STMicroelectronics TS3121AICT

Overview

TS3121AICT from STMicroelectronics is a rail-to-rail input, open-drain single comparator qualified to AEC-Q100 Grade 1, featuring 2 mV max input offset voltage at 25 °C, 70 μA typical supply current, 1.7–5.5 V supply range, and 60 ns propagation delay (high-to-low, 100 mV overdrive). It operates across –40 to +125 °C and supports overcurrent protection and industrial sensor interface applications.

For engineers reviewing the TS3121AICT datasheet, TS3121AICT pinout, TS3121AICT application, or TS3121AICT equivalent, key selection considerations include guaranteed start-up time (10–15 µs), output sink capability up to 140 mA at 5 V, rail-to-rail input common-mode range (–0.2 to VCC+ + 0.2 V), and embedded hysteresis (1 mV) for noise immunity in noisy automotive environments.

Technical Context

The TS3121AICT implements a high-speed, low-power comparator core with built-in hysteresis and rail-to-rail input stage, enabling accurate threshold detection even near supply rails. Its open-drain output supports flexible pull-up configurations and withstands voltages beyond VCC, allowing interfacing with higher-voltage logic domains.

It features guaranteed start-up behavior without external reset circuitry, operates down to 1.7 V supply, and maintains stable performance across temperature due to low input offset drift (3–20 µV/°C) and high CMRR (55–70 dB) and SVR (58–80 dB).

Key Specifications

Pinout & Package

TS3121AICT is housed in a SC70-5 (SOT23-5 compatible) 5-pin surface-mount package, optimized for space-constrained PCB layouts in automotive and industrial modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar single comparator applications.

Compared with TS3121AICT, TS3021ICT trades open-drain flexibility for simpler drive capability, while TS3011ICT sacrifices automotive qualification and low-power operation for raw speed-making TS3121AICT the optimal choice for AEC-Q100-compliant, low-quiescent-current threshold detection.

Availability

TS3121AICT is available at Aetrix Electronics and suitable for automotive body electronics, industrial overcurrent protection systems, and power tool controller designs requiring stable component supply, long-term lifecycle support, and AEC-Q100 compliance.

Supply support for TS3121AICT 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, designing and manufacturing microcontrollers, power management ICs, sensors, and analog components for automotive, industrial, and consumer markets.

The TS3121 series belongs to ST's precision analog comparators product line, engineered specifically for robust, low-power threshold detection in harsh-temperature automotive and industrial environments.

FAQ

What is the maximum output sink current for TS3121AICT at 3.3 V supply?

At VCC = 3.3 V and T = 25 °C, TS3121AICT guarantees a minimum sink current of 45 mA (typ. 70 mA) with VOL ≤ 50 mV at 1 mA load. Full datasheet specifications confirm 35–70 mA across –40 to +125 °C, making it suitable for driving LEDs or small MOSFET gates directly.

Does TS3121AICT require external hysteresis for stable operation?

No. TS3121AICT integrates 1 mV of internal hysteresis, eliminating the need for external positive feedback resistors. This built-in feature suppresses output oscillation during slow or noisy input transitions, simplifying design and reducing BOM count in motor control and sensor monitoring applications.

Can TS3121AICT operate from a 1.8 V supply in battery-powered applications?

Yes. TS3121AICT is fully specified from 1.7 V to 5.5 V. At 1.8 V, it delivers 78–81 μA supply current, 60–85 ns propagation delay (tPHL), and maintains rail-to-rail input operation - enabling reliable use in coin-cell or single-cell Li-ion powered equipment such as portable diagnostic tools.

How does the TS3121AICT differ from the TS3121P variant?

TS3121AICT lacks the embedded Power-on Reset (PoR) circuit present in TS3121P. While both share identical comparator performance, offset, and speed, TS3121P guarantees known output state during power ramp-up (tPoR = 10–15 µs), whereas TS3121AICT relies on natural start-up (tstart-up = 10–15 µs) without forced reset assertion.