DS1816 DALLAS | Alldatasheet

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Technical content

FEATURES

/elevenoclock Automatically restarts a microprocessor after power failure /elevenoclock Maintains reset for 150 ms after VCC returns to an in-tolerance condition /elevenoclock Reduces need for discrete components /elevenoclock Precision temperature-compensated voltage reference and voltage sensor /elevenoclock Accurate 5%, 10% or 20% power monitoring /elevenoclock 20% tolerance for use with 3.0-volt systems /elevenoclock Low-cost TO-92 or space saving SOT-23 packages available /elevenoclock Efficient open-drain output with internal 5 kΩ =pull-up resistor /elevenoclock Operating temperature -40°C to +85°C PIN ASSIGNMENT PIN DESCRIPTION TO-92

1 RST Active Low Reset Output

2 V CC Power Supply

3 GND Ground

DESCRIPTION

The DS1816 EconoReset uses a precision temperature reference and comparator circuit to monitor the status of the power supply (V CC). When an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces reset to the active state. When V CC 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. DS1816 3.3V EconoReset with Open Drain Output www.dalsemi.com SOT-23 PACKAGE 1 2 3 1 2 3 TO-92 PACKAGE See Mech. Drawings Section

The DS1816 provides the functions of detecting out-of-tolerance power supply conditions and warning a processor-based system of impending power failure. When V CC 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

TIMING DIAGRAM: POWER-UP Figure 3 TIMING DIAGRAM: POWER-DOWN Figure 4

ABSOLUTE MAXIMUM RATINGS* Voltage on VCC Pin Relative to Ground -0.5V to +7.0V Voltage on RST Relative to Ground -0.5V to V CC +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 CC 0.0 5.5 V 1 DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Output Current @ 0.4 V I OL +10 mA 2, 3 Operating Current VCC < 5.5V I CC 28 35 µA 4 VCC Trip Point (DS1816-5) V CCTP 2.98 3.06 3.15 V 1 VCC Trip Point (DS1816-10) V CCTP 2.80 2.88 2.97 V 1 VCC Trip Point (DS1816-15) V CCTP 2.47 2.55 2.64 V 1 Internal Pull-Up Resistor R P 3.5 5.5 7.5 kΩ 7 Output Capacitance C OUT 10 pF AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES RESET Active Time t RST 100 150 250 ms 5 VCC Detect to RST tRPD 25 µs VCC Slew Rate (VCCTP (MAX) to VCCTP (MIN)) tF 300 µs 8 VCC Slew Rate (VCCTP (MIN) to VCCTP (MAX)) tR 0n s VCC Detect to RST tRPU 100 150 250 ms 5, 6

NOTES: 1. All voltages are referenced to ground. 2. Measured with VCC ≥ 2.7V. 3. A 1kΩ =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.