STMicroelectronics STM817MM6E

Overview

STM817MM6E from STMicroelectronics is a 5 V microprocessor supervisory IC with integrated battery switchover, power-fail comparator (PFI/PFO), and watchdog timer. It provides active-low RST and active-high RST outputs, guarantees reset assertion down to VCC = 1.0 V, and supports external low-power static RAM (LPSRAM) backup via VOUT. Used in industrial embedded systems requiring reliable power monitoring and non-volatile memory retention during main supply failure.

For engineers reviewing the STM817MM6E datasheet, STM817MM6E pinout, STM817MM6E application, or STM817MM6E equivalent, key selection criteria include guaranteed reset assertion at 1.0 V VCC, 200 ms typical reset timeout (trec), 1.6 s watchdog timeout, automatic VCC-to-VBAT switchover, and dual push-pull reset outputs for flexible MCU interface.

Technical Context

The STM817MM6E implements a precision voltage reference and comparator to monitor VCC against a 4.63 V reset threshold (VRST) with ±1.5% accuracy. Its internal P-channel MOSFET switch enables seamless switchover from VCC to VBAT when VCC falls below the lesser of VRST or VBAT (VSO), with 100 Ω on-resistance and guaranteed operation for VBAT ≥ 1 V.

It integrates a 1.6 s typ watchdog timer cleared by WDI edge transitions, a power-fail comparator with VPFI = 2.4 V (±2%), and dual push-pull reset outputs - RST (active-low) and RST (active-high) - both asserted synchronously for trec ≥ 200 ms after any fault condition (VCC drop, MR low, or watchdog timeout).

Key Specifications

Pinout & Package

STM817MM6E is housed in an SO8 (Small Outline 8-pin) package per JEDEC MS-012, with 1.27 mm pitch, body size 4.9 × 3.9 mm, and 1.75 mm max height. Pin 1 marked by notch or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX692AESA+ and TPS3823-46DBVR, STM817MM6E uniquely integrates battery switchover, watchdog, and power-fail comparator in a single SO8 package - enabling compact, feature-complete supervision without external components or firmware overhead.

Availability

STM817MM6E is available at Aetrix Electronics and suitable for industrial PLC controllers, smart metering systems, medical diagnostic equipment, and automotive telematics units requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for STM817MM6E 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, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The STM69x/70x/80x/81x supervisor family was engineered specifically for robust, low-power microprocessor supervision in harsh industrial environments - emphasizing guaranteed reset behavior, battery-backed memory retention, and early power-failure detection.

FAQ

What is the function of the E and ECON pins on STM817MM6E?

E is the chip-enable input that controls gating of the external LPSRAM. When E is low and reset is not asserted, ECON goes low to enable SRAM access; during reset or when E is high, ECON remains high to isolate the memory. This prevents unintended writes during power transitions or system faults.

Does STM817MM6E require external components to operate?

No external components are required for basic reset supervision. A 0.1 µF decoupling capacitor on VCC is recommended. For PFI monitoring or MR debouncing in noisy environments, additional 0.1 µF capacitors may be added, but they are not mandatory per datasheet specifications.

How does the battery freshness seal work on STM817MM6E?

The battery freshness seal disables VBAT discharge until first power-up: when VCC rises above VRST after initial application, the internal seal is broken, enabling VBAT-to-VOUT switchover. This prevents battery drain during storage and ensures full capacity is available at system commissioning.

Can STM817MM6E be used with 3.3 V microcontrollers?

Yes - while VCC must be 5 V, the RST and RST outputs are push-pull and tolerate 5 V logic levels. Interface with 3.3 V MCUs requires external level-shifting or series resistors to limit current into 3.3 V I/O pins, as absolute maximum ratings prohibit direct 5 V input to 3.3 V-tolerant GPIO.