PART TEMP RANGE PIN-PACKAGE

Transcription

1 General Description The MAX6701 microprocessor (µp) supervisory circuits reduce the complexity and components required to monitor power-supply functions in µp systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components. The MAX6701 family provides 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 1.6s; a 0.62 threshold detector for power-fail warning; and an active-low manual reset input. The MAX6701 family offers several pinout options to accommodate a variety of multivoltage microprocessor supervision applications. The MAX6701(A)/MAX6702(A)/MAX6703(A) monitor three supply voltages (one fixed threshold and two adjustable) to drive a single reset output and include a manual reset input and a watchdog timer with an independent output. The MAX670 monitors a single-supply voltage to drive complementary reset outputs and includes an independent adjustable power-fail-in/powerfail-out comparator, a manual reset input, and a resetbased watchdog timer. The MAX670(A)/MAX6706(A)/ MAX6707(A) monitor a single-supply voltage to drive a single reset output and include an independent adjustable power-fail-in/power-fail-out comparator, a manual reset input, and a watchdog timer with an independent output. The is the same as the MAX670 but without the watchdog timer function. See the Detailed Description for differences between non-a and A versions. Applications Computers Controllers Intelligent Instruments Critical µp Power Monitoring White Goods Networking Telecommunications Typical Operating Circuit and Selector Guide appear at end of data sheet. Features Small 8-Pin SOT23 Package Precision Monitoring of +., +3.3, +3., +2. Supply oltages 10ms Reset Timeout Delay Power-Fail Input with Independent Output; Monitor Inputs Down to 0.62 (MAX670 ) Dual Adjustable Reset Input for Triple-oltage Monitoring (MAX6701(A)/MAX6702(A)/MAX6703(A)) 1.6s Watchdog Timeout Period (MAX6701(A) MAX6707(A)) Independent Watchdog Output (MAX6701(A)/MAX6702(A)/MAX6703(A)/ MAX670(A)/MAX6706(A)/MAX6707(A)) Manual Reset Input Four Reset Output Stage Options Active Low Push-Pull (MAX6701(A), MAX670(A)) Active Low Open Drain (MAX6703(A), MAX6707(A)) Active High Push-Pull (MAX6702(A), MAX6706(A)) Dual Active Low/High Push-Pull (MAX670, ) Guaranteed Reset alid to = 1 Immune to Short Falling Transients Low Cost, Few External Components Ordering Information PART TEMP RANGE PIN-PACKAGE MAX6701_KA-T -0 C to +12 C 8 SOT23 MAX6701A_KA-T -0 C to +12 C 8 SOT23 Insert the desired suffix letter (from the Threshold Suffix Guide table) into the blank to complete the part number. All devices must be ordered in increments of 200 pieces. Sample stock is typically held on standard versions only. Contact factory for availability. Devices are available in both leaded and lead-free packaging. Specify lead-free by replacing -T with +T when ordering. Ordering Information continued at end of data sheet. Pin Configurations TOP IEW 1 2 GND 3 RST_IN1 ( ) ARE FOR MAX6702(A) ONLY. MAX6701(A) MAX6702(A) MAX6703(A) SOT () Pin Configurations continued at end of data sheet. 6 RST_IN ; Rev ; /1

2 Absolute Maximum Ratings to +6. Open-Drain,, to +6. Push-Pull,,, to ( + 0.3),, PFI, RST_IN1, RST_IN to ( + 0.3) Input Current ( )...20mA Output Current (O, )...20mA Continuous Power Dissipation (T A = +70 C) 8-Pin SOT23 (derate 8.9mW/ C above +70 C)...71mW Operating Temperature Range C to +12 C Junction Temperature C Storage Temperature Range C to +10 C Lead Temperature (soldering, 10s) 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 ( = +.2 to +. for L/M versions, = +2. to +3.6 for the T/S/R versions, = +2.1 to +2.7 for the Z/Y versions. T A = -0 C to +12 C, unless otherwise specified. Typical values are at T A = +2 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS T A = 0 C to +12 C 1.0. Operating oltage Range T A = -0 C to +12 C 1.2. Supply Current Unconnected Reset Threshold ( falling) Reset Threshold Temperature Coefficient I CC < 3.6, no load 9 20 <., no load 12 2 TH < 3.6, no load ( only) 6 20 MAX670_L/MAX670_AL T A = -0 C to +8 C T A = -0 C to +12 C.7.78 MAX670_M/MAX670_AM T A = -0 C to +8 C T A = -0 C to +12 C.22.3 MAX670_T/MAX670_AT MAX670_S/MAX670_AS MAX670_R/MAX670_AR MAX670_Z/MAX670_AZ MAX670_Y/MAX670_AY T A = -0 C to +8 C T A = -0 C to +12 C T A = -0 C to +8 C T A = -0 C to +12 C T A = -0 C to +8 C T A = -0 C to +12 C T A = -0 C to +8 C T A = -0 C to +12 C T A = -0 C to +8 C T A = -0 C to +12 C TH 60 ppm/ C to Reset Output Delay falling at 10m/µs 12 µs T A = -0 C to +8 C Reset Timeout Period t RP T A = -0 C to +12 C Falling to Delay PFI, RST_IN1, RST_IN2 Threshold MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX670(A)/ MAX6706(A)/MAX6707(A) = 1.8 to. µa ms µs T A = -0 C to +8 C T A = -0 C to +12 C PFI Hysteresis 6 m m Maxim Integrated 2

3 Electrical Characteristics (continued) ( = +.2 to +. for L/M versions, = +2. to +3.6 for the T/S/R versions, = +2.1 to +2.7 for the Z/Y versions. T A = -0 C to +12 C, unless otherwise specified. Typical values are at T A = +2 C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PFI, RST_IN1, RST_IN2 Leakage Current (Note 2) T A = -0 C to +8 C T A = -0 C to +12 C PFI to Delay t PF 1 µs Input oltage IL 0.3 x IH 0.7 x Minimum Input Pulse 1 µs Glitch Rejection 100 ns to Reset Delay t MD 200 ns Rising to Delay MAX6701(A)/MAX6702(A)/MAX6703(A)/ MAX670(A)/MAX6706(A)/MAX6707(A) Note 1: Over-temperature limits are guaranteed by design and not production tested. Devices are tested at T A = +2 C. Note 2: Guaranteed by design. Not production tested. na 100 ns Pullup Resistance kω T A = -0 C to +8 C Watchdog Timeout Period t WD T A = -0 C to +12 C Pulse Width t (Note 2) 0 ns Input oltage IL 0.3 x IH 0.7 x Input Current I = or µa, Output Low (Push-Pull or Open Drain) Output Low (Push-Pull or Open Drain),, Output High (Push-Pull Only),, Output Open-Drain Leakage Current Output High (Push-Pull Only) Output Low (Push-Pull Only) OL 1., I SINK = 0µA, output asserted (T A = 0 C to +12 C) 1.2, I SINK = 100µA, output asserted , I SINK = 1.2mA, output asserted 0.3.2, I SINK = 3.2mA, output asserted 0. OL 2., I SINK = 1.2mA, output asserted , I SINK = 200µA, output asserted 0.3.2, I SINK = 3.2mA, output asserted 0. OH 2.7, I SOURCE = 00µA, output not asserted 0.8 x.7, I SOURCE = 800µA, output not asserted 0.8 x I LKG > TH, output not asserted 1.0 µa 1., I SOURCE = 1µA, reset asserted (T A = 0 C to +12 C) 0.8 x OH 1.2, I SOURCE = 0µA, reset asserted 0.8 x 2., I SOURCE = 00µA, reset asserted 0.8 x.2, I SOURCE = 800µA, reset asserted 0.8 x 2.7, I SINK = 1.2mA, reset not asserted 0.3 OL.7, I SINK = 3.2mA, reset not asserted s Maxim Integrated 3

4 Typical Operating Characteristics (T A = +2 C, unless otherwise noted.) SUPPLY CURRENT (µa) = SUPPLY CURRENT vs. TEMPERATURE = 3.3 MAX670(A) MAX6701 toc01 TIMEOUT PERIOD (ms) TIMEOUT PERIOD vs. TEMPERATURE MAX6701 toc02 CC TO OUTPUT DELAY (s) TO OUTPUT DELAY vs. TEMPERATURE MAX6701 toc TEMPERATURE ( C) TEMPERATURE ( C) TEMPERATURE ( C) WATCHDOG TIMEOUT PERIOD (s) WATCHDOG TIMEOUT PERIOD vs. TEMPERATURE MAX6701 toc0 NORMALIZED THRESOLD NORMALIZED THRESHOLD vs. TEMPERATURE MAX6701 toc0 MAXIMUM TRANSIENT DURATION (µs) MAXIMUM TRANSIENT DURATION vs. THRESHOLD OERDRIE OCCURS ABOE LINE MAX670_Y MAX6701 toc TEMPERATURE ( C) TEMPERATURE ( C) THRESHOLD OERDRIE (m) OUTPUT-OLTAGE LOW vs. SINK CURRENT MAX6701 toc OH vs. SOURCE CURRENT MAX6701 toc08 OL (m) 0 CC - OH (m) SINK CURRENT (µa) SOURCE CURRENT (µa) Maxim Integrated

5 Pin Description MAX6701(A) MAX6702(A) MAX6703(A) MAX670 PIN MAX670(A) MAX6706(A) MAX6707(A) NAME CC FUNCTION Active-Low, Manual Reset Input, Internal 0kΩ Pullup to. Pull low to force a reset. Reset remains active as long as is low and the reset timeout period after goes high. Leave unconnected or connect to if unused. deasserts when is low (MAX6701(A)/ MAX6702(A)/MAX6703(A)/ MAX670(A)/ MAX6706(A)/ MAX6707(A) only) Supply oltage for MAX6701 and Input for Primary Reset Threshold Monitor. Push-pull outputs are powered by GND Ground PFI Power-Fail oltage Monitor Input. High-impedance input for internal power-fail comparator. Connect this pin to an external resistive-divider network to set the reset threshold voltage; 0.62 (typ) threshold. Connect to GND or when not used. Power-Fail Monitor Output. Open drain or push-pull active low. goes low when PFI is less than Watchdog Input. If remains high or low for longer than the watchdog timeout period, the internal watchdog timer runs out and is asserted. is asserted low after each watchdog overflow and remains low until the watchdog timer is cleared (the reset output is not affected). The internal watchdog timer clears whenever a /RST_IN1/RST_IN2 reset is asserted, the manual reset is asserted, or sees a rising or falling edge. The watchdog timer remains cleared until the reset output is deasserted. On the MAX670, pulse asserts for the reset timeout period after each watchdog timeout overflow. The watchdog timer cannot be disabled. 6 N.C. No Connection. Not internally connected Active-Low Reset Output (Open Drain or Push-Pull). changes from high to low when the input drops below the selected reset threshold (or RST_IN1/ RST_IN2 for the MAX6701(A)/MAX6702(A)/MAX6703(A), is pulled low, or the watchdog triggers a reset (MAX670 only). remains low for the reset timeout period after the reset conditions are terminated. Maxim Integrated

6 Pin Description (continued) MAX6701(A) MAX6702(A) MAX6703(A) MAX670 PIN MAX670(A) MAX6706(A) MAX6707(A) * active-high for the MAX6702(A)/MAX6706(A). NAME 8 8 7* 8 7* 8 RST_IN1 RST_IN2 FUNCTION Active-Low Watchdog Output (Open Drain or Push- Pull). is asserted whenever the watchdog times out and or the reset inputs are below their respective thresholds. deasserts after a valid transition without a reset timeout period. In the A versions, deasserts without a timeout delay when, RST_IN1, and RST_IN2 rises above its threshold. Pull low to assert (MAX6701/MAX6702/ MAX6703/MAX670/MAX6706/MAX6707 only). Pull low to deassert (MAX6701(A)/MAX6702(A) / MAX6703(A)/ MAX670(A)/MAX6706(A)MAX6707(A) only) Active-High Reset Output (Push-Pull). changes from low to high when the input drops below the selected reset threshold (or RST_IN1/RST_IN2 for MAX6701(A)/MAX6702(A)/ MAX6703(A), is pulled low, or the watchdog triggers a reset (MAX670 only). remains high for the reset timeout period after the reset conditions are terminated. Input for User-Adjustable 2 Monitor. Highimpedance input for second internal reset comparator. Connect this pin to an external resistive-divider network to set the reset threshold voltage; 0.62 (typ) threshold. Connect to when not used. Reset is asserted when either, RST_IN1, or RST_IN2 are below threshold. Input for User-Adjustable 3 Monitor. Highimpedance input for third internal reset comparator. Connect this pin to an external resistive-divider network to set the reset threshold voltage; 0.62 (typ) threshold. Connect to when not used. Reset is asserted when either, RST_IN1, or RST_IN2 are below threshold. Detailed Description Figures 1, 2, and 3 are functional diagrams for the MAX670(A)/MAX6706(A)/MAX6707(A), MAX670/, and MAX6701(A)/MAX6702(A)/MAX6703(A), respectively. Reset Output A microprocessor s (µp s) reset input starts the µp in a known state. The MAX6701 assert reset during power-up and prevent code execution errors during power-down or brownout conditions. On power-up, once reaches 1, is a guaranteed logic-low of 0. or less. As rises, stays low. After, RST_IN1, or RST_IN2 rise above the reset threshold, an internal timer holds low for about 200ms. pulses low whenever dips below the reset threshold, including brownout conditions. If a brownout occurs in the middle of a previously initiated reset pulse, the pulse continues for at least another 10ms. On power-down, once falls below the reset threshold, stays low and is guaranteed to be 0. or less, until drops below 1. The MAX6702(A)/MAX670/MAX6706(A)/ active-high output is the complement of the output, and is guaranteed to be valid with down to 1. Maxim Integrated 6

7 6 1 2 CC PFI 0kΩ REF WATCHDOG TIMER GENERATOR MAX670(A) MAX6706(A) MAX6707(A) 8 7 () RST_IN1 0kΩ REF GENERATOR MAX6701(A) MAX6702(A) MAX6703(A) WATCHDOG TIMER () RST_IN ( ) ARE FOR MAX6706(A) ONLY. 3 GND ( ) ARE FOR MAX6702(A) ONLY. Figure 1. MAX670(A)/MAX6706(A)/MAX6707(A) Functional Diagram Figure 3. MAX6701(A)/MAX6702(A)/MAX6703(A) Functional Diagram 1 2 0kΩ MAX670 GENERATOR 8 7 TH TH t RP t RP WATCHDOG TIMER 6 (MAX670 ONLY) t MD REF PFI 0.62 GND 3 EXTERNALLY DRIEN LOW NOTE: THE MAX6706 OUTPUT IS THE INERSE OF THE SHOWN. Figure 2. MAX670/ Functional Diagram Figure. MAX670/MAX6706/MAX6707,,, and Timing Maxim Integrated 7

8 Standard- vs. A-ersion Comparison The MAX6701/MAX6702/MAX6703/MAX670/MAX6706/ MAX6707s latches low when one of the following events occurs: The watchdog timer times out (1.6s, typ)., RST_IN1, or RST_IN2 is below its reset threshold. is pulled low. only deasserts with a valid transition. The MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX670(A)/ MAX6706(A)/ MAX6707(A)s asserts when either, RST_IN1, or RST_IN2 is below its reset threshold. deasserts without a timeout delay when the undervoltage situation has expired. is latched low when the watchdog timer elapses without seeing a transition. deasserts with a valid transition OR by pulling low. See Figures and for standard-version timing. See Figures 6 and 7 for A-version timing. Watchdog Timer The MAX6701 MAX6707 watchdog circuit monitors the µp s activity. If the µp does not toggle the within 1.6s, goes low. When is asserted, the watchdog timer stays cleared and does not count. As soon as reset is released, the timer starts counting. deasserts after a valid transition is detected at. Pulses as short as 0ns can be detected. Typically, is connected to the NMI input of a µp. When, RST_IN1, or RST_IN2 drop below the reset threshold, goes low whether or not the watchdog timer has timed out. Normally this would trigger an NMI, but goes low simultaneously, and thus overrides the NMI. The MAX670 watchdog circuit does not have an independent watchdog output (). If the µp does not toggle the watchdog input within 1.6s, the MAX670 asserts a reset output pulse for the reset timeout period. Manual Reset The manual reset input () allows reset to be triggered by a pushbutton switch. The switch is effectively debounced by the reset pulse width. is 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 MAX6701(A)/MAX6702(A)/ MAX6703(A)/MAX670(A)/MAX6706(A)/MAX6707(A) by connecting to. Power-Fail Comparator The uncommitted power-fail comparator can be used for various purposes because its noninverting input and output are externally available. The inverting input is internally connected to a 0.62 reference. To build an early warning circuit for power failure, connect the PFI pin to a voltage-divider (see the Typical Operating Circuit). Choose the voltage-divider ratio so that the voltage at PFI falls below 0.62 just before the regulator drops out. Use to interrupt the µp so it can prepare for an orderly power-down. The low-input current at this pin allows for large resistor values in the divider. t t WD t WD TH TH t RP t RP () ( ) ARE FOR MAX6702/MAX6706 ONLY. EXTERNALLY TRIGGERED BY t RP t MD t Figure. MAX6701/MAX6702/MAX6703/MAX670/MAX6706/ MAX6707 Watchdog Figure 6. MAX6701(A)/MAX6702(A)/MAX6703(A)/ MAX670(A)/ MAX6706(A)/MAX6707(A),, and Timing with Three-Stated Maxim Integrated 8

9 t t WD t WD t WD EXTERNAL MAX6701(A) R1 PFI, RST_IN1, OR RST_IN2 () ( ) ARE FOR MAX6702(A)/MAX6706(A) ONLY. t RP R2 EXT-TH = (1 + R1 ) x 0.62 R R1 = R2 x ( EXT-TH - 1 ) 0.62 WHERE EXT-TH IS THE EXTERNAL OLTAGE TRIP LEEL. Figure 7. MAX6701(A)/MAX6702(A)/MAX6703(A)/ MAX670(A)/ MAX6706(A)/MAX6707(A) Watchdog Timing Figure 8. Calculating Adjustable oltage Thresholds Reset Input The MAX6701(A)/MAX6702(A)/MAX6703(A) include two adjustable reset inputs for monitoring up to a total of three system voltages (including ). The thresholds for the monitored RST_IN supplies are externally set with resistor-divider networks (Figure 8). The reset output is asserted if any of the monitored supplies (, RST_IN1, or RST_IN2) go below its specified threshold and remains asserted for the reset timeout period after all supplies are above their thresholds. Applications Information Ensuring a alid Output Down to = 0 When falls below 1, the MAX6701 output no longer sinks current; it becomes an open circuit. High-impedance CMOS logic inputs can drift to undetermined voltages if left undriven. If a pulldown resistor is added to the pin, as shown in Figure 9, any stray charge or leakage currents are drained to ground, holding low. A resistor value (R1) is not critical; 100kΩ is large enough not to load and small enough to pull to ground. This application works for push-pull output only (not for open-drain resets). Monitoring Other System oltages Other systems can be monitored by connecting a voltage-divider to PFI and adjusting the ratio appropriately. In noisy systems, a capacitor between PFI and GND reduces the power-fail circuit s sensitivity to highfrequency noise on the line being monitored. Reset can be asserted on other voltages in addition to the supply line. Connect to to initiate a reset output pulse when PFI drops below Figure 10 shows the MAX670 configured to assert a reset output when the secondary supply falls below the reset threshold. Generating a Reset from Watchdog Overflow Connect to to force a watchdog timeout to generate a reset pulse for only the reset timeout period on the MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX670(A)/ MAX6706(A)/MAX6707(A). When the MAX670 watchdog times out, reset outputs are automatically asserted (no external connections required). For the MAX6701/ MAX6702/MAX6703/MAX670/MAX6706/MAX6707 non-a versions, do not connect to ; this creates a locked condition. Maxim Integrated 9

10 0.9 MAX6701(A) MAX670 MAX670(A) R1 (100kΩ) 3.3 PFI MAX670 () I/O SUPPLY µp CORE SUPPLY () ARE FOR MAX670/MAX6706(A)/ ONLY. Figure 9. alid to Ground Circuit Figure 10. Monitoring Other System oltages Selector Guide PART PP = push-pull, OD = open drain. * deasserts when is pulled low. See the Standard- vs. A-ersion Comparison section for the differences on. SUFFIX PP LOW Bold indicates standard version. PP HIGH THRESHOLD () L.63 M.38 T 3.08 S 2.93 R 2.63 Z 2.32 Y 2.19 OD-LOW PFI, RST_IN1, RST_IN2 MAX6701 PP MAX6701A* PP MAX6702 PP MAX6702A* PP MAX6703 OD MAX6703A* OD MAX670 PP MAX670 PP PP MAX670A* PP PP MAX6706 PP PP MAX6706A* PP PP MAX6707 OD OD MAX6707A* OD OD PP Threshold Suffix Guide Maxim Integrated 10

11 Pin Configurations (continued) TOP IEW GND 2 3 MAX GND 2 3 MAX670(A) MAX6706(A) MAX6707(A) 7 6 () GND N.C. PFI PFI PFI SOT23 SOT23 ( ) ARE FOR MAX6706(A) ONLY. SOT23 Typical Operating Circuit UNREGULATED DC PACKAGE TYPE PUSHBUTTON SWITCH DC-DC REGULATOR PACKAGE CODE PFI MAX670(A) MAX6706(A) MAX6707(A) OUTLINE NO. µp I/O NMI INTERRUPT 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. LAND PATTERN NO. 8 SOT23 K Ordering Information (continued) PART TEMP RANGE PIN-PACKAGE MAX6702_ KA-T -0 C to +12 C 8 SOT23 MAX6702A_ KA-T -0 C to +12 C 8 SOT23 MAX6703_ KA-T -0 C to +12 C 8 SOT23 MAX6703A_ KA-T -0 C to +12 C 8 SOT23 MAX670_KA-T -0 C to +12 C 8 SOT23 MAX670_KA-T -0 C to +12 C 8 SOT23 MAX670A_KA-T -0 C to +12 C 8 SOT23 MAX6706_KA-T -0 C to +12 C 8 SOT23 MAX6706A_KA-T -0 C to +12 C 8 SOT23 MAX6707_KA-T -0 C to +12 C 8 SOT23 MAX6707A_KA-T -0 C to +12 C 8 SOT23 _KA-T -0 C to +12 C 8 SOT23 Insert the desired suffix letter (from the Threshold Suffix Guide table) into the blank to complete the part number. All devices must be ordered in increments of 200 pieces. Sample stock is typically held on standard versions only. Contact factory for availability. Devices are available in both leaded and lead(pb)-free packaging. Specify lead-free by replacing -T with +T when ordering. T = Tape and reel. Chip Information TRANSISTOR COUNT: 716 PROCESS: BiCMOS Maxim Integrated 11

12 Revision History REISION NUMBER REISION DATE DESCRIPTION PAGES CHANGED /1 No / OPNs; removed Automotive reference from Applications section 1 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. 201 Maxim Integrated Products, Inc. 12