STMicroelectronics STM6824RWY6F

STM6824RWY6F Supervisor IC Product Summary

The STM6824RWY6F, manufactured by STMicroelectronics, is a precision supervisor IC designed for critical system monitoring tasks in embedded and industrial environments. Housed in a compact SOT-23-5 package, it offers a combination of high-reliability features including supply voltage monitoring, an integrated watchdog timer, and a manual reset input. With robust operation across a wide temperature range (−40°C to +85°C) and support for key voltage rails (5V, 3.3V, 3V, and 2.5V), the STM6824RWY6F is well-suited to safeguarding microcontrollers and digital logic systems against voltage faults and software malfunctions.

Main Attributes of STM6824RWY6F for Engineering Purposes

The STM6824RWY6F delivers a comprehensive set of features geared toward reliability and design flexibility:

Precision VCC monitoring with reset thresholds tailored for common supply voltages.

Active low, push-pull reset output ensures compatibility and integration simplicity.

Adjustable reset pulse width options: typical values of 1.4 ms, 200 ms, or 240 ms.

Watchdog timer with a 1.6 s typical timeout to detect system hang-ups.

Manual reset input (MR) equipped with internal pull-up for easy external triggering.

Guaranteed RESET assertion down to VCC = 1.0 V, maintaining protection even during brown-out scenarios.

Ultra-low supply current (3μA typical), minimizing impact on overall system power.

RoHS compliant and available in ECOPACK® environmental grades.

This feature set positions STM6824RWY6F as an ideal solution for mission-critical processors, industrial controllers, point-of-sale terminals, network appliances, and IoT devices that require fault-tolerant operation.

Operating Logic and Functional Analysis of STM6824RWY6F

The STM6824RWY6F operates by continuously monitoring the supply voltage VCC. If VCC drops below the established threshold, the device asserts a reset (RST) signal to the host processor, maintaining system integrity during undervoltage events. The active low, push-pull RST output can directly drive digital inputs without the need for external components.

The internal logic integrates a watchdog timer governed by the WDI (watchdog input) pin. The timer expects periodic toggling—if the MCU fails to pulse WDI within 1.6 seconds (indicative of software malfunction), a reset is triggered. The manual reset (MR) input allows external or user-initiated system resets, providing an additional path for recovery in unforeseen operational failures.

In systems where bidirectional reset pins are required, the STM6824RWY6F can be safely interfaced using a series resistor to mitigate contention between MCU and supervisor outputs. The IC also incorporates design safeguards to ensure valid output logic even at extremely low VCC values, further enhancing reliability.

STM6824RWY6F Working Principles

Upon power-up, the STM6824RWY6F keeps the reset output active until the VCC level is established and stable above the threshold, followed by a timed de-assertion to enforce proper startup sequencing. Any voltage dip below the threshold leads to immediate assertion of the reset, followed by a hold period (t_rec) once VCC returns to valid levels.

For manual resets, pulling the MR pin low asserts reset for the duration of the input plus t_rec after release. The internal pull-up on MR simplifies wiring, while optional external capacitance on MR can improve noise immunity in electrically noisy or remote-triggered layouts.

The watchdog timer function can be disabled by leaving WDI unconnected, or driving it from a three-state buffer, accommodating systems that may temporarily suspend watchdog servicing.

Design Considerations for Real-World Use of STM6824RWY6F

Engineers must pay particular attention to input wiring and output termination for optimal performance. For open drain reset configurations, as found in related supervisors, a carefully selected pull-up resistor ensures reliable logic levels for all connected loads; however, the STM6824RWY6F’s push-pull output eliminates this concern, providing direct drive.

Noise immunity on the MR line is critical in noisy environments or for long cable runs; a modest 0.1μF capacitor from MR to ground can greatly enhance interference rejection. For applications demanding guaranteed reset signaling all the way to VCC = 0V, external passive pull-downs (for active low outputs) or pull-ups (for active high outputs) are recommended.

Systems with microcontrollers employing bidirectional reset lines should introduce a series resistor (for example, 4.7kΩ) to prevent potential output contention, reducing risk of both device damage and unpredictable system behavior.

Standard Performance Parameters of STM6824RWY6F

The STM6824RWY6F maintains stable performance across a broad temperature and supply voltage range. Key performance graphs illustrate:

Reset output delay versus temperature, ensuring predictable system start-up across environmental conditions.

Supply current profile, demonstrating minimal power draw and suitability for battery-powered or low-power applications.

MR-to-reset setup and hold times, along with watchdog timeout period and reset threshold voltage normalization over temperature, emphasize robustness for high-reliability designs.

Electrical output characteristics reveal low saturation voltages for push-pull outputs under specified sink and source currents, ensuring reliable logic signaling even when driving extended loads.

Absolute Ratings and Safety Precautions for STM6824RWY6F

The STM6824RWY6F must be operated within its specified absolute maximum ratings to prevent damage and ensure longevity. Key ratings include peak reflow temperature (260°C max, with a thermal budget), voltage, current, and environmental tolerance. Exceeding these limits—even briefly—may permanently alter device function, so system designers should reference the full datasheet for detailed recommendations, particularly for high-reliability and harsh environment applications.

STM6824RWY6F Electrical Characteristics and Timing Parameters

DC and AC performance for the STM6824RWY6F has been rigorously characterized. Standard measurement conditions include VCC ranges spanning 1.2 V to 5.5 V, ambient temperature from −40°C to +85°C, and typical loading scenarios. Quoted specifications encompass reset threshold voltages, output drive capability, leakage currents, timing parameters (reset and watchdog periods), and MR/WDI pin behaviors.

It is essential for designers to match the operating environment of their circuit to the conditions under which specifications are quoted, especially for timing-sensitive or ultra-low voltage designs.

STM6824RWY6F Package Details and Physical Dimensions

Physical integration is streamlined with the STM6824RWY6F’s SOT-23-5 package, supporting automated surface-mount assembly and high-density board layouts. The ECOPACK® options guarantee compliance with environmental directives, and detailed mechanical drawings, carrier tape dimensions, and pin mapping are published for straightforward PCB footprint development and process validation.

Alternative or Substitute Models for STM6824RWY6F

For applications where sourcing flexibility or alternate voltage thresholds are needed, STMicroelectronics' supervisor IC family offers several equivalent devices:

STM6823, STM6825: Variants featuring alternative reset logic configurations (such as open drain or active high outputs).

STM632x series: Similar function with minor feature or threshold differences for tailored applications.

STM6821, STM6822: Devices with modified watchdog settings or manual reset options.

Cross-referencing with these models enables system designers and procurement teams to align device selection with key requirements such as output type, watchdog period, supply voltage range, and package compatibility.

Conclusion

The STM6824RWY6F supervisor IC from STMicroelectronics combines robust voltage monitoring, watchdog supervision, and manual reset capabilities in a compact package with ultra-low power consumption. Its precise voltage thresholds and integrated protection features make it a reliable cornerstone for microcontroller-based system integrity, offering versatility to engineers designing for consumer, industrial, and IoT applications. Careful consideration of operational principles, interface requirements, and environmental parameters will help ensure optimal choice and implementation. Alternative models within the STM632x and STM682x families further expand flexibility for custom system needs, supporting engineering and procurement teams in achieving dependable, high-performance embedded solutions.