STMicroelectronics STM6778SFWB6F

Overview

STM6778SFWB6F from STMicroelectronics is a dual ultra-low-voltage supervisor IC with push-button reset and factory-programmed reset thresholds (VCC1 = 2.93 V, VCC2 = 1.58 V), active-low push-pull RST output, manual reset (MR), and delayed manual reset (MRC) input. It monitors primary and secondary supply rails in battery-powered embedded systems and guarantees valid reset state down to VCC ≥ 0.8 V.

For engineers reviewing the STM6778SFWB6F datasheet, STM6778SFWB6F pinout, STM6778SFWB6F application, or STM6778SFWB6F equivalent, key selection criteria include dual-supply monitoring tolerance, MRC programmable delay capability, push-pull RST drive strength, low 11 µA supply current, and SOT23-6 industrial-grade packaging.

Technical Context

The STM6778 implements independent voltage comparators for VCC1 and VCC2, each with factory-trimmed thresholds (2.93 V and 1.58 V respectively), plus an MR input with internal 50 kΩ pull-up. Its logic diagram confirms simultaneous monitoring: RST asserts low if any monitored rail falls below threshold or MR is pulled low.

RST remains asserted for a guaranteed minimum trec delay (13.2 ms, 210 ms, or 900 ms typ) after all supplies recover and MR returns high. The MRC pin enables external capacitor-controlled delay of MR assertion-critical for debouncing mechanical switches without added circuitry.

Key Specifications

Pinout & Package

SOT23-6 (WB) package: 6-pin surface-mount, 1.3 mm × 2.9 mm footprint, 1.45 mm height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UT29D3+ and TPS3808G12DBVR, STM6778SFWB6F uniquely delivers verified dual-rail supervision with factory-set thresholds, MRC-based delay configurability, and guaranteed push-pull RST behavior down to 0.8 V-enabling simpler, more robust power management in compact embedded designs.

Availability

STM6778SFWB6F is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, and set-top box power sequencing requiring stable component supply, long-lifecycle support, and industrial-temperature qualification.

Supply support for STM6778SFWB6F 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 sensing solutions for industrial, automotive, and consumer markets.

STM67xx is ST's ultra-low-voltage supervisor product line, engineered specifically for battery-constrained and multi-rail embedded systems requiring precise, low-current, and pin-efficient power monitoring.

FAQ

What is the function of the MRC pin on STM6778SFWB6F?

The MRC (Manual Reset Delay) pin accepts an external capacitor between itself and VSS to introduce a user-defined delay between MR assertion and RST activation. With a 3.3 µF capacitor, delay reaches ~4 s; leaving MRC open yields minimum 6 µs delay. This replaces discrete RC debounce circuits and supports flexible reset timing without firmware intervention.

Can STM6778SFWB6F monitor a 1.2 V supply rail?

Yes-via the RSTIN pin using an external resistor divider referenced to the internal 0.626 V reference. For a 1.2 V rail, a standard divider (e.g., R1 = 100 kΩ, R2 = 110 kΩ) scales the input to 0.626 V at threshold. VCC1 and VCC2 thresholds are factory-fixed (2.93 V and 1.58 V), so RSTIN is required for non-standard voltages.

Is STM6778SFWB6F compatible with 5 V systems?

Yes-its absolute maximum VCC rating is 7.0 V, and VCC1/VCC2 operate up to 5.5 V. The 2.93 V VCC1 threshold is optimized for 3.3 V systems, but the device functions reliably as a supervisor for 5 V rails when used with appropriate external resistor networks on RSTIN or selected variants with higher factory thresholds.

Does STM6778SFWB6F require external pull-up resistors on RST?

No-the RST output is active-low push-pull, meaning it actively drives both high and low states. Unlike open-drain variants (e.g., STM6777), no external pull-up is needed. This simplifies layout, reduces component count, and ensures fast rise/fall times without signal integrity concerns.