AD7150BRMZ-REEL(Rev0) View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD7150BRMZ-REEL
(Rev.:Rev0)

Ultra-Low Power, 2-Channel, Capacitance Converter for Proximity Sensing

Analog Devices 

AUTOCAPDAC ADJUSTMENT

In adaptive threshold mode, the part can dynamically adjust the

CAPDAC to keep the CDC in an optimal operating capacitive

range. When the AutoDAC function is enabled, the CAPDAC

value is automatically incremented when the data average

exceeds three-fourths of the CDC full range, and the CAPDAC

value is decremented when the data average goes below one-

fourth of the CDC full range. The AutoDAC increment or

decrement step depends on the selected CDC capacitive input

range. See the Setup Registers section.

POWER-DOWN TIMER

In power sensitive applications, the AD7150 can be set to

automatically enter power-down mode after a programmed

period of time in which the outputs have not been activated.

The AD7150 can be then returned to a normal operational

mode either via the serial interface or by the power supply

off/on sequence.

AD7150

POWER SUPPLY MONITOR

When the AD7150 VDD power supply voltage drops below a

defined level needed for correct CDC operation, the on-chip

power supply monitor stops the adaptive threshold logic and

holds it in reset. After the VDD reaches the required level, the

threshold logic is released, and the data average is reset to the

value of the first conversion finished at the correct power supply

voltage.

This feature prevents the adaptive threshold from being set

incorrectly after a very slow rise of the VDD voltage or from

being corrupted by accidental drops in the VDD voltage.

The other AD7150 functions continue working below the

power supply monitor threshold, down to approximately

1.0V..1.8V, the exact level depending on the manufacturing

process variation. In the region of the low VDD voltage, the part is

still accessible via the serial interface and continues conversion.

However, the conversion results may be incorrect and,

therefore, the data should not be considered valid if the part

operates below the power supply monitor threshold.

The status of the power supply monitor can be determined by

reading the PwrDown bit in the AD7150 status register.

Rev. 0 | Page 13 of 28

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