STWD100NWWY3F

STWD100 Watchdog timer circuit Datasheet - production data Description The STWD100 watchdog timer circuits are selfcontained devices which prevent system failures that are caused by certain types of hardware errors (such as, non-responding peripherals and bus contention) or software errors (such as a bad code jump and a code stuck in loop). The STWD100 watchdog timer has an input, WDI, and an output, WDO . The input is used to Features Current consumption 13 µA typ. Available watchdog timeout periods are 3.4 ms, 6.3 ms, 102 ms, and 1.6 s Chip enable input Open drain or push-pull WDO output Operating temperature range: –40 to 125 °C Packages: SOT23-5 and SC70-5 (SOT323-5) ESD performance HBM: 2000 V CDM: 1000 V Automotive qualified clear the internal watchdog timer periodically within the specified timeout period, twd. While the system is operating correctly, it periodically toggles the watchdog input, WDI. If the system fails, the watchdog timer is not reset, a system alert is generated and the watchdog output, WDO , is asserted. The STWD100 circuit also has an enable pin, EN , which can enable or disable the watchdog functionality. The EN pin is connected to the internal pull-down resistor. The device is enabled if the EN pin is left floating. Applications Telecommunications Alarm systems Industrial equipment Networking Medical equipment UPS (uninterruptible power supply) Automotive January 2017 DocID14134 Rev 11 This is information on a product in full production. 1/20 www.st.com Contents STWD100 Contents 1 Package pin connections and pin description table ..................... 3 2 Functional description .................................................................... 4 3 Operation ......................................................................................... 5 3.1 Watchdog input (WDI) ....................................................................... 5 3.2 Watchdog output ( WDO ) ................................................................ 5 3.3 Chip enable input ( EN ) ................................................................... 6 3.4 Applications information .................................................................... 7 4 Watchdog timing ............................................................................. 8 5 Maximum ratings ........................................................................... 11 6 DC and AC parameters ................................................................. 12 7 Package information ..................................................................... 14 7.1 SOT23-5 package information ........................................................ 15 7.2 SC70-5 (or SOT323-5) package information ................................... 16 8 Ordering information..................................................................... 17 9 Revision history ............................................................................ 19 2/20 DocID14134 Rev 11 STWD100 1 Package pin connections and pin description table Package pin connections and pin description table Figure 1: SOT23-5 and SC70-5 (SOT323-5) pin connections Table 1: SOT23-5 and SC70-5 (SOT323-5) pin description Pin number Name Description 1 WDO Watchdog output 2 GND Ground 3 EN Enable pin 4 WDI Watchdog input 5 VCC Supply voltage DocID14134 Rev 11 3/20 Functional description 2 STWD100 Functional description Figure 2: Logic diagram 1. The WDO output is available in open drain or push-pull configuration. Figure 3: Block diagram 1. 4/20 If the positive pulse on the enable pin, EN , is longer than 1 µs, it resets the watch. DocID14134 Rev 11 STWD100 3 Operation Operation The STWD100 device is used to detect an out-of-control MCU. The user has to ensure watchdog reset within the watchdog timeout period, otherwise the watchdog output is asserted and the MCU is restarted. The STWD100 can also be enabled or disabled by the chip enable pin. 3.1 Watchdog input (WDI) The WDI input has to be toggled within the watchdog timeout period, tWD, otherwise the watchdog output, WDO , is asserted. The internal watchdog timer, which counts the tWD period, is cleared as follows: 1. by a transition on the watchdog output, WDO (see Figure 8: "Timeout without re-trigger") or 2. by a pulse on the enable pin, EN (see Figure 10: "Enable pin, EN , triggering") or 3. by toggling the WDI input (low-to-high on all versions and high-to-low on the STWD100xW, STWD100xX and STWD100xY only). The pulses on the WDI input with a duration of at least 1 µs are detected and glitches shorter than 100 ns are ignored. If the WDI is permanently tied high or low and EN is tied low, the WDO toggles every 3.4 ms (tWD) on the STWD100xP and every tWD and tPW on the STWD100xW, STWD100xX and STWD100xY (see Figure 8: "Timeout without re-trigger"). 3.2 Watchdog output ( WDO ) When the VCC exceeds the timer startup voltage, VSTART, after power-up, the internal watchdog timer starts counting. If the timer is not cleared within the tWD, the WDO goes low (see Figure 6: "Power-up"). After exceeding the tWD, the WDO is asserted for tPW on STWD100xW, STWD100xX and STWD100xY regardless of possible WDI transitions (see Figure 9: "Trigger after timeout"). On the STWD100xP, WDO is asserted for a minimum of 10 µs and a maximum of tWD after exceeding the tWD period (see Figure 8: "Timeout without re-trigger" and Figure 9: "Trigger after timeout"). The STWD100 has an active low open drain or push-pull output. An external pull-up resistor connected to any supply voltage up to 6 V is required in case of an open drain WDO output (see Figure 4: "Open drain WDO output connection"). Select a resistor value large enough to register a logic low, and small enough to register a logic high while supplying all input current and leakage paths connected to the reset output line. A 10 kΩ pull-up resistor is sufficient in most applications. DocID14134 Rev 11 5/20 Operation STWD100 Figure 4: Open drain WDO output connection 3.3 Chip enable input ( EN ) All states mentioned in Section 3.1: "Watchdog input (WDI)" and Section 3.2: "Watchdog output ( WDO )" are valid under the condition that EN is in logical low state. The behavior of EN is common to all versions (i.e. STWD100xP, STWD100xW, STWD100xX and STWD100xY). If the EN goes high after power-up, in less than tWD from the moment that VCC exceeds the timer startup voltage, VSTART, the WDO stays high for the same time period as EN , plus tWD (see Figure 10: "Enable pin, EN , triggering"). If the EN goes high anytime during normal operation, the WDO goes high as well, but the minimum possible WDO pulse width is 10 µs (see Figure 10: "Enable pin, EN , triggering"). Pulses on the EN pin with a duration of at least 1 µs are detected and glitches shorter than 100 ns are ignored. 6/20 DocID14134 Rev 11 STWD100 3.4 Operation Applications information Interfacing to microprocessors with bidirectional reset pins Microprocessors with bidirectional reset pins can contend with the STWD100 watchdog output, WDO . For example, if the WDO output is driven high and the micro wants to pull it low, signal contention is the result. To prevent this from occurring, connect a 4.7 kΩ resistor between the WDO output and the microprocessors reset I/O as in Figure 5: "Interfacing to microprocessors with bidirectional reset I/O". Figure 5: Interfacing to microprocessors with bidirectional reset I/O DocID14134 Rev 11 7/20 Watchdog timing 4 STWD100 Watchdog timing Figure 6: Power-up 8/20 DocID14134 Rev 11 STWD100 Watchdog timing Figure 7: Normal triggering Figure 8: Timeout without re-trigger DocID14134 Rev 11 9/20 Watchdog timing STWD100 Figure 9: Trigger after timeout Figure 10: Enable pin, EN , triggering 10/20 DocID14134 Rev 11 STWD100 5 Maximum ratings Maximum ratings Stressing the device above the ratings listed in Table 2: "Absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in Table 3: "Operating and AC measurement conditions" of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE program and other relevant quality documents. Table 2: Absolute maximum ratings Symbol TSTG TSLD Parameter Storage temperature (VCC off) (1) Lead solder temperature for 10 seconds Value –55 to 150 260 –0.3 to VCC + 0.3 Unit °C VIO Input or output voltage VCC Supply voltage –0.3 to 7.0 IO Output current 20 mA PD Power dissipation 320 mW V Notes: (1)Reflow at peak temperature of 260 °C (total thermal budget not to exceed 245 °C for greater than 30 seconds). The maximum ratings related to soldering conditions are marked on the inner box label of the product packages. DocID14134 Rev 11 11/20 DC and AC parameters 6 STWD100 DC and AC parameters This section summarizes the operating measurement conditions, and the DC and AC characteristics of the device. The parameters in that follow, are derived from tests performed under the measurement conditions summarized in Table 3: "Operating and AC measurement conditions". Designers should check that the operating conditions in their circuit match the operating conditions when relying on the quoted parameters. Table 3: Operating and AC measurement conditions Parameter Value Unit VCC supply voltage 2.7 to 5.5 V Ambient operating temperature (TA) –40 to 125 °C ≤5 ns Input rise and fall times Input pulse voltages 0.2 to 0.8 VCC Input and output timing ref. voltages 0.3 to 0.7 VCC V Table 4: DC and AC characteristics Test condition (1) Symbol Description VCC Operating voltage ICC VCC supply current ILO Open drain output leakage current From output to the GND or VCC Min. Typ. Max. Unit 2.7 5 5.5 V 13 26 -1 1 Input leakage current (WDI) -1 1 VIH Input high voltage (WDI, EN ) 0.7 VCC VIL Input low voltage (WDI, EN ) VOL VOH Output low voltage ( WDO ) Output high voltage ( WDO ), push-pull only µA 0.3 VCC VCC ≥ 2.7 V, ISINK = 1.2 mA 0.3 VCC ≥ 4.5 V, ISINK = 3.2 mA 0.4 V VCC ≥ 2.7 V, ISOURCE = 500 µA 0.8 VCC VCC ≥ 4.5 V, ISOURCE = 800 µA 0.8 VCC Enable pin ( EN ) EN input pulse width 1 µs EN glitch rejection 100 EN - to - WDO delay (2) 200 ns EN pull-down resistance 12/20 DocID14134 Rev 11 32 63 100 kΩ STWD100 DC and AC parameters Symbol Description Test condition (1) Min. Typ. Max. Unit 1.9 2.2 2.7 V STWD100xP 2.3 3.4 4.6 STWD100xW 4.3 6.3 8.6 STWD100YxW 5.1 6.3 8.6 STWD100xX 71 102 142 STWD100xY 1.12 1.6 2.24 s 140 210 280 ms Watchdog timer VSTART Timer startup voltage ms tWD Watchdog timeout period tPW Watchdog active time WDI - to - WDO delay (3) WDI pulse width WDI glitch rejection 150 1 ns µs 100 ns Notes: (1)Valid for ambient operating temperature: TA = –40 to 125 °C; VCC = 2.7 V to 5.5 V except where noted. (2) WDO asserts for minimum of 10 µs even if EN transitions high. (3) WDO asserts for minimum of 10 µs regardless of transition on WDI (valid for STWD100xP only). DocID14134 Rev 11 13/20 Package information 7 STWD100 Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK ® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. 14/20 DocID14134 Rev 11 STWD100 7.1 Package information SOT23-5 package information Figure 11: SOT23-5 package outline Table 5: SOT23-5 mechanical data Dimensions Ref. A Millimeters Inches Min. Typ. Max. Min. Typ. Max. 0.90 1.20 1.45 0.035 0.047 0.057 A1 0.15 0.006 A2 0.90 1.05 1.30 0.035 0.041 0.051 B 0.35 0.40 0.50 0.014 0.016 0.020 C 0.09 0.15 0.20 0.004 0.006 0.008 D 2.80 2.90 3.00 0.110 0.114 0.118 D1 1.90 0.075 e 0.95 0.037 E 2.60 2.80 3.00 0.102 0.110 0.118 F 1.50 1.60 1.75 0.059 0.063 0.069 L 0.10 0.35 0.60 0.004 0.014 0.024 K 0 degrees 10 degrees 0 degrees DocID14134 Rev 11 10 degrees 15/20 Package information 7.2 STWD100 SC70-5 (or SOT323-5) package information Figure 12: SC70-5 (or SOT323-5) package outline SIDE VIEW DIMENSIONS IN MM GAUGE PLANE COPLANAR LEADS SEATING PLANE TOP VIEW Table 6: SC70-5 (or SOT323-5) mechanical data Dimensions Ref. Millimeters Min. A Typ. 0.80 A1 Max. Min. 1.10 0.032 Typ. 0.80 b 0.90 Max. 0.043 0.10 A2 0.004 1.00 0.032 0.15 0.30 0.006 0.012 c 0.10 0.22 0.004 0.009 D 1.80 2.00 2.20 0.071 0.079 0.087 E 1.80 2.10 2.40 0.071 0.083 0.094 E1 1.15 1.25 1.35 0.045 0.049 0.053 e 0.65 e1 16/20 Inches 0.26 < 0° 0.36 0.039 0.025 1.30 L 0.035 0.051 0.46 0.010 8° 0° DocID14134 Rev 11 0.014 0.018 8° STWD100 8 Ordering information Ordering information Table 7: Order codes Order code Temperature range STWD100NWWY3F STWD100YNWWY3F (1) STWD100NYWY3F STWD100YNYWY3F (1) STWD100NPWY3F -40 to 125 °C Package Packing Topside marking SOT23-5 WNW SOT23-5 (automotive grade) WYNW SOT23-5 WNY SOT23-5 (automotive grade) WYNY SOT23-5 Tape and reel WNP STWD100YNPWY3F (1) SOT23-5 (automotive grade) WYNP STWD100PYW83F SC70 (SOT323-5) WPY STWD100NXWY3F SOT23-5 WNX SOT23-5 (automotive grade) WYNX STWD100YNXWY3F (1) Notes: (1)Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC Q001 and Q002 or equivalent. DocID14134 Rev 11 17/20 Ordering information STWD100 Figure 13: Ordering information scheme Please check device version availability on: www.st.com. Please contact local ST sales office for new device version request. 18/20 DocID14134 Rev 11 STWD100 9 Revision history Revision history Table 8: Document revision history Date Revision 08-Nov-2007 1 Initial release. 23-Jan-2008 2 Updated cover page and Table 4; document status upgraded to full datasheet. 28-Jan-2008 3 Updated cover page. 17-Mar-2008 4 Updated cover page, Figure 4, 7, 9, and Table 4, 9. 31-Jul-2008 5 Updated Features on cover page and Table 4. 05-Mar-2012 6 Added product maturity information and section Applications, updated Section 1, Section 3.4, Section 5, Section 6, Section 8 and Section 8, ECOPACK® text, minor text corrections throughout document. 7 Updated Features (added ESD information). Added Table 1: Device summary. Updated Table 7 (added automotive grade version to the device type). Minor corrections throughout document. 8 Updated Table 1: Device summary and Table 7: Ordering information scheme Added STWD100YxW and values to tWD in Table 4: DC and AC characteristics 25-Sep-2015 9 Updated layout: added Section 1: Package connections and pin description and Section 2: Functional description; renamed Section 7: Part numbering as Section 8: Ordering information; renamed Table 1: Device summary as Table 7: Order codes and moved to Section 8: Ordering information. Added new order code STWD100YNXWY3F to Table 7: Order codes. Removed Section 8: Package marking information 22-Sep-2016 10 Updated document layout and made some small text changes. Features: added automotive qualification Applications: added automotive 20-Jan-2017 11 26-Oct-2012 11-Mar-2014 Changes Features: replaced "RCDM" with "CDM". Table 2: "Absolute maximum ratings": updated value of VIO. Table 7: "Order codes": added new order code STWD100NXWY3F. 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All other product or service names are the property of their respective owners. Information in this document supersedes and replaces information previously supplied in any prior versions of this document. © 2017 STMicroelectronics – All rights reserved 20/20 DocID14134 Rev 11