Samsung Circuit Description free download

File name Circuit Description.pdf

5. Special Circuit Descriptions 5-1 RF Amp Block 5-1-1 RF Amplifier The two currents from input pins PD1 (A+C) and PD2 (B+D) are converted into voltages through I/V Amp, and they are added to RF summing Amp. The photo diode (A+B+C+D) signal which is I-V changed is outputted by RFO (pin74). At this pin, the eye pattern can be checked. 58K PD1 65 - VA 10K - + 74 RFO IV AMP + VC RF SUMMINGAMP VC 58K PD2 66 - VB 10K 73 RF- + IV AMP VC 5-1-2 Focus Error Amp The output of the focus error amp is the difference between RF I-V AMP(1) output Va and RF I-V AMP(2) output Vb,just is the Photo Diode ((A+C) - (B+D)) signal which is I-V changed. The focus error bias voltage applied to the (+) of focus error amp can be changed by D/A converter as shown in diagram, so that the offset of focus error amp can be adjust automatical. Focus error bias can be adjusted from the range of +100mV ~ -100mV by connectiong the resistor with pin 63 (FEBIAS). 164K 32K VB> - 32K 59 FE1 VA> + sev-stopb 160K SW1 FEBIAS 63 sev-stop <5 Bit Counter>