MAS6512 Datasheet, PDF (1/26 Pages) Micro Analog systems – Capacitive Sensor Signal Interface IC

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product under development. Micro Analog
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changes without notice.
DA6512.000
11 July, 2012
MAS6512
Capacitive Sensor Signal Interface IC
• 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-
directional 2-wire I²C bus and 4-wire SPI bus, is
used for conversion setup, starting a conversion
and reading the conversion result.
FEATURES
APPLICATIONS
• Single and Differential Capacitive Sensors
• Sensor Offset and Gain Adjustment
• Changing Capacitance Range 2pF…30pF
• Internal Offset Capacitance Matrix 0pF…22pF
• 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
• I²C 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
I²C is a registered trademark of NXP.
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