STMicroelectronics STM704TDS6F

Overview

STM704TDS6F from STMicroelectronics is a 3 V industrial-grade microprocessor supervisory IC with battery switchover, active-low push-pull RST output, manual reset (MR) input, power-fail comparator (PFI/PFO), and guaranteed reset assertion down to VCC = 1.0 V. It provides non-volatile SRAM backup control, 200 ms typical reset timeout (trec), and operates from –40 °C to +85 °C in SO8 package.

For engineers reviewing the STM704TDS6F datasheet, STM704TDS6F pinout, STM704TDS6F application, or STM704TDS6F equivalent, key selection criteria include reset threshold accuracy, battery switchover behavior, PFI/PFO response timing, MR debounce tolerance, and compatibility with external LPSRAM retention circuits.

Technical Context

The STM704TDS6F integrates a precision voltage reference and comparator monitoring VCC against a fixed 2.63 V reset threshold (VRST) with 100 mV hysteresis. Its internal trec generator ensures 200 ms (typ) reset pulse width after power-up, MR release, or VCC recovery - independent of supply ramp rate.

It implements automatic battery switchover via internal P-channel MOSFET: VOUT connects to VCC when VCC ≥ 2.4 V (VSW), and switches to VBAT when VCC falls below VSW. Vccsw provides a push-pull logic-level signal indicating switchover state, enabling external PMOS gate drive for >75 mA IOUT.

Key Specifications

Pinout & Package

STM704TDS6F is housed in an 8-pin SO8 (Small Outline Integrated Circuit) package, 3.9 mm × 4.9 mm body, 1.27 mm pitch, RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX691ACSA+ and TPS3823-33DBVR, STM704TDS6F uniquely integrates battery switchover, MR, PFI/PFO, and Vccsw in a single SO8 package - making it the only option among the three that supports full LPSRAM retention with early power-fail warning and field-service reset capability.

Availability

STM704TDS6F is available at Aetrix Electronics and suitable for smart energy meters, industrial PLC controllers, point-of-sale terminals, and medical infusion pumps requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for STM704TDS6F 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The STM690/704/795/802/804/805/806 family was engineered specifically for robust microprocessor supervision in battery-backed embedded systems - emphasizing low-power SRAM retention, precise reset timing, and seamless power-rail handover.

FAQ

What is the function of the Vccsw pin on STM704TDS6F?

Vccsw is a push-pull output that goes high when VOUT switches from VCC to VBAT, and low when VOUT reconnects to VCC. It provides a logic-level signal to drive the gate of an external PMOS transistor, enabling higher current (>75 mA) battery backup for LPSRAM where the internal 100 Ω switch is insufficient.

Can STM704TDS6F be used without a backup battery?

Yes. When no battery is used, connect both VBAT and VOUT directly to VCC. The device disables battery switchover logic and operates solely as a reset supervisor with PFI/PFO monitoring and MR functionality, maintaining full 3 V operation and 200 ms trec timing.

How does the PFI/PFO circuit provide early warning of power failure?

PFI monitors an external voltage (e.g., scaled VCC) against a 2.45 V threshold. When PFI falls below this level, PFO asserts low within 100–200 µs - typically 150 µs before VCC crosses the 2.63 V reset threshold - giving firmware time to save critical data before RST activates.

Is the MR input internally debounced, and what is its pull-up value?

Yes, the MR input is internally debounced and requires no external RC network. It features a 40 kΩ internal pull-up resistor, allowing direct connection to a momentary switch (MR to GND) or TTL/CMOS logic. In noisy environments, a 0.1 µF capacitor from MR to GND adds immunity without affecting timing.