STMicroelectronics STM708TDS6F

Overview

STM708TDS6F from STMicroelectronics is a 3 V precision voltage supervisor IC with dual active-low and active-high reset outputs, 200 ms reset timeout, power-fail comparator (PFI/PFO), and manual reset input (MR). It monitors VCC for out-of-tolerance conditions down to 1.0 V and asserts reset during power-up, brownout, or watchdog timeout. Used in industrial controllers and embedded systems requiring reliable power sequencing and fault detection.

For engineers reviewing the STM708TDS6F datasheet, STM708TDS6F pinout, STM708TDS6F application, or STM708TDS6F equivalent, key selection criteria include reset threshold accuracy (3.00–3.15 V), guaranteed RST assertion at VCC ≥ 1.0 V, TSSOP8 package compatibility, and PFI/PFO undervoltage warning capability for early power failure detection.

Technical Context

The STM708TDS6F integrates a precision voltage reference and comparator to monitor VCC against a fixed 3.00–3.15 V reset threshold. It features independent push-pull RST and RST outputs, enabling simultaneous reset signaling to multiple logic families or bidirectional microprocessor interfaces.

It includes a dedicated power-fail comparator with 1.25 V typical VPFI threshold, decoupled from the main reset comparator, allowing early warning of supply collapse before VCC drops below operational limits. The MR input has an internal 40 kΩ pull-up and supports direct switch-to-ground connection without external debounce.

Key Specifications

Pinout & Package

STM708TDS6F is housed in an 8-pin TSSOP package (3 mm × 3 mm body, 0.65 mm pitch), RoHS-compliant and rated for industrial temperature operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM706TDS6F and MAX6326UT29D3+T, STM708TDS6F uniquely delivers dual-reset polarity and integrated PFI/PFO in the same compact TSSOP8 package - essential for systems requiring both fault resilience and graceful shutdown capability.

Availability

STM708TDS6F is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, smart energy meters, and automated test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM708TDS6F 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 specializing in automotive, industrial, and power management solutions, with broad portfolio coverage from discrete devices to complex SoCs.

The STM70x series is designed specifically for robust microprocessor supervision in harsh industrial environments, emphasizing precision threshold stability, low quiescent current, and dual-output flexibility for mixed-signal system integration.

FAQ

What is the function of the NC pin on STM708TDS6F?

Pin 3 is a no-connect (NC) terminal - it is internally unbonded and must remain unconnected on the PCB. Routing traces to or placing solder pads on this pin may cause mechanical stress or contamination risks during assembly. STMicroelectronics specifies NC pins as electrically and physically isolated; no pull-up, pull-down, or bypass capacitor should be applied.

Can STM708TDS6F be used with a 3.3 V supply?

Yes - the STM708TDS6F is specified for V_CC operation from 2.7 V to 5.5 V, and its 3.00–3.15 V reset threshold is intentionally set below 3.3 V to ensure reliable assertion during 3.3 V rail brownout. At 3.3 V, supply current remains within 40 µA typical, and all timing parameters (t_rec, PFI response) meet datasheet specifications across –40 °C to +85 °C.

How does the power-fail comparator interact with the reset outputs?

The PFI/PFO circuit operates independently of the main reset comparator: PFO goes low when PFI falls below 1.25 V, but this does not directly assert RST or RST. To generate reset from PFO, it must be externally wired to the MR pin. This architecture allows designers to choose whether power-fail triggers immediate reset (via MR) or initiates a software-handled shutdown sequence (via interrupt or polling of PFO).

Is the MR input compatible with open-drain microcontroller GPIO?

Yes - the MR pin has an internal 40 kΩ pull-up resistor and accepts logic-low signals down to 0.8 V (V_IL). An open-drain GPIO configured as active-low can directly drive MR without external components. When MR is pulled low, reset remains asserted for the full 200 ms t_rec after the GPIO releases, satisfying most MCU reset timing requirements.