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Texas Instruments TL431BCLPRE3
- Part No.:
- TL431BCLPRE3
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
TL431BCLPRE3.pdf
- Description:
- IC VREF SHUNT PREC ADJ TO-92-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,000
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Product details
Overview
TL431BCLPRE3 from Texas Instruments is a precision programmable shunt voltage reference in SOT-23-3 package, delivering 2.483–2.507 V reference voltage at 25°C with ±0.5% initial tolerance (B grade), 14 mV max reference voltage drift over −40°C to 125°C (Q-temp grade), 0.2 Ω typical dynamic impedance, and 1–100 mA sink-current capability. It serves as an adjustable voltage reference or Zener diode replacement in secondary-side regulation of isolated flyback SMPS.
For engineers reviewing the TL431BCLPRE3 datasheet, TL431BCLPRE3 pinout, TL431BCLPRE3 application, or TL431BCLPRE3 equivalent, key selection criteria include its Q-grade temperature range (−40°C to 125°C), tight 0.5% Vref tolerance, low 2–4 µA reference input current, and compatibility with two-resistor feedback networks for output voltages from 2.5 V to 36 V.
Technical Context
The TL431BCLPRE3 implements a three-terminal adjustable shunt regulator architecture with an internal error amplifier, reference, and NPN output transistor. Its sharp turn-on characteristic and low 0.2 Ω dynamic impedance enable stable closed-loop regulation without external compensation in many configurations.
It operates as a voltage-controlled current sink: when the REF pin voltage exceeds the internal 2.495 V reference, the cathode-anode path conducts, sinking current up to 100 mA. The device requires ≥0.4 mA minimum cathode current for regulation and exhibits <0.5 µA off-state leakage at 36 V cathode voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Vref @ 25°C | 2.483–2.507 V - Tight 0.5% tolerance enables high-accuracy feedback in power supply designs |
| VI(dev) over −40°C to 125°C | 14 mV max - Ensures ≤0.56% reference drift across full automotive/military temperature range |
| IKA operating range | 1–100 mA - Supports robust sink-current capability for driving optocoupler LEDs or error amplifiers |
| |zKA| dynamic impedance | 0.2 Ω typical - Provides low-output-impedance reference node, minimizing load-induced voltage error |
| Iref (reference input current) | 2–4 µA - Enables high-impedance resistor dividers (e.g., 1 MΩ/100 kΩ) with minimal divider current error |
| Min cathode current (Imin) | 0.4 mA - Defines lowest stable regulation current; critical for low-power standby modes |
| Off-state cathode current (Ioff) | ≤0.5 µA at 36 V - Ensures negligible quiescent loss when reference is inactive |
Pinout & Package
SOT-23-3 package (2.90 mm × 1.30 mm body size), surface-mount, RoHS-compliant. Pin 1 = Cathode, Pin 2 = Reference (REF), Pin 3 = Anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Cathode) | Current sink output | Connects to regulated rail or optocoupler LED anode; sinks current when REF > Vref |
| Pin 2 (REF) | Reference input sensing node | High-impedance input (2–4 µA) tied to resistor divider midpoint; controls conduction threshold |
| Pin 3 (Anode) | Common return / ground reference | Typically connected to system ground or power supply return; defines voltage reference point for REF pin |
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 references |
| Temperature stability | 14 mV max Vref deviation over −40°C to 125°C - Meets automotive AEC-Q100 Grade 1 requirements |
| Low output noise & impedance | 0.2 Ω typical dynamic impedance + low noise - Reduces output ripple in sensitive analog feedback paths |
| Zener diode replacement capability | Sharp turn-on + 100 mA sink current - Direct drop-in upgrade for 2.5–36 V Zener applications with improved accuracy |
| Wide operating temperature range | −40°C to +125°C - Qualified for under-hood automotive, industrial control, and telecom power systems |
Applications
| Secondary-Side Flyback Regulation | Zener Diode Replacement |
|---|---|
|
Use Scenario: Isolated DC-DC converter using optocoupler feedback to regulate output voltage on secondary side. IC Role / Device Role / Timing Role: Precision shunt reference providing accurate voltage sense signal to optocoupler LED driver. Use Value: Enables ±1% output regulation across line/load/temperature with no primary-side controller modification. |
Use Scenario: On-board 5 V or 12 V rail stabilization where space and accuracy exceed standard Zener capabilities. IC Role / Device Role / Timing Role: Adjustable shunt regulator replacing discrete Zener + resistor network. Use Value: Reduces component count by 2× while improving reference accuracy from ±5% to ±0.5% and lowering tempco by 5×. |
| Voltage Monitoring & Supervision | Programmable Current Sink |
|
Use Scenario: Microcontroller reset circuit detecting undervoltage condition on 3.3 V supply rail. IC Role / Device Role / Timing Role: Threshold comparator with integrated reference, triggering reset when supply drops below setpoint. Use Value: Achieves 2.5 V trip point with <±10 mV hysteresis and <1 µA quiescent current in SOT-23 footprint. |
Use Scenario: Constant-current LED driver or sensor biasing circuit requiring precise current control. IC Role / Device Role / Timing Role: Adjustable current sink configured with REF-to-Anode resistor. Use Value: Delivers 1–100 mA sink current with <0.5% setpoint error and <1% current drift over temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBVR | SOT-23-3, same B-grade tolerance and Q-temp rating, but TI's newer DBV package variant with identical pinout and specs | Identical functional replacement; differs only in tape-and-reel packaging and date code traceability | Select TL431BIDBVR for new designs requiring latest TI manufacturing lot traceability and enhanced ESD robustness (HBM ±2000 V) |
| AS431ARTDT-33 | 2.5 V fixed reference (not adjustable), SOT-23-3, ±1% tolerance, −40°C to 105°C operation, 1 µA Iref | Limited to fixed 2.5 V outputs; unsuitable for >2.5 V or programmable applications | Choose AS431ARTDT-33 only when fixed 2.5 V reference suffices and cost sensitivity outweighs adjustability needs |
Compared with TL431BCLPRE3, TL431BIDBVR offers identical electrical performance with updated packaging logistics, while AS431ARTDT-33 trades adjustability and extended temperature range for lower unit cost in fixed-voltage use cases.
Availability
TL431BCLPRE3 is available at Aetrix Electronics and suitable for automotive power management, industrial SMPS design, and telecom voltage supervision requiring stable component supply with guaranteed long-term availability and full lifecycle support.
Supply support for TL431BCLPRE3 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 discrete Zener diodes in feedback, monitoring, and regulation circuits across automotive, industrial, and computing power systems.
FAQ
What is the operating temperature range of the TL431BCLPRE3?
The TL431BCLPRE3 is rated for operation from −40°C to +125°C (Q-grade), making it suitable for under-hood automotive, industrial control, and telecom power applications where ambient temperatures exceed commercial-grade limits. This range is explicitly specified in the Electrical Characteristics table for TL431BQ devices and confirmed in the Device Information section.
Does TL431BCLPRE3 require external capacitors for stability?
The TL431BCLPRE3 does not require external compensation capacitors in most standard two-resistor feedback configurations due to its internally compensated error amplifier and sharp turn-on characteristic. However, when driving capacitive loads >1 nF or used in high-gain optocoupler loops, a 1–10 nF capacitor from cathode to anode may be needed to prevent oscillation - per TI Application Report SLVA487.
Can TL431BCLPRE3 be used as a comparator with integrated reference?
Yes, TL431BCLPRE3 functions as a precision comparator with built-in 2.495 V reference: when REF voltage exceeds Vref, the cathode sinks current; when below, it remains off. This enables undervoltage lockout, battery monitoring, and reset generation without external reference components - confirmed in Applications section of SLVS543P.
What is the minimum cathode current required for regulation in TL431BCLPRE3?
The TL431BCLPRE3 requires a minimum cathode current (Imin) of 0.4 mA to maintain regulation, as specified in Section 7.11 (TL431BC characteristics) and validated across all B-grade variants including TL431BQ. This value ensures stable reference behavior even in ultra-low-power standby modes.
How does the reference input current (Iref) of TL431BCLPRE3 affect resistor divider design?
The TL431BCLPRE3 has a reference input current (Iref) of 2–4 µA, which flows into the REF pin. To limit divider current error to <0.1%, total divider resistance should be ≤200 kΩ (e.g., 180 kΩ + 18 kΩ for 11× gain). Higher values increase sensitivity to Iref drift and temperature variation - per Figure 21 and Section 7.11 test conditions.
TL431BCLPRE3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Bulk
- 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:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL431BCLPRE3 FAQ
1.How can I place an order for TL431BCLPRE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL431BCLPRE3 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 TL431BCLPRE3 reliable?
The price and inventory of TL431BCLPRE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL431BCLPRE3 is usually 5 days.
3.What payment methods are accepted for TL431BCLPRE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL431BCLPRE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL431BCLPRE3?
TL431BCLPRE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL431BCLPRE3 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 TL431BCLPRE3?
For technical support, including TL431BCLPRE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL431BCLPRE3 requirements.
6.How does Aetrix verify that TL431BCLPRE3 is sourced from the original manufacturer or authorized distributors?
All TL431BCLPRE3 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 TL431BCLPRE3 meets industry standards.
7.What is the process for return or replacement of TL431BCLPRE3?
All TL431BCLPRE3 units undergo pre-shipment inspection (PSI). If there is an issue with TL431BCLPRE3, 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 TL431BCLPRE3 part is unused and in its original packaging.
Return procedure for TL431BCLPRE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TL431BCLPRE3 Tags
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