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Cap
sense ICs |
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| Analog Microelectronics |
http://www.analogmicro.de |
CAV414 , 10-2000pF,
2kHz BW, differential
with two grounded caps, C1-C2 analog output, no guard. Several interface app notes.
About $2.13/1000, Germany. |
| QProx Sensors Site |
www.qprox.com/ |
Six low-cost chips, including liquid level and
arrays, proprietary circuit, grounded caps, 200uS response, no
guard,UK. |
| MicroSensors |
www.microsensors.com/ |
MS3110, high precision chip, 8 kHz BW, digital
adjustment of offset, gain, BW, 0.25-10pF, 4 aF/sqrtHz, charge balance,
US. |
| Melexis Microelectronic Integrated Systems |
http://www.melexis.com/ |
General purpose sensor interfaces |
| Smartec sensors, interface, evaluation kits |
http://www.smartec.nl/ |
UTI interface chip, 1-5 floating caps, low BW,
gain and offset compensation, PWM output works with uC, Netherlands. About
$3/1000 qty. |
| Goal Semiconductor, Inc., custom ASICs |
http://www.goalasic.com/ |
Fabless ASIC company with sensor
experience, Canada |
| VTI, silicon micromachined chips |
http://www.vti.fi/ |
Design and production of micromachined acceleration,
shock, inclination, vibration and pressure sensors. |
| XEMICS - Low-power semiconductors |
http://www.xemics.com/ |
XE2204, 0-120 pF; charge balance, 10kHz
BW, 7uV/sqrtHz (5kHz), digital adjustment of offset, gain, linearity, and BW. <0.25aF/sqrtHz resolution, Swiss.
About $4/10,000 qty. |
| The
charge balance types use two floating sense capacitors with a common
connection and are shielded by ground.
The Smartec part uses 1-5 floating sense capacitors in an RC oscillator
circuit and are shielded by ground.
The Q-prox parts mostly use one one-plate-grounded sense capacitors. No
guard available. |
| Note
that standard parts can be used for capacitive sensing, such as
the TLC555 oneshot or the HC7404 CMOS inverter. No programmable registers
are available if you use standard parts, but often a local microprocessor
can handle these features. |
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