DS1832中文资料

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FEATURES

Automatically restarts microprocessor after power failure

Maintains active-high reset for 350 ms after V CC returns to an in-tolerance condition

Accurate 5%, 10% or 15% microprocessor 5V power supply monitoring

Reduces need for discrete components

Precision temperature-compensated voltage reference and voltage sensor

Low-cost TO-92 package or surface mount SOT-223 package

Internal 5k pull-up resistor

Operating temperature of -40°C to +85°C

PIN ASSIGNMENT

PIN DESCRIPTION

PIN 1Ground PIN 2Reset PIN 3V CC

PIN 4

Ground (SOT-223 only)

DESCRIPTION

The DS1833 EconoReset uses a precision temperature compensated 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 (high) state. When V CC returns to an in-tolerance condition, the reset signal is kept in the active state for approximately 350 ms to allow the power supply and processor to stabilize.

OPERATION - POWER MONITOR

The DS1833 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, as defined by the tolerance of the part selected, the RST signal is asserted. On power-up, RST is kept active for approximately 350 ms after the power supply has reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST is released.

DS1833

5V EconoReset

TO-92 PACKAGE

See Mech.Drawings Section

SOT-223 PACKAGE

See Mech.Drawings Section

DS1833 BLOCK DIAGRAM Figure 1

APPLICATION EXAMPLE Figure 2

POWER-UP Figure 3

POWER-DOWN Figure 4

ABSOLUTE MAXIMUM RATINGS*

Voltage on V CC Pin Relative to Ground -0.5V to +7.0V

Voltage on I/O 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 1.2 5.0 5.5V1

DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; V DD=5V ± 10%) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Low Level @ RST V OL0.4V1 Output Current @ 0.4V I OL+8mA

Operating Current I CC 1.52mA

V CC Trip Point 5%V CCTP1 4.5 4.625 4.74V1

V CC Trip Point 10%V CCTP2 4.25 4.375 4.49V1

V CC Trip Point 15%V CCTP3 4.0 4.125 4.24V1 Output Capacitance C OUT10pF

Internal Pull-Up Resistor R P 3.755 6.25k?

AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; V CC=5V ± 10%) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Reset Active Time t RST250350450ms

V CC Detect to RST t RPD100ns

V CC Slew Rate (4.75V - 4.00V)t F300μs

V CC Slew Rate (4.00V - 4.75V)t R0ns

V CC Detect to RST t RPU250350450ms NOTES:

1.All voltages are referenced to ground.