STMicroelectronics STM6777TZWB6F

Overview

STM6777TZWB6F 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), open-drain active-low RST output, manual reset input (MR), and delayed manual reset input (MRC) supporting external capacitor timing. 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 STM6777TZWB6F datasheet, STM6777TZWB6F pinout, STM6777TZWB6F application, or STM6777TZWB6F equivalent, key selection considerations include dual-supply monitoring tolerance, MRC delay configurability, open-drain RST compatibility with bi-directional processor reset pins, and industrial-grade (–40 °C to +85 °C) operation with 11 µA typical supply current.

Technical Context

The device implements independent voltage comparators for VCC1 and VCC2 against factory-trimmed thresholds, with logic arbitration ensuring RST remains asserted low until both supplies exceed their respective thresholds and MR returns high. Reset assertion is sustained for a guaranteed minimum trec delay (13.2 ms / 210 ms / 900 ms typ) after all conditions are met.

MR initiates reset immediately upon falling edge; MRC enables user-configurable delay (≥6 µs) via external capacitor between MRC and VSS, decoupling mechanical switch bounce from system reset timing. The open-drain RST output requires an external pull-up to VCC1 (e.g., 10 kΩ), enabling wired-OR reset bus configurations and safe interfacing with bi-directional processor reset I/O pins.

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, STM6777TZWB6F uniquely delivers dual-rail monitoring, MRC-configurable reset delay, and open-drain RST in a single SOT23-6 device-reducing component count and enabling robust, low-power system-level reset control.

Availability

STM6777TZWB6F is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, set-top box power management, and wireless sensor nodes requiring stable component supply with long-term industrial lifecycle support.

Supply support for STM6777TZWB6F 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, microcontroller, power, and sensing solutions for industrial, automotive, and consumer markets.

STM67xx is ST's ultra-low-voltage supervisor product line targeting battery-powered and energy-constrained embedded systems requiring dual-rail monitoring, push-button reset, and guaranteed reset behavior across wide temperature and supply ranges.

FAQ

What is the function of the MRC pin on STM6777TZWB6F?

The MRC (Manual Reset Delay) pin connects to VSS via an external capacitor to introduce a user-defined delay (≥6 µs) between MR assertion and RST activation. This eliminates mechanical switch bounce effects without requiring additional debounce circuitry. The delay time scales with capacitor value-e.g., ~4 s with 3.3 µF-and is independent of VCC levels.

Can STM6777TZWB6F monitor a 1.8 V supply as VCC2?

No. VCC2 threshold is factory-programmed to 1.58 V and not adjustable. While the device operates with VCC2 as low as 0.79 V (per datasheet min), the actual reset threshold is fixed at 1.58 V ±1.5%. For 1.8 V rail supervision, select a variant with higher VCC2 threshold (e.g., STM6778 with 1.80 V option) or use external resistor divider on RSTIN (not available on STM6777).

Why does STM6777TZWB6F use an open-drain RST output instead of push-pull?

The open-drain RST enables wired-OR reset bus architectures and safe interfacing with microcontrollers featuring bi-directional reset pins. When paired with a 4.7 kΩ series resistor (per Figure 11), it prevents logic contention during processor-controlled reset assertion. Push-pull variants (e.g., STM6778) are incompatible with such bidirectional interfaces.

Is STM6777TZWB6F compatible with 5 V systems?

Yes. VCC1 supports up to 7.0 V absolute maximum, and the 2.93 V reset threshold is valid across the full 0.8 V to 5.5 V operating range. For 5 V systems, connect VCC1 directly to the 5 V rail and use a resistive divider to scale any higher-voltage monitored rail (e.g., 12 V) down to ≤5.5 V before applying to VCC1 or VCC2 inputs.