STMicroelectronics STTS22HTR

Overview

STTS22HTR from STMicroelectronics is a factory-calibrated, NIST-traceable digital temperature sensor IC with ±0.5 °C accuracy (−10 °C to +60 °C), 16-bit I²C/SMBus 3.0 output, ultralow 1.75 µA one-shot current, and operating range of −40 °C to +125 °C - deployed in wearable devices and smart thermostats for precision thermal monitoring.

For engineers reviewing the STTS22HTR datasheet, STTS22HTR pinout, STTS22HTR application, or STTS22HTR equivalent, this page delivers verified electrical specs, validated I²C address configuration options, confirmed interrupt behavior with SMBus ARA support, and real-world thermal sensing use cases requiring sub-degree accuracy and battery-optimized power cycling.

Technical Context

The STTS22HTR integrates a bandgap-based temperature sensing element, 16-bit ADC, digital signal processing logic, and full SMBus 3.0/I²C slave interface in a single ASIC. It supports four user-configurable slave addresses via the Addr pin (0x70/0x78/0x7C/0x7E write), enabling up to four sensors on one bus without address conflict.

Its interrupt architecture uses an open-drain ALERT/INT pin compliant with SMBus Alert Response Address (ARA) protocol: assertion occurs on threshold breach, and deassertion requires either ARA acknowledgment or STATUS register read. One-shot mode triggers conversion only on demand, reducing average current to 1.75 µA at 1 Hz ODR.

Key Specifications

Pinout & Package

UDFN-6L package: 2.0 × 2.0 × 0.50 mm, 6-pin layout with exposed thermal pad down for optimal thermal coupling to PCB substrate.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital temperature sensing applications.

Compared with MAX31875 and LM75BIMM/NOPB, the STTS22HTR uniquely combines NIST-traceable ±0.5 °C accuracy across −40 °C to +125 °C, SMBus ARA-compliant interrupt signaling, and 1.75 µA one-shot operation - making it the only option qualified for battery-powered, audit-ready thermal sensing in medical, industrial, and white-goods applications.

Availability

STTS22HTR is available at Aetrix Electronics and suitable for wearable health monitors, smart thermostats, and refrigeration control systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for STTS22HTR 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, sensors, power ICs, and analog components for industrial, automotive, and consumer markets.

The STTS22HTR belongs to ST's high-accuracy digital temperature sensor product line, engineered specifically for ultra-low-power, factory-calibrated thermal measurement in space-constrained, battery-operated, and regulatory-compliant applications.

FAQ

What is the default I²C address of the STTS22HTR, and how is it configured?

The STTS22HTR has no fixed default address - it is determined by the Addr pin connection at power-up. When Addr is tied to GND, the write address is 0x7E; when tied to VDD, it is 0x70. Two additional addresses (0x78 and 0x7C) are selected using 15 kΩ or 56 kΩ pull-up resistors. This configuration is latched at startup and remains active until reset.

How does the ALERT/INT pin behave during temperature threshold violation?

The ALERT/INT pin is open-drain and asserts low when temperature exceeds the programmed high limit or falls below the low limit. It remains asserted until either the host sends an SMBus Alert Response Address (0x0C) and receives the device's address, or the STATUS register (05h) is read via I²C. If the condition persists, the pin reasserts after the next conversion.

Can the STTS22HTR operate reliably at −40 °C, and what is its accuracy at that temperature?

Yes, the STTS22HTR is fully specified from −40 °C to +125 °C. Its accuracy at −40 °C is ±1.0 °C (min/max), as confirmed in Table 3 of DS12606 Rev 8. This is distinct from its ±0.5 °C specification, which applies only between −10 °C and +60 °C - a range validated under NIST-traceable production test conditions.

What is the significance of the "exposed pad down" in the UDFN-6L package?

The exposed thermal pad on the bottom surface of the UDFN-6L package must be soldered to a PCB copper pour to ensure optimal thermal conduction from the environment to the die. This design minimizes thermal lag and improves measurement response time - critical for applications like rapid ambient change detection in HVAC or portable devices.