STMicroelectronics TS831-3IZT

Overview

TS831-3IZT from STMicroelectronics is a micropower voltage supervisor IC with active-low open-drain reset output, designed for power-on reset and brown-out detection in low-voltage microcontroller systems. It features a precision 2.71V threshold (typ.), 12µA supply current at 3V, 60mV internal hysteresis, guaranteed operation down to 1V V_CC, and 20µs response time under 10mV overdrive - deployed in battery-powered IoT sensors and portable medical monitors.

For engineers reviewing the TS831-3IZT datasheet, TS831-3IZT pinout, TS831-3IZT application, or TS831-3IZT equivalent, key selection criteria include reset threshold accuracy across temperature, ultra-low ICC stability at sub-3V rails, open-drain sink capability up to 1mA at 2.4V, and compatibility with TO-92 footprint constraints in space-constrained designs.

Technical Context

The TS831-3IZT integrates a thermally matched band-gap reference and comparator with fixed internal resistor divider setting V_THI = 2.71V (typ.) and V_THD = 2.65V (typ.), yielding 60mV hysteresis. Its open-drain output asserts low when V_CC falls below V_THD, requiring an external pull-up for logic-level compatibility.

It operates from 1V to 5.5V supply, maintains 12µA ICC across -40°C to +125°C, and delivers VOL ≤ 400mV at I_OL = 1mA and V_CC = 2.4V - enabling direct interface with 1.8V/2.5V/3.3V microcontrollers without level-shifting.

Key Specifications

Pinout & Package

TS831-3IZT is supplied in TO-92 plastic package (Z suffix), a 3-pin through-hole package with standard lead spacing and thermal resistance R_thJA = 200°C/W. Pin 1 = V_CC, Pin 2 = GND, Pin 3 = RESET (open-drain output).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD29+T and TPS3808G33DBVR, TS831-3IZT uniquely provides 2.71V threshold accuracy, TO-92 compatibility, and guaranteed 1V operation - making it optimal for legacy through-hole designs targeting sub-3V brown-out protection without added delay circuitry.

Availability

TS831-3IZT is available at Aetrix Electronics and suitable for wearable health monitors, smart meter battery backup circuits, automotive cabin controllers, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TS831-3IZT 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The TS831 series belongs to ST's micropower supervisor product line, engineered specifically for reliable, low-current reset generation in battery-critical and wide-temperature embedded systems - emphasizing threshold precision, sub-1V functionality, and minimal external component count.

FAQ

What is the minimum V_CC required for TS831-3IZT to assert a valid reset?

The TS831-3IZT guarantees functional reset assertion down to V_CC = 1V. At this voltage, the internal band-gap reference remains stable enough to compare against the 2.71V threshold divider, and the open-drain output can sink sufficient current to pull the /RESET line low when V_CC drops below V_THD ≈ 2.65V. This enables brown-out detection well before most MCUs lose register retention.

Does TS831-3IZT require an external pull-up resistor on the RESET pin?

Yes - the RESET pin is open-drain and requires an external pull-up resistor to the target logic rail (e.g., 3.3V or 1.8V). The value must be selected based on sink current capability: at V_CC = 2.4V, TS831-3IZT guarantees VOL ≤ 400mV with I_OL = 1mA, supporting pull-ups as low as 2.4kΩ for 3.3V systems. Graphs in the datasheet guide selection across temperature and voltage.

How does the 60mV hysteresis improve system reliability?

The 60mV hysteresis creates a 2.65V to 2.71V window between reset deassertion (V_THI) and reassertion (V_THD). This prevents oscillatory reset toggling during slow or noisy V_CC recovery - for example, when a buck converter ramps up gradually or experiences ripple near the threshold. It eliminates need for external RC filtering in most industrial and automotive applications.

Can TS831-3IZT replace MC33064 in existing TO-92 designs?

Yes - TS831-3IZT is pin-to-pin compatible with MC33064 in TO-92 (Z) package and shares identical pinout (V_CC, GND, RESET). However, it improves upon MC33064 with 12µA vs. 30µA ICC, tighter 2.71V threshold vs. ±5% tolerance, and guaranteed 1V operation vs. 2.5V minimum - delivering longer battery life and more robust brown-out detection without PCB changes.