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Technical content

Features

  • Maximum supply current: 30µA
  • Debounced manual reset input is TTL/CMOS compatible
  • Reset pulse width: 200ms
  • Watchdog timer: 1.6s (MIC706)
  • Precision supply voltage monitor
  • Easy power-fail warning or low-battery detect

Applications

  • Laptop and desktop computers
  • Intelligent systems
  • Critical microprocessor power monitoring
  • Printers
  • Controllers Typical Application Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com May 28, 2014 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T

Ordering Information

Part Number Threshold (V) /RESET RESET WDI Junction Temperature Range Package MIC706PMY 2.63 √ √ –40°C to +85°C 8-Pin SOIC MIC706RMY 2.63 √ √ –40°C to +85°C 8-Pin SOIC MIC706SMY 2.93 √ √ –40°C to +85°C 8-Pin SOIC MIC706TMY 3.08 √ √ –40°C to +85°C 8-Pin SOIC MIC708RMY 2.63 √ √ –40°C to +85°C 8-Pin SOIC MIC708SMY 2.93 √ √ –40°C to +85°C 8-Pin SOIC MIC708TMY 3.08 √ √ –40°C to +85°C 8-Pin SOIC Pin Configuration MIC706 8-Pin SOIC (M) (Top View) MIC708 8-Pin SOIC (M) (Top View) Pin Description Pin Number MIC706 Pin Number MIC708 Pin Name Pin Name 1 1 /MR Manual reset input forces reset outputs to assert when pulled below 0.8V. An internal pull-up current of 250µA on this input forces it high when left floating. This input can also be driven from TTL or CMOS logic. 2 2 VCC Primary supply input, +5V. 3 3 GND IC ground pin, 0V reference. 4 4 PFI Power-Fail Input: Internally-connected to the power-fail comparator which is referenced to 1.25V. The power-fail output (/PFO) remains high if PFI is above 1.25V. PFI should be connected to GND or VOUT if the power-fail comparator is not used. 5 5 /PFO Power-Fail Output: The power-fail comparator is independent of all other function on this device.

6 N/A WDI

Watchdog Input. The WDI input monitors microprocessor activity; an internal watchdog timer resets itself with each transition on the watchdog input. If the WDI pin is held high or low for longer than the watchdog timeout period, /WDO is forced to active low. The watchdog function can be disabled by floating the WDI pin. N/A 6 N/C Not internally connected. May 28, 2014 2 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T Pin Description (Continued) Pin Number MIC706 Pin Number MIC708 Pin Name Pin Name 7 7 /RESET /RESET is asserted if either VCC goes below the reset threshold voltage or by low signal on the manual reset input (/MR). /RESET remains asserted for one reset timeout period (200ms) after VCC exceeds the reset threshold voltage or after the manual reset pin transition from low to high. The watchdog timer will not assert /RESET unless /WDO is connected to /MR.

8 N/A /WDO

Output for the watchdog timer. The watchdog timer resets itself with each transition to the watchdog input. If the WDI pin is held high or low for longer than the watchdog timeout period, /WDO is forced low. /WDO will also be forced low if VCC is below the reset threshold voltage and will remain low until VCC returns to a valid level. (MIC706P) 8 RESET RESET is the compliment of /RESET and is asserted if either VCC goes below the reset threshold voltage or by a low signal on the manual reset input (/MR). RESET is suitable for microprocessor systems that use active high reset. May 28, 2014 3 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T Absolute Maximum Ratings(1) Terminal Voltage Input Current Operating Ratings(2) Thermal Resistance Electrical Characteristics(3) TA = Operating Temperature Range, bold values indicate –40°C ≤ TA ≤ +85°C, unless noted. Parameter Condition Min. Typ. Max. Units Operating Voltage Range 1.4 5.5 V Supply Current 30 µA Reset Voltage Threshold MIC70_P/R 2.55 2.63 2.70 V MIC70_S 2.85 2.93 3.00 MIC70_T 3.00 3.08 3.15 Reset Threshold Hysteresis 20 mV Reset Pulse Width (tRS) 140 200 280 ms /RESET Output Voltage (MIC70_R/S/T) ISOURCE = 200µA 0.8 × VCC V ISINK = 1.2mA 0.3 ISINK = 50µA, VCC = 1.4V 0.3 RESET Output Voltage (MIC706P) ISOURCE = 200µA 0.8 × VCC V ISINK = 1.2mA 0.3 RESET Output Voltage (MIC708R/S/T) ISOURCE = 200µA 0.8 × VCC V ISINK = 500µA 0.3 Watchdog Timeout Period (tWD) 1.0 1.6 2.25 s WDI Minimum Input Pulse (tWP) VIL = 0.4V, VIH = 80% of VCC 100 ns VIL = 0.4V, VIH = 80% of VCC > 4.5V 50 WDI Threshold Voltage VIH 0.7 × VCC V VIL 0.6 WDI Input Current WDI = 0V or VCC −1 1 µA WDO Output Voltage ISOURCE = 200µA 0.8 × VCC V ISINK = 500µA 0.3 /MR Pull-Up Current /MR = 0V 20 250 600 µA Notes: 1. Exceeding the absolute maximum ratings may damage the device. 2. The device is not guaranteed to function outside its operating ratings. 3. Specification for packaged product only. May 28, 2014 4 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T Electrical Characteristics(3) (Continued) TA = Operating Temperature Range, bold values indicate –40°C ≤ TA ≤ +85°C, unless noted. Parameter Condition Min. Typ. Max. Units /MR Pulse Width (tMR) VCC > 4.5V 500 ns 150 /MR Input Threshold VIL 0.6 V VIH 0.7 × VCC /MR-to-Reset Output Delay (tMD) 750 ns PFI Input Threshold 1.2 1.25 1.3 V PFI Input Current −25 0.01 +25 nA /PFO Output Voltage ISINK = 1.2mA 0.3 V ISOURCE = 200µA 0.8 × VCC May 28, 2014 5 Revision 2.0

Figure 1. Timing Diagram for Reset

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T Block Diagram MIC706 Block Diagram MIC708 Block Diagram May 28, 2014 7 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T

Application Information

An additional comparator which is independent of the other functions on the MIC706P and MIC708 is provided for early warning of power failure. An external voltage divider can be used to compare unregulated DC to an internal 1.25V reference. The voltage divider ratio on the input of the power-fail comparator (PFI) can be chosen so as to tr ip the power -fail comparator a few milliseconds before V CC falls below the maximum reset threshold voltage. The output of the power -fail comparator (/PFO) can be used to interrupt the microprocessor when used in this mode and exec ute shutdown procedures prior to power loss. Hysteresis c an be added to this comparator with external resistors, as is comm only done with any comparator. Figure 2. Power-Fail Comparator high-to-low on the WDI pin will reset the watchdog timer. if WDI sees a valid transition within the watchdog period. valid with VCC as low as 1.4V.

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T Package Information and Recommended Landing Pattern(4) 8-Pin SOIC (M) Note: May 28, 2014 9 Revision 2.0

Micrel, Inc. MIC706P/R/S/, MIC708R/S/T 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 Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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 a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2000 Micrel, Incorporated. May 28, 2014 10 Revision 2.0