The AD6655 is a mixed-signal intermediate frequency (IF) receiver consisting of dual 14-bit, 80 MSPS/105 MSPS/125 MSPS/150 MSPS ADCs and a wideband digital downconverter (DDC). The AD6655 is designed to support communications applications where low cost, small size, and versatility are desired.
The dual ADC core features a multistage, differential pipelined architecture with integrated output error correction logic. Each ADC features wide bandwidth differential sample-and-hold analog input amplifiers supporting a variety of user-selectable input ranges. An integrated voltage reference eases design considerations. A duty cycle stabilizer is provided to compensate for variations in the ADC clock duty cycle, allowing the converters to maintain excellent performance.
ADC data outputs are internally connected directly to the digital downconverter (DDC) of the receiver, simplifying layout and reducing interconnection parasitics. The digital receiver has two channels and provides processing flexibility. Each receive channel has four cascaded signal processing stages: a 32-bit frequency translator (numerically controlled oscillator (NCO)), a half-band decimating filter, a fixed FIR filter, and an fADC/8 fixed-frequency NCO.
In addition to the receiver DDC, the AD6655 has several functions that simplify the automatic gain control (AGC) function in the system receiver. The fast detect feature allows fast overrange detection by outputting four bits of input level information with short latency.
In addition, the programmable threshold detector allows monitoring of the incoming signal power using the four fast detect bits of the ADC with low latency. If the input signal level exceeds the programmable threshold, the coarse upper threshold indicator goes high. Because this threshold indicator has low latency, the user can quickly turn down the system gain to avoid an overrange condition.
The second AGC-related function is the signal monitor. This block allows the user to monitor the composite magnitude of the incoming signal, which aids in setting the gain to optimize the dynamic range of the overall system.
After digital processing, data can be routed directly to the two external 14-bit output ports. These outputs can be set from 1.8 V to 3.3 V CMOS or as 1.8 V LVDS. The CMOS data can also be output in an interleaved configuration at a double data rate using only Port A.
The AD6655 receiver digitizes a wide spectrum of IF frequencies. Each receiver is designed for simultaneous reception of the main channel and the diversity channel. This IF sampling architecture greatly reduces component cost and complexity compared with traditional analog techniques or less integrated digital methods.
Flexible power-down options allow significant power savings, when desired.
Programming for setup and control is accomplished using a 3-bit SPI-compatible serial interface.
The AD6655 is available in a 64-lead LFCSP and is specified over the industrial temperature range of −40°C to +85°C.
|Title||Content Type||File Type|
|AD6655: IF Diversity Receiver Data Sheet (Rev A, 09/2009) (pdf, 3181 kB)||Data Sheets|
|AN-1142: Techniques for High Speed ADC PCB Layout (pdf, 392 kB)||Application Notes|
|AN-0974: Multicarrier TD-SCMA Feasibility (pdf, 634 kB)||Application Notes|
|AN-878: High Speed ADC SPI Control Software (pdf, 585 kB)||Application Notes|
|AN-807: Multicarrier WCDMA Feasibility (pdf, 969 kB)||Application Notes|
AN-808: Multicarrier CDMA2000 Feasibility
(pdf, 1535 kB)
The goal of this application note is to determine the feasibility of implementing a multicarrier CDMA2000 transceiver and what the major subsystem performances must be.
|AN-827: A Resonant Approach to Interfacing Amplifiers to Switched-Capacitor ADCs (pdf, 203 kB)||Application Notes|
|AN-877: Interfacing to High Speed ADCs via SPI (pdf, 1594 kB)||Application Notes|
|AN-905: VisualAnalog Converter Evaluation Tool Version 1.0 User Manual (pdf, 2124 kB)||Application Notes|
|AN-935: Designing an ADC Transformer-Coupled Front End (pdf, 363 kB)||Application Notes|
|AN-835: Understanding High Speed ADC Testing and Evaluation (pdf, 985 kB)||Application Notes|
AN-812: MicroController-Based Serial Port Interface (SPI) Boot Circuit (pdf, 452,449 bytes)
(pdf, 441 kB)
This application note describes the operation of a general-purpose, microcontroller-based Serial Port Interface (SPI) boot circuit.
|AN-851: A WiMax Double Downconversion IF Sampling Receiver Design (pdf, 262 kB)||Application Notes|
|AN-742: Frequency Domain Response of Switched-Capacitor ADCs (pdf, 401 kB)||Application Notes|
|AN-715: A First Approach to IBIS Models: What They Are and How They Are Generated (pdf, 370 kB)||Application Notes|
Matching An ADC To A Transformer
by Rob Reeder, Analog Devices, Inc.
(Microwaves & RF, 7/2007)
Two-Chip IF Receiver Prepares For 3G Standards
(Microwaves & RF, 4/2007)
|What is Digital Up/Down Converters: VersaCOMM™?||Overview||HTML|
|RAQs index||Rarely Asked Questions||HTML|
|Glossary of EE Terms||Glossary||HTML|
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ADIsimADC is Analog Devices' Analog-to-Digital Behavioral Model that accurately models the typical performance characteristics of many of our High Speed Converters. The model faithfully reproduces the errors associated with both static and dynamic features such as AC linearity, clock jitter, and many other product specific anomalies.
|ADIsim Design/Simulation Tools||HTML|
|AD6655 IBIS Models||IBIS Models||HTML|
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.