STMicroelectronics TS3121ILT

Overview

TS3121ILT from STMicroelectronics is a rail-to-rail input, open-drain single comparator with 60 ns propagation delay (typ.), 2 mV max offset voltage (A-grade), 70 μA typical supply current, and operation from 1.7 to 5.5 V. It features built-in hysteresis (1 mV), -40 °C to +125 °C extended temperature range, and AEC-Q100 qualification-enabling precise overcurrent detection in automotive power distribution modules.

For engineers reviewing the TS3121ILT datasheet, TS3121ILT pinout, TS3121ILT application, or TS3121ILT equivalent, key selection considerations include its 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 V to VCC+0.2 V), and compatibility with low-voltage industrial sensor interfaces requiring robust ESD tolerance (4 kV HBM).

Technical Context

The TS3121ILT implements a high-speed CMOS comparator core with internal hysteresis and open-drain output stage capable of sinking up to 140 mA at 5 V while maintaining rail-to-rail input operation down to 1.7 V supply. Its input bias current remains below 200 pA across temperature, enabling high-impedance sensing in battery-powered systems.

Unlike push-pull comparators, the open-drain output allows flexible pull-up configuration (e.g., to higher voltage rails), and the device's output pin withstands voltages exceeding VCC-supporting level-shifting and mixed-voltage interface designs without external components.

Key Specifications

Pinout & Package

TS3121ILT is housed in a 5-pin SC70 package (2.0 mm × 1.25 mm, 0.65 mm pitch), optimized for space-constrained PCB layouts in automotive ECUs and portable power tools.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TS3121ILT, TS3021ILT trades power efficiency for speed and output flexibility, while TS880IYLT sacrifices response time to halve supply current-making TS3121ILT the balanced choice for automotive and industrial applications demanding both speed and low power.

Availability

TS3121ILT is available at Aetrix Electronics and suitable for automotive battery management, industrial overcurrent protection, and power tool motor control requiring stable component supply across extended temperature and AEC-Q100-compliant production cycles.

Supply support for TS3121ILT 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, analog ICs, power devices, and sensors for automotive, industrial, and consumer markets.

The TS3121 series belongs to ST's precision analog comparator product line, engineered specifically for high-reliability automotive and industrial applications requiring fast response, low power, and extended temperature operation.

FAQ

What is the maximum output sink current for TS3121ILT at 1.8 V supply?

At VCC = 1.8 V, the TS3121ILT guarantees a minimum output sink current of 9 mA (typ. 11 mA) with VOL ≤ 80 mV at Isink = 1 mA. The absolute maximum rating allows 18 mA continuous sink, but design margin should respect the 9 mA min. value across temperature for reliable switching into standard LED or logic loads.

Does TS3121ILT require external hysteresis for noise immunity?

No. TS3121ILT integrates 1 mV of internal hysteresis, defined as the voltage difference between rising and falling input thresholds. This eliminates the need for external positive feedback resistors in most industrial and automotive applications, reducing component count and layout sensitivity to parasitic capacitance.

Can TS3121ILT operate with VCC = 1.7 V and still meet propagation delay spec?

Yes. The datasheet specifies tPHL/tPLH ≤ 250 ns (max) at VCC = 1.8 V and CL = 15 pF. At 1.7 V, performance degrades slightly but remains functional; however, ST characterizes and guarantees specs starting at 1.8 V. For production designs, 1.8 V is the minimum validated supply for full parametric compliance.

Is the TS3121ILT pin-compatible with TS3121A or TS3121P variants?

Yes. All TS3121 variants-including TS3121ILT (industrial grade), TS3121A (A-grade, tighter offset), and TS3121P (with Power-on Reset)-share identical SC70-5 pinout, electrical interface, and footprint. Only internal functionality (offset spec, POR circuit) differs; no PCB redesign is needed when upgrading between versions.