SP8861

SP8861 1·3GHz Low Power Single-Chip Frequency Synthesiser Supersedes version in the1996 Professional Products IC Handbook, HB2480 - 3.0 DS3640 - 4.0 April 1998 The SP8861 is a low power single chip synthesiser intended for professional radio applications, containing all the elements (apart from the loop amplifier) required to build a PLL frequency synthesis loop The device is serially programmable by a three-wire data highway and contains three independent buffers to store one reference divider word and two local oscillator divider words. A digital phase detector with two charge pumps, programmable in phase and gain, are provided to improve lock-up performance. The preset operation of the charge pumps can be overwritten or the comparison frequencies switched to output ports under control of the divider word. The dual modulus ratio and so operating range is also programmable through the same word. A power down mode is incorporated as a battery economy feature. LOCK DETECT PD1 OUTPUT FPD* VEE3 4 3 2 1 28 27 26 25 24 23 FREF* POWER DOWN VEE4 VCC4 VCC1 RF INPUT RF INPUT NC Cd IC 5 6 7 8 9 10 11 12 13 14 15 16 17 18 PD2 OUTPUT RPD VCC3 GROUND XTAL 1 XTAL2 VEE2 SP8861 22 21 20 19 FEATURES s Improved Digital Phase Detector Eliminates HP28 ‘Dead Band’ Effects s Low Operating Power, Typically 175mW *FPD and FREF outputs are reversed by the phase detector sense bit in the F1/F2 programming word. The s 1·3GHz Operating Frequency above diagram is correct when the sens...