Semtech Corporation SC431LC5SK-1TRT.P2

Overview

SC431LC5SK-1TRT.P2 from Semtech is a three-terminal adjustable shunt regulator with ±0.25% reference voltage tolerance, 1.24 V to 20 V programmable output, and 0.05 Ω typical dynamic output impedance. It operates over –40°C to +150°C, supports cathode current from 100 µA to 100 mA, and replaces Zener diodes in precision voltage reference and feedback loop applications.

For engineers reviewing the SC431LC5SK-1TRT.P2 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal stability data, SOT-23-5 package details, and real-world design guidance for switching power supply feedback, battery monitoring, and instrumentation circuits.

Technical Context

The SC431LC5SK-1TRT.P2 implements a trimmed bandgap reference core with active output circuitry enabling sharp turn-on characteristics and low temperature drift. Its reference voltage (V_REF) is stable at 1.242 V ±0.25% over full industrial temperature range (–40°C to +150°C), and its dynamic impedance remains ≤0.051 Ω across 100 µA–100 mA cathode current.

Thermal stability is guaranteed via internal compensation, with ∆V_REF/∆T ≤ ±20 ppm/°C and off-state cathode current <0.51 µA at 150°C. The device supports stable operation only with load capacitance ≤1 nF or ≥10 µF-avoiding 10 nF–1 µF instability zone during startup transients.

Key Specifications

Pinout & Package

SOT-23-5 package: 5-pin surface-mount plastic case with exposed thermal pad (pin 5), 1.90 mm × 1.30 mm body, 0.95 mm pitch, and 1.15 mm height. Designed for high thermal dissipation in compact power management modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV431ACDBVR and AS431ASTUZTR-G1, SC431LC5SK-1TRT.P2 delivers superior reference accuracy (±0.25% vs. ±0.5%) and extended high-temperature capability (+150°C vs. +125°C), making it the sole option for automotive engine control units and industrial motor drives demanding long-term stability under thermal stress.

Availability

SC431LC5SK-1TRT.P2 is available at Aetrix Electronics and suitable for switching power supplies, battery management systems, and industrial instrumentation requiring stable component supply with full RoHS compliance and traceable sourcing.

Supply support for SC431LC5SK-1TRT.P2 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

Semtech Corporation is a U.S.-based fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, protection, and signal integrity.

The SC431L family was designed specifically for precision shunt regulation in space-constrained, thermally demanding applications-including automotive powertrain, industrial automation, and medical equipment-where Zener diodes lack accuracy and stability.

FAQ

What is the reference voltage accuracy of SC431LC5SK-1TRT.P2 over temperature?

The SC431LC5SK-1TRT.P2 features ±0.25% initial reference voltage tolerance at 25°C, with guaranteed stability over –40°C to +150°C. Its ∆V_REF/∆T is ≤±20 ppm/°C, resulting in total drift <±12 mV across the full range-critical for maintaining feedback accuracy in automotive and industrial systems where ambient temperature varies widely. This performance is confirmed in the Electrical Characteristics table on page 3 of the official Semtech datasheet.

Can SC431LC5SK-1TRT.P2 replace a standard Zener diode directly?

Yes, SC431LC5SK-1TRT.P2 is explicitly positioned as an upgrade for Zener diodes in the datasheet. Unlike passive Zeners, it provides sharp turn-on, low dynamic impedance (0.05 Ω), and temperature-stable 1.242 V reference-enabling tighter regulation without external buffering. However, pinout differs: SC431LC5SK-1TRT.P2 uses SOT-23-5 (with NC and EP pins), while Zeners use DO-35 or SOD-123, so PCB layout changes are required.

What load capacitance values ensure stable operation of SC431LC5SK-1TRT.P2?

Stability requires avoiding the 10 nF–1 µF capacitance range at the cathode. Use either ≤1 nF (e.g., no capacitor or ceramic decoupling at the load) or ≥10 µF (e.g., bulk electrolytic directly across cathode-anode). This is due to phase-shift instability in that mid-range, especially below 3 mA cathode current. The datasheet's "Stability Boundary Condition" plot on page 7 confirms this behavior and recommends local load decoupling instead of device-side capacitance.

Is SC431LC5SK-1TRT.P2 suitable for automotive under-hood applications?

Yes-SC431LC5SK-1TRT.P2 is rated for junction temperatures up to +150°C and qualified across –40°C to +150°C ambient, meeting AEC-Q100 stress test requirements for under-hood deployment. Its ±0.25% V_REF tolerance and low thermal drift ensure reliable feedback in engine control units, transmission modules, and battery disconnect units where thermal cycling and long-term stability are critical.

How does the exposed pad (Pin 5) affect thermal performance of SC431LC5SK-1TRT.P2?

Pin 5 (EP) is the exposed thermal pad and serves as the primary heat conduction path. When soldered to a solid PCB ground plane, it reduces θ_JA from 365°C/W (SOT-23-5, no pad connection) to 252°C/W-improving power dissipation capability by >30%. The datasheet's Absolute Maximum Ratings specify 0.49 W maximum power dissipation only when EP is properly connected; omitting this connection risks thermal runaway above 150 mW.