MAX809REUR+T is a reset monitor chip from Maxim Integrated. The MAX809REUR+T is a 3-pin microprocessor reset circuit designed to monitor power supplies in microprocessors (µP) and digital systems. It eliminates external components, provides excellent circuit reliability and low cost, and can be used with +5V, +3.3V, +3.0V or +2.5V supply circuits.

When the MAX809REUR+T detects a power problem, it generates a reset signal on a pin to the connected microprocessor or other system component to ensure that the system is restarted or appropriate countermeasures are taken.

Ⅰ.Specification parameters of MAX809REUR+T

•Product type:monitoring circuit
•Type:Voltage Supervisory
•Installation style:SMD/SMT
•Accuracy:1.5%
•Height:0.94 mm
•Length:2.92 mm
•Width:1.3 mm
•Threshold voltage:2.63 V
•Supply current:17.0 µA
•Output:push-pull/totem pole
•Type:Simple reset/power-on reset
•Number of monitored inputs:1 Input
•Output type:Active Low, Push-Pull
•Manual reset:No Manual Reset
•Reset delay time:240 ms
•Battery backup switch:No Backup
•Watchdog timer:No Watchdog
•Supply voltage-Max:5.5 V
•Minimum operating temperature:-40℃
•Maximum operating temperature:+105℃
•Overvoltage threshold:2.66 V
•Undervoltage threshold:2.59 V
•Supply voltage-Minimum:1.2 V
•Operating power supply current:60 uA
•Pd-Power dissipation:320 mW
•Output current(Max):20 mA
•Reset voltage(Min):2.59 V
•Reset voltage(Max):2.66 V
•Power supply voltage(DC):1.20V (min)
•Chip enable signal:No Chip Enable
•Package/Case:TO-236-3, SC-59, SOT-23-3

Ⅱ.Main functions of MAX809REUR+T

1.Power supply monitoring: The core function of the MAX809REUR+T is to monitor the power supply voltage of the connected system. It can detect whether the power supply voltage is within a safe operating range. The MAX809REUR+T triggers a reset when the supply voltage exceeds or falls below a specified threshold. This is important to ensure that the microprocessor or digital system is not damaged when the power supply is unstable.

2.Prevent unstable operation: By regularly monitoring the supply voltage and triggering a reset when a problem is detected, the MAX809REUR+T helps prevent unpredictable system behavior when the power supply is unstable or insufficient.

3.Reset trigger: MAX809REUR+T can trigger a reset operation when the power supply voltage is unstable or exceeds the safe range, thereby protecting the microprocessor or digital system from damage. Its internal circuitry monitors the supply voltage and generates a reset signal if the voltage is too high or too low. This reset signal can be used to reset the microprocessor or other system components and restore the system to a known initial state. When the supply voltage falls below or exceeds a programmed threshold, the MAX809REUR+T automatically detects this condition and generates a reset signal. This process is automatic and requires no human intervention.

4.Power supply stability: MAX809REUR+T can monitor the stability of the power supply to ensure reliable operation of the system. It detects whether the supply voltage is within a safe operating range and triggers a reset operation when the supply voltage is too high or too low. The MAX809REUR+T reduces the risk of system failure or data corruption.

Ⅲ.Pin configuration of MAX809REUR+T

•Pin1(GND):Ground

•Pin2(RESET):RESET Output remains low while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold.

•Pin3(VCC):Supply Voltage (+5V, +3.3V, +3.0V, or +2.5V)

Ⅳ.Application scenarios of MAX809REUR+T

1.Microcontroller and microprocessor systems: MAX809REUR+T is often used to monitor the power supply voltage of a microcontroller or microprocessor to ensure that the system starts running when the power supply is working properly. As a power supply monitoring and reset IC, MAX809REUR+T provides an effective power supply stability monitoring and protection mechanism for microcontroller or microprocessor systems. Microcontrollers and microprocessor systems play an important role in many fields, such as controlling the automated operation of equipment, data acquisition and transmission, etc. Power supply stability is critical to the proper operation of these systems, as power supply problems can cause system failure, data loss or corruption, and may even damage the microcontroller or microprocessor itself.

2.Communication equipment: In communication equipment that requires stable power supply, MAX809REUR+T can be used to monitor the power status to ensure that the equipment is working under good power conditions. Power issues can cause communication interruptions, data loss, or equipment damage, affecting equipment performance and reliability.

3.Embedded systems: In embedded systems, the reliability of the power supply is crucial to the stability and reliability of the system. The MAX809REUR+T ensures that the system takes appropriate reset measures when the power supply is unstable or abnormal. Embedded systems are usually used to control and monitor the operation of various equipment and systems, involving various industrial controls, smart instruments, medical equipment and other fields. In these systems, the stability of the power supply directly affects the normal operation of the system and the accuracy of the data.

4.Medical equipment: Medical equipment has high requirements on power supply reliability. MAX809REUR+T can help monitor and ensure that medical equipment is operating under safe power conditions and trigger a reset operation when the power supply is unstable or exceeds the safe range. This reset operation restores the device to a known initial state, preventing device failure or data corruption due to power issues.

5.Power management system: In the power management circuit, MAX809REUR+T can be used to monitor the main system power supply and reset it when necessary to maintain system stability. In the power management circuit, MAX809REUR+T can be used as a power monitor to monitor the voltage level of the system power supply in real time.

6.Automotive electronic systems: In automobiles, fluctuations in power supply may affect the electronic systems on the vehicle. The MAX809REUR+T can be used to ensure power supply stability for vehicle electronic systems. There are more and more electronic systems in cars, from engine control, braking systems to entertainment systems, etc., all of which have high requirements for the stability of the power supply. The MAX809REUR+T can monitor the power supply voltage in automotive electronic systems to ensure that it is within a safe operating range.

Ⅴ.Electrical Characteristics of MAX809REUR+T

Ⅵ.Circuit diagram of MAX809REUR+T

Ⅶ.MAX809REUR+T triggers reset operation

1.Supply voltage below threshold: When the supply voltage of the connected system drops below the set reset threshold, the MAX809REUR+T generates a reset signal. This helps ensure that the system does not continue to operate during a power outage to prevent unpredictable behavior.

2.Power supply monitoring at startup: When the system is started, MAX809REUR+T can be used to monitor the stability of the power supply voltage to ensure that the system will only start normal operation when the power supply voltage reaches a safe level.

3.The power supply voltage exceeds the threshold: In some special applications, the MAX809REUR+T can also trigger a reset when the power supply voltage exceeds the set upper limit threshold. This helps cope with abnormal increases in supply voltage.

4.Noise filtering during power rise or fall: MAX809REUR+T usually also includes some filtering functions to prevent unnecessary resets caused by brief power supply voltage fluctuations. It can trigger a reset after the supply voltage remains outside the threshold for a period of time to avoid erroneous operations caused by power supply noise.

Ⅷ.How MAX809REUR+T improves system reliability

1.Voltage monitoring: MAX809REUR+T continuously monitors the power supply voltage. If the voltage falls below a predetermined threshold or exceeds an upper threshold, a reset operation is triggered. This prevents the system from operating outside the specified voltage range, thereby reducing the risk of failure.

2.Extended component life: Continuous monitoring and prevention of substandard power conditions helps extend the life of system components. It reduces the risk of components being exposed to conditions that could cause accelerated wear or damage.

3.Safe system startup: During system startup, the MAX809REUR+T ensures that the power supply voltage reaches a stable level before the system can begin normal operation. This helps avoid problems related to power fluctuations during startup.

4.Prevent unstable operation: By generating a reset signal when the supply voltage falls outside the acceptable range, the MAX809REUR+T helps prevent the system from operating under unstable power conditions. Erratic operation may result in erratic behavior, data corruption, or component damage.

5.Enhanced robustness: The MAX809REUR+T enhances the overall robustness of the system by providing a mechanism to handle power-related issues. It helps systems recover from transient voltage events or sudden power interruptions.

6.Power failure protection: If a power failure or voltage drop occurs, the MAX809REUR+T triggers a reset, bringing the system to a known state. This is critical to prevent the system from continuing to operate in an unreliable or unpredictable manner.

Frequently Asked Questions

1.What is the power consumption of MAX809REUR+T?
The power consumption of MAX809REUR+T is 320mW.

2.What are the advantages of MAX809REUR+T?
The advantages of MAX809REUR+T include: power monitoring and reset functions, ensuring system stability, and customizable power supply voltage thresholds.

3.What should you pay attention to when using MAX809REUR+T?
Attention needs to be paid to supply voltage range, reset threshold, grounding, operating temperature and compatibility and interoperability.