U5020M Digital Window Watchdog Timer Description The digital window watchdog timer, U5020M, is a CMOS integrated circuit. In application where safety is critical, it is especially important to monitor the microcontroller. Normal microcontroller operation is indicated by a cyclically transmitted trigger signal, which is received by a window watchdog timer within a defined time window. A missing or a wrong trigger signal makes the watchdog timer reset the microcontroller. The IC is tailored for microcontrollers which can work in both full-power and sleep mode. With an additional voltage monitoring (power-on reset and supply voltage drop reset) U5020M offers a complete monitoring solution for microsystems in automotive and industrial applications. Features D Low current consumption: IDD < 100 mA D RC–oscillator D Internal reset during power-up and supply voltage drops (POR) D Trigger input D Six wake-up inputs D Reset output D Enable output D “Short” trigger window for active mode “long” trigger window for sleep mode D Cyclical wake-up of microcontroller in sleep mode Ordering Information Extended Type Number U5020M–FP Package SO16 Remarks Block Diagram C VDD R1 10 nF VDD OSC 15 C1 RC Oscillator OSC Reset 10 mC 95 10387 13 Input ts 16 State machine OSC Trigger 11 Mode 12 Wake up 3–8 Input signal conditioning POR 9 Enable Power–on reset 14 GND POR External switching circuitry Test logic 2 Test 1 Test Figure 1. Block diagram with external circuit TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 1 (8) Preliminary Information U5020M Pin Description Pin 1 2 3 to 8 TM 1 16 ts TM 2 15 Osc Wake-up 3 14 GND Wake-up 13 VDD 4 Wake-up 5 12 Mode Wake-up 6 11 Trig Wake-up 7 10 Reset Wake-up 8 9 Symbol Function TM Test must not be connected TM Test must be connected to GND Wake-up Wake-up inputs (pull-down resistor) There are six digitally debounced wake-up inputs. During the long trigger mode each signal slope at the inputs initiates a reset pulse at Pin 10. Ena Enable output (push-pull) It is used for the control of peripheral components. It is activated after the processor triggers three times correctly. Reset Reset output (open drain) Resets the processor in the case of a trigger error or if a wake-up pulse occurs during the long watchdog period. Trig Trigger input (pull-up resistor) It is connected to the microprocessor’s trigger signal. Mode Mode input (pull-up resistor) The processor’s mode signal initiates the switchover between the long and the short watchdog time. VDD Supply voltage GND Ground, reference voltage Osc RC oscillator ts Time switch input Programming pin to select different time durations for the long watchdog time. 9 10 11 12 Ena 95 10635 13 14 15 16 Figure 2. Pin connections Functional Description Supply, Pin 13 1t where t 1.35 1.57 R f The U5020M requires a stabilized supply voltage 5% to comply with its electrical VDD = 5 V characteristic. An external buffer capacitor of C = 10 nF may be connected between Pin 13 and GND. RC-Oscillator, Pin 15 The clock frequency, f, can be adjusted with the components R1 and C1 according to the formula: 1 (C 1 0.01) R 1 in kW, C 1 in nF and t in ms The clock frequency determines all time periods of the logic part as shown in the last section of the data sheet (timing). With an appropriate selection of components, the clock frequency, f, is nearly independent of the supply voltage as shown in figure 3. Frequency tolerance 1%, C1 = 5%. Dfmax = 10% with R1 2 (8) Preliminary Information TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 U5020M 1000.00 100.00 t (ms) 4.5 V 10.00 5.0 V 5.5 V C1 = 500 pF 1.00 1 10 100 R1 (kW) 1000 95 10636 Figure 3. Period t vs. R1, @ C1 = 500 pF Pin 13 V DD to t6 Pin 10 Reset Out t1 Pin 12 Mode 95 10637 Figure 4. Power-up reset and mode switchover Supply Voltage Monitoring, Pin 10 The integrated power-on reset (POR) circuitry sets the internal logic to a defined basic status and generates a reset pulse at the reset output, Pin 10, during ramp-up of the supply voltage and in the case of voltage drops of the supply. A hysteresis in the POR threshold prevents the circuit from oscillating. During ramp–up of the supply voltage the reset output stays active for time, to, in order to bring the microcontroller in its defined reset status (see figure 4). Pin 10 has an open-drain output. Switch-over Mode Time, Pin 12 The switch-over mode time enables the synchronous operation of micro and watchdog. After the power-up reset time the watchdog has to be switched to its monitoring mode by the micro with a “low” signal transmitted to the mode pin (Pin 12) within the time out period, t1,. If the low signal does not occur within time, t1, (see figure 4) the watchdog generates a reset pulse, t6, TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 and the time, t1, starts again. Micro and watchdog are synchronized with the switchover mode time, t1, each time a reset pulse is generated. Microcontroller in Active Mode Monitoring with the “Short” Trigger Window After the switch-over mode the watchdog works in the short watchdog mode and expects a trigger pulse from the microcontroller within the defined time window, t3, (enable time). The watchdog generates a reset pulse which resets the microcontroller if D the trigger pulse duration is too long, D the trigger pulse is within the disable time, t2 D there is no trigger pulse Figure 5 shows the pulse diagram with a missing trigger pulse. 3 (8) Preliminary Information U5020M V DD Pin 13 to t1 Pin 10 Reset Out t3 t2 Pin 12 Mode Pin 11 Trigger 95 10638 Figure 5. Pulse diagram with no trigger pulse during the short watchdog time Figure 6 shows a correct trigger sequence. The positive edge of the trigger signal starts a new monitoring cycle with the disable time, t2. To ensure a correct operation of the microcontroller the watchdog needs to be triggered three times correctly before it sets its enable output. This feature is used to activate or deactivate safety critical components, which have to be switched to a certain condition (emergency status) in the case of a microcontroller malfunction. As soon as there is an incorrect trigger sequence the enable signal is reset and it takes again a three correct trigger sequence before enable is reset. Microcontroller in Sleep Mode Monitoring with the “Long” Trigger Window The long watchdog mode allows cyclical wake up of the micro during the sleep mode. Like in the short watchdog mode there is a disable time, t4, and an enable time, t5, in which a trigger signal is accepted. The watchdog can be switched from the short trigger window to the long trigger window with a “high” potential at the mode pin (Pin 12). In contrast to the short watchdog mode the time periods are now much longer and the enable output remains inactive that other components can be switched off to effect a further decrease in current consumption. As soon as a wake-up signal at one of the 6 wake up inputs (Pins 3 to 8) is detected, the long watchdog mode ends, a reset pulse wakes-up the sleeping microcontroller and the normal monitoring cycle starts with the mode switch-over time. With the help of a low or high potential at Pin 16 (time switch) the long watchdog time can be selected in two values. Pin 13 VDD t0 t1 Pin 10 Reset Out t3 t2 t2 Mode Pin 12 Pin 11 Trigger t trig Pin 9 Enable 95 10639 Figure 6. Pulse diagram of a correct trigger sequence during the short watchdog time 4 (8) Preliminary Information TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 U5020M Figure 7 shows the switch-over from the short to the long watchdog mode. The wake up signal during the enable time, t5, activates a reset pulse, t6. The watchdog can be switched back from the long to the short watchdog mode with a low potential at the mode pin (Pin 12). t6 t1 Pin 10 Reset out Wake-up Pins 3 to 8 t4 t5 Pin 12 Mode t2 Pin 11 Trigger Pin 9 Enable 95 10640 Figure 7. Pulse diagram of the long watchdog time Application Hint In order to prevent the IC from an undesired reset output signal which may be caused by transcients on the supply under certain conditions a pc board connection from Pin 2 to GND is strongly recommended. Absolute Maximum Ratings ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ " ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ Parameters Supply voltage Output current Input voltage Ambient temperature range Storage temperature range Symbol VDD IOUT Value 6.5 VIN Tamb Tstg –0.5 V to VDD + 0.5 V –40 to +85 –55 to +150 2 Unit V mA V °C °C Thermal Resistance ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁÁÁÁ ÁÁÁÁÁ Junction ambient Parameters SO16 TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 Symbol RthJA Value 160 Unit K/W 5 (8) Preliminary Information U5020M Electrical Characteristics VDD = 5 V; Tamb = 25 °C; reference point is ground (Pin14); figure 4, unless otherwise specified ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ W m ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ m ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁÁÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ ÁÁÁÁ Parameters Supply voltage Current consumption Test Conditions / Pins Pin 13 R1 = 66 k Pin 13 Power-on reset Power-on reset Power-on reset Inputs Upper threshold (“1”) Lower threshold (“0”) Input voltage range Input current Logic functions Pin 13 VDD Threshold Pin 13 VPOR Hysteresis Pin 13 Vhys Pins 3 to 8, 11, 12 and 16 VIH VIL VIN Depending on pin I IN Output Pin 9 Max. output current Upper output voltage (“1”) Lower output voltage (“0”) Output Pin 10 Max. output current Lower output voltage (“0”) Timing Debounce period Debounce period Max. trigger pulse period Power-up reset time Time out period Short disable time Short enable time Long disable time Long enable time Long disable time Long enable time Reset out time Symbol VDD IDD Min. 4.5 4.0 1.0 –0.4 –20 2 4.5 2 IOUT = –1mA IOUT VOL VDD + 0.2 20 3 96 Unit V A V V mV 3.8 100 IOUT VOH VOL Input switch = low (0) Pin 16 Input switch = low (0) Pin 16 Input switch = high (1) Pin 16 Input switch = high (1) Pin 16 Max. 5.5 100 1 IOUT = 1mA IOUT = –1mA Trig, Mode, Pins 11 and 12 Wake-up 1–6, Pins 3 to 8 Typ. V V V A 0.5 mA V V 0.5 mA V to t1 t2 t3 t4 45 201 1112 130 124 71970 cyc cyc cyc cyc cyc cyc cyc cyc t5 30002 cyc t4 1200 cyc t5 400 cyc t6 40 cyc 6 (8) Preliminary Information 4 128 TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 U5020M Package Information Package SO16 Dimensions in mm 5.2 4.8 10.0 9.85 3.7 1.4 0.25 0.10 0.4 1.27 6.15 5.85 8.89 16 0.2 3.8 9 technical drawings according to DIN specifications 1 TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97 13036 8 7 (8) Preliminary Information U5020M Ozone Depleting Substances Policy Statement It is the policy of TEMIC TELEFUNKEN microelectronic GmbH to 1. Meet all present and future national and international statutory requirements. 2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems with respect to their impact on the health and safety of our employees and the public, as well as their impact on the environment. It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as ozone depleting substances ( ODSs). The Montreal Protocol ( 1987) and its London Amendments ( 1990) intend to severely restrict the use of ODSs and forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these substances. TEMIC TELEFUNKEN microelectronic GmbH semiconductor division has been able to use its policy of continuous improvements to eliminate the use of ODSs listed in the following documents. 1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively 2 . Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental Protection Agency ( EPA) in the USA 3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C ( transitional substances ) respectively. TEMIC can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 ( 0 ) 7131 67 2831, Fax number: 49 ( 0 ) 7131 67 2423 8 (8) Preliminary Information TELEFUNKEN Semiconductors Rev. A3, 27-Feb-97