Description
iC-LNG is an optoelectronic encoder IC for absolute linear and angle measuring systems, such as glass scales and encoders. Photodiodes, amplifiers, and comparators, the entire signal conditioning unit, and interfaces for position data output have been monolithically integrated into the device. An integrated LED current control with a driver stage allows a transmitting LED to be directly connected (e.g. iC-SN85). The optical receive power is kept constant by the control unit, regardless of temperature and aging effects. The receive power setpoint can be programmed. Should the LED current control exit its operating range, this is indicated at the error message output (end-of-life alarm at pin ERR). The photocurrent offset and photocurrent amplitude of the analog sine/cosine signals can be calibrated. These calibrated voltage signals are lead out to pins PSIN, NSIN, PCOS, and NCOS and are used by the integrated 6-bit interpolator. iC-LNG synchronizes the interpolator and singleturn data to form a contiguous Gray-coded position data word. A shift register or SPI interface are available for position data output. iC-LNG also outputs incremental A/B/Z signals, the resolution of which can be programmed. After startup iC-LNG is configured using the SPI interface. To make connection to a 3.3 V microcontroller easier, all digital I/O ports, including the SPI, can be run on 3.3 V. Test currents can be applied to test pins TPS, TNS, TPC, and TNC to simulate photocurrents. Allocation to various tracks can be selected as required, enabling a full function test of the IC with the exception of the sensors.
Features