ds1720 Maxim Integrated Products, Inc., ds1720 Datasheet - Page 2

• Manufacturer Part Number: ds1720
• Description: Ds1720 Econ-digital Thermometer And Thermostat
• Manufacturer: Maxim Integrated Products, Inc.

ORDER INFORMATION
ORDERING
NUMBER
DS1720S+
DS1720S+T&R
DS1720S
DS1720S/T&R
Note: A “+” symbol will also be marked on the package near the Pin 1 indicator.
OPERATION–MEASURING TEMPERATURE
A block diagram of the DS1720 is shown in Figure 1. The DS1720 measures temperatures through the
use of an on–board proprietary temperature measurement technique. A block diagram of the temperature
measurement circuitry is shown in Figure 2.
The DS1720 measures temperature by counting the number of clock cycles that an oscillator with a low
temperature coefficient goes through during a gate period determined by a high temperature coefficient
oscillator. The counter is preset with a base count that corresponds to –55°C. If the counter reaches zero
before the gate period is over, the temperature register, which is also preset to the –55°C value, is
incremented, indicating that the temperature is higher than –55°C. At the same time, the counter is then
preset with a value determined by the slope accumulator circuitry. This circuitry is needed to compensate
for the parabolic behavior of the oscillators over temperature. The counter is then clocked again until it
reaches zero. If the gate period is still not finished, then this process repeats.
The slope accumulator is used to compensate for the nonlinear behavior of the oscillators over
temperature, yielding a high resolution temperature measurement. This is done by changing the number
of counts necessary for the counter to go through for each incremental degree in temperature. To obtain
the desired resolution, therefore, both the value of the counter and the number of counts per degree C (the
value of the slope accumulator) at a given temperature must be known.
PACKAGE
MARKING
DS1720 (see note)
DS1720 (see note)
DS1720
DS1720
DESCRIPTION
DS1720 in Lead-Free 208mil 8-pin SO
DS1720 in Lead-Free 208mil 8-pin SO, 2500 Piece
Tape-and-Reel
DS1720 in 208mil 8-pin SO
DS1720 in 208mil 8-pin SO, 2500 Piece Tape-and-Reel
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DS1720