STMicroelectronics CLT03-2Q3

Overview

CLT03-2Q3 from STMicroelectronics is a dual-channel, self-powered digital input current limiter for industrial PLC and remote I/O modules. It provides 4 mA typical input current limiting, ±2 kV IEC 61000-4-2 ESD protection, and operates across –30 °C to +125 °C ambient without external supply. It supports high-side/low-side and isolated/non-isolated configurations while meeting IEC 61131-2 Type 1 and Type 3 input characteristics.

For engineers reviewing the CLT03-2Q3 datasheet, CLT03-2Q3 pinout, CLT03-2Q3 application, or CLT03-2Q3 equivalent, key selection criteria include dual-channel current limiting accuracy (2.5–4 mA), fault-mode overvoltage response (30–40 V threshold), deglitch-filtered propagation delay (2–5 µs), and QFN-16L thermal resistance (41 °C/W).

Technical Context

The CLT03-2Q3 integrates two independent current-limiting channels with built-in deglitch filtering, test-pulse diagnostics, and dual-mode output drive (isolated LVTTL-compatible or non-isolated with internal pull-down). Each channel features programmable fault detection at ≥30 V input voltage and automatic current reduction to 1–2.5 mA in fault mode.

Its U-I characteristic conforms to IEC 61131-2 Type 1 (UL_{max_H} = 15 V) and Type 3 (UL_{max_H} = 11 V) limits, enabling direct interface with 24 V DC field sensors. The device draws zero quiescent power in OFF state and activates solely from input signal energy.

Key Specifications

Pinout & Package

CLT03-2Q3 is housed in a thermally optimized QFN-16L package (4.0 × 2.0 mm, 0.5 mm pitch) with exposed thermal pad (TAB1/TAB2) for enhanced heat dissipation in high-density industrial PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital input current limiting applications.

Compared with CLT03-1SC3, the CLT03-2Q3 delivers dual-channel density and superior thermal performance (41 vs. 120 °C/W), while TI ISO1211 offers higher isolation rating but lacks integrated current limiting, fault response, and self-test - making CLT03-2Q3 optimal for compact, self-powered, safety-aware industrial input modules.

Availability

CLT03-2Q3 is available at Aetrix Electronics and suitable for programmable logic controller digital input modules, remote I/O terminal units, industrial safety monitoring systems, and machine control cabinet input interfaces requiring stable component supply and long-term industrial lifecycle support.

Supply support for CLT03-2Q3 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with strong focus on functional safety and industrial reliability.

The CLT03 series belongs to ST's industrial interface portfolio, designed specifically to replace discrete current-limiting networks in PLC and distributed I/O systems while delivering integrated EMC robustness, fault safety, and self-powered operation.

FAQ

Does CLT03-2Q3 require an external power supply?

No. CLT03-2Q3 is fully self-powered - it draws operating energy directly from the input signal and consumes zero current in the OFF state. Internal charge pump circuitry, stabilized by external VBUF capacitors, enables this functionality without auxiliary rails or regulators.

How does the test pulse feature work and what capacitor value is needed?

The test pulse feature uses an external capacitor between TP and OUTN pins to set pulse frequency: 100–4700 pF yields 4.1–219 kHz. At each period (256 × t_TP), OUTP is forced low for t_TP duration. This enables periodic functional verification without external test equipment, satisfying IEC 61508 diagnostic coverage requirements.

What is the difference between isolated and non-isolated modes?

In isolated mode, OUTP drives optocouplers using OUTN as dedicated ground; in non-isolated mode, PD pins provide internal 2.85–4.25 kΩ pull-downs to interface directly with 3.3 V LVTTL receivers. Configuration is determined by external circuit topology - no mode-select pin is required.

Can CLT03-2Q3 be used with both high-side and low-side field wiring?

Yes. CLT03-2Q3 supports both high-side and low-side sourcing due to its bidirectional input architecture and reverse-plug compatible INA/INB terminals. This eliminates wiring polarity concerns during installation and enables reuse across regional OEM standards without hardware changes.