AD7150 Analog Devices, AD7150 Datasheet - Page 20

• Manufacturer Part Number: AD7150
• Description: Ultra-Low Power, 2-Channel, Capacitance Converter for Proximity Sensing
• Manufacturer: Analog Devices

Specifications of AD7150

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: n/a
• Interface: I²C/Ser 2-Wire,Ser
• Analog Input Type: SE-Uni
• Ain Range: 0.5 pF,1 pF,2 pF,4 pF
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7150
POWER-DOWN TIMER REGISTER
Address Pointer 0x10
8 Bits, Read/Write, Factory Preset 0x00
Table 14. Power-Down Timer Register Bit Map
Bit
Mnemonic
Default
Table 15.Power-Down Timer Register Bit Descriptions
Bit
[7:6]
[5:0]
CAPDAC REGISTERS
Ch1 Address Pointer 0x11
Ch2 Address Pointer 0x12
8 Bits, Read/Write, Factory Preset 0x00
Table 16. CAPDAC Registers Bit Map
Bit
Mnemonic
Default
Table 17. CAPDAC Registers Bit Descriptions
Bit
7
6
[5:0]
SERIAL NUMBER REGISTER
Address Pointer 0x13, 0x14, 0x15, 0x16
32 Bits, Read-Only, 0xXXXX
This register holds a serial number, unique for each individual part.
Mnemonic
–
Power-Down
Timeout
Mnemonic
DacEn
DacAuto
DacValue
Description
These bits must be 0 for proper operation.
Defines period duration of the power-down timeout.
If the output comparator outputs have not been activated during the programmed period, the part enters
power-down mode automatically. The part can be then returned to a normal operational mode either via the
serial interface or by the power supply off/on sequence.
The period is programmable in steps of four hours. For example, setting the value to 0x06 sets the duration to
24 hours. The maximum value of 0x3F corresponds to approximately 10.5 days.
The value of 0x00 disables the power-down timeout, and the part does not enter power-down mode
automatically.
Description
DacEn = 1 enables capacitive DAC.
DacAuto = 1 enables the AutoDAC function in the adaptive threshold mode.
When the AutoDAC function is enabled, the part dynamically adjusts the CAPDAC to keep the CDC in an
optimal operating capacitive range. The CAPDAC value is automatically incremented when the data average
exceeds ¾ of the CDC full range, and the CAPDAC value is decremented when the data average goes below ¼
of the CDC full range. The AutoDAC increment or decrement step depends on the selected CDC capacitive
input range.
Bit has no effect in fixed threshold mode; the AutoDAC function is always disabled in the fixed threshold mode.
CAPDAC value, Code 0x00 ≈ 0 pF, Code 0x3F ≈ CAPDAC full range.
DacEn
Bit 7
Bit 7
–
0
1
DacAuto
Bit 6
Bit 6
–
0
1
Bit 5
Bit 5
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Bit 4
Bit 4
CHIP ID REGISTER
Address Pointer 0x17
8 Bits, Read-Only, 0xXX
This register holds the chip identification code, used in factory
manufacturing and testing.
Power-Down Timeout (6-Bit Value)
DacValue (6-Bit Value)
Bit 3
Bit 3
0x00
0x00
Bit 2
Bit 2
Bit 1
Bit 1
Bit 0
Bit 0