STMicroelectronics STM6777TGWB6F

Overview

STM6777TGWB6F from STMicroelectronics is a dual ultra-low-voltage supervisor IC with push-button reset and delayed manual reset capability. It monitors primary (VCC1) and secondary (VCC2) supplies, features factory-programmed reset thresholds (4.63 V to 1.58 V on VCC1; 3.08 V to 0.79 V on VCC2), provides active-low open-drain RST output, and supports MRC-based manual reset delay up to seconds via external capacitor. It is used in battery-powered networking equipment for reliable power-on and brownout detection.

For engineers reviewing the STM6777TGWB6F datasheet, STM6777TGWB6F pinout, STM6777TGWB6F application, or STM6777TGWB6F equivalent, key selection criteria include dual-supply monitoring tolerance, guaranteed RST state down to 0.8 V supply, 11 µA typical quiescent current, SOT23-6 package compatibility, and MRC-controlled reset timing flexibility in space-constrained embedded systems.

Technical Context

This supervisor implements independent voltage comparators for VCC1 and VCC2, each with factory-trimmed thresholds, plus an MR input with internal 50 kΩ pull-up. The MRC pin enables user-configurable delay of the MR-initiated reset assertion using an external capacitor to ground - enabling precise control over reset hold time without software intervention.

The RST output is active-low open-drain, requiring an external pull-up to VCC1 (e.g., 10 kΩ), and remains asserted for trec (13.2 ms / 210 ms / 900 ms typ) after all monitored voltages exceed thresholds and MR returns high. Device operation is guaranteed from –40 °C to +85 °C with supply current as low as 11 µA at 3.6 V.

Key Specifications

Pinout & Package

SOT23-6 (WB) package: 6-pin surface-mount, 1.3 mm × 2.9 mm footprint, 1.45 mm height, lead pitch 0.95 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US29D3+ and TPS3808G12DBVR, STM6777TGWB6F uniquely integrates dual fixed-threshold monitoring and capacitor-programmable MR delay in a 6-pin SOT23, reducing BOM count and firmware dependency in multi-rail industrial designs.

Availability

STM6777TGWB6F is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, DSL routers, and smart meter communication subsystems requiring stable component supply and long-term lifecycle support.

Supply support for STM6777TGWB6F 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, and analog/mixed-signal components for industrial, automotive, and consumer markets.

STM67xx is ST's ultra-low-power dual/triple voltage supervisor product line, engineered specifically for robust power-on reset and brownout protection in battery-powered and multi-rail embedded systems.

FAQ

What is the function of the MRC pin on STM6777TGWB6F?

The MRC (Manual Reset Delay) pin accepts an external capacitor connected to VSS to introduce a programmable delay between MR assertion and RST activation. With a 3.3 µF capacitor, it delivers ~4 s delay; smaller values yield shorter delays (minimum 6 µs). This enables hardware-controlled reset hold timing without firmware involvement.

Does STM6777TGWB6F support monitoring of three supply rails?

No - STM6777TGWB6F monitors two supplies: VCC1 (primary) and VCC2 (secondary). While the broader STM67xx family includes variants with RSTIN for third-rail monitoring (e.g., STM6779), STM6777 lacks RSTIN and is strictly dual-supply. Its pinout confirms only VCC1, VCC2, MR, MRC, RST, and VSS.

What is the recommended pull-up resistor value for the RST pin?

A 10 kΩ pull-up resistor to VCC1 is recommended for the open-drain RST output. This value ensures sufficient drive strength for most microcontrollers while minimizing current draw during reset assertion. Values between 4.7 kΩ and 100 kΩ are acceptable depending on bus capacitance and noise immunity requirements.

Can STM6777TGWB6F operate with VCC1 below 1.58 V?

No - the lowest factory-programmed VCC1 threshold is 1.58 V, and the device requires VCC1 ≥ 0.8 V to guarantee correct RST output state. Operation below 0.8 V is outside specification; below 1.58 V, the supervisor cannot assert reset based on VCC1 violation, though MR and VCC2 monitoring remain functional if their respective supply conditions are met.