DS1818R-10+T&R

DS1818 3.3V EconoReset with Pushbutton BENEFITS AND FEATURES • Improves Reliability of Processor Operation o Temperature-Compensated Voltage Monitor for Precise, Automated PowerFail Detection o Automatically Restarts a Microprocessor After Power Failure o Maintains Reset for 150ms After VCC Returns to Tolerance for Processor Stabilization o Monitors Pushbutton for External Override o Active-Low Reset Output PIN ASSIGNMENT 1 1 2 3 • Operates in Most Commercial and Industrial Environments o -40°C to +85°C Operating Temperature Range • MXD1818 Offers Improved Performance over the DS1818 2 TOP VIEW SOT-23 PACKAGE See Mech. Drawings Section On Website 1 2 3 • Efficient Open-Drain Output with Internal 5.5kΩ Pullup Resistor Saves Power and Space o 35µA (max) Quiescent Current • Allows for Easy Design with No Complicated Settings o Fixed 3.3V Reset Threshold o 5%, 10%, and 20% Tolerance Versions Available 3 DALLAS DS1818 Econo Reset BOTTOM VIEW TO-92 PACKAGE See Mech. Drawings Section On Website PIN DESCRIPTION TO-92 1 2 3 RST VCC GND Active Low Reset Output Power Supply Ground SOT-23 1 2 3 RST VCC GND Active Low Reset Output Power Supply Ground DESCRIPTION The DS1818 EconoReset uses a precision temperature-compensated reference and comparator circuit to monitor the status of the power supply (VCC). When an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces reset to the active state. When VCC returns to an in-tolerance 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 VCC Pin Relative to Ground Voltage on RST Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * -0.5V to +7.0V -0.5V to +5VCC +0.5V -40°C to +85°C -55°C to +125°C 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 PARAMETER SYMBOL MIN Supply Voltage VCC 1.0 DC ELECTRICAL CHARACTERISTICS PARAMETER Output Current @ 0.4 V SYMBOL IOL Voltage Input Low VIL Voltage Input High VIH Operating Current VCC < 5.5V ICC (-40°C to +85°C) TYP MAX UNITS NOTES 5.5 V 1 (-40°C to +85°C; VCC=1.2V to 5.5V) MIN +10 TYP MAX UNITS mA NOTES 2, 3 0.4 V 1 V 1 0.7 *VCC 28 35 µA 4 VCC Trip Point (DS1818-5) VCCTP 2.98 3.06 3.15 V 1 VCC Trip Point (DS1818-10) VCCTP 2.80 2.88 2.97 V 1 VCC Trip Point (DS1818-20) VCCTP 2.47 2.55 2.64 V 1 RP 3.50 5.5 7.5 kΩ 7 10 pF Internal Pull-up Resistor Output Capacitance COUT AC ELECTRICAL CHARACTERISTICS PARAMETER (-40°C to +85°C; VCC=1.2V to 5.5V) SYMBOL MIN TYP MAX UNITS NOTES RESET Active Time tRST 100 150 250 ms 5 VCC Detect to RST tRPD 2 5 µs VCC Slew Rate (VCCTP (MAX) to VCCTP (MIN)) tF 300 µs VCC Slew Rate (VCCTP (MIN) to VCCTP (MAX)) tR 0 ns VCC Detect to RST tRPU 100 Pushbutton Detect to RST tPB 1 tPBRST 100 Pushbutton Reset 4 of 6 150 250 ms 8 5, 6 µs 150 250 ms 5 DS1818 NOTES: 1. All voltages are referenced to ground. 2. Measured with VCC ≥ 2.7V. 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 ≤ VCC ≤ 3.3V. 6. tR = 5 µs. 7. VOH and IOH are a function of the value of RP and the associated output load conditions. 8. The tF value is for reference in defining values for tRPD and should not be considered a requirement for proper operation or use of the device. PART MARKING CODES “A”, “B”, &“C” represent the device type. 810 DS1810 811 DS1811 812 DS1812 813 DS1813 815 DS1815 816 DS1816 817 DS1817 818 DS1818 “D” represents the device tolerance. A 5% B 10% C 15% D 20% 5 of 6 DS1818 REVISION HISTORY REVISION NUMBER REVISION DATE 1 3/15 PAGES CHANGED DESCRIPTION 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. 6 of 6 © 2015 Maxim Integrated Products, Inc.