Texas Instruments TLV431AILPM5

Overview

TLV431AILPM5 from Texas Instruments is a low-voltage adjustable precision shunt regulator with 1.24 V reference voltage, ±1% initial tolerance at 25°C, 0.25 Ω typical dynamic impedance, 80 µA typical cathode current for regulation, and operation from 1.24 V to 6 V output range. It serves as an ultra-low-voltage Zener replacement in isolated feedback loops of 3-V/3.3-V flyback SMPSs.

For engineers reviewing the TLV431AILPM5 datasheet, TLV431AILPM5 pinout, TLV431AILPM5 application, or TLV431AILPM5 equivalent, key selection criteria include reference accuracy over temperature (±6 mV from –40°C to 85°C), low operational cathode current, SC-70 package footprint, and compatibility with optocoupler-based secondary-side regulation circuits.

Technical Context

The TLV431AILPM5 implements a 3-terminal shunt-regulator architecture with internal bandgap reference and high-gain NPN-based error amplifier driving a Darlington sink output stage. Its regulation mechanism relies on feedback between cathode and reference pins to maintain V_REF = 1.24 V across external resistor dividers.

It operates without external compensation, achieving stability with capacitive loads up to 10 nF at VKA = 2.5 V (phase margin >45°), and supports continuous cathode currents from 0.1 mA to 15 mA within its 1.24–6 V output range and –40°C to 85°C industrial temperature grade.

Key Specifications

Pinout & Package

TLV431AILPM5 is packaged in the SC-70 (DCK) outline: 6-pin, 2.00 mm × 1.25 mm body, 0.65 mm pitch, exposed pad optional. Pin 1 = CATHODE, Pin 2 = NC (no internal connection), Pin 3 = REF, Pin 4 = ANODE, Pins 5–6 = NC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431BILPR, TLV431AILPM5 trades 0.5% accuracy for lower unit cost and sufficient stability for industrial power supplies; compared with TLVH431ILP, it offers smaller SC-70 size and lower minimum operating voltage but lacks extended voltage range and current capability.

Availability

TLV431AILPM5 is available at Aetrix Electronics and suitable for industrial power supplies, isolated DC-DC converters, and precision voltage monitoring systems requiring stable component supply and long-term manufacturability.

Supply support for TLV431AILPM5 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 delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The TLV431 family was designed specifically as a low-voltage, precision shunt reference for isolated feedback in compact, energy-efficient switch-mode power supplies - targeting space- and accuracy-constrained applications where traditional TL431 devices cannot operate.

FAQ

What is the reference voltage tolerance of TLV431AILPM5 at 25°C?

The TLV431AILPM5 has a reference voltage tolerance of ±1% at 25°C, meaning its VREF is guaranteed between 1.228 V and 1.252 V under nominal conditions. This tolerance is specified per the TLV431A variant designation in the device family and applies directly to TLV431AILPM5 as confirmed in Section 6.6 of the official datasheet. The part maintains this accuracy across its rated industrial temperature range (–40°C to 85°C) with a maximum deviation of ±6 mV.

Can TLV431AILPM5 replace a standard Zener diode in a 3.3-V regulator circuit?

Yes, TLV431AILPM5 can directly replace low-voltage Zener diodes (e.g., 2.4-V or 3.3-V types) in shunt regulation circuits. Its 1.24-V reference, adjustable output (1.24–6 V), sharp turn-on, and 0.25-Ω dynamic impedance provide superior accuracy, lower temperature drift, and better regulation than discrete Zeners. In a 3.3-V application, use R1/R2 resistive divider to set cathode voltage; TLV431AILPM5 will sink current to hold REF at 1.24 V - replicating Zener behavior with enhanced performance.

What is the minimum cathode current required for regulation in TLV431AILPM5?

The TLV431AILPM5 requires a minimum cathode current (IK(min)) of 80 µA typical to maintain regulation, as specified in Section 6.6 of the datasheet for the TLV431A variant. This value is valid across the full industrial temperature range (–40°C to 85°C). Below this threshold, the internal amplifier exits linear region and regulation fails. Designers must ensure external circuitry supplies ≥80 µA into the CATHODE pin under all operating conditions, including light-load and startup scenarios.

Which package does TLV431AILPM5 use, and how does it compare to SOT-23-3?

TLV431AILPM5 uses the SC-70 (DCK) package: 6-pin, 2.00 mm × 1.25 mm body size, 0.65 mm pitch. Per TI's Device Information table, this is 40% smaller in footprint than the SOT-23-3 package (2.90 mm × 1.30 mm). Though pin-count differs (6-pin SC-70 vs 3-pin SOT-23-3), both share functional equivalence for shunt regulation - pins 1, 3, and 4 of DCK map to CATHODE, REF, and ANODE respectively, with remaining pins designated NC.

Does TLV431AILPM5 require an external compensation capacitor for stability?

No, TLV431AILPM5 does not require an external output capacitor for stability. As stated in Section 8.3, it is internally compensated and remains stable without a cathode-to-anode bypass capacitor - a key advantage over many linear regulators. Stability testing (Figure 18) confirms robust operation with capacitive loads up to 10 nF at VKA = 2.5 V. However, designers should avoid excessive PCB trace capacitance (>100 pF) directly at the CATHODE node to prevent unintended phase shifts.