μp Supervisory Circuits

Transcription

1 MAX6351 MAX636 General Description The MAX6351 MAX636 microprocessor (μp) supervisors with multiple reset voltages significantly improve system reliability and accuracy compared to separate ICs or discrete components. If any input supply voltage drops below its associated preset threshold, all reset outputs are asserted. In addition, the outputs are valid as long as either input supply voltage remains greater than +1.. All devices in this series have an active-low debounced manual-reset input. In addition, the MAX6358/MAX6359/ MAX636 offer a watchdog timer input with a 46.4s startup timeout period and a 2.9s timeout period. The MAX6355/ MAX6356/MAX6357 offer an additional voltage-monitor input to monitor a third voltage. The MAX6351 features two active-low, push-pull reset outputs, one is referenced to CC 1 and the other is referenced to. The MAX6353/MAX6356/MAX6359 offer an active-low, push-pull reset output referenced to CC1. The MAX6354/MAX6357/MAX636 offer an active-low, push-pull reset output referenced to. All these devices are offered with a wide variety of voltage threshold levels, as shown in the oltage-threshold Levels table. They are available in 5- and 6-pin SOT23 packages and operate over the extended (-4 C to +85 C) temperature range. oltage Threshold Levels PART NO. SUFFIX ( ) CC 1 NOMINAL OLTAGE THRESHOLD () NOMINAL OLTAGE THRESHOLD () LT LS LR MT MS TZ TY TW T SZ SY SW S UW U RW R Note: Standard versions are shown in bold. Sample stock is generally held on the standard versions only. Contact factory for availability. Features Precision Monitoring of Multiple +1.8, +2.5, +3., +3.3, and +5 Power-Supply oltages Precision Factory-Set Power-Supply Reset Thresholds 2μA Supply Current 1ms min Power-On-Reset Pulse Width Debounced TTL/CMOS-Compatible Manual-Reset Input Watchdog Timer 46.4s Startup Timeout 2.9s Normal Timeout Fully Guaranteed Over Temperature Guaranteed RESET alid to CC 1 = 1 or = 1 Power-Supply Transient Immunity No External Components for Dual-oltage Systems Small 5- and 6-Pin SOT23 Packages Low Cost Applications Computers Intelligent Instruments Controllers Multivoltage Systems Portable/Battery- Powered Equipment Ordering Information PART TEMP RANGE PIN-PACKAGE MAX6351 UT-T -4 C to +85 C 6 SOT23 MAX6352 UK-T -4 C to +85 C 5 SOT23 MAX6353 UK-T -4 C to +85 C 5 SOT23 MAX6354 UK-T -4 C to +85 C 5 SOT23 MAX6355 UT-T -4 C to +85 C 6 SOT23 MAX6356 UT-T -4 C to +85 C 6 SOT23 MAX6357 UT-T -4 C to +85 C 6 SOT23 MAX6358 UT-T -4 C to +85 C 6 SOT23 MAX6359 UT-T -4 C to +85 C 6 SOT23 MAX636 UT-T -4 C to +85 C 6 SOT23 *The are placeholders for the threshold voltage levels of the devices. Substitute the part number suffix in the oltage Threshold Levels table for the desired voltage level. All devices are available in tape-and-reel only. There is a 25 piece minimum order increment for the SOT package. Devices are available in both leaded and lead(pb)-free packaging. Specify lead-free by replacing -T with +T when ordering. Pin Configurations appear at end of data sheet. Selector Guide appears at end of data sheet ; Rev 7; 5/14

2 MAX6351 MAX636 Absolute Maximum Ratings CC 1, to to +6 RST (MAX6352/MAX6355/MAX6358) to +6 RST,, WDI, RST1, RSTIN (MAX6351/MAX6353/ MAX6356/MAX6359) to ( CC 1 +.3) RST, RST2 (MAX6351/MAX6354/ MAX6357/MAX636) to ( +.3) Input/Output Current, All Pins...2mA Continuous Power Dissipation (T A = +7 C) 5-Pin SOT23 (derate 7.1mW/ C above +7 C)...571mW 6-Pin SOT23 (derate 8.7mW/ C above +7 C)...695mW Operating Temperature Range C to +85 C Junction Temperature C Storage Temperature Range C to +15 C 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 ( CC 1 = = +1.2 to +5.5, T A = -4 C to +85 C, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply oltage (Note 2) Supply Current CC 1, I CC 1 + I CC 2 CC 1 Threshold (Note 3) TH 1 Threshold (Note 3) TH 2 T A = C to +7 C TA = -4 C to +85 C CC1 = 5.5, CC2 = 3.6, all I/O pins open MAX63 L_ MAX63 M_ MAX63 T_ MAX63 S_ MAX63 U_ MAX63 R_ MAX63 _T MAX63 _S MAX63 _R MAX63 _Z MAX63 _Y MAX63 _W MAX63 _ 2 5 µa T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C T A = +25 C T A = -4 C to +85 C Maxim Integrated 2

3 MAX6351 MAX636 Electrical Characteristics (continued) ( CC 1 = = +1.2 to +5.5, T A = -4 C to +85 C, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Reset Threshold Tempco Δ TH / C 2 ppm/ C Reset Threshold Hysteresis TH /5 CC to Reset Delay 1m overdrive 2 µs Reset Timeout Period t RP CC 1 > TH 1 (MAX), > TH 2 (MAX) ms RESET Output oltage Low RESET Output-oltage High (MAX6351/MAX6353/MAX6354/ MAX6356/MAX6357/MAX6359/ MAX636 only) OL OH WATCHDOG INPUT (MAX6358/MAX6359/MAX636) CC 1 or 2.7, I SINK = 1.2mA.3 CC 1 or 4.5, I SINK = 3.2mA.4 CC 1 or 1, I SINK = 5µA, T A = C to +7 C CC 1 or 1.2, ISINK = 5µA; T A = -4 C to +85 C (_W, _ versions only), CC 1 > TH 1 (MAX), I SOURCE = 35µA.8 x CC > TH 2 (MAX) (_Y versions only), CC 1 > TH 1 (MAX), I SOURCE = 5µA.8 x CC > TH 2 (MAX) (_T, _S, _R versions only), CC 1 > TH 1 (MAX), I SOURCE = 8µA CC > TH 2 (MAX) First timeout period after reset Watchdog Timeout Period t WD After first WDI falling edge WDI Pulse Width (Note 4) t WDI IL =.4, IH =.8 x CC 5 ns.3.3 s WDI Input oltage (Note 5) WDI Input Current (Note 6) MANUAL RESET INPUT Input oltage IL.3 x CC CC 1 = 5 IH.65 x CC WDI = CC WDI = µa IL MAX63 L_, MAX63 M_, CC 1 > TH 1 (MAX).8 IH MAX63 L_, MAX63 M_, CC 1 > TH 1 (MAX) 2.3 IL MAX63 _Y, CC 1 > TH 1 (MAX).3 x CC IH MAX63 _Y, CC 1 > TH 1 (MAX).7 x CC Maxim Integrated 3

4 MAX6351 MAX636 Electrical Characteristics (continued) ( CC 1 = = +1.2 to +5.5, T A = -4 C to +85 C, unless otherwise noted. Typical values are at T A = +25 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Pullup Resistance kω Minimum Pulse Width t RP 1 µs Glitch Rejection 1 ns to Reset Delay t MD.1 µs ADJUSTABLE RESET COMPARATOR INPUT (MAX6355/MAX6356/MAX6357) RSTIN Input Threshold RSTIN CC 1 > TH 1(MAX), > TH 2(MAX) T A = +25 C T A = -4 C to +85 C RSTIN Input Current I RSTIN < RSTIN < CC na RSTIN Hysteresis 2.5 m Note 1: Overtemperature limits are guaranteed by design and not production tested. Note 2: The reset output is guaranteed to be in the correct state if either CC 1 or is within its specified region of operation. Note 3: The reset output(s) is asserted if either CC 1 or drops below its associated trip point. Note 4: Guaranteed by design. Not production tested. Note 5: WDI is internally serviced within the watchdog timeout period if WDI is left unconnected. Note 6: The WDI input current is specified as the average input current when the WDI input is driven high or low. Typical Operating Characteristics ( CC 1 = +5, T A = +25 C, unless otherwise noted.) SUPPLY CURRENT (µa) SUPPLY CURRENT vs. TEMPERATURE I CC 1 ( CC 1 = 5., = 3.3) I CC 1 ( CC 1 = 3.3, = 2.5) I CC 2 ( CC 1 = 5., = 3.3) I CC 2 ( CC 1 = 3.3, = 2.5) TEMPERATURE ( C) MAX6351/6-1 RESET () RESET vs. CC 1 ( > TH 2) CC 1 () MAX6356L_ TH MAX6351/6-2 RESET () RESET vs. CC 1 ( = ) CC 1 () MAX6351/6-3 Maxim Integrated 4

5 MAX6351 MAX636 Typical Operating Characteristics (continued) ( CC 1 = +5, T A = +25 C, unless otherwise noted.) NORMALIZED PERIOD NORMALIZED RESET/WATCHDOG PERIOD vs. TEMPERATURE MAX6351/6-4 TRANSIENT DURATION (µs) MAXIMUM CC TRANSIENT DURATION vs. RESET THRESHOLD OERDRIE RESET OCCURS ABOE LINE MAX6351/6-5 RESET DELAY (µs) RESET DELAY vs. RESET THRESHOLD OERDRIE DELAY FROM FALL OF DELAY FROM FALL OF CC 1 MAX6351/ TEMPERATURE ( C) RESET THRESHOLD OERDRIE, RST - CC () RESET THRESHOLD OERDRIE, RST - CC () RST1 PUSH-PULL PULLUP CHARACTERISTICS MAX6351/6-7 5 MANUAL-RESET INPUT TO DELAY MAX6351/6-8 5 OPEN-DRAIN RST2 PUSH-PULL 4ns/div R PULLUP = 1kΩ C LOAD = 1pF 5 3 OPEN-DRAIN RST2 PUSH-PULL RST1 PUSH-PULL R PULLUP = 1kΩ C LOAD = 1pF 4ns/div Maxim Integrated 5

6 MAX6351 MAX636 Pin Description MAX6351 MAX6352 MAX6353 MAX6354 PIN MAX6355 MAX6356 MAX6357 MAX6358 MAX6359 MAX636 NAME DESCRIPTION 1 RST1 Active-Low, CMOS Reset Output Referenced to CC RST Active-Low Reset Output. Open drain for the MAX6352/ MAX6355/MAX6358, push-pull with respect to CC 1 for the MAX6353/MAX6356/MAX6359, and push-pull with respect to for the MAX6354/MAX6357/MAX Ground Manual-Reset Input. Pull low to force a reset. RST, RST1, and RST2 remain active as long as is low and for the timeout period after goes high. Leave unconnected or connect to CC 1 if unused. must not exceed CC Supply Input. Powers the device when it is above CC 1 and monitors its own voltage. 5 RST2 Active-Low, CMOS Reset Output Referenced to 5 RSTIN 5 WDI CC 1 Undervoltage-Reset Comparator Input. Asserts reset when the monitored voltage falls below Set the reset threshold with an external resistive divider. Connect to CC 1 if unused. RSTIN must not exceed CC 1. Watchdog Input. If WDI remains either high or low longer than the timeout period, then reset is triggered. The timer clears when reset is asserted or whenever WDI sees a rising or falling edge. Leave unconnected to disable if unused. Supply Input. Powers the device when it is above and monitors its own voltage. Maxim Integrated 6

7 MAX6351 MAX636 Detailed Description Supply oltages The MAX6351 MAX636 microprocessor (μp) supervisory circuits maintain system integrity by alerting the μp to fault conditions. These ICs monitor multiple-supply systems. The output reset state is guaranteed to remain viable while either CC 1 or is above +1. Threshold Levels All the possible input voltage threshold-level combinations are indicated by a two-letter code in the oltage Threshold Levels table. (5) 6 4 (5) CC 1 (RSTIN) TH 1 TH GLITCH FILTER RESET GENERATOR RST (1) RST2 (5) RST1 (1) Reset Outputs The MAX6351 provides two active-low, push-pull reset outputs, one corresponding to each of its two monitored voltages. The MAX6353/MAX6356/MAX6359 have an active-low, push-pull reset output that is referenced to CC 1. The MAX6354/MAX6357/MAX636 have an active-low, push-pull reset output that is referenced to. The MAX6352/MAX6355/MAX6358 provide an active-low open-drain reset. The reset outputs are maintained as long as at least one of the supplies is above +1. Negative-Going CC Transients The MAX6351 MAX636 are designed to ignore short negative-going CC 1 and transients. See the Maximum CC Transient Duration vs. Reset Threshold Overdrive graph in the Typical Operating Characteristics. Third Input oltage (MAX6355/MAX6356/MAX6357) The MAX6355/MAX6356/MAX6357 provide an additional input to monitor a third voltage. The threshold voltage at RSTIN is typically To monitor a voltage higher than 1.22, connect a resistive divider to the circuit, as shown in Figure 2. The threshold at EXT is: R1 + R2 EXT_TH = 1.22 R2 Note that RSTIN is powered by CC 1, and its voltage must therefore remain lower than or equal to CC 1. Watchdog Input (MAX6358/MAX6359/MAX636) The MAX6358/MAX6359/MAX636 include a dual-mode watchdog timer to monitor μp activity. The flexible timeout architecture provides a startup mode, allowing complicated systems to complete lengthy boots, and a normal mode, allowing the supervisor to provide quick alerts when processor activity fails. (5) (WDI) WATCHDOG TIMER EXT R1 MAX6355 MAX6356 MAX MAX6351 MAX636 R2 RSTIN NOTE: PIN 1 IS RST1 FOR THE MAX6351 AND RST FOR THE MAX6352 MAX636. PIN 5 IS RST2 FOR THE MAX6351, RSTIN FOR THE MAX6355/MAX6356/MAX6357, WDI FOR THE MAX6358/ MAX6359/MAX636, AND CC 1 FOR THE MAX6352/MAX6353/MAX6354. Figure 1. Functional Diagram CC 1 RSTIN Figure 2. Monitoring a Third oltage Maxim Integrated 7

8 MAX6351 MAX636 During the normal operating mode, the supervisor issues a reset pulse for the reset timeout period (14ms min) if the μp does not update the WDI with a valid transition (high to low or low to high) within the standard timeout period (1.6s min). After each reset event ( CC power-up, manual reset, or watchdog reset), there is an initial watchdog startup timeout period of 25.6s. The startup mode provides an extended period for the system to power up and fully initialize all μp and system components before assuming responsibility for routine watchdog updates. The normal watchdog timeout period (1.6s min) begins at the conclusion of the startup timeout period or after the first transition on WDI before the conclusion of the startup period (Figure 3). CC 1 CC 1 RST RST2 RST1 MAX6351 MAX6356 MAX6353 MAX6357 MAX6354 MAX6359 MAX636 1kΩ Applications Information Ensuring a alid RESET Output Down to CC = In some systems, it is necessary to ensure a valid reset even if CC falls to. In these applications, use the circuit shown in Figure 4. Note that this configuration does not work for the open-drain outputs of the MAX6352/ MAX6355/MAX6358. Interfacing to μps with Bidirectional Reset Pins Microprocessors with bidirectional reset pins contend with the push-pull outputs of these devices. To prevent this, connect a 4.7kΩ resistor between RESET and the μp s reset I/O port, as shown in Figure 5. Buffer RESET, as shown in the figure, if this reset is used by other components in the system. Figure 4. Ensuring a alid Reset Low to CC 1 and = CC 1 CC 1 BUFFERED RESET TO OTHER SYSTEM COMPONENTS RST RST2 RST1 MAX6351 MAX kΩ µp RESET TH CC WDI t WDI-NORMAL 1.6s MAX t WDI-STARTUP 25.6s MAX Figure 5. Interfacing to μps with Bidirectional Reset I/O 1.6s MAX RESET 14ms Figure 3. Normal Watchdog Startup Sequence Maxim Integrated 8

9 MAX6351 MAX636 Pin Configurations TOP IEW RST1 1 6 CC 1 RST* 1 5 CC 1 2 MAX RST2 2 MAX6352 MAX6353 MAX6354 *MAX6352: OPEN-DRAIN *MAX6353: PUSH-PULL ( CC 1) *MAX6354: PUSH-PULL () SOT23 5 SOT23 RST* 1 6 CC 1 RST* 1 6 CC 1 2 MAX6355 MAX6356 MAX RSTIN *MAX6355: OPEN-DRAIN *MAX6356: PUSH-PULL ( CC 1) *MAX6357: PUSH-PULL () 2 MAX6358 MAX6359 MAX636 5 WDI *MAX6358: OPEN-DRAIN *MAX6359: PUSH-PULL ( CC 1) *MAX636: PUSH-PULL () SOT23 6 SOT23 Selector Guide PART PIN COUNT NUMBER OF SUPPLIES MONITORED RST1 RST2 OPEN-DRAIN RESET WATCHDOG TIMER MAX ü ü ü MAX ü ü MAX ü ü MAX ü ü MAX ü ü MAX ü ü MAX ü ü MAX ü ü ü MAX ü ü ü MAX ü ü ü MANUAL RESET Maxim Integrated 9

10 MAX6351 MAX636 Chip Information PROCESS: BiCMOS 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 OUTLINE NO. LAND PATTERN NO. 5 SOT23 U SOT23 U Maxim Integrated 1

11 MAX6351 MAX636 Revision History REISION NUMBER REISION DATE DESCRIPTION PAGES CHANGED 7 5/14 Changed the minimum value for the WDI input voltage spec in the Electrical Characteristics table on page 3; rebranded data sheet 1 11 For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim Integrated s website at 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. 214 Maxim Integrated Products, Inc. 11