ADF4252BCPZ-R7

Overview

The ADF4252BCPZ-R7 is a dual fractional-N/integer-N frequency synthesizer manufactured by Analog Devices Inc. It integrates two independent synthesizers: an RF section supporting up to 3 GHz with fractional-N capabilities, and an IF section operating up to 1.2 GHz using integer-N division. The device operates on a 2.7 V to 3.3 V supply and features separate power pins (VP1, VP2) allowing extended tuning voltages up to 5.5 V. Key specifications include a programmable dual modulus prescaler, digital lock detect, and a 3-wire serial interface for register control.

Feature Summary

• Dual synthesizer architecture with a Fractional-N RF loop (up to 3 GHz) and an Integer-N IF loop (up to 1.2 GHz).
• Programmable charge pump currents with high matching accuracy (2%) and low leakage (1 nA three-state).
• Separate VP1 and VP2 pins support extended tuning voltages up to 5.5 V for flexible VCO interfacing.
• Integrated digital lock detect and MUXOUT pin for monitoring RF or IF status.

Applications

• Base stations for mobile radio systems including GSM, PCS, DCS, CDMA, and WCDMA.
• Wireless handsets utilizing GSM, PCS, DCS, CDMA, and WCDMA standards.
• Wireless LAN infrastructure equipment.
• Communications test and measurement equipment.
• CATV signal processing equipment.

Procurement Notes

Verify the component matches the LFCSP-24 package and Rev E datasheet specifications. Confirm that the RSET resistor value aligns with the required minimum charge pump current, as the internal reference sets ICP_MIN = 1.6875/RSET. Ensure proper decoupling of VDD1, VDD2, VDD3, and DVDD pins to the ground plane during assembly.

Selection Notes

Select this component when a single IC must provide both high-frequency fractional-N synthesis for RF local oscillators and lower-frequency integer-N synthesis for IF stages. The device requires external loop filters and voltage-controlled oscillators (VCOs) to complete the phase-locked loops. Designers should account for the separate analog and digital ground planes (AGND and DGND) to minimize noise coupling between the RF and IF sections.

Part Context

This part belongs to the ADF4252 series of dual synthesizers from Analog Devices. It is designed to replace discrete PLL solutions in compact wireless designs. The 'R7' suffix indicates tape and reel packaging. The device is distinct from single-loop synthesizers like the ADF41020 or integrated VCO synthesizers like the ADF4350.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should verify pin compatibility and electrical parameters if considering alternative dual-synthesizer ICs from other manufacturers.

FAQ

What is the maximum input frequency for the RF and IF sections?

The RF input frequency (RFINA, RFINB) supports up to 3.0 GHz, while the IF input frequency (IFINA, IFINB) supports up to 1.2 GHz.

How is the charge pump current determined?

The minimum charge pump current is set by an external resistor connected to the RSET pin. The relationship is defined as ICP_MIN = 1.6875 / RSET, where RSET is in kΩ and ICP_MIN is in mA.

Can the RF and IF synthesizers operate simultaneously?

Yes, the device contains two independent synthesizers. However, they share the same power supply rails (VDD1-VDD3) and reference input (REFIN), requiring careful power management and filtering design.