iC-HO
GENERAL PURPOSE SENSOR INTERFACE
iC-HO suits for various applications: mass flow metering, gas
sensing and pressure sensing. Besides the IC only a few exter-
nal components are required: a cost effective microcontroller
and/or an EEPROM, and the sensor itself. iC-HO is completely
controllable and monitorable by the microcontroller via SPI.
Alternatively, stand-alone applications can boot from the CRC-
secured external SPI EEPROM.
Instrumentation PGA inputs allow gain and offset calibration,
and temperature stabilization. An integrated look-up table (LUT)
featuring 9 breakpoints can be used to correct nonlinear sensor
characterstics directly within the sensor interface IC.
A digital PI-controller is available to drive a wide range of
MEMS heater resistors with up to 115 mW in an absolute or
relative temperature range from -25 °C to + 660 °C. A fixed set
point or sequence controller mode can be selected.
Matching constant current sources are available to bias up to
three sensor resistors. The analog ratiometric differential output
signal is implemented with a 10-bit D/A converter.
Applications
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Flow Sensors
Pressure Sensors
Gas Sensors
Features
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Ultra-low
offset and low-noise PGA inputs
11-bit analog to digital conversion
Signal offset correction
Configurable temperature drift compensation
Linearization of sensor characteristic by look-up table
Measurement data output digital and analog (10-bit D/A)
Differential output of ratiometric voltage
Adjustable PI
heater control
Signal and system monitoring functions
Fault indication at open-drain
error output
Sensor resistor bias by adjustable current sources
Integrated 8-bit temperature sensing
SPI-master (for EEPROM) and SPI-slave interfaces for
device configuration and controller operation
5 V supply voltage
Operating temperature range of -20 °C to 105 °C
VAMP
VDD
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VDDA
VDDAS
SUS3
SUS2
SUS1
GNDAS
VREF
Configurable Sensor
Supply
Bandgap
Reference
Osillator
Error Monitor
NERR
PGA Input
SPIN
SNIN
+
A
D
Look Up Table
Analog Output
-
A
D
+
OUTP
OUTN
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iC-HO
Heater Control
RBP
RBN
NCS_S
I/O Interface
A
D
PI
RAM
Main Control
Chip Temp.
SCK_S
MOSI_S
MISO_S
SPI Slave
HEATP
HEATN
A
D
D
A
Power-Down
Reset
NCS_M
IHEAT
GNDHS
EEPROM
Interface
SPI Master
SCK_M
MOSI_M
MISO_M
GNDA
GND
Am Kuemmerling 18 • D-55294 Bodenheim, Germany
Tel. +49 61 35 / 92 92-30 0 • Fax +49 61 35 / 92 92-19 2 • http://www.ichaus.com
ICHAUS [ IC-HAUS GMBH ]
