MIC811/812 Micrel, Inc. MIC811/812 Microprocessor Reset Circuits Final Information General Description Features The MIC811 and MIC812 are inexpensive microprocessor Precision voltage monitor for 3V, 3.3V or 5V power supervisory circuit that monitors power supplies in micropro- supplies cessor based systems. /RESET remains valid with V as low as 1.4V CC <15A supply current The function of this device is to assert a reset if either the 140ms minimum reset pulse width available power supply drops below a designated reset threshold level Manual reset input or /MR is forced low. Several different reset threshold levels Available in 4-pin SOT-143 package are available to accommodate 3V, 3.3V or 5V powered systems. Applications The MIC811 has an active low /RESET output, while the Portable equipment MIC812 offers an active high RESET output. The reset output Intelligent instruments is guaranteed to remain asserted for a minimum of 140ms Critical microprocessor power monitoring after V has risen above the designed reset threshold level. CC Printers/computers Having a push-pull output stage, MIC811/812 does not Embedded controllers require a pull-up resistor at the output. The MIC811/812 comes in a 4-pin SOT-143 package. If a microprocessor voltage supervisor with an open-drain output stage is needed, see MIC6315. Ordering Information Standard Pb-Free Threshold Operating Part Number Marking Part Number Marking Voltage Temp. Range Package MIC811LU KL MIC811LUY KL 4.63 40C to +85C 4-lead SOT-143 MIC811MU KM MIC811MUY KM 4.38 40C to +85C 4-lead SOT-143 MIC811JU KJ MIC811JUY KJ 4.00 40C to +85C 4-lead SOT-143 MIC811UU KU MIC811UUY KU 3.00 40C to +85C 4-lead SOT-143 MIC811TU KT MIC811TUY KT 3.08 40C to +85C 4-lead SOT-143 MIC811SU KS MIC811SUY KS 2.93 40C to +85C 4-lead SOT-143 MIC811RU KR MIC811RUY KR 2.63 40C to +85C 4-lead SOT-143 MIC812LU LL MIC812LUY LL 4.63 40C to +85C 4-lead SOT-143 MIC812MU LM MIC812MUY LM 4.38 40C to +85C 4-lead SOT-143 MIC812JU LJ MIC812JUY LJ 4.00 40C to +85C 4-lead SOT-143 MIC812UU LU MIC812UUY LU 3.00 40C to +85C 4-lead SOT-143 MIC812TU LT MIC812TUY LT 3.08 40C to +85C 4-lead SOT-143 MIC812SU LS MIC812SUY LS 2.93 40C to +85C 4-lead SOT-143 MIC812RU LR MIC812RUY LR 2.63 40C to +85C 4-lead SOT-143 *Under bar symbol ( ) may not be to scale. Typical Application Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC811/812 Micrel, Inc. Pin Configuration MIC811 4-Lead SOT-143 MIC812 4-Lead SOT-143 Pin Description Pin Number Pin Number MIC811 MIC812 Pin Name Pin Function 11 GND IC Ground Pin 2 N/A /RESET /RESET goes low if V falls below the reset threshold and remains CC asserted for one reset timeout period (140ms min.) after V exceeds the CC reset threshold N/A 2 RESET RESET goes high if V falls below the reset threshold and remains CC asserted for one reset timeout period (140ms min.) after V exceeds the CC reset threshold 33 /MR Manual Reset Input. A logic low on /MR forces a reset. The reset will remain asserted as long as /MR is held low and for one reset timeout period (140ms min.) after /MR goes high. This input can be shorted to ground via a switch or driven from CMOS or TTL logic. Float if unused. 44 VCC Power Supply Input. MIC811/812 2 February 2005