MIC809/810 Microprocessor Reset Circuits General Description Features The MIC809 and MIC810 are inexpensive microprocessor supervisory circuits that monitor power supplies in microprocessor based systems. The function of these devices is to assert a reset if the power supply drops below a designated reset threshold level. Several different reset threshold levels are available to accommodate 3V, 3.3V or 5V powered systems. The MIC809 has an active-low /RESET output, while the MIC810 offers an active-high RESET output. The reset output is guaranteed to remain asserted for a minimum of 140ms after VCC has risen above the designated reset threshold level. Having a push-pull output stage, the MIC809/810 does not require a pull-up resistor at the output. The MIC809/810 comes in a 3-pin SOT-23 and SC-70 package. The MIC809 is also available with a shorter reset timeout (30ms min.). See the MIC809-5. All support documentation can be found on Micrel’s web site at www.micrel.com. • Precision voltage monitor for 3V, 3.3V or 5V power supplies • /RESET remains valid with VCC as low as 1.4V for SOT23 packaged part • /RESET remains valid with VCC as low as 1V for SC70 packaged part • Typically less than15µA supply current for SOT-23 packaged part • 5µ typical supply current for SC70 packaged part • 140ms minimum reset pulse widths available • Available in 3-pin SOT-23 and SC-70 package Typical Application Applications • • • • • Portable equipment Intelligent instruments Critical microprocessor power monitoring Printers/computers Controllers VCC VCC VCC MIC809 µP RESET RESET Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com April 2005 1 M0450-041405 MIC809/810 Micrel Ordering Information Part Number 3-lead SOT-23 Package3-lead SC-70 Package Marking Threshold Voltage Operating Temp. Range Lead Finish MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard MIC809LUY MIC809LYC3 IL 4.63 –40°C to +85°C Pb-Free MIC809MUY MIC809MYC3 IM 4.38 –40°C to +85°C Pb-Free Pb-Free MIC809JUY MIC809JYC3 IJ 4.00 –40°C to +85°C MIC809TUY MIC809TYC3 IT 3.08 –40°C to +85°C Pb-Free MIC809SUY MIC809SYC3 IS 2.93 –40°C to +85°C Pb-Free MIC809RUY MIC809RYC3 IR 2.63 –40°C to +85°C Pb-Free MIC810LUY MIC810LYC3 JL 4.63 –40°C to +85°C Pb-Free MIC810MUY MIC810MYC3 JM 4.38 –40°C to +85°C Pb-Free MIC810JUY MIC810JYC3 JJ 4.00 –40°C to +85°C Pb-Free MIC810TUY MIC810TYC3 JT 3.08 –40°C to +85°C Pb-Free MIC810SUY MIC810SYC3 JS 2.93 –40°C to +85°C Pb-Free MIC810RUY MIC810RYC3 JR 2.63 –40°C to +85°C Pb-Free Note: Contact factory for SC70 packaged Pb-free options.. Pin Configuration GND 1 GND 1 MIC809 MIC810 3 VCC 3 VCC RESET 2 RESET 2 MIC809 3-Lead SOT23 MIC809 3-Lead SC70 MIC810 3-Lead SOT23 MIC810 3-Lead SC70 Pin Description Pin Number MIC809 Pin Number MIC810 Pin Name Pin Function IC Ground Pin. 1 1 GND 2 N/A /RESET /RESET goes low if VCC falls below the reset threshold and remains asserted for one reset timeout period (140ms min.) after VCC exceeds the reset threshold. N/A 2 RESET RESET goes high if VCC falls below the reset threshold and remains asserted for one reset timeout period (140ms min.) after VCC exceeds the reset threshold. 3 3 VCC M0450-041405 Power Supply Input. 2 April 2005 MIC809/810 Micrel Absolute Maximum Ratings(1) Operating Ratings(2) Terminal Voltage (VCC) ...................................–0.3V to 6.0V Input Current (VCC)..................................................... 20mA Output Current (RESET, /RESET) .............................. 20mA Lead Temperature (soldering, 10 sec.) ...................... 300°C Storage Temperature (TS) .......................... –65°C to 150°C Rate of Rise (VCC) .................................................. 100V/µs ESD Rating(3) ............................................ 3kV (SC70 Package) Operating Temperature Range MIC809 ..................................................... –40°C to 85°C MIC810 ..................................................... –40°C to 85°C Power Dissipation (TA = +70°C) .............................. 320mW Electrical Characteristics(4) For typical values, VCC = 5V for MIC8_L/M/J, VCC = 3.3V for MIC8_S/T, VCC = 3V for MIC8_R; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted. Symbol Parameter Condition Min VCC Operating Voltage Range TA = 0°C to 70°C ICC Supply Current TA = –40°C to 85°C tRST 1.4 5.5 V 1.6 5.5 V 5.5 V MIC809L/M/J, MIC810L/M/J SOT-23 Package 1 9 15 µA For SC-70 Package: MIC809L/M/J, MIC810L/M/J 5 15 µA VCC < 3.6V, MIC809R/S/T, MIC810R/S/T SOT-23 package 6 10 µA 5 10 µA SC70 package /RESET Output Voltage VOL /RESET Output Voltage VOL 4.50 4.63 4.75 V 4.25 4.38 4.50 V MIC809J, MIC810J 3.89 4.00 4.10 V MIC809T, MIC810T 3.00 3.08 3.15 V MIC809S, MIC810S 2.85 2.93 3.00 V MIC809R, MIC810R 2.55 2.63 2.70 V 140 240 560 ms ISOURCE = 800µA, MIC809L/M/J MIC809 MIC809 ISOURCE = 500µA, MIC809R/S/T VCC–1.5V 0.8×VCC RESET Output Voltage MIC810 RESET Output Voltage MIC810 V V 0.4 V VCC = VTH min., ISINK = 1.2mA, MIC809R/S/T 0.3 V 0.3 V For SC-70 Package: VCC = 1V, ISINK = 50µA A TA = –40°C to 85°C 0.3 V VCC = VTH min., ISINK = 3.2mA, MIC809L/M/J VCC > 1.4V, ISINK = 50µA, TA = 0°C to +70°C ` VOH MIC809L, MIC810L MIC809M, MIC810M Reset Timeout Period VOH Units SOT-23 package TA = –40°C to 85°C Reset Voltage Threshold Max SOT-23 package For SC-70 Package: VCC < 3.6V, MIC809R/S/T, MIC810R/S/T VTH Typ VCC > 1.6V, ISINK = 50µA, TA = –40° to +85°C 1.8V < VCC < VTH min., ISOURCE = 150µA ISINK = 3.2mA, MIC810L/M/J 0.3 0.8×VCC ISINK = 1.2mA, MIC810R/S/T V V 0.4 V 0.3 V Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only. April 2005 3 M0450-041405 MIC809/810 Micrel Timing Diagram VCC VTH VTH tRST tRST /RESET Reset Timing Diagram Functional Diagram + VCC (3) Reset Threshold (V) RESET GENERATOR - RESET (2) RESET (MIC810) GND (1) M0450-041405 4 April 2005 MIC809/810 Micrel Applications Information Interfacing to Bidirectional Reset Pins The MIC809/810 can interface with µPs with bidirectional reset pins by connecting a 4.7kΩ resistor in series with the MIC809/810 output and the µP reset pin. /RESET Valid at Low Voltage A resistor can be added from the /RESET pin to ground to ensure the /RESET output remains low with VCC down to 0V. A 100kΩ resistor connected from the /RESET to ground is recommended. The resistor should be small enough to pull-down any stray leakage currents and large enough not to load the reset output. See Figure below. Microprocessor Reset The /RESET (or RESET) pin is asserted whenever VCC falls below the reset threshold voltage. The /RESET pin remains asserted for a period of 140ms after VCC has risen above the reset threshold voltage. The reset function ensures the microprocessor is properly reset and powers up in a known condition after a power failure. /RESET will remain valid with VCC as low as 1.4V (1V for SC-70 package). VCC Transients The MIC809/810 are relatively immune to negative-going VCC glitches below the reset threshold. Typically, a negative-going transient 125mV below the reset threshold with a duration of 20µs or less (SC70 package) will not cause a reset. VCC VCC VCC MIC809 µP RESET RESET 100K Reset Valid to VCC = 0V April 2005 5 M0450-041405 MIC809/810 Micrel Package Information 1.40 (0.055) 2.50 (0.098) 1.19 (0.047) 2.10 (0.083) CL 2.36 (0.093) 2.28 (0.090) CL DIMENSIONS : MM (INCH) 1.15 (0.045) 0.76 (0.030) 3.05 (0.120) 2.67 (0.105) 0.445 (0.0175) TYP 3 PLACES 8 0 0.10 (0.004) 0.013 (0.0005) 0.15 (0.006) 0.076 (0.0030) 0.41 (0.016) 0.13 (0.005) 3-lead SOT-23 (M3) 3-Lead SC-70 (C3) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. M0450-041405 6 April 2005