ADF4156BRUZ

Overview

The ADF4156BRUZ is a 6.2 GHz fractional-N frequency synthesizer manufactured by Analog Devices Inc. It operates on a 2.7 V to 3.3 V power supply and features a separate VP pin for extended tuning voltage up to 5.5 V. The device integrates a low-noise digital phase-frequency detector, a precision charge pump with programmable currents, and a Σ-Δ based fractional interpolator. It supports a reference input frequency range of 10 MHz to 250 MHz and an RF input range of 0.5 GHz to 6.2 GHz. Control is managed via a 3-wire serial interface, and the component includes cycle slip reduction circuitry for faster lock times.

Feature Summary

• RF bandwidth extending to 6.2 GHz with a programmable fractional modulus.
• Separate VP pin allows extended tuning voltage up to 5.5 V.
• Cycle slip reduction (CSR) circuitry enables faster lock times without loop filter modifications.
• Pin-compatible with ADF4110, ADF4111, ADF4112, ADF4113, ADF4106, ADF4153, and ADF4154.

Applications

• CATV equipment
• Base stations for mobile radio including WiMAX, GSM, PCS, DCS, SuperCell 3G, CDMA, and WCDMA
• Wireless handsets supporting GSM, PCS, DCS, CDMA, and WCDMA
• Communications test equipment

Procurement Notes

Verify the specific package variant required, as the ADF4156 is available in both TSSOP-16 and LFCSP_VQ packages. Confirm that the ordering suffix corresponds to the desired physical footprint before procurement. Ensure all electrical parameters align with the target system requirements.

Selection Notes

Select the ADF4156BRUZ when an RF output frequency up to 6.2 GHz is required. The B version specifies an operating temperature range of -40°C to +85°C. Designers should utilize ADIsimPLL for loop filter design and ensure the RSET resistor value correctly sets the maximum charge-pump current according to the datasheet specifications.

Part Context

The ADF4156 belongs to the ADF41xx family of fractional-N frequency synthesizers from Analog Devices. It shares pin compatibility with several other models in this series, facilitating design upgrades or replacements within existing hardware architectures without requiring PCB layout changes.

Replacement Considerations

The ADF4156 is pin-compatible with the ADF4110, ADF4111, ADF4112, ADF4113, ADF4106, ADF4153, and ADF4154. Verify that the replacement part meets the specific RF frequency and noise performance requirements of the application.

FAQ

How is the maximum charge-pump current determined?

The maximum charge-pump current is set by connecting a resistor between the RSET pin and ground. For example, an RSET value of 5.1 kΩ results in a typical maximum current of 5 mA.

What is the function of the CSR feature?

Cycle Slip Reduction (CSR) circuitry reduces lock times by preventing cycle slips during frequency transitions, allowing for faster locking without modifying the external loop filter.

Can the RF output phase be programmed?

Yes, the RF output phase is programmable via the Phase Register (R1), allowing for a phase relationship between the output and the reference with a resolution of 360°/MOD.