onsemi CS5204-3GT3

Overview

CS5204-3GT3 from onsemi is a 4.0 A, 3.3 V fixed-output linear regulator in TO-220-3 package with ±2.0% output accuracy, 1.1 V dropout at full load, thermal shutdown, and SOA protection. It serves as a post-regulator for microprocessor core supplies where low-voltage operation and fast transient response are critical, such as in embedded control units and industrial PLC power rails.

For engineers reviewing the CS5204-3GT3 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, package configuration, real-world use cases, and validated alternative parts - all grounded in the official ON Semiconductor CS5204−3/D datasheet (Rev. 9, Sept. 2006).

Technical Context

The CS5204-3GT3 implements a composite PNP-NPN output stage optimized for high-current, low-dropout regulation. Its internal bandgap reference and error amplifier maintain stable 3.3 V output across 10 mA–4.0 A load range, with line regulation of 0.04% typical and load regulation of 0.05% typical under specified conditions.

Protection architecture integrates three independent circuits: current limiting (4.5–8.5 A depending on VIN–VOUT), thermal shutdown (150–180°C activation), and Safe Operating Area (SOA) circuitry that dynamically reduces max output current as input-output differential increases - preventing destructive power dissipation during high-VIN/low-VOUT operation.

Key Specifications

Pinout & Package

CS5204-3GT3 uses the TO-220-3 (T suffix, Case 221A) package with tab connected to VOUT. The case serves as the primary heat path and must be electrically isolated if VOUT is not ground-referenced.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output linear regulator applications.

Compared with LM350K STEEL and LT1529CT-3.3, the CS5204-3GT3 uniquely combines 4.0 A capability, SOA protection, and 1.1 V dropout - making it the only option among the three qualified for sustained 12 V→3.3 V conversion at full rated current in thermally constrained enclosures.

Availability

CS5204-3GT3 is available at Aetrix Electronics and suitable for industrial PLC power rails, embedded microcontroller core supplies, test equipment backplanes, and medical sensor interfaces requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for CS5204-3GT3 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The CS5204-3GT3 belongs to the CS5204-x family of high-current linear regulators designed specifically for post-regulation in microprocessor and FPGA power systems where low dropout, fast transient response, and integrated fault protection are mandatory.

FAQ

What is the maximum input voltage rating for the CS5204-3GT3?

The CS5204-3GT3 has an absolute maximum supply voltage (VCC) rating of 17 V. Operation above this voltage risks permanent damage to the internal PNP-NPN output transistor and protection circuitry. For reliable long-term use, the recommended maximum continuous input is 15 V, as specified in the datasheet's electrical characteristics table under standard test conditions.

Does the CS5204-3GT3 require an external output capacitor, and what type is recommended?

Yes, the CS5204-3GT3 requires an external output capacitor for loop stability and transient response. A 22 µF tantalum capacitor is the minimum recommended value; aluminum electrolytic capacitors are acceptable but exhibit greater ESR variation at low temperatures. Ceramic capacitors alone are not recommended due to near-zero ESR, which can cause instability - however, parallel ceramic-tantalum networks improve high-frequency transient performance in microprocessor applications.

How does the SOA protection in the CS5204-3GT3 differ from standard overcurrent limiting?

Unlike fixed-threshold current limiting, the CS5204-3GT3's SOA protection dynamically reduces the maximum allowable output current as the input-output voltage differential increases. For example, at VIN–VOUT = 3.0 V, current limit remains ~4.5 A, but at VIN–VOUT = 9.0 V, it drops to ~1.0 A - preventing destructive power dissipation (e.g., >36 W) that would otherwise exceed safe junction temperature limits even with thermal shutdown active.

Can the CS5204-3GT3 be used without a heatsink?

The CS5204-3GT3 can operate without an external heatsink only at very low power dissipation - for instance, ≤0.5 W (e.g., 5 V input → 3.3 V @ 0.3 A). At full 4.0 A load with 12 V input, power dissipation exceeds 34 W, requiring a heatsink with RJA ≤ 1.5°C/W. The TO-220-3 package has RJC = 1.6°C/W; therefore, heatsink selection must account for interface resistance (RCS) and ambient conditions to keep TJ ≤ 150°C.

Is the metal tab of the CS5204-3GT3 electrically isolated from the pins?

No - the metal tab of the CS5204-3GT3 is internally connected to Pin 2 (VOUT). This means the tab carries the full 3.3 V output potential and must be electrically isolated from chassis ground using an insulating pad and thermal compound if mounted to a grounded heatsink. Failure to isolate may cause short circuits or ground loops in systems where VOUT is not referenced to system ground.