AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n General Description The AME8510/8520/8530 family allows the user to customize the CPU monitoring function without any external components. The user has a large choice of reset voltage thresholds and output driver configurations, all of which are preset at the factory. Each wafer is trimmed to the customer's specifications. These circuits will ignore fast negative going transients on VDD. The state of the reset output is guaranteed to be correct down to 1V. After VDD crosses above a factory preset threshold, the AME8510/8520/8530 assert a reset signal. After a predetermined time (the "reset" interval) the reset is deasserted. If VDD ever drops below the threshold voltage a reset is asserted immediately. In addition to a supply monitoring function the AME8510/8520 also monitor transitions at the watch dog (WDI) input. If a logic transition does not occur at the WDI pin within a certain time interval (the "watchdog" interval) then a reset is asserted. The reset deasserts after the reset interval, as explained earlier. n Features l Small packages: SOT-23-5 l 7 voltage threshold options l Tight voltage threshold tolerance --- 1.50% l 12 output driver configuration options l Wide temperature range -------- -45oC to 85oC l Low temperature coefficient --- 100ppm/oC (max) l Low quiescent current < 3.0A l 3 bonding options n Pin Configuration SOT-25 Top View The AME8510/8530 can both assert a reset manually by pulling the MRB input to ground. VDD Space saving SOT25 packages and micropower quiescent current make this family a natural for portable battery powered equipment. AME8510 AME8511 AME8510 RESET/ RESETB l l l l Motherboards Computer peripherals Portable electronics Applications using CPUs Consumer electronics WDI MRB VDD AME8510 AME8511 l VDD GND AME8520 RESET/ RESETB GND MRB AME8530 AME851 n Applications WDI AME8530 RESETB/ RESET RESET/ RESETB GND RESETB/ RESET 1 AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n Ordering Information AME8510AEEV X X X XX AME8520AEEV X X X XX AME8530AEEV X X X XX VDD Threshold Voltage 22: VTH=2.19V 23: VTH=2.32V 26: VTH=2.63V 29: VTH=2.93V 31: VTH=3.08V 44: VTH=4.38V 46: VTH=4.63V Watch Dog Interval (TWDNOM) E: TD=1760mS X: Without WDI option Reset Time (TD2NOM) TD=210mS V DD Output Driver Option Pin 1 Polarity WDI/MRB Pin 3 * Polarity * A: RESETB PP N/A N/A B: RESETB OD N/A N/A AME8530 AME851 F: 8510/20/30 C: RESET PP N/A N/A --For example-- D: RESET OD N/A N/A AME8520AEEVEFE29 means: E: RESETB PP RESET PP Output at pin 1 is RESETB, push pull F: RESETB PP RESET OD Output at pin 3 is RESET, push pull G: RESETB OD RESET PP Reset time is 210mS H: RESETB OD RESET OD PP = Push pull output Watch dog interval is 1760mS I: RESET PP RESETB PP OD = Open drain output VDD threshold voltage is 2.93V J: RESET PP RESETB OD N/A = Not available (8510) No temperature shutdow n PIN 1 G N D PIN 3 * Output Driver Chart Explanation: K: RESET OD RESETB PP RESET = Active high L: RESET OD RESETB OD RESETB = Active low Please consult AME sales office or authorized Rep. for other RESET TIME interval and Watch Dog time interval. 2 AME, Inc. AME8510 / 8520 / 8530 Micropower P Watch Dog Timer n Absolute Maximum Ratings Parameter Maximum Unit Supply Voltage 6 V ESD Classification B Caution: Stress above the listed absolute rating may cause permanent damage to the device n Recommended Operating Conditions Parameter Supply Voltage Rating 0.9 - 5 V o Ambient Temperature Range - 40 to +85 C Junction Temperature - 40 to +125 C o n Thermal Information Parameter Maximum Unit o Thermal Resistance (SOT-25) 256 Maximum Junction Temperature 150 o Maximum Lead Temperature ( 10 Sec) 300 o C /W C C 3 AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n Electrical Specifications T A = 25 o C unless otherwise noted PARAMETER VDD Range SYMBOL TEST CONDITIONS VRANGE Supply Current IDD Reset Threshold* VTH ResetB Output Voltage Hgh WDI and MRB unconnected VDD<VTH min VDD<VTH min VOL Reset Output Voltage Low 3 VTH - 1.5% VDD>VTH max ResetB Output Voltage Low TYP 1 VOH Reset Output Voltage Hgh MIN VDD>VTH max VDD to Reset Delay TD1 VDD = VTH - 100mV Reset Timeout Period* TD2 TA=-40~850C Watch Dog Timeout Period* TWD WDI Pulse Width TWDI ISOURCE=0.5mA, TA=-40~850C UNITS 5.5 V 10 A VTH + 1.5% V 0.8VDD V ISNK=1.2mA, 0.5 TA=-40~850C Version F Version E 140 210 280 mS 1120 1760 2400 mS 50 nS 0.7 0.8VDD IIL WDI = 0V -15 V -8 A WDI Input Current IIH WDI = VDD = 5.0V 8 V VDD = VTH x 1.2 MRBIH 0.8VDD TWMRB 1 MRB Noise Immunity (pulse width with no reset) TDMRB MRB Pull Up Resistance * See the chart on page 2 for available values of this parameter. 4 15 0.7 MRBIL MRB Input Threshold MRB to Reset Delay V VDD = VTH x 1.2 WDIIH MRB Pulse Width V S 40 WDIIL WDI Input Threshold MAX 80 S 100 nS 500 nS 120 Kohm AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n Pin Description Pin Number AME8510 AME8520 AME8530 1 1 1 2 2 2 N/A 3 4 5 3 N/A 4 5 3 4 N/A 5 Name Description This pin may be either RESET or RESETB. RESETB is active low. In the case of the AME8520 and AME8530 this RESET/ pin will always be the opposite polarity from RESETB pin 3. This pin can be push/pull or open drain. GND Ground This pin may be either RESETB or RESET. RESET is active high. In the case of the AME8520 and AME8530 this pin will RESET/ always be the opposite polarity from pin 1. RESETB This pin can be either push/pull or open drain. MRB WDI V DD Manual Reset. Active low. Pulling this pin low forces a reset. After a low to high transition reset remains asserted for exactly one reset timeout period. This pin is internally pulled high. If this function is unused then float this pin or tie it to VDD . Watch Dog Input. Any transition on this pin will reset the watch dog timer. If this pin remains high or low for longer than the watch dog interval then a reset is asserted. Float or tristate this pin to disable the watch dog feature. Positive power supply. A reset is asserted after this voltage drops below a predetermined level. After VDD rises above that level reset remains asserted until the end of the reset timeout period. 5 AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n Detailed Description Manual Reset Input The AME8510/8520/8530 are designed to interface with the reset input of a microprocessor and to prevent CPU execution errors due to power up, power down, and other power supply errors. The AME8510/8520 also monitor the CPU health by checking for signal transitions from the CPU at the WDI input. Reset Output Each output pin in the family can be configured to be either push/pull or open drain. In addition each output may be either active high or active low with the condition that parts with two outputs must have opposite polarities. Active high reset outputs are denoted as RESET. Active low reset outputs are denoted as RESETB. The selection guide on page 2 of this data sheet shows all possible combinations of output driver configuration. A reset will be asserted if any of three things happen: 1) VDD drops below the threshold (VTH) 2) The MRB pin is pulled low. 3) The WDI pin does not detect a transition within the watch dog interval (TWD). The reset will remain asserted for the prescribed reset interval after: 1) VDD rises above the threshold (VTH) 2) MRB goes high 3) The watch dog timer has timed out causing the reset to assert. V Release The AME8510 and AME8530 feature a manual reset feature (MRB). A logic low on the MRB pin asserts a reset. The reset remains asserted as long as the MRB pin remains low. After the MRB pin transitions to a high state the reset remains asserted for the prescribed reset interval (TD2). The MRB pin is internally pulled up to VDD by a 100k resistor. It is internally debounced to reject switching transients. The MRB pin is ESD protected by diodes connected to VDD and GND. So the MRB pin should never be driven higher than VDD or lower than GND. Watchdog Input The AME8510 and AME8520 are equipped with a watchdog input (WDI). If the microprocessor does not produce a valid logic edge at the the watchdog input (WDI) within the prescribed watchdog interval (TWD) then a reset asserts. The reset remains asserted for the required reset interval (TD2) At the end of the reset interval the reset is deasserted and the watchdog interval timer starts again from zero. If the watchdog input is left unconnected or is connected to a tri-stated buffer the watchdog function is disabled. As soon as the WDI input is driven either low or high the watchdog function resumes with the watchdog timer set to zero. V TH V TH VDD VDD T D2 T D2 T D2 TW D 50% T D1 50% RESETB RESET T D2 50% T D1 50% WDI RESETB Reset Timing Diagram 6 Watchdog Timing Diagram AME, Inc. AME8510 / 8520 / 8530 Micropower P Watch Dog Timer n Detailed Description (contd.) Watchdog Input Current The watchdog input pin (WDI) typically sources/sinks 8A when driven high or low. So from a power dissipation point of view the duty cycle of the waveform at WDI is unimportant. When the WDI pin is floating or tri-stated the power supply current falls to less than 3.0A. Glitch Rejection The AME8510/8520/8530 family will reject negative going transients on the VDD line to some extent. The smaller the duration of the transient the larger its amplitude may be without triggering a reset. The "Glitch Rejection" chart in the graphs section of this datasheet shows the relation between glitch amplitude and allowable glitch duration to avoid unintended resets. Accurate Output State at Low VDD With VDD voltage on the order of the MOS transistor threshold (<1.0V) the outputs of the AME8510/8520/8530 may become undefined. For parts with active low output (RESETB) a resistor placed between RESETB and GND on the order of 100k will ensure that the RESETB output stays low when VDD is lower than the threshold voltage of the part. In a like manner a resistor on the order of 100k when placed between RESET and VDD will ensure parts with active high output (RESET) will remain high when VDD is lower than the threshold voltage of the part. 7 AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 Glitch Rejection Reset time vs Temperature 140 220 215 Reset Time (mS) Glitch Duration ( S) 120 100 80 60 40 210 205 Vth=2.63V 200 195 20 190 0 0.01 0.1 -45 1 2.30 2.646 2.644 2.642 Vth=2.63V 2.15 2.640 2.638 2.636 2.634 2.10 2.632 2.630 2.20 -5 25 55 85 115 0 Temperature ( C) RESETB VOL vs Temperature Reset VOL @ 0.8mA (V) 0.265 0.260 0.255 0.250 0.245 0.240 0.235 Vth=2.63V 0.230 0.225 0.220 -45 -5 25 55 Temperature (0C) 8 55 85 115 Reset Vth vs Temperature 2.650 2.648 Reset Vth (V) Supply Current @ 5V (uA) IDD vs Temperature 2.35 -45 25 Temperature (0C) Glitch Amplitude (V) 2.25 -5 85 115 Vth=2.63V -45 -5 25 55 Temperature (0C) 85 115 AME, Inc. Micropower P Watch Dog Timer AME8510 / 8520 / 8530 n Package Dimension SOT-25 A A1 A2 b C D E e H L MILLIMETERS MIN MAX 1.00 1.45 0.00 0.15 0.70 1.25 0.35 0.55 0.08 0.25 2.70 3.10 1.40 1.80 1.90 BSC 2.60 3.00 0.30 - 1 S1 0 0.85 SYMBOLS 10 1.05 INCHES MIN MAX 0.0394 0.0571 0.0000 0.0591 0.0276 0.0492 0.0138 0.0217 0.0031 0.0098 0.1063 0.1220 0.0551 0.0709 0.07480 BSC 0.1024 0.1181 0.0118 0 0.0335 10 0.0413 9 www.ame.com.tw E-Mail: info@ame.com.tw Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. AME, Inc., January 2002 Document: 2007-DS8510/8520/8530-B U.S. Headquarters Corporate Headquarters Analog Microelectronics, Inc. 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