JAJSN48B October 2021 – June 2022 LMX2571-EP
PRODUCTION DATA
TI recommends placing a 100-nF capacitor close to each of the power supply pins. If fractional spurs are a large concern, using a ferrite bead to each of these power supply pins may reduce spurs to a small degree.
VcpExt is the power supply pin for the 5-V charge pump. In PLL mode, the 5-V charge pump is active and a 5 V is required at VcpExt pin. In synthesizer mode, although the 5-V charge pump is not active, either a 3.3-V or 5-V supply is still needed at this pin.
Because LMX2571-EP has integrated LDOs, the requirement to external power supply is relaxed. In addition to LDO, LMX2571-EP is able to operate with DC-DC converter. The switching noise from the DC-DC converter would not affect performance of the LMX2571-EP. Table 9-1 lists some of the suggested DC-DC converters.
PART NUMBER | TOPOLOGY | VIN | VOUT | IOUT | SWITCHING FREQUENCY |
---|---|---|---|---|---|
TPS560200 | Buck | 4.5 V to 17 V | 0.8 V to 6.5 V | 500 mA | 600 kHz |
TPS62050 | Buck | 2.7 V to 10 V | 0.7 V to 6 V | 800 mA | 1 MHz |
TPS62160 | Buck | 3 V to 17 V | 0.9 V to 6 V | 1000 mA | 2.25 MHz |
TPS562200 | Buck | 4.5 V to 17 V | 0.76 V to 7 V | 2000 mA | 650 kHz |
TPS63050 | Buck Boost | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 500 mA to 1 A | 2.5 MHz |