STMicroelectronics STM819MDS6F

Overview

STM819MDS6F from STMicroelectronics is a 5 V microprocessor supervisor IC with integrated battery switchover, power-fail comparator (PFI/PFO), and manual reset (MR) input - designed for non-volatile SRAM backup in industrial embedded systems. It guarantees RST assertion down to VCC = 1.0 V, features 200 ms typical reset timeout (trec), operates from –40 °C to +85 °C, and draws only 40 µA typical supply current.

For engineers reviewing the STM819MDS6F datasheet, STM819MDS6F pinout, STM819MDS6F application, or STM819MDS6F equivalent, this device serves as a precision voltage-monitoring supervisor for LPSRAM retention during main power loss - with verified MR-triggered reset timing, PFI threshold accuracy, and VBAT/VCC switchover behavior per DocID10522 Rev 11.

Technical Context

The STM819MDS6F implements dual-reset outputs (RST and RST) with push-pull drivers, monitors VCC against a precision 4.65 V reset threshold (VRST), and asserts reset on power failure, MR activation, or sustained VCC undervoltage. Its internal logic ensures trec ≥ 140 ms (min) and guarantees valid reset assertion even when VCC drops to 1.0 V - critical for safe SRAM data hold.

Unlike STM817/818, the STM819 lacks watchdog timer and chip-enable gating but adds dedicated MR input with 40 kΩ internal pull-up and noise-immunity support via optional 0.1 µF capacitor. It includes PFI/PFO for early power-fail warning and automatic VOUT switchover from VCC to VBAT at VSO = min(VBAT, VRST), enabling seamless LPSRAM backup without external circuitry.

Key Specifications

Pinout & Package

STM819MDS6F is housed in an SO8 (Small Outline 8-pin) package with standard 1.27 mm pitch, JEDEC MS-012AC compliant outline, and Pb-free RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM817MDS6F and STM704MDS6F, the STM819MDS6F uniquely combines MR input, PFI/PFO, and guaranteed 1.0 V RST assertion - making it optimal for applications demanding both user-initiated reset and predictive power-loss response without watchdog overhead.

Availability

STM819MDS6F is available at Aetrix Electronics and suitable for industrial PLC memory backup, medical device data retention, smart meter firmware protection, and automotive telematics logging requiring stable component supply across extended product lifecycles.

Supply support for STM819MDS6F 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, delivering robust analog, mixed-signal, and power management solutions for industrial, automotive, and embedded markets.

The STM8xx supervisor family targets reliable power monitoring and SRAM backup in harsh environments - engineered specifically for deterministic reset behavior, low-power battery operation, and seamless integration with external LPSRAM.

FAQ

What is the function of the PFI and PFO pins on STM819MDS6F?

The PFI pin monitors an auxiliary voltage rail and triggers the PFO output to go low when PFI falls below 2.4 V. This provides early warning of impending power failure before VCC drops to the reset threshold. PFO is a push-pull output capable of directly driving logic inputs or interrupt lines without external pull-ups.

Does STM819MDS6F support battery backup for external SRAM?

Yes. STM819MDS6F provides automatic switchover of the VOUT pin from VCC to VBAT when VCC falls below the switchover voltage (VSO = min(VBAT, VRST)). This maintains power to external LPSRAM during main supply loss, with typical battery supply current of only 0.4 µA to maximize backup runtime.

How does the MR (manual reset) input behave during power-up?

The MR input has an internal 40 kΩ pull-up resistor and is sampled continuously. When pulled low, it asserts RST for the duration of the low signal plus the full trec period (200 ms typ) after release. During power-up, MR can be used to force a synchronized reset independent of VCC ramp rate or stability.

Is STM819MDS6F pin-compatible with other devices in the STM8xx family?

No. STM819MDS6F uses the same SO8 package but differs in pin function allocation: it places MR on pin 6 and PFI on pin 5, whereas STM817/818 assign E/ECON to those positions. Direct replacement requires PCB layout revision due to incompatible pin mapping and missing watchdog/CE gating functions.