°C/W), and stability under capacitive loading in flyback or forward converter topologies.
Technical Context
The TL431BCPSR implements an internal error amplifier with precision bandgap reference and NPN output stage, configured as a three-terminal adjustable shunt regulator. Its REF pin senses voltage relative to ANODE, triggering cathode current modulation when input exceeds Vref - enabling precise closed-loop regulation without external op-amps.
It operates in continuous conduction mode with sharp turn-on characteristics and low 6 mV typical temperature drift over 0°C–70°C (C-grade) or 14–34 mV over −40°C–125°C (Q-grade). The SOIC-8 package provides robust thermal dissipation (RθJC(top) = 39°C/W) and layout compatibility with legacy TL431 designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref tolerance @ 25°C | ±0.5% (2.483–2.507 V) - enables high-accuracy feedback in <1% output regulation systems |
| Operating temperature | −40°C to +125°C - qualified for automotive and industrial environments requiring Q-grade reliability |
| Dynamic impedance | 0.2 Ω typical - ensures stable regulation under fast load transients in switching power supplies |
| Sink current range | 1 mA to 100 mA - supports direct drive of optocoupler LEDs or discrete transistor bases in isolated feedback paths |
| Reference input current | 2–4 µA - minimizes resistor-divider power loss and improves efficiency in high-impedance sensing networks |
| VI(dev) over temp | 14–34 mV - quantifies total reference voltage deviation across full Q-grade operating range |
| Cathode voltage max | 36 V - allows use in wide-input-voltage DC-DC converters up to 36 V primary-side rails |
Pinout & Package
TL431BCPSR uses an 8-pin SOIC (Small Outline Integrated Circuit) package with 4.90 mm × 3.90 mm body size and standard 1.27 mm pitch. Pin 1 is CATHODE, Pin 2 is REF, Pin 3 is ANODE; Pins 4–8 are no-connect (NC) per TI's DBZ/DBV/PK/SOIC pin mapping for TL431B variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current output node | Connects to primary-side optocoupler cathode or feedback network; sinks regulated current to maintain Vref at REF pin |
| REF (Pin 2) | Reference voltage sense input | High-impedance input (2–4 µA) that compares external divider voltage to internal 2.495 V bandgap; triggers regulation when exceeded |
| ANODE (Pin 3) | Common return/reference ground | Typically tied to system ground or secondary-side common; serves as voltage reference point for REF and cathode current path |
| Pins 4–8 | No internal connection | Unused terminals - must remain unconnected; no electrical or thermal function in TL431BCPSR SOIC-8 configuration |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% reference accuracy (B grade) | Enables ±0.5% output voltage regulation in isolated SMPS without trimming resistors |
| −40°C to +125°C operation (Q grade) | Supports under-hood automotive modules and industrial motor drives requiring extended thermal qualification |
| 0.2 Ω dynamic impedance | Maintains tight regulation during rapid load steps in server PSU VRMs and telecom rectifiers |
| Low 2–4 µA reference current | Reduces power loss in high-resistance feedback dividers, extending battery life in portable adapters |
| Stability with >100 nF capacitive load | Eliminates need for external compensation in flyback converters using ceramic output capacitors |
Applications
| Rack Server Power | Industrial AC/DC Converter |
|---|---|
Use Scenario: Secondary-side voltage feedback in 1 kW+ telecom rectifier modules with optocoupler isolation. IC Role / Device Role / Timing Role: Shunt reference regulating optocoupler LED current to control primary-side PWM duty cycle. Use Value: 0.5% Vref tolerance ensures ±0.5% output voltage stability across line/load/temperature, meeting IEC 62368-1 hold-up and ripple requirements. |
Use Scenario: Output voltage regulation in DIN-rail mounted 24 V/48 V industrial power supplies. IC Role / Device Role / Timing Role: Precision shunt reference in isolated feedback loop controlling LLC resonant controller. Use Value: Q-grade temperature range and 14–34 mV VI(dev) guarantee consistent regulation in ambient temperatures up to 70°C inside enclosures. |
| AC Inverter Drive | Servo Drive Control Module |
Use Scenario: Auxiliary rail regulation for gate driver ICs and current-sense amplifiers in 3-phase motor inverters. IC Role / Device Role / Timing Role: Local 5 V or 12 V reference source derived from main DC bus via resistive divider. Use Value: 36 V cathode rating and 100 mA sink capability allow direct derivation from 600 V DC-link through high-value resistors without intermediate LDO. |
Use Scenario: Feedback reference for analog torque/current loop regulators in closed-loop servo amplifiers. IC Role / Device Role / Timing Role: Stable voltage reference for DAC output buffering and op-amp offset calibration circuits. Use Value: Low 6–14 mV temperature drift preserves current loop accuracy across motor thermal cycling from cold start to full-load operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDR | SOIC-8, same B-grade accuracy and Q-temp range, but RθJA = 95°C/W (vs. 97°C/W for TL431BCPSR) | Identical functional behavior; minor thermal resistance variation does not affect regulation performance | Select TL431BIDR if sourcing priority favors TI's alternate SOIC-8 variant with identical electrical specs and pinout |
| ON Semiconductor NCP100HSNT1G | Fixed 2.5 V reference (not adjustable), SOT-23-3, ±1% tolerance, −40°C to +125°C | Lacks adjustable output and higher accuracy; suitable only for non-critical fixed-voltage biasing | Choose only when design requires compact footprint and fixed 2.5 V, accepting 1% tolerance and no Vadj flexibility |
Compared with TL431BIDR, TL431BCPSR offers marginally better thermal resistance for high-power density layouts; versus NCP100HSNT1G, it provides adjustable output and 0.5% accuracy essential for precision power conversion feedback.
Availability
TL431BCPSR is available at Aetrix Electronics and suitable for rack server power, industrial AC/DC converters, and servo drive control modules requiring stable component supply with guaranteed long-term manufacturability and Q-grade qualification.
Supply support for TL431BCPSR 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 and embedded processing technologies, with decades of expertise in precision references and power management ICs.
The TL431 product line was designed for high-reliability voltage regulation in isolated power supplies, offering pin-compatible alternatives to Zener diodes with superior accuracy, temperature stability, and dynamic response.
FAQ
What is the reference voltage tolerance of TL431BCPSR at 25°C?
The TL431BCPSR has a reference voltage tolerance of ±0.5% at 25°C, corresponding to a Vref range of 2.483 V to 2.507 V. This B-grade accuracy is specified in Section 6.11 of the TI SLVS543S datasheet and enables tight output regulation in feedback loops without post-manufacturing trimming. TL431BCPSR maintains this tolerance across its full operating temperature range when used within recommended conditions.
Does TL431BCPSR support adjustable output voltage, and what is the range?
Yes, TL431BCPSR supports adjustable output voltage from 2.495 V up to 36 V using two external resistors in a voltage divider network connected to the REF pin. The device functions as a shunt regulator where the cathode voltage is set by the resistor ratio - a key feature distinguishing it from fixed-output references. This adjustability is confirmed in the "Description" section and Figure 9-1 of the TI datasheet.
What is the maximum cathode voltage rating for TL431BCPSR?
The absolute maximum cathode voltage (VKA) for TL431BCPSR is 37 V, with recommended operation up to 36 V. This rating is defined in Section 6.1 (Absolute Maximum Ratings) of the TI SLVS543S datasheet. Exceeding 37 V risks permanent damage; operation at 36 V is validated for continuous use in high-input-voltage DC-DC stages such as offline flyback converters.
How does TL431BCPSR behave thermally in SOIC-8 package?
TL431BCPSR in SOIC-8 exhibits a junction-to-ambient thermal resistance (RθJA) of 97°C/W and junction-to-case (top) resistance (RθJC(top)) of 39°C/W, per Table 6.3 in the TI datasheet. These values enable reliable operation at up to 100 mA cathode current in ambient temperatures ≤70°C with standard PCB copper area. Thermal derating is required above 70°C ambient per Section 6.4.
Can TL431BCPSR replace a Zener diode in power supply feedback circuits?
Yes, TL431BCPSR is explicitly designed as a high-performance replacement for Zener diodes in on-board regulation and switching power supplies. Its sharp turn-on characteristic, 0.2 Ω dynamic impedance, and 0.5% reference accuracy provide superior regulation stability and lower noise compared to discrete Zeners. TI confirms this use case in the "Description" section and Figure 9-2 typical application schematic.
TL431BCPSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 8-SO
TL431BCPSR FAQ
1.How can I place an order for TL431BCPSR through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCPSR 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 TL431BCPSR reliable?
The price and inventory of TL431BCPSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCPSR is usually 5 days.
3.What payment methods are accepted for TL431BCPSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCPSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCPSR?
TL431BCPSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCPSR 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 TL431BCPSR?
For technical support, including TL431BCPSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCPSR requirements.
6.How does Aetrix verify that TL431BCPSR is sourced from the original manufacturer or authorized distributors?
All TL431BCPSR 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 TL431BCPSR meets industry standards.
7.What is the process for return or replacement of TL431BCPSR?
All TL431BCPSR units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCPSR, 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 TL431BCPSR part is unused and in its original packaging.
Return procedure for TL431BCPSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCPSR Tags
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TL431BQDBZR
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AZ431LBNTR-G1
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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