DS1629

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The crystal frequency is internally divided by a factor that the user defines. The divided output is buffered

and can be used to clock a microcontroller.

The DS1629 features an open-drain alarm output. It can be configured to activate on a thermal event, time

event, either thermal or time, or neither thermal nor time (disabled, power-up state). The thermal alarm

becomes active when measured temperature is greater than or equal to the value stored in the TH

thermostat register. It will remain active until temperature is equal to or less than the value stored in TL,

allowing for programmable hysteresis. The clock alarm will activate at the specific minute of the week

that is programmed in the clock alarm register. The time alarm is cleared by reading from or writing to

either the clock register or the clock alarm register.

The DS1629 configuration register defines several key items of device functionality. It sets the

conversion mode of the digital thermometer and what event, if any, will constitute an alarm condition. It

also sets the active state of the alarm output. Finally, it enables/disables and sets the division factor for the

oscillator output.

The DS1629 also features 32 bytes of SRAM for storage of general information. This memory space has

no bearing on thermometer or chronograph operation.

Possible uses for this memory are

time/temperature histogram storage, thermal datalogging, etc.

Digital data is written to/read from the DS1629 via a 2-wire interface, and all communication is MSb

first. Individual registers are accessed by unique 8-bit command protocols.

The DS1629 features a wide power supply range (2.2V

≤ V

DD

≤ 5.5V) for clock functionality, SRAM

data retention, and 2-wire communication. EEPROM writes and temperature conversions should only be

performed at 2.7V

≤V

DD

≤5.5V for reliable results.