供应KP229E2701压力芯片

KP229E2701
1 Product Description
The KP229E2701 is a miniaturized Analog Manifold Air Pressure Sensor
IC based on a caPACitive principle. It is surface micromachined with a
monolithic integrated signal conditioning circuit implemented in BiCMOS
technology.
The sensor converts a pressure into an analog output signal. The
calibrated transfer function converts a pressure of 10 kPa to 300 kPa into
a voltage range of 0.40 V to 4.65 V.
The chip is packaged in a “green” SMD housing. The sensor has been
primarily developed for measuring manifold air pressure, but can also be
used in other application fields. The high accuracy and the high sensitivity
of the device makes it a perfect fit for advanced automotive applications
as well as in industrial and consumer applications.

1.1 Features
Following features are supported by the KP229E2701:
• High precision pressure sensing (± 2.5 kPa)
• Ratiometric analog output
• Large temperature range (-40 °C to 140 °C)
• Broken wire detection
• Clamping
• “Green” 8 pin SMD housing
• Automotive qualified

1.2 Target Applications
The KP229E2701 is defined for use in following target applications:
• Automotive applications (manifold air pressure measurement)
• Industrial control
• Consumer applications
• Medical applications
• Weather stations
• Altimeters

2 Functional Description
The pressure is detected by an array of capacitive surface micromachined sensor cells. The sensor cell output is
amplified, temperature compensated and linearized to obtain an output voltage that is proportional to the applied
pressure.
The transfer function for linearization is computed in the digital part of the sensor using a third order polynomial
calculation. The transfer function is created from the following parameters:
• Minimum and maximum rated pressure
• Voltage level at minimum and maximum rated pressure
• Clamping levels
The output is analog and ratiometric with respect to the supply voltage.
All parameters needed for the complete calibration algorithm — such as offset, gain, temperature coefficients of
offset and gain, and linearization parameters — are determined after assembly. The parameters are stored in an
integrated E²PROM. The E²PROM content is protected with forward error correction (a one bit error is detected
and corrected, errors of more than one bit are detected and the output signal is switched to ground potential).
Clamping
The output voltage is limited internally to two clamping threshold levels. Based on this feature, the open bond
detection (OBD) is simplified and improved.
Open Bond Detection
The open bond detection, in conjunction with the clamping levels, eases the implementation of error and
malfunction detection strategies (e.g. for On-Board Diagnosis requirements). The microcontroller can sample the
output of the sensor and compare it with programmed overvoltage and undervoltage limits. When the sensor’s
output voltage exceeds those limits, a broken wire condition is identified.
When the chip is not powered properly, the JFET transistors of the broken wire detection stage are selfconducting.
For example, if the GND connection is interrupted, the output is drawn strongly to VDD. Similarly, if
the VDD connection is broken, the output is drawn to GND.