Overview
The MAX708ESA+TG002 is a low-cost microprocessor (µP) supervisory circuit produced by Maxim Integrated, now part of Analog Devices Inc. This device is designed to monitor power-supply and battery functions in µP systems, enhancing system reliability and accuracy. It integrates multiple supervisory functions into a single package, reducing the complexity and number of components required in the system.
Key Specifications
| Parameter | Symbol | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|---|
| Operating Voltage Range | VCC | 4.5 | 5.5 | V | ||
| Supply Current | ISUPPLY | 150 | 350 | 500 | µA | |
| Reset Threshold | VRT | 4.25 | 4.40 | 4.50 | V | |
| Reset Pulse Width | tRS | 140 | 200 | 280 | ms | |
| Watchdog Timeout Period | tWD | 1.00 | 1.60 | 2.25 | s | |
| Manual-Reset Input Threshold | MR | 0.8 | 2.0 | V | ||
| Power-Fail Comparator Input Threshold | PFI | 1.20 | 1.25 | 1.30 | V |
Key Features
- Supervisory-Function Integration: Integrates reset output, watchdog timer, power-fail warning, and manual-reset input to improve system reliability and reduce board space.
- Precision-Supply Voltage Monitor: Generates a reset pulse when the supply voltage drops below 4.40V for the MAX706/MAX708 models.
- Watchdog Timer: Monitors the µP’s activity and triggers a reset if the watchdog input is not toggled within 1.6 seconds.
- Manual-Reset Input: Allows reset to be triggered by a pushbutton switch with internal debouncing.
- Power-Fail Comparator: Provides a warning for power-fail or low-battery conditions.
- Debounced TTL/CMOS-Compatible Inputs: Ensures compatibility with various logic lines.
- Guaranteed RESET Valid at Low VCC: RESET output is valid down to VCC = 1V.
- Compact Packaging: Available in 8-pin DIP, SO, and µMAX packages.
Applications
- Computers: Ensures reliable operation during power-up, power-down, and brownout conditions.
- Controllers: Monitors and controls power supply in various control systems.
- Intelligent Instruments: Provides critical power monitoring and reset functions in intelligent instruments.
- Critical µP Power Monitoring: Essential for systems requiring high reliability and accurate power monitoring.
Q & A
- What is the primary function of the MAX708ESA+TG002?
The primary function is to monitor power-supply and battery functions in microprocessor systems, providing reset, watchdog, and power-fail warning capabilities.
- What is the reset threshold voltage for the MAX706/MAX708 models?
The reset threshold voltage is between 4.25V and 4.50V.
- How does the watchdog timer function?
The watchdog timer monitors the microprocessor’s activity and triggers a reset if the watchdog input is not toggled within 1.6 seconds.
- What is the purpose of the manual-reset input?
The manual-reset input allows a reset to be triggered by a pushbutton switch, which is internally debounced.
- What is the power-fail comparator used for?
The power-fail comparator provides a warning for power-fail or low-battery conditions.
- What are the available package types for the MAX708ESA+TG002?
The device is available in 8-pin DIP, SO, and µMAX packages.
- What is the operating temperature range for the MAX708?
The operating temperature range is from 0°C to +70°C for the commercial grade and from -40°C to +85°C for the extended grade.
- How does the device handle supply voltage drops?
The device generates a reset pulse when the supply voltage drops below the reset threshold and stays low until VCC drops below 1V.
- Is the RESET output valid at low VCC levels?
Yes, the RESET output is guaranteed to be valid down to VCC = 1V.
- What is the typical supply current for the MAX708?
The typical supply current is between 150µA and 350µA.
