Serial-Input PLL Freq. Syn. With Dual-Mod.Presclr: ML145170

The new MC145170.2 is pin for pin compatible with the MC145170.1. A comparison of the two parts is shown in the available datasheet. The MC145170.2 is recommended for new designs and has a more robust power on reset (POR) circuit that is more responsive to momentary power supply interruptions. The two devices are actually the same chip with mask options for the POR circuit. The more robust POR circuit draws approximately 20 µA additional supply current. Note that the maximum specification of 100 µA quiescent supply current has not changed.

The MC145170.2 is a single.chip synthesizer capable of direct usage in the MF, HF, and VHF bands. A special architecture makes this PLL easy to program. Either a bit. or byte oriented format may be used. Due to the patented BitGrabber? registers, no address/steering bits are required for random access of the three registers. Thus, tuning can be accomplished via a 2.byte serial transfer to the 16.bit N register.

The device features fully programmable R and N counters, an amplifier at the fin pin, on.chip support of an external crystal, a programmable reference output, and both single. and double.ended phase detectors with linear transfer functions (no dead zones). A configuration (C) register allows the part to be configured to meet various applications. A patented feature allows the C register to shut off unused outputs, thereby minimizing noise and interference.