DS75

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Applications for the DS75 include personal computers/servers, cellular telephones, office equipment, or

any microprocessor–based thermally–sensitive system.

DETAILED PIN DESCRIPTION Table 1

PIN

SYMBOL

DESCRIPTION

1SDA

Data input/output pin for 2–wire serial communication port.

2SCL

Clock input/output pin for 2–wire serial communication port.

3

O.S.

configuration defines means to clear over–temperature state.

4

GND

Ground pin.

Address input pin.

Address input pin.

Address input pin.

Supply Voltage 2.7V – 5.5V input power pin.

OVERVIEW

A block diagram of the DS75 is shown in Figure 1. The DS75 consists of five major components:

1. Precision temperature sensor

2. Analog–to–digital converter

3. 2–wire interface electronics

4. Data registers

5. Thermostat comparator

The factory–calibrated temperature sensor requires no external components. Upon power–up, the DS75

begins temperature conversions with the default resolution of 9 bits (0.5

°C resolution). The host can

periodically read the value in the temperature register, which contains the last completed conversion. As

conversions are performed in the background, reading the temperature register does not affect the

conversion in progress.

In power–sensitive applications, the user can put the DS75 into a shutdown mode, under which the sensor

will complete and store the conversion in progress and revert to a low–power standby state. In

applications where small incremental temperature changes are critical, the user can change the conversion

resolution from 9–bits to 10, 11, or 12. Each additional bit of resolution approximately doubles the

conversion time. This is accomplished by programming the configuration register. The configuration

register defines the conversion state, thermometer resolution/conversion time, active state of the

thermostat output, number of consecutive faults to trigger an alarm condition, and the method to

terminate an alarm condition.

°C and that for T

°C. The result of each

temperature control, the comparator mode and the interrupt mode. This allows the user the flexibility to

customize the condition that would generate and clear a fault condition. Regardless of the mode chosen,

the O.S. output will become active only after the measured temperature exceeds the respective trippoint a

consecutive number of times; the number of consecutive conversions beyond the limit to generate an O.S.

is programmable. The power–up state of the DS75 is in the comparator mode with a single fault

generating an active O.S. Digital data is written to/read from the DS75 via a 2–wire interface, and all

communication is MSb first. Multipoint sensing is possible with the DS75 by uniquely setting the 3–bit

address of up to 8 parts on the 2–wire bus.