Texas Instruments TLV431BILP

Overview

TLV431BILP from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±0.5% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, and operation down to 1.24 V cathode-anode voltage. It functions as a programmable Zener replacement in isolated flyback secondary-side regulation, voltage monitoring, and comparator applications requiring tight reference stability.

For engineers reviewing the TLV431BILP datasheet, TLV431BILP pinout, TLV431BILP application, or TLV431BILP equivalent, this page delivers verified electrical parameters, TO-92 package mechanical data, functional mode distinctions (open-loop comparator vs closed-loop shunt regulator), thermal performance (140°C/W RθJA), and real-world design implications for 3.3 V SMPS feedback and low-voltage sensing circuits.

Technical Context

The TLV431BILP implements an internal bandgap reference and NPN-based error amplifier driving a Darlington sink output stage. Its open-loop configuration provides high-gain comparator functionality with integrated 1.24 V reference, while closed-loop operation-using external resistive feedback between cathode and reference pins-enables precise shunt regulation from 1.24 V to 6 V.

It achieves stable regulation with no mandatory output capacitor, thanks to internal compensation. Minimum cathode current is 55–100 µA depending on temperature grade, and reference input current remains ≤0.5 µA across –40°C to 125°C, enabling ultra-low-power biasing in battery-sensitive designs.

Key Specifications

Pinout & Package

TLV431BILP uses the LP (TO-92, 3-pin) package: molded plastic case with axial leads, 5.2 mm length × 3.68 mm diameter, lead pitch 1.27 mm, rated for 150°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar shunt regulator applications.

Compared with TLV431AILP, TLV431BILP offers tighter reference accuracy critical for precision feedback; compared with TL431ACLP, it enables lower-voltage operation and cuts minimum cathode current by 10×, reducing standby power in modern SMPS designs.

Availability

TLV431BILP is available at Aetrix Electronics and suitable for isolated flyback power supplies, voltage monitoring circuits, and programmable current sources requiring stable component supply, long-term manufacturability, and through-hole assembly compatibility.

Supply support for TLV431BILP 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, designing and manufacturing analog, embedded processing, and logic ICs for industrial, automotive, and communications markets.

The TLV431 family was developed to replace TL431 in low-voltage applications, delivering 1.24 V reference capability, sub-100 µA operating current, and TO-92/SOT-23 packaging for space- and power-constrained power management and sensing systems.

FAQ

What is the maximum cathode-anode voltage (VKA) rating for TLV431BILP?

The absolute maximum cathode-anode voltage for TLV431BILP is 7 V, as specified in the Absolute Maximum Ratings table. Operating beyond this risks permanent damage. For reliable regulation, VKA should remain between 1.24 V and 6 V per Recommended Operating Conditions - ensuring the device stays within its linear, controlled shunt region without entering breakdown or saturation.

Can TLV431BILP be used in place of TL431 in existing TO-92 designs?

Yes, TLV431BILP is pin-compatible with TL431ACLP and TL431BCLP in the TO-92 (LP) package and shares identical anode–cathode–reference pinout. However, because TLV431BILP regulates from 1.24 V (not 2.5 V), resistor values must be recalculated to achieve the same output voltage - and minimum cathode current drops from 1 mA to 55 µA, allowing lower-power operation.

What is the thermal resistance (RθJA) of TLV431BILP in the TO-92 package?

The junction-to-ambient thermal resistance (RθJA) for TLV431BILP in the LP (TO-92) package is 140°C/W, as documented in Section 5.4. This value assumes standard JEDEC high-K board conditions. In compact layouts or still-air environments, derating is required above 85°C ambient to maintain junction temperature ≤150°C.

Does TLV431BILP require an output capacitor for stability?

No, TLV431BILP is internally compensated and does not require an output capacitor for basic shunt regulator stability. However, if a capacitive load is added (e.g., for noise filtering), Figure 5-19 in the datasheet shows phase margin vs. capacitive load - stability is maintained up to ~1 nF at 1.25 V VKA, but larger values may induce oscillation and require series resistance.

How does the reference input current (Iref) of TLV431BILP affect resistor divider design?

TLV431BILP's reference input current is 0.1–0.5 µA (max), meaning a 1 MΩ–100 kΩ resistor divider introduces <0.5% error at 25°C. For highest accuracy, use ≤100 kΩ total divider resistance; for ultra-low power, ≥1 MΩ is viable but adds temperature-dependent offset due to Iref drift - confirmed in Figure 5-3.