ASIC- und Mikrosensoranwendung Chemnitz

2-Channel Interpolation Circuit with Nonius Calculation GC-NIP




Interpolation rate of up to 8 192
Input frequency max. 130kHz
Adjustable input low pass filter 10kHz … 150kHz
Maximum propagation delay of 8µs at 26MHz clock
Patented internal gain and offset control

Output signals: ABZ, SPI, SSI, BiSS
EEPROM, reference mark adjustment, preset function
Power supply: 3.3V / 5V*
Package: QFN64 (9mm x 9mm)

The 2-channel interpolation circuit GC-NIP serves to increase the resolution of absolute position and angular measuring systems with 2 sinusoidal output signals (nonius signal). Aside from the calculation of the absolute position, the GC-NIP may also operate as one- or two-channel incremental measuring system.
The input signals are subjected to a AMAC/GEMAC patented internal gain and offset control and the signal period is divided up to 8192 times. For the absolute position of a two-channel nonius system, a resolution of up to 22 bit can be achieved. Input and output of the GC-NIP are designed for 3.3V interfaces. The IC comprises six instrumentation amplifiers with adjustable gain factors. Encoders with voltage interface or measuring brigdes can be connected directly. Sensors with current interface and photodiode-arrays are adapted by a simple external circuit. The IC operates on both singleended or 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. The quality of the signals issued by the sensors is monitored in the IC. For that purpose it is possible to activate 9 sources separately producing an error signal. For the calculation of the absolute position a set of sensor- or scalespecific correction coefficients can be placed in the EEPROM of the IC. In that way, harmonics of the sinusoidal signals or inaccuracies of the measuring scale do not lead to errors in the absolute position value. The determination of the correction coefficients is realized by a simple software-based calibration procedure. Providing absolute position and incremental square-wave-signals (ABZ) in parallel, the GC-NIP is well-suited for the use in motor-feedback-systems. The four integrated output interfaces (ABZ/SPI/SSI/BiSS) and further features like the multistage trigger signal processing, the processing of distance coded reference marks, the possibility to adjust the reference mark as well as adjustment and storage of the zero position make the IC suitable for direct use in industrial controls or in fast absolute or multi-channel incremental position measuring systems. The GC-NIP can be configured according to specific applications using the integrated EEPROM, via configuration inputs or via the serial interface (SPI/BiSS).

Technical Data


Analog input:

Sinusoidal / cosinusoidal / reference (index) signals, differential or single-ended
Adjustable amplification for 660mVPP / 250mVPP  / 120 mVPP  / 60mVPP
Input frequency max. 130kHz for all resolutions


90° square-wave sequences (A/B/Z)
Adjustable width of zero signal Z to ¼ or 1 period A/B
Service signals for sensor adjustment


30-bit counter value / 9-bit sensor state
Up to 15MHz, compatible to standard-SPI 16 bit
Up to 500 000 measurement values per second
Signal filtering for suppression of disturbances

SSI and BiSS:

30-bit counter value / 2-bit sensor state
Gray code / binary code
Adjustable timing, SSI ring operation

Interpolation / Signal Processing

Interpolation rate:

Nonius calculation: 256 ... 8 192
Interpolation (ABZ): 32 ... 8 192

Signal correction:

Patented digital controller for the offset, control range ±10% of the standard amplitude
Patented digital controller for the amplitude, control range 60% … 120% of the standard amplitude
Digital potentiometer with 64 steps for phase correction; selectable range ±5° or ±10°

Suppression of disturbances:

Selectable low pass filter 10kHz, 75kHz, 150kHz, disabled
Digital hysteresis for suppression of the edge noise at the output (configurable 0 … 7)
Selectable minimum edge distance at the output

Reference mark adjustment:

Selectable reference mark position
Definition of the optimum reference position via SPI or service signals
Processing of distance coded reference marks
Measured-value trigger at the reference mark position


2-stage measured value trigger
Preset signal for adjustment and storage of the zero position of the sensor
Integrated EEPROM for configuration

Important Characteristics


QFN64 (9mm x 9mm)

Operating voltage:

3.3VDC / 5VDC*

Temperature range:

-40°C … 125°C

*Configuration of 5V-systems possible via Level-Shifter GC-LS





Ordering Information

Product Type


Article Number


Interpolation circuit GC-NIP, QFN64



Demoboard for Interpolation circuit GC-NIP



4-channel / analog Level-Shifter 5V to 3.3V, QFN32


USB zu SPI Adapter

USB-Adapter zur SPI-Schnittstelle


USB zu BiSS Adapter

USB-Adapter zur BiSS-Schnittstelle