onsemi CS8126-2GT5

Overview

CS8126-2GT5 from ON Semiconductor is a 5V, 750mA low dropout linear regulator with integrated delayed RESET function, reverse battery protection (±50V/60V), thermal shutdown, and short-circuit current limiting. It delivers 3% output accuracy, 0.6V dropout at 0.5A, and operates across automotive temperature range (−40°C to +125°C) for engine control units and body electronics.

For engineers reviewing the CS8126-2GT5 datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-220-5 package, programmable RESET delay via external capacitor, open-collector RESET output, and guaranteed operation down to 1V output voltage during fault conditions.

Technical Context

The CS8126-2GT5 implements a PNP-based low-dropout architecture with anti-saturation and current-limit circuitry, enabling stable 5V regulation under high line transients (up to 95V). Its dual comparator system features hysteresis on both RESET and DELAY thresholds (200–250mV and 200–800mV respectively) for noise immunity.

It integrates a latching discharge circuit that fully discharges the external delay capacitor to ≤0.5V upon any output fault-short circuit, thermal shutdown, overvoltage, or undervoltage-ensuring deterministic RESET pulse generation independent of input voltage.

Key Specifications

Pinout & Package

CS8126-2GT5 uses a 5-lead TO-220 straight-mount package with tab connected to GND for thermal and electrical grounding. The package meets JEDEC TO-220 mechanical standards and supports up to 50°C/W junction-to-ambient thermal resistance with adequate heatsinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5V automotive LDO regulator applications.

Compared with LM2925T-5.0/NOPB and TLE4260G, CS8126-2GT5 uniquely combines programmable RESET delay with full capacitor discharge, −50 V reverse battery tolerance, and 750 mA output - making it optimal for cost-sensitive, high-reliability automotive modules where deterministic reset behavior and transient resilience are mandatory.

Availability

CS8126-2GT5 is available at Aetrix Electronics and suitable for engine control units, body control modules, and telematics systems requiring stable component supply across extended temperature and harsh electrical environments.

Supply support for CS8126-2GT5 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

ON Semiconductor is a global semiconductor supplier specializing in energy-efficient electronics for automotive, industrial, and cloud power applications.

The CS8126-2GT5 belongs to ON Semiconductor's automotive-grade linear regulator product line, engineered specifically for under-hood and body electronics demanding high transient immunity, extended temperature operation, and integrated system supervision functions.

FAQ

What is the maximum input voltage the CS8126-2GT5 can withstand during load dump events?

The CS8126-2GT5 is rated for +60 V peak transient voltage per ISO 7637-2 Pulse 5a, allowing direct connection to vehicle battery rails without external clamping. This specification is verified across −40°C to +125°C ambient and applies to both powered and unpowered states. The device remains functional after such events, provided junction temperature stays within 150°C limits. CS8126-2GT5 achieves this via integrated Zener-like clamp structures and robust PNP pass transistor design.

Does the CS8126-2GT5 require an external capacitor on the Delay pin, and what happens if it is omitted?

Yes, the CS8126-2GT5 requires an external capacitor (typically 0.1 µF) between Delay pin and GND to set RESET assertion time. If omitted, the RESET output asserts immediately upon power-up or fault detection with no delay - effectively disabling the programmable timing feature. The internal delay comparator still functions, but without capacitance, the charge time collapses to nanoseconds. CS8126-2GT5 will operate safely in this mode, but system-level reset sequencing must be handled externally.

How does the CS8126-2GT5 handle reverse battery connection, and what is the safe voltage limit?

The CS8126-2GT5 incorporates monolithic reverse battery protection rated for −50 V with a 10 Ω load, per datasheet Absolute Maximum Ratings. When reverse polarity is applied, internal protection diodes block conduction while limiting reverse current to safe levels (<100 µA typical). No external components are needed. This protection remains active across the full operating temperature range. CS8126-2GT5 survives such events without latch-up or parametric shift, ensuring long-term reliability in service environments where battery terminals may be misconnected.

Can the CS8126-2GT5 be used without a heatsink in a 750 mA application at 85°C ambient?

No - at 750 mA load and 85°C ambient, the CS8126-2GT5 in TO-220-5 package exceeds safe junction temperature without heatsinking. Using R_ΘJA = 50°C/W and worst-case dropout (0.6 V), power dissipation reaches ~450 mW, raising junction temperature to ~107°C above ambient (≈192°C), exceeding the 150°C absolute maximum. A minimum 15 cm² copper pour (2 oz) or small clip-on heatsink is required. CS8126-2GT5 thermal performance data confirms this in Package Specification Table on page 7 of the datasheet.

Is the RESET output of the CS8126-2GT5 compatible with 3.3 V logic microcontrollers?

Yes - the RESET output is an open-collector NPN transistor with V_OL ≤ 0.4 V at 3 mA sink current, making it directly compatible with 3.3 V CMOS/TTL inputs when pulled up to 3.3 V. No level-shifting circuitry is needed. The output remains valid down to V_OUT = 1 V, ensuring reliable signaling even during severe brownout. CS8126-2GT5's RESET pin meets standard microcontroller reset input thresholds across temperature and supply variations.