CAT809RSDI-GT3

Supervisors Overview

The CAT809RSDI-GT3 is a voltage supervisory circuit manufactured by onsemi, designed to monitor power supplies in digital systems. It operates within a supply voltage range of 1.2 V to 5.5 V and features a threshold voltage of 4.38 V with an overvoltage threshold of 4.45 V. The device provides an active low, push-pull reset output with a fixed reset delay time of 240 ms. It does not include manual reset, watchdog timer, or battery backup switch functions. The component is housed in an SC-70-3 package (SC-70-3_L2.0-W1.3-P1.30-LS2.1-BR) and supports surface mount installation. It functions correctly at Vcc levels as low as 1.0 V and ignores fast transients on the power supply. The operating temperature range extends from -40 °C to +85 °C.

Supervisors Feature Summary

• Generates a reset signal when the monitored power supply voltage drops below a preset threshold level.
• Asserts the reset signal for a minimum duration after the power supply rises above the threshold.
• Provides an active low, push-pull reset output compatible with various digital logic families.
• Ignores fast transients on the power supply to prevent false reset assertions.

Supervisors Applications

• Monitoring power supplies in microprocessor-based digital systems
• Industrial applications requiring operation over the industrial temperature range
• Direct replacement for MAX809 in existing designs

Supervisors Procurement Notes

Verify the specific package type and pinout configuration against the official datasheet before procurement, as the SC-70-3 variant may have distinct mechanical dimensions compared to standard SOT-23 packages. Confirm the threshold voltage specification matches the target application requirements, as the CAT809 series offers multiple threshold options. Ensure that the active low push-pull output characteristics are compatible with the downstream circuitry. Check for any end-of-life notices or obsolescence status directly from the manufacturer, as availability may be limited for certain variants.

Supervisors Selection Notes

Select the CAT809RSDI-GT3 when a 4.38 V threshold is required for monitoring 5 V or 3.3 V systems. The push-pull output eliminates the need for external pull-up resistors, simplifying board layout. Consider the SC-70-3 package if space constraints favor this smaller footprint over the SOT-23-3 option available in other CAT809 variants. Verify that the 240 ms reset delay meets the system's startup timing requirements. Ensure the operating temperature range covers the intended environmental conditions.

Supervisors Part Context

The CAT809 series consists of voltage supervisory circuits that monitor power supplies in digital systems. These devices are direct replacements for the MAX809 in applications operating over the industrial temperature range. The series utilizes underlying floating gate technology to provide various custom reset thresholds. While the CAT809 generates an active low reset signal, the related CAT810 provides an active high reset signal. The CAT803 variant offers an open-drain output instead of push-pull.

Supervisors Replacement Considerations

The CAT809RSDI-GT3 is a direct replacement for the Maxim Integrated MAX809 in industrial temperature range applications. When substituting, ensure the threshold voltage and reset delay time are compatible with the original design specifications. Verify that the SC-70-3 package dimensions fit the existing PCB footprint if replacing a part in a different package style.