ADM709

a FEATURES Precision Supply Voltage Monitor +5 V, +3.3 V, +3 V Power Supply Monitor 35 ␮ A Quiescent Current 140 ms (min) Power-On Reset Pulse Low Cost 8-Pin DIP/SO Packages Upgrade for MAX709 APPLICATIONS Microprocessor Systems Computers Controllers Intelligent Instruments Critical ␮ P Monitoring Automotive Systems Critical ␮ P Power Monitoring GENERAL DESCRIPTION VCC VTH Power Supply Monitor with Reset ADM709 FUNCTIONAL BLOCK DIAGRAM ADM709 RESET GENERATOR RESET GND VCC VCC ADM709 RESET GND RESET µP GND The ADM709 contains a power supply monitor which generates a system reset during power-up, power-down and brownout conditions. When VCC falls below the reset threshold, RESET goes low and holds the µP in reset. On power-up the RESET output is held low for 140 ms after VCC rises above the threshold. The RESET output remains operational with VCC as low as 1 V. Three supply-voltage threshold levels are available suitable for +5 V, +3.3 V and for +3 V supply monitoring. The actual reset voltage threshold is given below. The ADM709 is available in 8-pin DIP and SOIC packages. Table I. Reset Threshold Typical Operating Circuit ORDERING GUIDE Model ADM709LAN ADM709LAR ADM709MAN ADM709MAR ADM709TAN ADM709TAR ADM709SAN ADM709SAR ADM709RAN ADM709RAR Reset Threshold 4.65 V 4.65 V 4.40 V 4.40 V 3.08 V 3.08 V 2.93 V 2.93 V 2.63 V 2.63 V Temperature Range –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40...