AD7152 Datasheet, PDF (1/24 Pages) Analog Devices – 12-Bit Capacitance-to-Digital Converter

12-Bit Capacitance-to-Digital Converter
AD7152/AD7153
FEATURES
Capacitance-to-digital converters
Interfaces to floating sensors
Resolution down to 0.25 fF (that is, up to 12 ENOB)
Linearity: 0.05%
Common-mode (not changing) capacitance up to 5 pF
Four capacitance ranges selectable per operation mode
±0.25 pF to ±2 pF in differential mode
0.5 pF to 4 pF in single-ended mode
Tolerant of parasitic capacitance to ground up to 50 pF
Conversion time per channel: 5 ms, 20 ms, 50 ms, and 60 ms
Internal clock oscillator
2-wire serial interface (I²C-compatible)
Power
2.7 V to 3.6 V single-supply operation
100 μA current consumption
Operating temperature: −40°C to +85°C
10-lead MSOP package
APPLICATIONS
Automotive, industrial, and medical systems for
Pressure measurement
Position sensing
Level sensing
Flowmeters
Humidity sensing
GENERAL DESCRIPTION
The AD7152/AD7153 are 12-bit sigma-delta (Σ-Δ) capacitance-to-
digital converters (CDCs). The capacitance to be measured
is connected directly to the device inputs. The architecture
features inherent high resolution (12-bit no missing codes,
up to 12-bit effective resolution) and high linearity (±0.05%).
The AD7152/AD7153 have four capacitance input ranges per
operation mode, ±0.25 pF to ±2 pF in differential mode and
0.5 pF to 4 pF in single-ended mode.
The AD7152/AD7153 can accept up to 5 pF common-mode
capacitance (not changing), which can be balanced by a
programmable on-chip, digital-to-capacitance converter
(CAPDAC).
The AD7153 has one capacitance input channel, while the
AD7152 has two channels. Each channel can be configured
as single-ended or differential. The AD7152/AD7153 are
designed for floating capacitive sensors.
The AD7152/AD7153 have a 2-wire, I²C®-compatible serial
interface. Both parts can operate with a single power supply
from 2.7 V to 3.6 V. They are specified over the temperature
range of −40°C to +85°C and are available in a 10-lead MSOP
package.
CIN1(+)
CIN1(–)
EXC1
CIN2(+)
CIN2(–)
EXC2
FUNCTIONAL BLOCK DIAGRAMS
VDD
VDD
CAP+
CAP–
AD7152
CLOCK
VOLTAGE
GENERATOR REFERENCE
CAP+
CAP–
AD7153
CLOCK
VOLTAGE
GENERATOR REFERENCE
MUX
12-BIT Σ-Δ
MODULATOR
I²C
SERIAL
INTERFACE
SDA
SCL
CIN1(+)
CIN1(–)
EXC1
MUX
12-BIT Σ-Δ
MODULATOR
I²C
SERIAL
INTERFACE
SDA
SCL
EXCITATION
DIGITAL
FILTER
CONTROL LOGIC
CALIBRATION
EXCITATION
DIGITAL
FILTER
CONTROL LOGIC
CALIBRATION
GND
Figure 1.
GND
Figure 2.
Rev. 0
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