MAX705 MAX708/MAX813L Low-Cost, µp Supervisory Circuits

Transcription

1 MAX0 MAX0/MAXL General Description The MAX0-MAX0/MAXL microprocessor (µp) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µp systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components. The MAX0/MAX0/MAXL provide four functions: ) A reset output during power-up, power-down, and brownout conditions. ) An independent watchdog output that goes low if the watchdog input has not been toggled within. seconds. ) A. threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than. ) An active-low manual-reset input. The MAX0/MAX0 are the same as the MAX0/ MAX0, except an active-high reset is substituted for the watchdog timer. The MAXL is the same as the MAX0, except is provided instead of. Two supply-voltage monitor levels are available: The MAX0/MAX0/MAXL generate a reset pulse when the supply voltage drops below., while the MAX0/MAX0 generate a reset pulse below.. All four parts are available in -pin DIP, SO and µmax packages. Applications Computers Controllers Intelligent Instruments Automotive Systems Critical µp Power Monitoring µmax is a registered trademark of Maxim Integrated Products, Inc. Typical Operating Circuit UNREGULATED DC PUSHBUTTON SWITCH MAX DC LINEAR REGULATOR MAX0 MAX0 MAXL µp I/O LINE NMI INTERRUPT Features Available in Tiny µmax Package Guaranteed alid at = Precision Supply-oltage Monitor. in MAX0/MAX0/MAXL. in MAX0/MAX0 00ms Reset Pulse Width Debounced TTL/CMOS-Compatible Manual-Reset Input Independent Watchdog Timer.s Timeout (MAX0/MAX0) Active-High Reset Output (MAX0/MAX0/MAXL) oltage Monitor for Power-Fail or Low-Battery Warning Ordering Information PART TEMP RANGE PIN-PACKAGE MAX0CPA Plastic DIP MAX0CSA SO MAX0CUA µmax MAX0C/D Dice* Ordering Information continued at end of data sheet. * Dice are specified at T A = + C. **Contact factory for availability and processing to MIL-STD-. Devices in PDIP, SO and µmax packages are available in both leaded and lead-free packaging. Specify lead free by adding the + symbol at the end of the part number when ordering. Lead-free not available for CERDIP package. Pin Configurations TOP IEW MAX0 MAX0 MAXL DIP/SO MAX0 MAX0 DIP/SO ( ) ARE FOR MAXL ONLY. Pin Configurations continued at end of data sheet. () WDI N.C. For pricing, delivery, and ordering information, please contact Maxim Direct at --9-, or visit Maxim s website at 9-; Rev. 9; /

2 MAX0 MAX0/MAXL ABSOLUTE MAXIMUM RATINGS Terminal oltage (with respect to ) CERDIP (derate.00mw/ C above +0 C)... 0mW to. Operating Temperature Ranges All Other Inputs (Note ) to ( + 0.) MAX0_C, MAXLC... Input Current MAX0_E, MAXLE mA MAX0_MJA... - C to + C... 0mA Storage Temperature Range... - C to +0 C Output Current (all outputs)... 0mA Lead Temperature (soldering, 0s) C Continuous Power Dissipation (T A = +0 C) Plastic DIP (derate 9.09mW/ C above +0 C)... mw Soldering Temperature (reflow) Lead(Pb)-free...+0 C SO (derate.mw/ C above +0 C)... mw Containing Lead(Pb)...+0 C µmax (derate.0mw/ C above +0 C)... 0mW Note : The input voltage limits on and can be exceeded if the input current is less than 0mA. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS ( =. to. for MAX0/MAX0/MAXL, =. to. for MAX0/MAX0, T A = T MIN to T MAX, unless otherwise noted.) Operating oltage Range PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS MAXLC.. MAX0_C.0. MAX0_E/M, MAXLE/M.. MAX0C, MAX0C, MAXLC 0 0 Supply Current I SUPPLY MAX0E/M, MAX0E/M, MAXLE/M 0 00 MAX0C, MAX0C 0 0 µa MAX0E/M, MAX0E/M 0 00 MAX0, MAX0, MAXL.0.. Reset Threshold (Note ) RT MAX0, MAX Reset Threshold Hysteresis (Note ) 0 m Reset Pulse Width (Note ) t RS ms I SOURCE = 00µA -. Output oltage I SINK =.ma 0. MAX0_C, =, I SINK = 0µA 0. MAX0_E/M, =., I SINK = 00µA 0. MAX0, MAX0, I SOURCE = 00µA -. MAX0, MAX0, I SINK =.ma 0. Output oltage MAXLC, I SOURCE = µa, =. 0. MAXLE/M, I SOURCE = µa, =. 0.9 MAXL I SOURCE = 00µA -. I SINK =.ma 0. Watchdog Timeout Period t WD MAX0, MAX0, MAXL s WDI Pulse Width t WP IL = 0., IH = ( ) (0.) 0 ns WDI Input Threshold Low MAX0, MAX0, MAXL, 0. High =. WDI Input Current MAX0, MAX0, MAXL, WDI = 0 0 MAX0, MAX0, MAXL, WDI = -0-0 µa Output oltage MAX0, MAX0, MAXL, -. I SOURCE = 00µA MAX0, MAX0, MAXL, 0. I SINK =.ma Maxim Integrated

3 MAX0 MAX0/MAXL ELECTRICAL CHARACTERISTICS (continued) ( =. to. for MAX0/MAX0/MAXL, =. to. for MAX0/MAX0, T A = T MIN to T MAX, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Pull-Up Current = µa Pulse Width t 0 ns Input Threshold Low High to Reset Out Delay (Note ) t MD 0 ns Input Threshold =.0..0 Input Current na Output oltage.0 I SOURCE = 00µA -. I SINK =.ma 0. Note : Applies to both in the MAX0 MAX0 and in the MAX0/MAX0/MAXL. 0. Maxim Integrated

4 MAX0 MAX0/MAXL Typical Operating Characteristics MAX0/MAX0 OUTPUT OLTAGE vs. SUPPLY OLTAGE T A = + C 00ms/div kω 0pF /div /div MAX0/MAX0 RESPONSE TIME 0kΩ 0pF µs/div T A = + C + /div +. POWER-FAIL COMPARATOR DE-ASSERTION RESPONSE TIME +. 0pF 00ns/div kω = T A = + C + +. POWER-FAIL COMPARATOR ASSERTION RESPONSE TIME MAX0, ASSERTION MAX0, DE-ASSERTION pF = T A = + C kω /div 0m/div +. = RT T A = + C 0kΩ 0kΩ 0pF 0pF /div CC = RT T A = + C 0kΩ 0kΩ 0pF 0pF /div 00ns/div 00ns/div 00ns/div MAX0/MAX0/MAXL OUTPUT OLTAGE vs. SUPPLY OLTAGE MAXL RESPONSE TIME T A = + C /div + 0pF 0kΩ /div 0pF 0kΩ + 00ms/div µs/div Maxim Integrated

5 MAX0 MAX0/MAXL Pin Description MAX0/MAX0 DIP/SO µmax PIN MAX0/MAX0 DIP/SO µmax MAXL DIP/SO µmax NAME FUNCTION Manual-Reset Input triggers a reset pulse when pulled below 0.. This active-low input has an internal 0µA pull-up current. It can be driven from a TTL or CMOS logic line as well as shorted to ground with a switch. Supply Input Ground Reference for all signals Power-Fail oltage Monitor Input. When is less than., goes low. Connect to or when not used. Power-Fail Output goes low and sinks current when is less than.; otherwise stays high. WDI Watchdog Input. If WDI remains high or low for.sec, the internal watchdog timer runs out and goes low (Figure ). Floating WDI or connecting WDI to a high-impedance three-state buffer disables the watchdog feature. The internal watchdog timer clears whenever reset is asserted, WDI is threestated, or WDI sees a rising or falling edge. N.C. No Connect Active-Low Reset Output pulses low for 00ms when triggered, and stays low whenever is below the reset threshold (. in the MAX0 and. in the MAX0). It remains low for 00ms after rises above the reset threshold or goes from low to high (Figure ). A watchdog timeout will not trigger unless is connected to. Watchdog Output pulls low when the internal watchdog timer finishes its.sec count and does not go high again until the watchdog is cleared. also goes low during low-line conditions. Whenever is below the reset threshold, stays low; however, unlike, does not have a minimum pulse width. As soon as rises above the reset threshold, goes high with no delay. Active-High Reset Output is the inverse of. Whenever is high, is low, and vice versa (Figure ). The MAXL has a output only. Maxim Integrated

6 MAX0 MAX0/MAXL WDI WATCHDOG TRANSITION DETECTOR WATCHDOG TIMER 0µA.* TIMEBASE FOR AND WATCHDOG GENERATOR MAX0 MAX0 MAXL () 0µA.* GENERATOR MAX0 MAX0.. *. FOR MAXO. ( ) ARE FOR MAXL ONLY. *. FOR MAXO. Figure. MAX0/MAX0/MAXL Block Diagram Figure. MAX0/MAX0 Block Diagram Detailed Description Reset Output A microprocessor s (µp s) reset input starts the µp in a known state. Whenever the µp is in an unknown state, it should be held in reset. The MAX0-MAX0/MAXL assert reset during power-up and prevent code execution errors during power-down or brownout conditions. On power-up, once reaches, is a guaranteed logic low of 0. or less. As rises, stays low. When rises above the reset threshold, an internal timer releases after about 00ms. pulses low whenever dips below the reset threshold, i.e. brownout condition. If brownout occurs in the middle of a previously initiated reset pulse, the pulse continues for at least another 0ms. On power-down, once falls below the reset threshold, stays low and is guaranteed to be 0. or less until drops below. The MAX0/MAX0/MAXL active-high output is simply the complement of the output, and is guaranteed to be valid with down to.. Some µps, such as Intel s 0C, require an active-high reset pulse. Watchdog Timer The MAX0/MAX0/MAXL watchdog circuit monitors the µp s activity. If the µp does not toggle the watchdog input (WDI) within.sec and WDI is not three-stated, goes low. As long as is asserted or the WDI input is three-stated, the watchdog timer will stay cleared and will not count. As soon as reset is released and WDI is driven high or low, the timer will start counting. Pulses as short as 0ns can be detected. Typically, will be connected to the non-maskable interrupt input (NMI) of a µp. When drops below the reset threshold, will go low whether or not the watchdog timer has timed out yet. Normally this would trigger an NMI interrupt, but goes low simultaneously, and thus overrides the NMI interrupt. If WDI is left unconnected, can be used as a lowline output. Since floating WDI disables the internal timer, goes low only when falls below the reset threshold, thus functioning as a low-line output. The MAX0/MAX0 have a watchdog timer and a output. The MAX0/MAX0 have both activehigh and active-low reset outputs. The MAXL has both an active-high reset output and a watchdog timer. Manual Reset The manual-reset input () allows reset to be triggered by a pushbutton switch. The switch is effectively debounced by the 0ms minimum reset pulse width. is TTL/CMOS logic compatible, so it can be driven by an external logic line. can be used to force a watchdog timeout to generate a reset pulse in the MAX0/ MAX0/MAXL. Simply connect to. Maxim Integrated

7 MAX0 MAX0/MAXL Power-Fail Comparator The power-fail comparator can be used for various purposes because its output and noninverting input are not internally connected. The inverting input is internally connected to a. reference. WDI () t WP twd t WD t WD ( ) ARE FOR MAXL ONLY. EXTERNALLY TRIGGERED BY Figure. MAX0/MAX0/MAXL Watchdog Timing RT RT Figure. MAX0/MAX0,, and Timing with WDI Three-Stated. The MAX0/MAX0/MAXL output is the inverse of shown. t RS t RS t RS t MD t EXTERNALLY DRIEN LOW To build an early-warning circuit for power failure, connect the pin to a voltage divider (see Typical Operating Circuit). Choose the voltage divider ratio so that the voltage at falls below. just before the regulator drops out. Use to interrupt the µp so it can prepare for an orderly power-down. Applications Information Ensuring a alid Output Down to = When falls below, the MAX0-MAX0 output no longer sinks currentit becomes an open circuit. High-impedance CMOS logic inputs can drift to undetermined voltages if left undriven. If a pull-down resistor is added to the pin as shown in Figure, any stray charge or leakage currents will be drained to ground, holding low. Resistor value (R) is not critical. It should be about 00kΩ, large enough not to load and small enough to pull to ground. Monitoring oltages Other Than the Unregulated DC Input Monitor voltages other than the unregulated DC by connecting a voltage divider to and adjusting the ratio appropriately. If required, add hysteresis by connecting a resistor (with a value approximately 0 times the sum of the two resistors in the potential divider network) between and. A capacitor between and will reduce the power-fail circuit s sensitivity to high-frequency noise on the line being monitored. can be asserted on other voltages in addition to the line. Connect to to initiate a pulse when drops below.. Figure shows the MAX0-MAX0 configured to assert when the supply falls below the reset threshold, or when the + supply falls below approximately. Monitoring a Negative oltage The power-fail comparator can also monitor a negative supply rail (Figure ). When the negative rail is good (a negative voltage of large magnitude), is low, and when the negative rail is degraded (a negative voltage of lesser magnitude), is high. By adding the resistors and transistor as shown, a high triggers reset. As long as remains high, the MAX0- MAX0/MAXL will keep reset asserted ( = low, = high). Note that this circuit s accuracy depends on the threshold tolerance, the line, and the resistors. Maxim Integrated

8 MAX0 MAX0/MAXL + MAX0_ MΩ % MAX0_ TO µp R 0kΩ % PARAMETER MIN TYP MAX UNIT + Reset Threshold at + C Figure. alid to Ground Circuit Figure. Monitoring Both and + 00kΩ BUFFERED TO OTHER SYSTEM COMPONENTS R R MAX0_ 00kΩ N90 TO µp MAX0_.kΩ µp - - TRIP.. TRIP =, TRIP < 0 R R Figure. Monitoring a Negative oltage Figure. Interfacing to µps with Bidirectional Reset I/O Interfacing to µps with Bidirectional Reset Pins µps with bidirectional reset pins, such as the Motorola HC series, can contend with the MAX0-MAX0 output. If, for example, the output is driven high and the µp wants to pull it low, indeterminate logic levels may result. To correct this, connect a.kω resistor between the output and the µp reset I/O, as in Figure. Buffer the output to other system components. Maxim Integrated

9 MAX0 MAX0/MAXL Ordering Information (continued) PART MAX0EPA MAX0ESA MAX0EUA MAX0MJA MAX0CPA MAX0CSA MAX0CUA MAX0C/D MAX0EPA MAX0ESA MAX0EUA MAX0MJA MAX0CPA MAX0CSA MAX0CUA MAX0C/D MAX0EPA MAX0ESA MAX0EUA MAX0MJA MAX0CPA MAX0CSA MAX0CUA MAX0C/D MAX0EPA MAX0ESA MAX0EUA MAX0MJA MAXLCPA MAXLCSA MAXLCUA MAXLC/D MAXLEPA MAXLESA MAXLEUA MAXLMJA TEMP RANGE - C to + C - C to + C - C to + C - C to + C - C to + C PIN-PACKAGE Plastic DIP SO µmax CERDIP** Plastic DIP SO µmax Dice* Plastic DIP SO µmax CERDIP** Plastic DIP SO µmax Dice* Plastic DIP SO µmax CERDIP** Plastic DIP SO µmax Dice* Plastic DIP SO µmax CERDIP** Plastic DIP SO µmax Dice* Plastic DIP SO µmax CERDIP** * Dice are specified at T A = + C. **Contact factory for availability and processing to MIL-STD-. Devices in PDIP, SO and µmax packages are available in both leaded and lead-free packaging. Specify lead free by adding the + symbol at the end of the part number when ordering. Lead free not available for CERDIP package. Pin Configurations (continued) TOP IEW () ( ) ARE FOR MAXL ONLY. MAX0 MAX0 MAXL µmax MAX0 MAX0 µmax WDI N.C. Chip Topography / 0.0" (.mm) ( ) ARE FOR MAXL ONLY. TRANSISTOR COUNT: SUBSTRATE MUST BE LEFT UNCONNECTED. () WDI/N.C. 0.0" (.0mm) Maxim Integrated 9

10 MAX0 MAX0/MAXL µp Supervisory Circuits Part Number Nominal Reset Threshold () Minimum Reset Pulse Width (ms) Active-Low Reset Active-High Reset R E S E T alid to CC = Nominal Watchdog Timeout Period (sec), if Available Separate Watchdog Output Backup-Battery Switch CC-to-OUT On Resistance Max (Ω) BATT-to-OUT On Resistance Max (Ω) C E Write Protect Power-Fail Comparator Manual-Reset Input Low-Line Output Battery-On Output ISUPPLY Operating Mode ma max (typ) ISUPPLY Backup Mode µa max (typ) Pins Price 000-up ($) MAX./. 0 0./0./. 0.(0.0). MAX90A/9A./ (0.) (0.0). MAX90R/S/T./.9/ (0.) (0.). MAX9A/9A./.0 0/adj../adj.. /0ns 0.(0.0) (0.0). MAX9 The MAX9 is a module with the MAX9A and a mah lithium battery MAX9 Adj. /adj../adj.. MAX9 Adj. /adj../adj.. MAX00./adj (0.). MAX0/0./ (0.) (0.0).* MAX0R/S/T./.9/ (0.) (0.).9 MAX0/0./ (0.).0* MAX0P (0.). MAX0R/S/T./.9/ (0.). MAX0/0./ (0.) 0.* MAX0R/S/T./.9/ (0.). MAX9. 0. /0ns 0.(0.0) (0.0).90 MAX9L/M/R/S/T./.0/ 0 /0ns 0.(0.0)../.9/.0 MAX9R/S/U/T./.9/.0/.0 0. TBD TBD TBD TBD MAX9 Adj. 0. TBD TBD TBD TBD MAX9R/S/U/T./.9/.0/.0 0 TBD TBD TBD TBD MAX00L/M.0/.0 0./adj.. /0ns /±% 0.(0.0) (0.0). MAX0L/N/M././. 0 /±.%. TBD TBD TBD TBD MAX0L/M/R/S/T.0/.0/ /±% 0.(0.) (0.0).9./.9/.0 MAX0R/S/T./.9/ /±% 0.(0.) (0.). MAX0L/M/R/S/T./.0/ (0.) (0.0)../.9/.0 MAX0R/S/T./.9/ /±% 0.(0.) (0.).90 MAX0L/N/M././. 0 /±.% /±.%. TBD TBD TBD TBD MAX0L/N/M././. 0 /±.% TBD TBD TBD TBD MAX09L/M/R/S/T./.0/ 0 0.0(0.0)./.9/.0 MAX0L/M/R/S/T./.0/ 0 0.0(0.0)./.9/.0 MAXL. 0. /±% 0.(0.).0* MAXK/L/N/T.0/.0/./.0 0 /±% /±% /±% TBD TBD MAXK/L/N/T.0/.0/./.0 0 /±%. /±% TBD TBD MAX Adj./±% 0 /±% TBD TBD MAX0L/M/R/S/T./.0/ 0 /0ns /±% 0.(0.0)../.9/.0 MXD0./.. 0.(0.) 0.(0.00). Prices provided are for design guidance and are FOB USA (unless otherwise noted). International prices will differ due to local duties, taxes, and exchange rates. Future productcontact factory for pricing and availability. Specifications are preliminary. *,000 pc. price, factory direct 0 Maxim Integrated

11 MAX0 MAX0/MAXL Package Information For the latest package outline information and land patterns (footprints), go to Note that a +, #, or - in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. µmax U- -00 Plastic DIP P- -00 SO S- -00 Maxim Integrated

12 MAX0 MAX0/MAXL REISION NUMBER REISION DATE DESCRIPTION Revision History PAGES CHANGED 0 /9 Initial release /0 Updated the Features, Absolute Maximum Ratings, Typical Operating Characteristics, Figures,,, and the Package Information sections.,,,,, 0 9 / Updated package code for SO package Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated 0 Rio Robles, San Jose, CA 9 USA Maxim Integrated Products, Inc. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.