PICOCAP: CAPACITANCE MEASUREMENT
Capacitance-to-Digital Converter
The PCap04 is a capacitance-to-digital converter (CDC) with integragrated digital signal processor (DSP) for on-chip data post processing. The front end is based on the ams PICOCAP principle.
This conversion principle offers outstanding flexibility with respect to power consumption, resolution and speed.The PCap04 covers a wide capacitance input range from a few femtofarads up to several hundred nanofarads. It is easy to configure the PCap04 for different capacitance measurement tasks, i.e. single as well as differential sensors in both, grounded or floating connection. The on-chip DSP allows for implementation of sensor algorithms like linearization and temperature compensation, with data output in a digital (SPI or IIC) or analog (PDM/PWM) way.
For customers that are unable to use the QFN24 packaged Pcap04 or require die for their own packaging, ams now offers die in wafer form. Customers requiring less than a wafer for smaller projects or first article builds, PMT (Precision Measurement Technologies) in Clearwater, Florida has wafer packs in 100 and 250 quantities available for quick turnaround. Whether you need just a few hundred or a few thousand, PMT, an ams Technology Center, ships worldwide and can help with your project.
Please contact Sales@pmt-fl.com or call 727-532-6144 for pricing.
| BENEFITS | FEATURES |
|---|---|
| High Flexibility: Easy adaption to various applications - ultra low power, high resolution or high speed - just by configuration |
|
| High resolution or high speed |
|
| On-chip DSP for sensor algorithms, signal post-processing including linearization and temperature compensation |
|
| On-chip and external temperature measurement capability |
|
| Description | Version | Size | Download |
|---|---|---|---|
| Development Support PCap04: Evaluation System for PCap04 | V1.0 | 4MB | PCAP04EVAL- DS.PDF |
| Datasheet PCap04: General Data | V1.0 | 3.2 KB | PCAP04.PDF |
| Datasheet PCap02, Vol. 1: General Data and Front-End | V1.6 | 2.6MB | DB_PCap02A_Vol1_en.pdf |
| Datasheet PCap02, Vol. 2: Digital Signal Processor | V0.2 | 1.6MB | DB_PCap02A_Vol2_en.pdf |
| Datasheet PCap02 Eval System: Evaluation System for PCap02 | V0.0 | 990kB | DB_PCap02-EVA-Kit_en.pdf |
| Datasheet PCap02 Eval System: Evaluation Software for PICOCAP Devices | V0.0 | 2MB | DB_PCap02plus_en.pdf |
| Datasheet PICOCAP DEVICES: Assembler Software PICOCAP Devices | V0.0 | 750kB | DB_PCap-Assembler_en.pdf |
| Datasheet PCap02, Linearize: Description of Linearization Firmware | V0.2 | 1.2MB | DB_PCap02_Linearize_en.pdf |
| Datasheet PCap01: Single-chip solution with standard firmware | V0.6 | 5MB | DB_PCap01Ax_0301_en.pdf |
| Datasheet PCap01: Single-chip solution for humidity measurement | V0.3 | 4MB | DB_PCap01AK-0101xx_en.pdf |
| Datasheet PCap01: Description of PCap01 DSP and Assembler | V0.2 | 3MB | DB_PCap01_DSP_e.pdf |
| Datasheet PCap01: General evaluation kit for PCap01 | V0.3 | 2.6MB | DB_PCap01-EVA-KIT_en.pdf |
| Datasheet PCap01: Description of humidity measurement demonstrator | V0.1 | 3MB | DB_PCap01_HUM_DEMO_en.pdf |
| Datasheet PCap01-Touch: Very-Low-Power IC for Capacitive Touch Sensor Solutions | V0.1 | 1.3MB | DB_PCap01_Touch_en.pdf |
| Description | Version | Size | Download |
|---|---|---|---|
| Screencasts PCap01: 2:44 min. webcast introduction into PCap01 Evaluation Kit | - | 7MB | PCap01_Evaluation-Software_en.zip |
| Screencasts PCap02plus: 9:37 min. webcast introducing a Sensor Scaling + PDM / PWM output with PCap02 | - | 26MB | PCap02plus-Scaling-PDM-PWM_en.zip |
| Description | Version | Size | Download |
|---|---|---|---|
| Software PCap04: Evaluation software for PICOCAP Devices Full installer package incl. drivers | 1.2.7 | 297MB | PCap04-EVA-SW_W7.zip |
| Software PCap04 (32-bit): Using our DLL combing with your own software. ZIP package incl. e.g. header file, example c-code | 1.0 | 423kB | PCap04-DLL-Library.zip |
| Software PCap04 (64-bit): Using our DLL combing with your own software. ZIP package incl. e.g. header file, example c-code | 1.0 | 378kB | linearize_r01.zip |
| Software PCap02: Evaluation software for PICOCAP Devices Full installer package incl. drivers | 1.3.1 | 168MB | PCap02plus.zip |
| Software PCap01: Evaluation software for PCap01-EVA-KIT and PCap01-HUM-EVA Full installer package incl. drivers | 0.80 | 150MB | PCap01-EVA-SW_W7_XP.zip |
| Software PCap01: Assembler software for PCap01, installer package | V20.4 | 160MB | PCap01_Assembler.zip |
| Software PCap01: Standard firmware for PCap01A | 03.01.02 | 25k | PCap01_standard.hex |
| Software PCap01: Firmware for humidity+temperature measurement | 01.01.04 | 25k | PCap01_humidity.hex |
| Software PICOPROG V3 (V2.0): Driver Installer Stand-Alone | R11 | 3.1MB | PicoProg_v2_Driver_Installer_Stand-Alone.zip |
The PICOCAP measuring principle shows a new approach to capacitance measurement. For this purpose the sense capacitor and a reference capacitor are connected to a resistor, forming a low-pass filter. Sense and reference capacitor should be in the same range to minimize gain drift. Practically there is no limit for the capacitor value. Sensors from nearly 0 fF up to tens of nF can be measured. The PICOCAP devices also support differential sensors with inside linearization.
The capacitors are charged to the supply voltage and then discharged through the resistor. The discharge time down to an arbitrary trigger level is measured with ultra-high precision using a TDC (Time-to-Digital Converter).
This measuring process is repeated in time-multiplex with both Capacitors, using the same resistor and the same comparator. Calculating the ratio of the results will turn out the absolute values and temperature dependencies of the resistor and the comparator.
The Compensated Mode offers the solution for highest resolution applications with low offset and extremely low gain drift. The capacitors are connected floating, not referenced to ground. They are switched alternately to the resistor by an integrated analog switch. Additional patented circuits and algorithms compensate for parasitic capacities. Parasitic capacities would have a negative effect on the gain drift over temperature. The compensation results in a very low gain drift over temperature down to 0.5 ppm / K. It is much better than the intrinsic gain drift of most sensors.
| Type | Part number | Package | RoHS compl. | Shipping package |
|---|---|---|---|---|
| PCap02: | ||||
| PCap02A | Dice | Yes | ||
| PCap02AE | QFN32 | Yes | ||
| PCap02-EVA-KIT | System | Yes | Box | |
| PCap01: | ||||
| PCap01A | MNR 1613 | Dice | Yes | |
| PCap01AD | MNR 1793 | QFN32 | Yes | |
| PCap01AK | MNR 1795 | QFN24 | Yes | |
| PCap01-EVA-KIT | MNR 1912-01 | System | Yes | Box |
| PCap01-HUM-EVA | MNR 1796 | System | Yes | Box |
| PCap01-HUM-DEMO | MNR 1792 | System | Yes | Box |