STMicroelectronics STM802MM6E

Overview

STM802MM6E from STMicroelectronics is a 5 V microprocessor supervisory IC with battery switchover, NVRAM supervision for external LPSRAM, dual active-low and active-high reset outputs (RST/RST), 200 ms typical reset timeout (trec), and integrated watchdog timer (1.6 s typical timeout). It operates from –40 °C to +85 °C and supports industrial systems requiring reliable power monitoring and non-volatile memory backup.

For engineers reviewing the STM802MM6E datasheet, STM802MM6E pinout, STM802MM6E application, or STM802MM6E equivalent, key selection criteria include guaranteed RST assertion down to VCC = 1.0 V, automatic VCC-to-VBAT switchover at VSO (lesser of VRST or VBAT), low 0.4 µA battery supply current, push-pull RST/RST outputs, and compatibility with LPSRAM write-protection schemes.

Technical Context

The STM802 implements a precision voltage comparator monitoring VCC against a 4.65 V reset threshold (VRST) with hysteresis, triggering RST/RST assertion on undervoltage, watchdog timeout, or manual reset via MR. Its internal P-channel MOSFET switch enables seamless VOUT switchover from VCC to VBAT when VCC falls below VSO, supporting SRAM data retention during main power loss.

It integrates a 1.6 s watchdog timer cleared by WDI edge transitions (not available on STM703/704/819), push-pull reset outputs guaranteed functional down to VCC = 1.0 V, and a power-fail comparator (PFI/PFO) with 2.4 V threshold-features confirmed in the STM690A–STM819 family datasheet (DocID10522 Rev 11).

Key Specifications

Pinout & Package

STM802MM6E is housed in an SO8 (Small Outline 8-pin) package per Table 8 and Figure 43 of DocID10522 Rev 11, with standard 1.27 mm pitch and surface-mount footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809SEUR+T and TPS3823MPW, STM802MM6E uniquely integrates battery switchover, dual reset polarity, and power-fail signaling in one SO8 device-reducing BOM count, PCB area, and validation effort for LPSRAM-based industrial designs.

Availability

STM802MM6E is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, point-of-sale terminals, and smart energy meters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM802MM6E 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 designing and manufacturing microcontrollers, analog ICs, power management devices, and sensors for industrial, automotive, and consumer markets.

STM802 belongs to ST's supervisor IC product line, engineered specifically for robust power monitoring, NVRAM backup, and fail-safe reset generation in harsh industrial environments.

FAQ

What is the reset threshold voltage and tolerance for STM802MM6E?

The STM802MM6E has a nominal reset threshold (VRST) of 4.65 V with ±1.5% tolerance over temperature and supply variations. This value is factory-trimmed and specified in Table 7 (DC and AC characteristics) of DocID10522 Rev 11. It ensures reliable reset assertion before the host MCU's minimum operating voltage is violated.

Does STM802MM6E support both VCC and battery-powered operation of external LPSRAM?

Yes. The device automatically routes VCC to VOUT during normal operation and switches to VBAT when VCC falls below VSO-the lesser of VRST (4.65 V) or VBAT voltage. This switchover occurs through an internal P-channel MOSFET with <100 Ω on-resistance, enabling direct LPSRAM backup without external diodes or FETs.

Can the watchdog timer be disabled, and how?

Yes. The watchdog function is disabled when the WDI pin is left floating or tri-stated. In this state, leakage current must remain below 10 µA and load capacitance under 200 pF to prevent spurious timeouts. No configuration register or external signal is required-disabling is purely hardware-based via pin state.

Is STM802MM6E pin-compatible with other devices in the STM690A–STM819 family?

No. STM802MM6E uses the SO8 pinout shared with STM690A, STM692A, STM703, STM704, STM805, and STM817, but differs from STM818/819 which add E/ECON pins. Pin compatibility is limited to devices listed in Table 3 (Pin description) with identical pin assignments-e.g., RST on pin 1, VOUT on pin 2, PFO on pin 3, etc.