DS1818 3.3V EconoReset with Pushbutton BENEFITS AND FEATURES PIN ASSIGNMENT • Improves Reliability of Processor Operation Temperature-Compensated Voltage 3 o DALLAS Monitor for Precise, Automated Power- DS1818 Econo Fail Detection Reset Automatically Restarts a Microprocessor o After Power Failure 1 2 Maintains Reset for 150ms After V o CC TOP VIEW Returns to Tolerance for Processor SOT-23 PACKAGE See Mech. Stabilization Drawings Section On Website o Monitors Pushbutton for External 1 2 3 Override Active-Low Reset Output 1 2 3 o • Efficient Open-Drain Output with Internal BOTTOM VIEW 5.5kΩ Pullup Resistor Saves Power and Space TO-92 PACKAGE See Mech. 35µA (max) Quiescent Current Drawings Section o On Website • Allows for Easy Design with No Complicated Settings PIN DESCRIPTION Fixed 3.3V Reset Threshold o TO-92 5%, 10%, and 20% Tolerance Versions o Available 1 RST Active Low Reset Output 2 V Power Supply • Operates in Most Commercial and Industrial CC 3 GND Ground Environments -40°C to +85°C Operating Temperature o SOT-23 Range 1 RST Active Low Reset Output • MXD1818 Offers Improved Performance over 2 V Power Supply CC the DS1818 3 GND Ground DESCRIPTION The DS1818 EconoReset uses a precision temperature-compensated reference and comparator circuit to monitor the status of the power supply (V ). When an out-of-tolerance condition is detected, an internal CC power-fail signal is generated which forces reset to the active state. When V returns to an in-tolerance CC condition, the reset signal is kept in the active state for approximately 150 ms to allow the power supply and processor to stabilize. The DS1818 also monitors a pushbutton on the reset output. If the reset line is pulled low, a reset is generated upon release and the DS1818 output will be held in reset output low for typically 150 ms. 1 of 5 19-7559; Rev 1; 3/15

DS1818 OPERATION - POWER MONITOR The DS1818 provides the functions of detecting out-of-tolerance power supply conditions and warning a processor-based system of impending power failures. When VCC is detected as out-of-tolerance, the RST signal is asserted. On power-up, RST is kept active for approximately 150 ms after the power supply has reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST is released. BLOCK DIAGRAM (OPEN-DRAIN OUTPUT) Figure 1 APPLICATION EXAMPLE Figure 2 OPERATION - PUSHBUTTON RESET The DS1818 provides a pushbutton switch for manual reset control. When the DS1818 is not in a reset cycle, a pushbutton reset can be generated by pulling the RST pin low for at least 1 µs. When the pushbutton is held low, the RST is forced active low and will remain active low for about 150 ms after the pushbutton is released. See Figure 2 for an application example and Figure 3 for the timing diagram. TIMING DIAGRAM: PUSHBUTTON RESET Figure 3 2 of 6

DS1818 TIMING DIAGRAM: POWER-UP Figure 4 TIMING DIAGRAM: POWER-DOWN Figure 5 3 of 6

DS1818 ABSOLUTE MAXIMUM RATINGS* Voltage on V Pin Relative to Ground -0.5V to +7.0V CC Voltage on RST Relative to Ground -0.5V to +5VCC +0.5V Operating Temperature -40°C to +85°C Storage Temperature -55°C to +125°C Soldering Temperature 260°C for 10 seconds * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. RECOMMENDED DC OPERATING CONDITIONS (-40°C to +85°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Supply Voltage V 1.0 5.5 V 1 CC DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; V =1.2V to 5.5V) CC PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Output Current @ 0.4 V I +10 mA 2, 3 OL Voltage Input Low V 0.4 V 1 IL Voltage Input High V 0.7 V 1 IH *V CC Operating Current V < 5.5V I 28 35 µA 4 CC CC V Trip Point (DS1818-5) V 2.98 3.06 3.15 V 1 CC CCTP V Trip Point (DS1818-10) V 2.80 2.88 2.97 V 1 CC CCTP V Trip Point (DS1818-20) V 2.47 2.55 2.64 V 1 CC CCTP Internal Pull-up Resistor R 3.50 5.5 7.5 kΩ 7 P Output Capacitance C 10 pF OUT AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; V =1.2V to 5.5V) CC PARAMETER SYMBOL MIN TYP MAX UNITS NOTES RESET Active Time t 100 150 250 ms 5 RST VCC Detect to RST tRPD 2 5 µs V Slew Rate t 300 µs 8 CC F (V (MAX) to V (MIN)) CCTP CCTP V Slew Rate t 0 ns CC R (V (MIN) to V (MAX)) CCTP CCTP t 100 150 250 ms 5, 6 VCC Detect to RST RPU Pushbutton Detect to RST tPB 1 µs Pushbutton Reset t 100 150 250 ms 5 PBRST 4 of 6

DS1818 NOTES: 1. All voltages are referenced to ground. 2. Measured with V ≥ 2.7V. CC 3. A 1 kΩ external pull-up resistor may be required in some applications for proper operation of the microprocessor reset control circuit. 4. Measured with RST output open. 5. Measured with 2.7V ≤ V ≤ 3.3V. CC 6. t = 5 µs. R 7. V and I are a function of the value of R and the associated output load conditions. OH OH P 8. The t value is for reference in defining values for t and should not be considered a requirement for F RPD proper operation or use of the device. PART MARKING CODES “A”, “B”, &“C” represent the device type. “D” represents the device tolerance. 810 - DS1810 A - 5% 811 - DS1811 B - 10% 812 - DS1812 C - 15% 813 - DS1813 D - 20% 815 - DS1815 816 - DS1816 817 - DS1817 818 - DS1818 5 of 6

DS1818 REVISION HISTORY REVISION REVISION PAGES DESCRIPTION NUMBER DATE CHANGED 1 3/15 Updated Benefits and Features section 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. 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. © 2015 Maxim Integrated Products, Inc. 6 of 6

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: M axim Integrated: DS1818-10 DS1818-10+T&R DS1818-20 DS1818-20+ DS1818-20+T&R DS1818-5+T&R DS1818R-10+T&R DS1818R-20+T&R DS1818R-5+T&R DS1818-5 DS1818-10+ DS1818-5+ DS1818R-5-U