PicoCap Capacitance Measurement

PICOCAP PCAP01

Capacitance-to-Digital Converter with Integrated Signal Processor

The PCap01 is a capacitance-to-digital converter that offers an unprecedent degree of flexibility. Thanks to the patented PICOCAP® concept, the device

covers a capacitance input range from a few fF up to several hundreds of nF and can be easily configured to the various needs in all areas of capacitance measurement. The PCap01 suits to applications with lowest current consumption of only a few µA just as well as solutions that require highest precision of 20-Bit and more, or update rates of up to 500,000 measurements per second.

The sensor data can be linearized on-chip and is provided via SPI or IIC digital serial interfaces. Additionally, the device offers IO’s for PWM/PDM signal outputs. Further IO’s can be used for interrupts, alarm level indication or for general purpose.

The sensor data can be linearized on-chip and is provided via SPI or IIC digital serial interfaces. Additionally, the device offers IO’s for PWM/PDM signal outputs. Further IO’s can be used for interrupts, alarm level indication or for general purpose.

PicoCap: Capacitance Measurement

PCAP01 SERIES

Product Part number Package Type
PCap01A 1613 Dice Capacitance-to-Digital Converter for up to 8 capacitors, 5 GPIOs
PCap01AD 1793 QFN32 Capacitance-to-Digital Converter for up to 8 capacitors, 5 GPIOs
PCap01AK 1795 QFN24 Capacitance-to-Digital Converter for up to 6 capacitors, 5 GPIOs

Features

  • Up to 8 capacitances in grounded mode
  • Up to 4 capacitances in floating mode (potential-free and with zero bias voltage)
  • Compensation of internal (grounded) and external parasitic capacities (floating)
  • High resolution: Up to 6 aF at 5 Hz and 10 pF base capacitance, 17 bit resolution at 5 Hz with 100 pF base capacitance and 10 pF excitation
  • High measurement rate, up to 500 kH
  • Extremely low current consumption possible, down to 4 μA at 3 Hz with 13.4 bit resolution
  • High stability with temperature, low offset drift (down to 30 aF per Kelvin), low gain
  • Internal temperature measurement (25 mK resolution) or dedicated ports for precision temperature measurement with Pt1000 sensors (5 mK resolution)
  • Serial peripheral interface (SPI compatible)
  • Inter-Integrated Circuit Interface (I2C compatible)
  • No need for a clock
  • RISC processor core using Harvard architecture: ƒƒ48 x 48 bit RAM Data
  • 4k x 8 bit volatile program memory for highspeed operation (40 to 100 MHz)
  • 4k x 8 bit non-volatile (OTP) program memory
  • Single power supply (2.1 to 3.6 V)
  • QFN24 or QFN32 package

INTERNAL DISCHARGE STRUCTURE

precision-measurement-pcap01-features-block-diagram

Specification

RESOLUTION IN AF V. UPDATE RATE

PCAP01 Picocap

OFFSET DRIFT V. TEMPERATURE

 

PCAP01 Picocap

NOISE V. DATA RATE

PCAP01 Picocap

GAIN DRIFT V. TEMPERATURE

PCAP01 Picocap

Specification

For a quick and easy start-up with the PICOCAP product line acam offers a general evaluation kit as well as an application specific test and evaluation system.

The systems are connected to the PC’s USB interface through the PICOPROG programming device. A comfortable evaluation software allows to program and configure the PCap01. The measurement data can be shown numerically and graphically. Finally, the data can be exported to text files for further analyses.

For a proper use of the evaluation system it is strongly recommended to refer to the current technical documentation and the latest software releases.

 

SCREEN SHOTS – EVALUATION SOFTWARE

precision-measurement-pcap01-eval-system-screen-1
precision-measurement-pcap01-eval-system-screen-2
precision-measurement-pcap01-eval-system-screen-3
precision-measurement-pcap01-eval-system-screen-4
precision-measurement-pcap01-eval-system-screen-5

Documentation & Downloads

Datasheet

Description

Development Support PCap04:
Evaluation System for PCap04

Version

V1.0

Size

4MB

Download

PCAP04EVAL- DS.pdf

Description

Datasheet PCap04:
General Data

Version

V1.0

Size

3.2MB

Download

PCAP04.pdf

Description

Datasheet PCap02, Vol. 1:
General Data and Front-End

Version

V1.6

Size

2.6MB

Download

DB_PCap02A_Vol1_en.pdf

Description

Datasheet PCap02, Vol. 2:
Digital Signal Processor

Version

V0.2

Size

1.6MB

Download

DB_PCap02A_Vol2_en.pdf

Description

Datasheet PCap02 Eval System:
Evaluation System for PCap02

Version

V0.0

Size

990KB

Download

DB_PCap02-EVA-Kit_en.pdf

Description

Datasheet PCap02 Eval System:
Evaluation Software for PICOCAP Devices

Version

V0.0

Size

2MB

Download

DB_PCap02plus_en.pdf

Description

Datasheet PicoCap Devices:
Assembler Software PICOCAP Devices

Version

V0.0

Size

750KB

Download

DB_PCap-Assembler_en.pdf

Description

Datasheet PCap02, Linearize:
Description of Linearization Firmware

Version

V0.2

Size

1.2MB

Download

DB_PCap02_Linearize_en.pdf

Description

Datasheet PCap01:
Single-chip solution with standard firmware

Version

V0.6

Size

5MB

Download

DB_PCap01Ax_0301_en.pdf

Description

Datasheet PCap01:
Single-chip solution for humidity measurement

Version

V0.3

Size

4MB

Download

DB_PCap01AK-0101xx_en.pdf

Description

Datasheet PCap01:
Description of PCap01 DSP and Assembler

Version

V0.2

Size

3MB

Download

DB_PCap01_DSP_e.pdf

Description

Datasheet PCap01:
General evaluation kit for PCap01

Version

V0.3

Size

2.6MB

Download

DB_PCap01-EVA-KIT_en.pdf

Description

Datasheet PCap01:
Description of humidity measurement demonstrator

Version

V0.1

Size

3MB

Download

DB_PCap01_HUM_DEMO_en.pdf

Description

Datasheet PCap01-Touch:
Very-Low-Power IC for Capacitive Touch Sensor Solutions

Version

V0.1

Size

1.3MB

Download

DB_PCap01_Touch_en.pdf

Software

Datasheet

Description

Development Support PCap04:
Evaluation System for PCap04

Version

V1.0

Size

4MB

Download

PCAP04EVAL- DS.pdf

Description

Datasheet PCap04:
General Data

Version

V1.0

Size

3.2MB

Download

PCAP04.pdf

Description

Datasheet PCap02, Vol. 1:
General Data and Front-End

Version

V1.6

Size

2.6MB

Download

DB_PCap02A_Vol1_en.pdf

Description

Datasheet PCap02, Vol. 2:
Digital Signal Processor

Version

V0.2

Size

1.6MB

Download

DB_PCap02A_Vol2_en.pdf

Description

Datasheet PCap02 Eval System:
Evaluation System for PCap02

Version

V0.0

Size

990KB

Download

DB_PCap02-EVA-Kit_en.pdf

Description

Datasheet PCap02 Eval System:
Evaluation Software for PICOCAP Devices

Version

V0.0

Size

2MB

Download

DB_PCap02plus_en.pdf

Description

Datasheet PicoCap Devices:
Assembler Software PICOCAP Devices

Version

V0.0

Size

750KB

Download

DB_PCap-Assembler_en.pdf

Description

Datasheet PCap02, Linearize:
Description of Linearization Firmware

Version

V0.2

Size

1.2MB

Download

DB_PCap02_Linearize_en.pdf

Description

Datasheet PCap01:
Single-chip solution with standard firmware

Version

V0.6

Size

5MB

Download

DB_PCap01Ax_0301_en.pdf

Description

Datasheet PCap01:
Single-chip solution for humidity measurement

Version

V0.3

Size

4MB

Download

DB_PCap01AK-0101xx_en.pdf

Description

Datasheet PCap01:
Description of PCap01 DSP and Assembler

Version

V0.2

Size

3MB

Download

DB_PCap01_DSP_e.pdf

Description

Datasheet PCap01:
General evaluation kit for PCap01

Version

V0.3

Size

2.6MB

Download

DB_PCap01-EVA-KIT_en.pdf

Description

Datasheet PCap01:
Description of humidity measurement demonstrator

Version

V0.1

Size

3MB

Download

DB_PCap01_HUM_DEMO_en.pdf

Description

Datasheet PCap01-Touch:
Very-Low-Power IC for Capacitive Touch Sensor Solutions

Version

V0.1

Size

1.3MB

Download

DB_PCap01_Touch_en.pdf

PicoCap Measurement Principle

he 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.

General Circuit

Cycle Time

Ordering Numbers

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

Ordering Numbers

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