? semiconductor components industries, llc, 2011 november, 2011 ? rev. 0 1 publication order number: cat871/d cat871, cat872 dual input reset generator description cat871, cat872 are dual input reset generators designed to restart microprocessor and microcontroller based systems when the watchdog timer or other resetting mechanisms have become disabled or failed. cat871, ca t872 monitor two inputs and output an active low reset pulse after both inputs have been active (logic low) for a factory preset minimum time. the reset pulse width is 2.2 ms for cat871 and 70 ms for cat872. releasing either input from its active state before the minimum timeout period resets the internal timer and both inputs must return to being active before the timer will restart with a fresh count down. cat871, cat872?s open drain output is capable of sinking up to 3 ma of current and may be wire ? or?d with other open drain devices to drive a common reset input. features ? operate on 1.65 v to 5.5 v power supplies ? ultra low quiescent current: 10 na (typical) ? schmitt trigger inputs ? 8 factory preset delay times from 0.5 s to 5 s to choose from ? small llga ? 6 package: 1.45 x 1.0 x 0.4 mm ? these devices are pb ? free, halogen free/bfr free and are rohs compliant typical applications ? mobile phones ? pdas ? mp3 players ? personal navigation devices figure 1. application schematic http://onsemi.com pin connections ullga ? 6 ul suffix case 613af marking diagram (top view) 1 see detailed ordering and shipping information in the package dimensions section on page 9 of this data sheet. ordering information vdd reset gnd mr1 mr2 nic 1 x = specific device code x = (j = cat871, k = cat872) m = date code xm
cat871, cat872 http://onsemi.com 2 functional block diagram reset pulse generator vdd mr2 mr1 gnd delay timer figure 2. functional block diagram reset table 1. pin function description pin no. pin name description 1 mr1 manual reset input #1. cmos input. 2 mr2 manual reset input #2. cmos input. 3 nic no internal connection. a voltage or signal applied to this pin will have no effect on device operation. 4 gnd system ground. 5 reset reset output. active ? low open drain output. 6 vdd positive power supply. table 2. absolute maximum ratings rating symbol value unit input voltage range v dd ? 0.3 to 6 v output voltage range v out ? 0.3 to 6 or (v dd + 0.3), whichever is lower v input voltage; mr2, mr1 v in ? 0.3 to 6 or (v dd + 0.3), whichever is lower v maximum junction temperature t j(max) 150 c output current; reset i out 10 ma storage temperature range t stg ? 65 to 150 c esd capability, human body model (note 1) esd hbm 2 kv esd capability, machine model (note 1) esd mm 200 v lead temperature soldering reflow (smd styles only), pb ? free versions (note 2) t sld 260 c stresses exceeding maximum ratings may damage the device. maximum ratings are stress ratings only. functional operation above t he recommended operating conditions is not implied. extended exposure to stresses above the recommended operating conditions may af fect device reliability. 1. this device series incorporates esd protection and is tested by the following methods: esd human body model tested per aec ? q100 ? 002 (eia/jesd22 ? a114) esd machine model tested per aec ? q100 ? 003 (eia/jesd22 ? a115) latch ? up current maximum rating: 150 ma per jedec standard: jesd78 2. for information, please refer to our soldering and mounting techniques reference manual, solderrm/d
cat871, cat872 http://onsemi.com 3 table 3. recommended operating conditions rating symbol min max unit input voltage; vdd v dd 1.65 5.5 v input voltage; mr1, mr2 v in 0 v dd v output current; reset i out 0 3 ma ambient temperature t a ? 40 85 c table 4. electrical operating characteristics (v dd = 1.65 v to 5.5 v. for typical values t a = 25 c, for min/max values t a = ? 40 c to +85 c unless otherwise noted.) parameter test conditions symbol min typ max unit power v dd supply voltage v dd 1.65 5.5 v quiescent supply current mr1 = mr2 = v dd . i dd 10 1000 na operating supply current mr1 = mr2 = 0 v measured during setup period. measurement includes current through internal 200 k pull ? up resistor on mr2 50 a logic inputs and outputs input voltage; high mr1, mr2 v ih 0.7 x v dd v input voltage; low mr1, mr2 v il 0.25xv dd v hysteresis v hys ? 250 mv input current mr1 = 0 v; v dd = 5 v (no internal pull ? up) i pu 50 300 na input current mr2 = 0 v; v dd = 5 v (internal 200 k pull ? up resistor) i pu 25 a output voltage; high external 10 k pull ? up resistor to v dd v oh v dd ? 0.1 v output voltage; low i sink = 3 ma, v dd = 1.8 v v ol 0.1 0.4 v timing timeout cat87x ? 05 t low_delay 0.41 0.50 0.59 s cat87x ? 10 0.82 1.00 1.18 s cat87x ? 15 1.23 1.50 1.77 s cat87x ? 20 1.64 2.00 2.36 s cat87x ? 25 2.05 2.50 2.95 s cat87x ? 30 2.46 3.00 3.54 s cat87x ? 40 3.28 4.00 4.72 s cat87x ? 50 4.1 5.00 5.9 s reset output pulse width cat871 t r 1.8 2.2 2.6 ms cat872 57 70 83 test mode (at t a = 25 c) (note 3) start test window t st 35 s test mode delay mr1=0 v, mr2 8 cycles, delay measured after 8 th rising edge of the mr2 clock pulse t d 250 s test mode clock frequency clock applied to mr2 f tm 1 mhz mr2 test mode clock setup time measured from mr1 falling edge to first falling edge of mr2 t p 1 s mr2 input voltage; low mr2, test mode operation v il_tm 0.2xv dd v mr2 pulse width t pw 500 ns 3. ?test mode? parameters are not tested in production.
cat871, cat872 http://onsemi.com 4 timing waveforms (note 4) figure 3. timing waveforms 4. the order of the mr inputs going low does not matter. the last input to go low marks the beginning of t low_delay typical characteristics figure 4. t low_delay vs. vdd (cat87x ? 1.5) figure 5. t low_delay vs. temperature (cat87x ? 1.5) vdd (v) temperature ( c) 5 4 3 2 1 1.25 1.30 1.40 1.45 1.55 1.60 1.70 1.75 125 100 75 50 25 0 ? 25 ? 50 1.25 1.30 1.40 1.45 1.55 1.60 1.70 1.75 t low_delay (s) t low_delay (s) 6 1.35 1.50 1.65 ? 40 c 25 c 90 c 150 1.35 1.50 1.65 1.6 v 3.2 v 5.6 v figure 6. t low_delay vs. vdd (cat87x ? 3.0) vdd (v) 6 5 4 3 2 0 2.5 2.6 2.9 3.1 3.3 3.5 t low_delay (s) 2.7 2.8 3.0 3.2 3.4 ? 40 c 25 c 90 c 1
cat871, cat872 http://onsemi.com 5 typical characteristics figure 7. i dd vs. vdd (mr1 = mr2 = 0) figure 8. i mr2 @ mr2 = 0 vdd (v) vdd (v) 6 5 4 3 2 1 0 0 5 10 15 20 25 30 6 5 4 3 2 1 0 5 10 15 20 25 figure 9. t r vs. vdd for cat871 figure 10. t r vs. temperature for cat871 vdd (v) temperature ( c) 4 3 2 1 1.8 1.9 2.0 2.1 2.2 2.3 2.5 2.6 125 100 75 50 25 0 ? 25 ? 50 1.8 1.9 2.0 2.1 2.3 2.4 2.5 2.6 i dd ( a) i mr2 ( a) t r (ms) t r (ms) 56 2.4 ? 40 c 25 c 85 c ? 40 c 25 c 85 c 2.2 150 1.6 v 3.2 v 5.6 v figure 11. reset pulse width for cat872 vdd (v) 6 5 4 3 2 1 0 57 63 67 71 75 79 83 t r (ms) ? 40 c 25 c 90 c 59 61 65 69 73 77 81
cat871, cat872 http://onsemi.com 6 system description and applications information general cat871, ca t872 are designed for the manual resetting of microprocessors and microcontrollers when normal resetting mechanisms have failed. to prevent accidental resets, cat871, cat872 require both manual reset inputs be held low for a prescribed period before a reset pulse is issued to the system processor. manual reset inputs mr1 and mr2 are schmitt trigger cmos inputs. both inputs must go low and stay low for a predetermined period (t low_delay ) to generate a single reset pulse on the output. mr1 and mr2 operate independently and may be brought low at any time and in any order. the last input to reach 0 v starts the delay timer. mr1 is a standard cmos input and mr2 is also a cmos input with an internal 200 k pull ? up resistor, thus mr2 can be left floating whereas mr1 must be biased by a pull ? up resistor, powered switch or some other means external to the ic. (consult factory for other input biasing options) delay timer when both mr1 and mr2 go low, an internal timing cycle is initiated. if any input goes high before the countdown timer has concluded its cycle, the timer will reset and will restart from the beginning when mr1 and mr2 return to being low. if both manual reset inputs (mr1 and mr2) remain low after a reset pulse is issued, no second reset pulse will be issued after that. reset output cat871, cat872 provide an active ? low open drain output to be wire ? or?d with other open drain reset devices. this output will sink up to 3 ma and as such will not be loaded down by low value (strong) pull ? up resistors. the reset pulse is typically 2 ms long for cat871 and 70 ms long for cat872 and is issued at the conclusion of the delay timer?s countdown sequence. cat871, cat872 will not generate a reset pulse at power ? up. delay timer testing to aid in ? circuit testing of the delay timer, a special test function has been included in cat871, cat872. this test mode, t oc, allows the delay timer to clock at an accelerated rate. upon the conclusion of the countdown a standard width reset pulse will be issued and the chip will exit test mode. to initiate toc, mr1 0 v and a fast external clk (typically 1 mhz) is applied on mr2, with the falling edge of the first clock pulse on mr2 delayed with tp from mr1 0 v. cat871, cat872 look for 8 sequential pulses to appear on mr2 within 35 s to confirm toc is desired. after the rising edge of the 8?th pulse, there will be a delay of 250 s typical followed by a standard reset pulse at the reset output. this delay is independent of the normal timeout delay setting. after issuing the reset pulse, cat871, cat872 exit toc mode and returns to normal operation. if at any time during toc both mr1 and mr2 are high, ca t871, cat872 will immediately exit toc mode. figure 12. toc mode
cat871, cat872 http://onsemi.com 7 application information reset pulse operation when both mr1 and mr2 inputs are kept low, a single reset pulse is generated after the delay t low_delay . even with both mr1 and mr2 maintained low continuously after that time, no second reset pulse will be generated. the delay timer restarts if either mr1 or mr2 (or both) input transitions from high to low, as shown in the timing diagram in figure 13. system with two different power supply voltages the reset generator can be used in a system where the supply vdd is different than the mr1, mr2 input logic. figure 14 shows an application schematic where the microcontroller uses a supply vbat (3.6 v) that is higher than the vdd rail (1.8 v). mr1 and mr2 inputs are activated here by two separate switches connected to gnd and pulling the inputs low when pressed. the schottky diode provides the supply isolation needed between the cat871/cat872 (vdd) and the microcontroller (vbat). operation with low vdd voltage and brownout condition the cat871, cat872 reset generators require a minimum supply voltage vdd of 1.65 v to guarantee the normal operation within the specification. to prevent small vdd supply glitch, a small ceramic capacitor can be added between the vdd pin and gnd. figure 13. reset timing diagram figure 14. application schematic in dual supply system
cat871, cat872 http://onsemi.com 8 package dimensions ullga6, 1.45x1.0, 0.5p case 613af ? 01 issue a notes: 1. dimensioning and tolerancing per asme y14.5m, 1994. 2. controlling dimension: millimeters. 3. dimension b applies to plated terminal and is measured between 0.15 and 0.30 mm from the terminal tip. 4. a maximum of 0.05 pull back of the plated terminal from the edge of the package is allowed. a b e d bottom view b e 6x 0.10 b 0.05 a c c l 5x note 3 0.10 c pin one reference top view 0.10 c 6x a a1 0.05 c 0.05 c c seating plane side view l1 1 3 4 6 dim min max millimeters a ??? 0.40 a1 0.00 0.05 b 0.15 0.25 d 1.45 bsc e 1.00 bsc e 0.50 bsc l 0.25 0.35 l1 0.30 0.40 note 4 soldermask defined* dimensions: millimeters 0.30 5x 0.49 6x 1.24 0.53 pitch *for additional information on our pb ? free strategy and soldering details, please download the on semiconductor soldering and mounting techniques reference manual, solderrm/d. 0.50 1 mounting footprint pkg outline
cat871, cat872 http://onsemi.com 9 table 5. ordering information device timeout (s) reset pulse width (ms) marking package shipping (note 5) cat871 ? 05ulgt3 (note 6) 0.5 2.2 jm llga ? 6 3,000 / tape & reel cat871 ? 10ulgt3 (note 6) 1 cat871 ? 15ulgt3 (note 6) 1.5 cat871 ? 20ulgt3 (note 6) 2 cat871 ? 25ulgt3 (note 6) 2.5 cat871 ? 30ulgt3 (note 6) 3 cat871 ? 40ulgt3 (note 6) 4 cat871 ? 50ulgt3 (note 6) 5 cat872 ? 05ulgt3 (note 6) 0.5 70 km cat872 ? 10ulgt3 (note 6) 1 cat872 ? 15ulgt3 1.5 cat872 ? 20ulgt3 (note 6) 2 cat872 ? 25ulgt3 (note 6) 2.5 cat872 ? 30ulgt3 3 cat872 ? 40ulgt3 (note 6) 4 cat872 ? 50ulgt3 (note 6) 5 5. for information on tape and reel specifications, including part orientation and tape sizes, please refer to our tape and reel packaging specifications brochure, brd8011/d. 6. contact factory for availability. on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to mak e changes without further notice to any products herein. scillc makes no warranty, representation or guarantee regarding the suitability of its products for an y particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including wi thout limitation special, consequential or incidental damages. ?typical? parameters which may be provided in scillc data sheets and/or specifications can and do vary in different application s and actual performance may vary over time. all operating parameters, including ?typicals? must be validated for each customer application by customer?s technical experts. scillc does not convey any license under its patent rights nor the rights of others. scillc products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the scillc product could create a sit uation where personal injury or death may occur. should buyer purchase or use scillc products for any such unintended or unauthorized application, buyer shall indemnify and hold scillc and its of ficers, employees, subsidiaries, af filiates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, direct ly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employer. this literature is subject to all applicable copyright laws and is not for resale in any manner. cat871/d publication ordering information n. american technical support : 800 ? 282 ? 9855 toll free usa/canada europe, middle east and africa technical support: phone: 421 33 790 2910 japan customer focus center phone: 81 ? 3 ? 5817 ? 1050 literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 303 ? 675 ? 2175 or 800 ? 344 ? 3860 toll free usa/canada fax : 303 ? 675 ? 2176 or 800 ? 344 ? 3867 toll free usa/canada email : orderlit@onsemi.com on semiconductor website : www.onsemi.com order literature : http://www.onsemi.com/orderlit for additional information, please contact your local sales representative
|
