SP5024

The SP5024 is a programming variant of the SP5510 allowing the design of one tuner with either I2C bus or 3-wire bus format depending on which device is inserted. The SP5024, when used with a TV varicap tuner, forms a complete phase locked loop tuning system. The circuit consists of a divide-by-8 prescaler with its own preamplifier and a 15 bit programmable divider controlled by a serially - loaded data register. Four open-collector outputs, each independently programmable, are included. The device has two modes of operation selected by the 'mode selected input'. In mode 1 the comparison frequency is 7.8125kHz and the programmable divider MSB is bypassed; mode 2 comparison frequency is 6.25kHz. The comparison frequencies are both obtained from a 4MHz crystal controlled on-chip oscillator. The comparator has a charge pump output with an output amplifier stage around which feedback may be applied. Only one external transistor is required for varicap line driving.