ET9561

3 CHANNEL DIFFERENTIAL AMPLIFIER-COMPARATOR Phototransistor input version of the standard ET9560 FEATURES Supply Voltage Range 4.5V to 30V Designed for phototransistor inputs Ungated index channel Current sink for LED drive (see application note APP-D2) Outputs short circuit protected 25mA peak drive current APPLICATIONS Optical Encoders Industrial Controls ET9561 DESCRIPTION These devices are specifically designed as receiver circuits for the phototransistor signals available in some optical encoders. Connect the emitters of the phototransistors to the input pins, with the collectors connected to Vcc. The inputs have 330 ohm resistors to terminate the phototransistors in an emitter follower mode. Differential inputs enhance noise rejection and performance over temperature. Care should be taken to use phototransistors on differential input pairs which have similar values of DC leakage current, as large differences in this charactersitic will affect wav...