LM3708  Product Folder

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 V_CC 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.

• 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 V_CC (RESET# option only)
• 28 µA V_CC supply current

• Embedded Controllers and Processors
• Intelligent Instruments
• Automotive Systems
• Critical µP Power Monitoring