DA6512.000
11 July, 2012
MAS6512
This is preliminary information on a new
product under development. Micro Analog
Systems Oy reserves the right to make any
changes without notice.
Capacitive Sensor Signal Interface IC
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Single or Dual Capacitance Sensors
Low Voltage Operation
Low Power Consumption
On Chip Temperature Sensor
Internal Clock Oscillator
16-Bit Ratiometric
∆Σ
CDC
EEPROM Calibration Memory
Serial Interface
DESCRIPTION
MAS6512 capacitive sensor signal Interface IC can
interface both single and dual capacitance sensors.
It uses a 16-bit Capacitance-to-Digital
Converter (CDC), which employs a delta-sigma
(
Σ)
conversion technique. The output data from
the
Σ-modulator
is processed by an on-chip
decimator filter, producing a high resolution
conversion result. The converter is run by an
internal clock oscillator making an external
converter clock unnecessary.
The converter input range is programmable
to meet various sensor offset and changing
capacitance values. Maximum sensor capacitance
is 40pF but higher maximum value can be reached
by using slower conversion speed or scaling the
signal by using an external series capacitor.
The measurement resolution depends on
the programmed capacitance range and over
sampling ratio (OSR) selections.
MAS6512 supports two capacitance
measurement modes. The output can be
proportional either to capacitance difference (C
S
-C
R
)
or to capacitance ratio (C
S
-C
R
)/C
S
.
The IC is designed especially to meet the
requirement for low power consumption, thus
making it an ideal choice for battery powered
systems. Current consumption values of 28 µA with
high resolution or 1.9 µA with low resolution, at a
conversion rate of one conversion per second, can
be achieved.
In addition to measuring capacitance the
device has an internal temperature sensor for
temperature measurement and temperature
compensation purposes. The 256-bit EEPROM
memory stores trimming and calibration coefficients
on chip.
A serial interface, compatible with a bi-
2
directional 2-wire I C bus and 4-wire SPI bus, is
used for conversion setup, starting a conversion
and reading the conversion result.
FEATURES
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Single and Differential Capacitive Sensors
Sensor Offset and Gain Adjustment
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Changing Capacitance Range 2pF…30pF
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Internal Offset Capacitance Matrix 0pF…22pF
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External Capacitance up to 40pF (or higher
using external clock)
Resolution 14 bit (OSR=4096,
∆C=20pF)
Internal Clock Oscillator
On Chip Temperature Sensor -40°C...+85°C
Low Voltage Operation 1.8 V…3.6 V
Low Supply Current: 1.9 µA...28 µA
Conversion Time 5.8ms...82.6ms (12Hz...173Hz)
16-bit Ratiometric
∆Σ
CDC
Internal 256-bit EEPROM Calibration Memory
APPLICATIONS
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I C and SPI Compatible Serial Interface
QFN-16 Package
Capacitive Pressure Sensors
Humidity Sensors
Medical Devices
Flow Meters
Sport Watches
Altimeter and Barometer Systems
Mobile and Battery Powered Systems
Low Frequency Measurement applications
Current/Power Consumption Critical Systems
Industrial and Process Control applications in
noisy environments
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I
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C is a registered trademark of NXP.
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