Analog Devices Inc. ADF4111BRUZ

Overview

ADF4111BRUZ from Analog Devices is a 1.2 GHz RF PLL frequency synthesizer IC used as a local oscillator in wireless transceiver up/downconversion stages. It features a dual-modulus prescaler (8/9, 16/17, 32/33, 64/65), programmable charge pump current (625 µA to 5 mA), 3-wire serial interface, and operates from 2.7 V to 5.5 V. It supports GSM/PCS/CDMA base station and handset RF front-ends.

For engineers reviewing the ADF4111BRUZ datasheet, ADF4111BRUZ pinout, ADF4111BRUZ application, or ADF4111BRUZ equivalent, key selection criteria include its 0.08–1.2 GHz RF input range (3 V supply), 200 kHz max phase detector frequency, −87 dBc/Hz phase noise at 900 MHz/1 kHz offset, lock detect capability, and TSSOP-16 package compatibility with industrial temperature operation (−40°C to +85°C).

Technical Context

The ADF4111BRUZ implements a digital phase-frequency detector (PFD), precision charge pump, 13-bit B counter, 6-bit A counter, 14-bit R counter, and dual-modulus prescaler (P/P+1) to realize an N-divider (N = BP + A). Its architecture enables fractional-N synthesis when combined with an external loop filter and VCO.

It supports hardware/software power-down modes, analog and digital lock detection, programmable antibacklash pulse width, and separate VP supply (up to 6.0 V) for extended tuning voltage headroom in 3 V systems - critical for wide-range VCO control in compact RF designs.

Key Specifications

Pinout & Package

TSSOP-16 package with exposed paddle (connected to AGND per datasheet Note 1); RoHS-compliant, 5 mm × 4.4 mm footprint, 1.05 mm height.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF PLL synthesizer applications.

Compared with ADF4113BRUZ, ADF4111BRUZ delivers optimal power-phase-noise trade-off below 1.2 GHz, while LMX2485EVM trades external VCO flexibility for integration - making ADF4111BRUZ the preferred choice for cost-sensitive, high-volume cellular infrastructure where discrete VCO control and VP scalability are essential.

Availability

ADF4111BRUZ is available at Aetrix Electronics and suitable for GSM/CDMA base station transmitters, wireless handset RF front-ends, and communications test equipment requiring stable component supply across industrial temperature ranges.

Supply support for ADF4111BRUZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and RF ICs, serving precision instrumentation, communications, and industrial markets since 1965.

The ADF411x family was designed specifically for wireless infrastructure and handset local oscillator synthesis, emphasizing low phase noise, flexible prescaling, and robust lock detection in demanding RF environments.

FAQ

What is the maximum RF input frequency supported by the ADF4111BRUZ?

The ADF4111BRUZ supports an RF input frequency range of 0.08 GHz to 1.2 GHz under 3 V supply conditions, and up to 1.4 GHz at 5 V supply. This makes it suitable for GSM (900/1800 MHz), PCS (1900 MHz), and CDMA (800/1900 MHz) bands when paired with appropriate external prescaling or VCO selection. The ADF4111BRUZ datasheet specifies these limits in Table 1 under "RF Input Frequency".

Does the ADF4111BRUZ require an external loop filter?

Yes, the ADF4111BRUZ requires an external passive loop filter between the CP pin and the VCO tuning input. The charge pump outputs ±ICP current, which must be integrated by the loop filter to generate the VCO control voltage. Filter design depends on desired loop bandwidth, phase margin, and VCO gain; Analog Devices provides design tools and reference schematics in AN-584 and the ADF4111BRUZ evaluation board documentation.

Can the ADF4111BRUZ operate with a 3 V supply and still drive a 6 V tuning range VCO?

Yes, the ADF4111BRUZ supports a separate VP supply pin rated from AVDD to 6.0 V. When AVDD = 3 V, VP can be set to 6 V, allowing the charge pump to generate a full 6 V tuning voltage swing at the VCO input - eliminating need for external charge pumps or level shifters. This is explicitly confirmed in the "POWER SUPPLIES" section of the ADF4111BRUZ datasheet (Rev. F, Page 4).

How does the ADF4111BRUZ indicate PLL lock status?

The ADF4111BRUZ provides both analog and digital lock detect outputs via the MUXOUT pin, selectable through register configuration. Digital lock detect asserts a logic-high signal when phase error falls within ±25% of PFD period; analog lock detect outputs a DC voltage proportional to lock quality. Both signals are accessible without additional components, enabling real-time system-level validation of PLL convergence in ADF4111BRUZ-based designs.

Is the ADF4111BRUZ pin-compatible with other devices in the ADF411x family?

Yes, the ADF4111BRUZ shares identical pinout and interface with ADF4110BRUZ, ADF4112BRUZ, and ADF4113BRUZ in the TSSOP-16 package (Figure 3). However, RF frequency range, current consumption, and phase noise performance differ across the family - so while PCB layout is reusable, firmware register settings and loop filter design must be validated per specific ADF411x variant.