AX8052F151 datasheet(36/51 Pages) ONSEMI

36 / 51 page

Transceiver

www.onsemi.com

AX8052F151

Loop Filter and Charge Pump

The AX8052F151 internal loop filter configuration together with the charge pump current sets the

synthesizer loop band width. The loop-filter has three configurations that can be programmed via

the register bits FLT[1:0] in register

AX5051_PLLLOOP, the charge pump current can be

programmed using register bits PLLCPI[1:0] also in register

AX5051_PLLLOOP. Synthesizer

bandwidths are typically 50 - 500 kHz depending on the

AX5051_PLLLOOP settings, for details

see the section 4.3: AC Characteristics.

Registers

Bits

Purpose

AX5051_PLLLOOP

FLT[1:0]

Synthesizer loop filter bandwidth, recommended usage is to increase

the bandwidth for faster settling time, bandwidth increases of factor 2

and 5 are possible.

PLLCPI[2:0]

Synthesizer charge pump current, recommended usage is to decrease

the bandwidth (and improve the phase-noise) for low data-rate

transmissions.

BANDSEL

Switches between 868 MHz/915 MHz and 433 MHz bands

AX5051_FREQ

Programming of the carrier frequency

AX5051_IFFREQHI, AX5051_IFFREQLO Programming of the IF frequency

AX5051_PLLRANGING

Initiate VCO auto-ranging and check results

AX8052F151 Datasheet(PDF) 36 Page - ON Semiconductor