STMicroelectronics STM6778SVWB6F

Overview

STM6778SVWB6F from STMicroelectronics is a dual ultra-low voltage supervisor IC with push-button reset and factory-programmed delay, monitoring primary supply (VCC1) at 2.93 V and secondary supply (VCC2) at 1.58 V, featuring active-low push-pull RST output, manual reset (MR), delayed manual reset (MRC), and guaranteed reset assertion down to VCC1/VCC2 ≥ 0.8 V - used in battery-powered networking equipment and portable embedded systems.

For engineers reviewing the STM6778SVWB6F datasheet, STM6778SVWB6F pinout, STM6778SVWB6F application, or STM6778SVWB6F equivalent, key selection criteria include dual-supply threshold accuracy (±1.5% over temperature), 11 µA typical supply current at 3.6 V, SOT23-6 package compatibility, and MRC-capacitor programmable manual reset delay up to seconds.

Technical Context

The STM6778 implements independent comparators for VCC1 and VCC2 with factory-trimmed thresholds (2.93 V and 1.58 V respectively), plus logic-controlled RST assertion triggered by MR or MRC input transitions. Its internal trec generator enforces fixed power-up reset delays of 13.2 ms, 210 ms, or 900 ms (typ), with reset hold time guaranteed until all monitored supplies exceed thresholds and MR returns high.

Reset output uses push-pull architecture referenced to VCC1, eliminating need for external pull-up; MRC pin enables user-configurable delay via external capacitor (e.g., 3.3 µF yields ~4 s delay), while internal 50 kΩ MR pull-up supports direct switch-to-VSS connection without debounce 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 pitch 0.95 mm, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM6778SVWB6F, STM6778SVWY6F sacrifices VCC2 monitoring and MRC functionality for smaller footprint, while TPS3808G33DBVR trades dual-rail capability and capacitor-programmable delay for resistor-adjustable timing and single-vendor ecosystem alignment.

Availability

STM6778SVWB6F is available at Aetrix Electronics and suitable for industrial gateways, portable medical sensors, set-top boxes, and wireless video transmitters requiring stable component supply across extended product lifecycles.

Supply support for STM6778SVWB6F 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 devices for industrial, automotive, and consumer markets.

The STM67xx family targets ultra-low-power, dual-rail system supervision in space-constrained portable and networking equipment, emphasizing factory-trimmed accuracy, minimal quiescent current, and integrated manual reset flexibility.

FAQ

What is the function of the MRC pin on STM6778SVWB6F?

The MRC (Manual Reset Delay) pin accepts an external capacitor connected to VSS to introduce a user-defined delay between MR activation and RST assertion. With a 3.3 µF capacitor, it delivers approximately 4 s delay; minimum delay is 6 µs when MRC is left open. This eliminates need for external timing ICs in field-service or safety-critical reset workflows.

Can STM6778SVWB6F monitor a 2.5 V supply rail?

No - STM6778SVWB6F has factory-programmed VCC1 and VCC2 thresholds of 2.93 V and 1.58 V respectively, with no user adjustment. It cannot supervise a 2.5 V rail directly. For 2.5 V monitoring, use STM6779/6780 variants with RSTIN pin and external resistor divider referencing the 0.626 V internal comparator.

Is the RST output compatible with processors having bidirectional reset I/O?

Yes - the push-pull RST output can interface with bidirectional reset pins using a 4.7 kΩ series resistor (per Figure 11 in datasheet), preventing logic contention. Unlike open-drain variants, no external pull-up is required, simplifying layout and reducing component count in compact designs.

What is the minimum operating voltage for reliable reset assertion?

The device guarantees correct RST logic state when VCC1 or VCC2 ≥ 0.8 V. Below this, reset behavior is undefined. This 0.8 V lower limit enables brown-out detection during battery discharge down to near-dead cell voltage, supporting graceful shutdown in portable systems before complete power loss.