Overview
The ADM705AR, produced by Analog Devices Inc., is a low-cost microprocessor supervisory circuit designed to monitor 5 V power supplies and microprocessor activity. This device is part of the ADM705/ADM706/ADM707/ADM708 family and is particularly suited for applications requiring power-on reset, watchdog timer functionality, and power-fail detection.
The ADM705AR provides essential functions such as power-on reset output during power-up, power-down, and brownout conditions, an independent watchdog timer, a 1.25 V threshold detector for power-fail warnings, and an active low debounced manual reset input.
Key Specifications
| Parameter | Min | Typ | Max |
|---|---|---|---|
| Supply Voltage (VCC) | 1 V | - | 5.5 V |
| Reset Threshold Voltage | - | 4.65 V | - |
| Watchdog Timeout Period (tWD) | 1.00 sec | 1.60 sec | 2.25 sec |
| WDI Pulse Width (tWP) | - | 50 ns | - |
| WDI Input Threshold (Logic Low) | 0.8 V | - | - |
| WDI Input Threshold (Logic High) | - | - | 3.5 V |
| MR Pull-Up Current | 100 μA | 250 μA | 600 μA |
| MR to Reset Output Delay | - | 250 ns | - |
| PFI Input Threshold | 1.2 V | 1.25 V | 1.3 V |
| PFO Output Voltage (ISOURCE = 800 μA) | 0.4 V | - | VCC - 1.5 V |
| PFO Output Voltage (ISINK = 1.2 mA) | 0.4 V | - | VCC - 1.5 V |
| Package Type | - | 8-SOIC | - |
Key Features
- Power-on reset output during power-up, power-down, and brownout conditions, operational with VCC as low as 1 V.
- Independent watchdog timer with a 1.60 sec timeout period.
- A 1.25 V threshold detector for power-fail warnings, low battery detection, or monitoring an additional power supply.
- Active low debounced manual reset input (MR) with an internal 250 μA pull-up current.
- Watchdog output (WDO) that goes low if the watchdog input has not been toggled within the specified time.
- Power-fail input (PFI) and power-fail output (PFO) for monitoring power supply conditions.
Applications
- Microprocessor systems
- Computers
- Controllers
- Intelligent instruments
- Critical microprocessor supply monitoring
- Automotive systems
Q & A
- What is the primary function of the ADM705AR?
The primary function of the ADM705AR is to monitor 5 V power supplies and microprocessor activity, providing power-on reset, watchdog timer functionality, and power-fail detection.
- What is the reset threshold voltage for the ADM705AR?
The reset threshold voltage for the ADM705AR is 4.65 V.
- How long does the watchdog timer timeout period last?
The watchdog timer timeout period lasts 1.60 seconds.
- What is the purpose of the power-fail input (PFI) and power-fail output (PFO)?
The power-fail input (PFI) and power-fail output (PFO) are used to monitor power supply conditions, with PFO going low when PFI is less than 1.25 V.
- What type of package is the ADM705AR available in?
The ADM705AR is available in an 8-SOIC package.
- What is the supply voltage range for the ADM705AR?
The supply voltage range for the ADM705AR is from 1 V to 5.5 V.
- Does the ADM705AR have an active high reset output?
No, the ADM705AR has an active low reset output. However, the ADM707 and ADM708, which are similar devices, offer both active high and active low reset outputs.
- How does the manual reset input (MR) work?
The manual reset input (MR) is an active low debounced input that generates a reset when taken below 0.8 V. It has an internal 250 μA pull-up current to hold the input high when floating.
- What are some typical applications for the ADM705AR?
Typical applications include microprocessor systems, computers, controllers, intelligent instruments, and critical microprocessor supply monitoring.
- Is the ADM705AR RoHS compliant?
