Overview: SL650/SL651 B/C SL650B & C SL651B & C
MODULATOR/PHASE LOCKED LOOP CIRCUITS FOR MODEMS The SL650/1 are versatile integrated circuits capable of performing all the common modulation functions (AM, PAM, SCAM, FM, FSK, PSK, PWM, tone-burst, delta-modulation, etc,). A wide variety of phase-locked loops can be realised using the SL650 or SL651, with all parameters accurately controllable; they can also be used to generate precise waveforms at frequencies up to 0.2MHz_
The highly accurate and stable variable frequency oscillator is programmable over a wide range of frequency by voltage, current, resistor or capacitor. In addition direct selection of one of four spot frequencies is facilitated by using the on-chip binary interface, which accepts standard logic levels at very low logic' l' input currents.
The differential input phase comparator has a wide common mode input voltage range. It has a high gain limiting amplifier at its input requiring only lmV input to maintain lock range in a typical phase-locked loop. The current output is programmable from zero to over 2mA by an external resistor or current input, and the gain is voltage -, current -, or resistance - programmable from zero to greater than 10,000.
An auxiliary amplifier with a voltage gain of, typically, 5000 is incorpated in the SL650 for use when it is required to interface to specified levels and impedances.
