Analog Devices Inc. AD8345-EVALZ

Overview

AD8345-EVALZ from Analog Devices is an evaluation board designed to characterize the AD8345 silicon RFIC quadrature modulator, a high-performance 140 MHz–1000 MHz direct-conversion modulator used in IF transmit paths of wireless transceivers. It supports differential I/Q baseband inputs, single-ended 50 Ω RF output, and operates from 2.7 V to 5.5 V with <0.5° RMS phase error and −155 dBm/Hz noise floor at 800 MHz.

For engineers reviewing the AD8345-EVALZ datasheet, AD8345-EVALZ setup guide, AD8345-EVALZ schematic, or AD8345-EVALZ compatibility with AD8345 modulator ICs, this board enables rapid validation of RF modulation performance-including sideband suppression (−48 dBc typ.), LO leakage (−42 dBm), EVM (1.3%), and ACPR (−72 dBc)-in W-CDMA, CDMA IS95, GSM, and digital TV transmitter designs.

Technical Context

The AD8345-EVALZ implements the full signal chain for the AD8345 modulator IC: it provides precision dc-biasing (0.7 V common-mode) for IBBP/IBBN and QBBP/QBBN inputs, balun-coupled differential LO drive to LOIP/LOIN, decoupled dual-supply rails (VPS1/VPS2), and ac-coupled 50 Ω RF output at VOUT. All COMx ground pins are tied to a low-inductance solid ground plane per Analog Devices' layout recommendations.

It integrates passive matching networks optimized for 800 MHz operation, includes test points for all critical nodes (I/Q inputs, LO, VOUT, ENBL), and supports both differential DAC-driven and single-ended baseband configurations via optional jumpers and external amplifier interfaces (e.g., AD8132). The board is calibrated for use with standard lab equipment including RF signal analyzers, vector signal generators, and DC power supplies.

Key Specifications

Availability

AD8345-EVALZ is available at Aetrix Electronics and suitable for W-CDMA base station development, CDMA IS95 transmitter validation, GSM/PCS transceiver prototyping, and digital TV/CATV modulator design requiring stable component supply and documented reference hardware.

Supply support for AD8345-EVALZ 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, Inc. is a global leader in high-performance analog, mixed-signal, and RF ICs, headquartered in Norwood, MA, with deep expertise in signal processing, precision conversion, and radio frequency design.

The AD8345-EVALZ belongs to Analog Devices' RF & Microwave Evaluation Platform family, engineered specifically to accelerate time-to-test for high-speed RF modulators used in cellular infrastructure, broadband access, and broadcast transmission systems.

FAQ

What is the primary purpose of the AD8345-EVALZ?

The AD8345-EVALZ is a fully assembled evaluation board designed exclusively to validate the performance of the AD8345 quadrature modulator IC. It provides all necessary biasing, matching, decoupling, and interface circuitry-enabling engineers to measure key RF metrics such as sideband suppression, LO leakage, EVM, and ACPR without custom PCB development. The AD8345-EVALZ directly implements the recommended application circuit from the AD8345 Rev. B datasheet.

Does the AD8345-EVALZ support both differential and single-ended baseband input drive?

Yes-the AD8345-EVALZ supports differential baseband drive by default via its IBBP/IBBN and QBBP/QBBN connectors, with on-board biasing to 0.7 V. For single-ended sources, the board includes footprint options and routing to integrate external differential amplifiers like the AD8132 or AD8138, as described in the AD8345 datasheet's "Single-Ended I and Q Drive" section. No modifications to the AD8345-EVALZ itself are required beyond component placement.

Can the AD8345-EVALZ be used to evaluate AD8345 performance at frequencies below 140 MHz?

The AD8345-EVALZ hardware is compatible with sub-140 MHz operation, but performance degrades outside the AD8345's specified 140–1000 MHz range due to reduced quadrature accuracy in the internal polyphase splitter. Figure 29 in the AD8345 Rev. B datasheet shows sideband suppression falling to −20 dBc at 70 MHz. While the AD8345-EVALZ can physically operate down to ~70 MHz, results must be interpreted against characterized limits-not the full AD8345-EVALZ specification.

What LO drive level is recommended for optimal noise performance on the AD8345-EVALZ?

A −2 dBm differential LO drive level is recommended for lowest noise floor (−155 dBm/Hz at 20 MHz offset) on the AD8345-EVALZ, per AD8345 Rev. B datasheet specifications. Reducing LO power to −10 dBm increases the noise floor by ~0.3 dB (Figure 21); increasing LO power degrades linearity and raises third-order distortion. The AD8345-EVALZ includes a balun (ETC1-1-13) and matching network optimized for −2 dBm operation at 800 MHz.

Is the AD8345-EVALZ pin-compatible or functionally interchangeable with evaluation boards for AD8346 or AD8349?

No-the AD8345-EVALZ is not pin-compatible or functionally interchangeable with AD8346-EVALZ or AD8349-EVALZ. Although the AD8345, AD8346, and AD8349 share pin-compatible packages and similar functional blocks, their internal biasing requirements, LO interface characteristics, and RF output drive capabilities differ. The AD8345-EVALZ layout, component values, and calibration are specific to the AD8345's electrical behavior and cannot be reused across that family without redesign and revalidation.