ADM8617YAYAKSZ-RL7

Low Voltage Supervisory Circuits with Watchdog Timer in 4-Lead SC70 ADM8616/ADM8617 Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM ADM8616 VCC VCC RESET GENERATOR VREF RESET WATCHDOG DETECTOR GND WDI 04795-001 Precision 1.8 V to 5 V power supply monitoring 9 RESET threshold options 1.58 V to 4.63 V 4 RESET timeout options 1 ms, 20 ms, 140 ms, 1120 ms 3 watchdog timeout options 6.3 ms, 102 ms, 1.6 sec RESET output stages Push-pull active-low (ADM8616) Open-drain active-low (ADM8617) Low power consumption (5 μA) Guaranteed reset output valid to VCC = 1 V Power supply glitch immunity Specified over −40°C to +85°C temperature range 4-lead SC70 package Figure 1. APPLICATIONS Microprocessor systems Computers Controllers Intelligent instruments Portable equipment GENERAL DESCRIPTION The ADM8616/ADM8617 are supervisory circuits that monitor power supply voltage levels and code execution integrity in microprocessor-based systems. A power-on reset signal generates when the supply voltage rises to a preset threshold level. The ADM8616/ ADM8617 have an on-chip watchdog timer that can reset the microprocessor if it fails to strobe within a preset timeout period. The parts differ in terms of reset output configuration. The ADM8616 is active-low with a push-pull output, while the ADM8617 is active-low with an open-drain output. The ADM8616/ADM8617 are available in 4-lead SC70 packages and typically consume only 5 μA, making them suitable for use in low power, portable applications. Each part is available in the following nine reset threshold options: 1.58 V, 1.67 V, 2.19 V, 2.32 V, 2.63 V, 2.93 V, 3.08 V, 4.38 V, and 4.63 V. There are four reset timeout options: 1 ms, 20 ms, 140 ms, and 1120 ms. There are also three possible watchdog timeouts available: 6.3 ms, 102 ms, and 1.6 sec. Not all device options are released for sale as standard models. See the Ordering Guide for details. Rev. C Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2005–2018 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADM8616/ADM8617 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Circuit Description............................................................................8 Applications ....................................................................................... 1 RESET Output ...............................................................................8 Functional Block Diagram .............................................................. 1 Watchdog Input .............................................................................8 General Description ......................................................................... 1 Application Information ...................................................................9 Revision History ............................................................................... 2 Watchdog Input Current ..............................................................9 Specifications..................................................................................... 3 Negative-Going VCC Transients ...................................................9 Absolute Maximum Ratings............................................................ 4 Ensuring RESET Valid to VCC = 0 V ...........................................9 ESD Caution .................................................................................. 4 Watchdog Software Considerations ............................................9 Pin Configuration and Function Descriptions ............................. 5 Outline Dimensions ....................................................................... 10 Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 10 REVISION HISTORY 2/2018—Rev. B to Rev. C Changes to General Description Section ...................................... 1 Added Note 1, Table 1 ...................................................................... 3 Moved Ordering Guide.................................................................. 10 Changes to Figure 16 and Ordering Guide ................................. 10 11/2006—Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 10 6/2005—Revision 0: Initial Version 1/2007—Rev. A to Rev. B Changes to Functional Block Diagram .......................................... 1 Rev. C | Page 2 of 10 Data Sheet ADM8616/ADM8617 SPECIFICATIONS VCC = full operating range, TA = −40oC to +85oC, unless otherwise noted. Table 1. Parameter SUPPLY VCC Operating Voltage Range Supply Current RESET THRESHOLD VOLTAGE 1 ADM861xL ADM861xM ADM861xT ADM861xS ADM861xR ADM861xZ ADM861xY ADM861xW ADM861xV RESET THRESHOLD TEMPERATURE COEFFICIENT Min Max Unit Test Conditions/Comments 10 5 5.5 20 12 V µA µA VCC = 5.5 V VCC = 3.6 V 4.75 4.50 3.15 3.00 2.70 2.38 2.25 1.71 1.62 V V V V V V V V V ppm/°C 1 4.50 4.25 3.00 2.85 2.55 2.25 2.12 1.62 1.52 4.63 4.38 3.08 2.93 2.63 2.32 2.19 1.67 1.58 40 2 × VTH RESET THRESHOLD HYSTERESIS RESET TIMEOUT PERIOD1 ADM861xxA ADM861xxB ADM861xxC ADM861xxD VCC TO RESET DELAY Typ 1 20 140 1120 1.4 28 200 1600 40 RESET OUTPUT VOLTAGE VOL (Open-Drain and Push-Pull) VOH (Push-Pull Only) 0.8 × VCC VCC − 1.5 4.3 71 1.12 50 5 25 1 6.3 102 1.6 9.3 153 2.4 ms ms ms ms µs V V V V V V ns µA ms ms sec ns V VCC falling at 1 mV/µs VCC ≥ 1.0 V, ISINK = 50 µA VCC ≥ 1.2 V, ISINK = 100 µA VCC ≥ 2.7 V, ISINK = 1.2 mA VCC ≥ 4.5 V, ISINK = 3.2 mA VCC ≥ 2.7 V, ISOURCE = 500 µA VCC ≥ 4.5 V, ISOURCE = 800 µA From 10% to 90% VCC, CL = 5 pF, VCC = 3.3 V VIL = 0.3 × VCC, VIH = 0.7 × VCC 0.3 × VCC 0.7 × VCC −20 1 2 40 280 2240 0.3 0.3 0.3 0.4 RESET Rise Time Open-Drain RESET Output Leakage Current WATCHDOG INPUT Watchdog Timeout Period1 ADM861xxxW ADM861xxxX ADM861xxxY WDI Pulse Width WDI Input Threshold VIL VIH WDI Input Current mV 120 −15 160 Not all device options are released for sale as standard models. See the Ordering Guide for details. Rev. C | Page 3 of 10 V µA µA VWDI = VCC VWDI = 0 ADM8616/ADM8617 Data Sheet ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 2. Parameter VCC RESET Output Current (RESET) Operating Temperature Range Storage Temperature Range θJA Thermal Impedance, SC70 Soldering Temperature Sn/Pb Pb-Free Rating −0.3 V to +6 V −0.3 V to +6 V 20 mA −40°C to +85°C −65°C to +150°C 146°C/W Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. ESD CAUTION 240°C, 30 sec 260°C, 40 sec Rev. C | Page 4 of 10 Data Sheet ADM8616/ADM8617 GND 1 RESET 2 ADM8616/ ADM8617 TOP VIEW (Not to Scale) 4 VCC 3 WDI 04795-002 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 2. Pin Configuration Table 3. Pin Function Descriptions Pin No. 1 2 Mnemonic GND RESET 3 WDI 4 VCC Description Ground. Active-Low RESET Output. Asserted whenever VCC is below the reset threshold (VTH). Push-Pull Output Stage for ADM8616. Open-Drain Output Stage for ADM8617. Watchdog Input. Generates a RESET if the logic level on the pin remains low or high for the duration of the watchdog timeout. The timer is cleared if a logic transition occurs on this pin, or if a reset is generated. Leave floating to disable the watchdog timer. Power Supply Voltage Being Monitored. Rev. C | Page 5 of 10 ADM8616/ADM8617 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS 1.20 10.0 9.5 8.5 NORMALIZED WATCHDOG TIMEOUT 9.0 VCC = 5V 8.0 ICC (µA) 7.5 7.0 6.5 VCC = 3.3V 6.0 5.5 5.0 4.5 VCC = 1.5V 1.15 1.10 1.05 1.00 0.95 –20 0 20 40 60 TEMPERATURE (°C) 80 100 120 0.90 –40 04795-003 Figure 3. Supply Current vs. Temperature 20 40 60 TEMPERATURE (°C) 80 100 120 1.05 1.04 NORMALIZED RESET THRESHOLD 1.15 NORMALIZED RESET TIMEOUT 0 Figure 6. Normalized Watchdog Timeout Period vs. Temperature 1.20 1.10 1.05 1.00 0.95 0.90 0.85 1.03 1.02 1.01 1.00 0.99 0.98 0.97 0.96 –20 0 20 40 60 TEMPERATURE (°C) 80 100 120 0.95 –40 04795-004 0.80 –40 –20 Figure 4. Normalized RESET Timeout Period vs. Temperature –20 0 20 40 60 TEMPERATURE (°C) 80 100 120 04795-007 3.5 –40 04795-006 4.0 Figure 7. Normalized RESET Threshold vs. Temperature 100 160 90 140 60 50 40 30 20 100 80 60 40 20 10 0 –40 120 –20 0 20 40 60 TEMPERATURE (°C) 80 100 120 Figure 5. VCC to RESET Output Delay vs. Temperature 0 10 VCC = 2.93V VCC = 4.63V 100 RESET THRESHOLD OVERDRIVE (mV) 1000 04795-008 MINIMUM PULSE WIDTH (µs) 70 04795-005 VCC TO RESET DELAY (µs) 80 Figure 8. Maximum VCC Transient Duration vs. RESET Threshold Overdrive Rev. C | Page 6 of 10 Data Sheet ADM8616/ADM8617 0.20 2.92 VCC = 2.9V VCC = 2.9V 2.90 0.15 VOUT (V) 0.10 2.86 0.05 0 0 1 2 3 4 ISINK (mA) 5 6 7 2.82 0 Figure 9. Voltage Output Low vs. ISINK 0.2 0.4 0.6 ISOURCE (mA) 0.8 Figure 10. Voltage Output High vs. ISOURCE Rev. C | Page 7 of 10 1.0 04795-010 2.84 04795-009 VOUT (V) 2.88 ADM8616/ADM8617 Data Sheet CIRCUIT DESCRIPTION RESET OUTPUT The ADM8616 features an active-low, push-pull RESET output, while the ADM8617 features an active-low, open-drain RESET output. The RESET signal is guaranteed to be logic low and logic high, respectively, for VCC down to 1 V. The RESET output is asserted when VCC is below the RESET threshold (VTH), or when WDI is not serviced within the watchdog timeout period (tWD). RESET remains asserted for the duration of the RESET active timeout period (tRP) after VCC rises above the RESET threshold or after the watchdog timer times out. Figure 11 illustrates the behavior of the RESET outputs. VCC VTH The ADM8616/ADM8617 feature a watchdog timer that monitors microprocessor activity. A timer circuit is cleared with every low-to-high or high-to-low logic transition on the watchdog input pin (WDI), which detects pulses as short as 50 ns. If the timer counts through the preset watchdog timeout period (tWD), RESET is asserted. The microprocessor is required to toggle the WDI pin to avoid being reset. Failure of the microprocessor to toggle WDI within the timeout period, therefore, indicates a code execution error, and the RESET pulse generated restarts the microprocessor in a known state. In addition to logic transitions on WDI, the watchdog timer is also cleared by a RESET assertion due to an undervoltage condition on VCC. When RESET is asserted, the watchdog timer is cleared and does not begin counting again until RESET deasserts. The watchdog timer can be disabled by leaving WDI floating or by three-stating the WDI driver. VCC RESET VTH 1V 0V VCC RESET tRP 0V tRD 04795-011 VCC WATCHDOG INPUT Figure 11. RESET Timing Diagram Rev. C | Page 8 of 10 VCC VTH 1V 0V VCC tRP tWD tRD 0V WDI VCC 04795-012 The ADM8616/ADM8617 provide microprocessor supply voltage supervision by controlling the microprocessors RESET input. Code execution errors are avoided during power-up, power-down, and brownout conditions by asserting a RESET signal when the supply voltage is below a preset threshold and by allowing supply voltage stabilization with a fixed timeout RESET after the supply voltage rises above the threshold. In addition, problems with microprocessor code execution can be monitored and corrected with a watchdog timer. By including watchdog strobe instructions in microprocessor code, a watchdog timer can detect if the microprocessor code breaks down or becomes stuck in an infinite loop. If this happens, the watchdog timer asserts a RESET pulse that restarts the microprocessor in a known state. 0V Figure 12. Watchdog Timing Diagram Data Sheet ADM8616/ADM8617 APPLICATION INFORMATION WATCHDOG INPUT CURRENT WATCHDOG SOFTWARE CONSIDERATIONS To minimize watchdog input current (and minimize overall power consumption), leave WDI low for the majority of the watchdog timeout period. When driven high, WDI can draw as much as 160 µA. Pulsing WDI low-high-low at a low duty cycle reduces the effect of the large input current. When WDI is unconnected, a window comparator disconnects the watchdog timer from the RESET output circuitry so that RESET is not asserted when the watchdog timer times out. In implementing the microprocessors watchdog strobe code, quickly switching WDI low to high and then high to low (minimizing WDI high time) is desirable for current consumption reasons. However, a more effective way of using the watchdog function can be considered. NEGATIVE-GOING VCC TRANSIENTS To avoid unnecessary resets caused by fast power supply transients, the ADM8616/ADM8617 are equipped with glitch rejection circuitry. The typical performance characteristic in Figure 8 plots VCC transient duration vs. transient magnitude. The curve shows combinations of transient magnitude and duration for which a RESET is not generated for 4.63 V and 2.93 V reset threshold parts. For example, with the 2.93 V threshold, a transient that goes 100 mV below the threshold and lasts 8 µs typically does not cause a RESET, but if the transient is any bigger in magnitude or duration, a RESET is generated. An optional 0.1 µF bypass capacitor mounted close to VCC provides additional glitch rejection. A low-high-low WDI pulse within a given subroutine prevents the watchdog from timing out. However, if the subroutine becomes stuck in an infinite loop, the watchdog does not detect this because the subroutine continues to toggle WDI. A more effective coding scheme for detecting this error involves using a slightly longer watchdog timeout. In the program that calls the subroutine, WDI is set high. The subroutine sets WDI low when it is called. If the program executes without error, WDI is toggled high and low with every loop of the program. If the subroutine enters an infinite loop, WDI is kept low, the watchdog times out, and the microprocessor is reset. ENSURING RESET VALID TO VCC = 0 V The active-low RESET output is guaranteed to be valid for VCC as low as 1 V. However, by using an external resistor, valid outputs for VCC as low as 0 V are possible. The resistor, connected between RESET and ground, pulls the output low when it is unable to sink current. A large resistance, such as 100 kΩ, must be used so that it does not overload the RESET output when VCC is above 1 V. START SET WDI HIGH RESET PROGRAM CODE INFINITE LOOP: WATCHDOG TIMES OUT SUBROUTINE 04795-014 SET WDI LOW RETURN Figure 14. Watchdog Flow Diagram VCC VCC RESET RESET RESET ADM8616/ ADM8617 100kΩ WDI µP I/O 04795-015 04795-013 ADM8616/ ADM8617 Figure 13. Ensuring RESET Valid to VCC = 0 V Figure 15. Typical Application Circuit Rev. C | Page 9 of 10 ADM8616/ADM8617 Data Sheet OUTLINE DIMENSIONS 2.20 1.80 0.65 0.65 BSC BSC 1.35 1.15 4 3 1 2.40 1.80 2 PIN 1 INDICATOR 0.50 BSC 0.40 0.10 1.10 0.80 0.10 MAX COPLANARITY 0.10 *0.70 0.50 0.30 0.15 SEATING PLANE 0.18 0.10 0.30 0.10 03-04-2014-B 1.00 0.80 *PACKAGE OUTLINE CORRESPONDS IN FULL TO EIAJ SC82 EXCEPT FOR WIDTH OF PIN 2 AS SHOWN. Figure 16. 4-Lead Thin Shrink Small Outline Transistor Package [SC70] (KS-4) Dimensions shown in millimeters ADM861 x x x x x KS x-RL7 GENERIC NUMBER (6/7) ORDERING QUANTITY RL7: 3,000 PIECE REEL Z: RoHS COMPLIANT PACKAGE CODE KS: 4-LEAD SC70 RESET TIMEOUT PERIOD A: 1ms (MIN) B: 20ms (MIN) C: 140ms (MIN) D: 1120ms (MIN) TEMPERATURE RANGE A: –40°C TO +85°C WATCHDOG TIMEOUT PERIOD W: 6.3ms (TYP) X: 102ms (TYP) Y: 1.6s (TYP) 04795-016 RESET THRESHOLD L: 4.63V M: 4.38V T: 3.08V S: 2.93V R: 2.63V Z: 2.32V Y: 2.19V W: 1.67V V: 1.58V Figure 17. Ordering Code Structure ORDERING GUIDE Model 1, 2, 3 ADM8616LCYAKSZ-RL7 ADM8616WCYAKSZ-RL7 ADM8617SAYAKSZ-RL7 ADM8617RCYAKSZ-RL7 Reset Threshold (V) 4.63 1.67 2.93 2.63 Reset Timeout Minimum (ms) 140 140 1 140 Watchdog Timeout (sec) 1.6 1.6 1.6 1.6 Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C −40°C to +85°C Qty 3,000 3,000 3,000 3,000 Package Description 4-Lead SC70 4-Lead SC70 4-Lead SC70 4-Lead SC70 Package Option KS-4 KS-4 KS-4 KS-4 Marking Code N0F N0F M4X M4X The ADM8616/ADM8617 include many device options; however, not all options are released for sale. Released options are called standard models and are listed in the Ordering Guide. The Watchdog Timers page on the Analog Devices website also lists standard models. Contact a sales representative for information on nonstandard models and be aware that samples and production units have very long lead times. 2 If ordering nonstandard models, complete the ordering code shown in Figure 17 by inserting reset threshold, reset timeout, and watchdog timeout suffixes. 3 Z = RoHS Compliant Part. 1 ©2005–2018 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04795-0-2/18(C) Rev. C | Page 10 of 10