ASIC- und Mikrosensoranwendung Chemnitz


Interpolation Circuit GC-IP2000




Interpolation rate up to 2,048
Input frequency max. 260 kHz for all resolutions
Highest dynamic with highest precision of measurement

Constant delay of 5 µs for all resolutions
Up to 500000 measurement values per second
Patented internal gain and offset control

The interpolation circuit GC-IP2000 serves to increase the resolution for incremental position and angular measuring systems with sinusoidal output signals offset by 90°. The IC divides the signal period up to 2,048 times. The GC-IP2000 comprises three instrument amplifiers with adjustable gain factors. Incremental encoders which possess a voltage interface and measuring bridges can be connected directly. Sensors with current interface and photodiode-arrays are adapted by a simple external circuit. The IC may operate with both single-ended and differential input signals. The noise of the sensor signals is prevented by a switching analog filter. Additionally, a digital hysteresis can suppress the edge noise of the output signals at low input frequencies and at standstill. Thus, in case of a short-time disturbance of the input signals, a subsequent interpolation counter will operate without errors. The input signals are subjected to a GEMAC-patented internal gain and offset control. The amplitude is controlled in the range between 60 % and 120 % of the nominal amplitude. The control range for the offset of the two input signals is ±10 % of the nominal amplitude. The phase displacement of the input signals can be corrected statically between -10° and +10° using a digital potentiometer. The quality of the signals issued by the sensors is monitored in the IC. For that purpose it is possible to activate separately 9 sources producing an error signal. The propagation delay of the IC is only 5µs. A fast serial interface (SPI) is implemented. This interface operates at a clock frequency of up to 25 MHz and is compatible to all important micro-controller and DSP families. In addition, a timer and a multi-stage trigger are implemented. This features make the GC-IP2000 an ideal choice for use in fast controllers or control systems.

Technical Data

Analog Part

Analog input:

Sinusoidal / cosinusoidal / reference (index) signals
Adjustable amplification for 1 Vpp / 500 mVpp / 250 mVpp / 75 mVpp
Input frequency max. 260 kHz for all resolutions

Digital Part

Interpolation rate :

100 / 128 / 200 / 256 / 400 / 500 / 512 / 800 / 1,000 / 1,024 / 1,600 / 2,000 / 2,048

Output signals:

30-bit counter value via serial interface (SPI)
Up to 500,000 measurement values per second
90° square-wave sequences (A/B/Z)
Error signal, interrupt signal to the µC
Auxiliary signals for sensor adjustment

Signal correction:

Digital controller for the offset, control range +/-10 % of the standard amplitude
Digital controller for the amplitude, control range factor 0.5 ... 1.5
Potentiometer with 40 steps for phase correction; selectable range ±5° or ±10° resp.
LED control signal

Possibilities of configuration:

Via configuration pins, the serial interface (SPI) or EEPROM


Compatible to the standard SPI: 16-bit, MSB first
SPI clock up to 25 MHz
For configuration and measuring value output; not required for trivial systems


Supression of disturbances:

Switching analog noise filter
Digital hysteresis for suppression of the edge noise at the output

Adaptation of IC to subsequent devices:

Adjustable minimum edge interval at the output
Behaviour of IC in case of sensor error can be programmed
Adjustable width zero signal Z ¼ or 1 period A/B

Data logging:

2-stage measured-value trigger
Programmable timer
Constant delay between sampling and measurement value of 5 µs for all resolutions

Important Characteristics

Operating voltage:

5 V DC

I/O voltage, digital:

3.3 V DC or 5 V DC

Temperature range:

- 40 °C ... 125 °C



Pitch 0.5mm, 8mm x 8mm package






Ordering Information

Product Type


Item No.


Interpolation IC GC-IP2000, QFN56



Evaluationboard of Interpolation IC GC-IP2000