Features
| • | Standard Reset Threshold voltage: 3.08V |
| • | Custom Reset Threshold voltages: For other voltages between 2.2V and 5.0V in 10mV increments, contact National Semiconductor Corp. |
| • | No external components required |
| • | Manual-Reset input |
| • | RESET# (LM3708) or RESET (LM3709) outputs |
| • | Precision supply voltage monitor |
| • | Factory programmable Reset and Watchdog Timeout Delays |
| • | Available in micro SMD package for minimum footprint |
| • | ±0.5% Reset threshold accuracy at room temperature |
| • | ±2% Reset threshold accuracy over temperature extremes |
| • | Reset assertion down to 1V VCC (RESET# option only) |
| • | 28 µA VCC supply current |
Description The LM3708/LM3709 series of microprocessor supervisory circuits provide the maximum flexibility for monitoring power supplies and battery controlled functions in systems without backup batteries. The LM3708/LM3709 series are available in a 9-bump micro SMD package.
Built-in features include the following:
Reset: Reset is asserted during power-up, power-down, and brownout conditions. RESET# is guaranteed down to VCC of 1.0V.
Manual Reset Input: An input that asserts reset when pulled low.
Low Line Output: This early power failure warning indicator goes low when the supply voltage drops to a value which is 2% higher than the reset threshold voltage.
Watchdog Timer: The WDI (Watchdog Input) monitors one of the µP's output lines for activity. If no output transition occurs during the watchdog timeout period, reset is activated.
Applications
| • | Embedded Controllers and Processors |
| • | Intelligent Instruments |
| • | Automotive Systems |
| • | Critical µP Power Monitoring |
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