DS1810 5V EconoReset with Push-Pull Output www.maxim-ic.com FEATURES PIN ASSIGNMENT (cid:1) Automatically restarts a microprocessor after power failure 3 (cid:1) Maintains reset for 150 ms after V returns DDASL1L8A10S CC Econo to an in-tolerance condition Reset (cid:1) Reduces need for discrete components (cid:1) Precision temperature-compensated voltage 1 2 reference and voltage sensor TOP VIEW (cid:1) Low-cost TO-92 or space saving surface SOT-23 PACKAGE See Mech. mount SOT-23 packages available Drawings Section (cid:1) Push-Pull output for low current operation 1 2 3 On Website (cid:1) Operating temperature -40°C to +85°C 1 2 3 BOTTOM VIEW TO-92 PACKAGE See Mech. Drawings Section On Website PIN DESCRIPTION TO-92 1 RST Active Low Reset Output 2 V Power Supply CC 3 GND Ground SOT-23 1 RST Active Low Reset Output 2 V Power Supply CC 3 GND Ground DESCRIPTION The DS1810 EconoReset uses a precision temperature reference and comparator circuit to monitor the status of the power supply (V ). When an out-of-tolerance condition is detected, an internal power-fail CC signal is generated which forces reset to the active state. When V returns to an in-tolerance condition, CC the reset signal is kept in the active state for approximately 150 ms to allow the power supply and processor to stabilize. 1 of 5 041002

DS1810 OPERATION - POWER MONITOR The DS1810 provides the function of detecting out-of-tolerance power supply conditions and warning a processor-based system of impending power failure. When V is detected as out-of-tolerance, the RST CC 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 (PUSH-PULL OUTPUT) Figure 1 APPLICATION EXAMPLE Figure 2 OUTPUT VALID CONDITIONS All versions of the DS1810 can maintain a valid output as long as V remains above 1.2 volt. However, CC the RST outputs on the DS1810 use a push-pull structure which can maintain a valid output below 1.2 volts on an input. To sink current below 1.2 volts, a resistor can be connected from RST to Ground (see Figure 3). This arrangement will maintain a valid value on the RST outputs even it V approaches 0 CC volts. During both power-up and -down this arrangement will draw current when RST is in the high state. A value of about 100 k(cid:1) should be adequate to maintain a valid condition. 2 of 5

DS1810 APPLICATION DIAGRAM: RST VALID TO 0 VOLTS VCC ON THE DS1810 Figure 3 TIMING DIAGRAM: POWER-UP Figure 4 TIMING DIAGRAM: POWER-DOWN Figure 5 3 of 5

DS1810 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 V +0.5V CC 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(cid:1)C to +85(cid:1)C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Supply Voltage V 1.2 5.5 V 1 CC DC ELECTRICAL CHARACTERISTICS (-40(cid:1)C to +85(cid:1)C; V =1.2V to 5.5V) CC PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Output Voltage @ 0-500 (cid:2)A V V -0.5V V -0.1V V 1 OH CC CC Output Current @ 2.4V I 350 (cid:2)A 2 OH Output Current @ 0.4V I +10 mA 2 OL Operating Current V < 5.5 I 30 40 (cid:2)A 3 CC CC V Trip Point (DS1810-5) V 4.50 4.62 4.75 V 1 CC CCTP V Trip Point (DS1810-10) V 4.25 4.37 4.49 V 1 CC CCTP V Trip Point (DS1810-15) V 4.00 4.12 4.24 V 1 CC CCTP Output Capacitance C 10 pF OUT AC ELECTRICAL CHARACTERISTICS (-40(cid:1)C to +85(cid:1)C; V =1.2V to 5.5V) CC PARAMETER SYMBOL MIN TYP MAX UNITS NOTES RESET Active Time t 100 150 300 ms RST V Detect to RST tRPD 2 5 (cid:2)s CC V Slew Rate t 300 (cid:2)s 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 100 150 300 ms 4 V Detect to RST RPU CC 4 of 5

DS1810 NOTES: 1. All voltages are referenced to ground. 2. Measured with V (cid:3) 2.7 volts. CC 3. Measured with RST output open. 4. t = 5 (cid:2)s. R PART MARKING CODES SOT-23 PACKAGE “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 5