Features and Benefits
- JESD204B (Subclass 1) coded serial digital outputs
- Support for lane rates up to 16 Gbps per lane
- 1.7 W total power per channel at 3 GSPS (default settings)
- Performance at −2 dBFS amplitude, 2.6 GHz input
- SFDR = 70 dBFS
- NSD = −148.0 dBFS/Hz
- Performance at −9 dBFS amplitude, 2.6 GHz input
- SFDR = 75 dBFS
- NSD = −151.4 dBFS/Hz
- Integrated input buffer
- Noise density = −152.0 dBFS/Hz
- 0.975 V, 1.9 V, and 2.5 V dc supply operation
- 9 GHz analog input full power bandwidth (−3 dB)
- Amplitude detect bits for efficient AGC implementation
- Two Integrated wideband digital processors per channel
- 48-bit NCO
- 4 cascaded half band filters
- Phase coherent NCO switching
- Up to 4 channels available
- Serial port control
- Integer clock divide by 2 and divide by 4
- Flexible JESD204B lane configurations
- On-chip dither
The AD6688 is a 1.2 GHz bandwidth, mixed-signal, direct radio frequency (RF) sampling receiver. It consists of two 14-bit, 3.0 GSPS analog-to-digital converters (ADCs) and various digital signal processing blocks consisting of four wideband digital downconverters (DDCs). The AD6688 has an on-chip buffer and a sample-and-hold circuit designed for low power, small size, and ease of use. This product is designed to support communications applications capable of direct sampling wide bandwidth analog signals of up to 5 GHz. The 3 dB bandwidth of the ADC input is greater than 9 GHz. The AD6688 is optimized for wide input bandwidth, high sampling rate, excellent linearity, and low power in a small package.
The dual ADC cores feature a multistage, differential pipelined architecture with integrated output error correction logic. Each ADC features wide bandwidth inputs supporting a variety of user-selectable input ranges. An integrated voltage reference eases design considerations. The analog input and clock signals are differential inputs. The ADC data outputs are internally connected to four DDCs through a crossbar mux. Each DDC consists of up to five cascaded signal processing stages: a 48-bit numerically controlled oscillator (NCO) and up to four half-band decimation filters. The NCO has the option to select preset bands over the general-purpose input/output (GPIO) pins, which enables selection of up to three bands. Operation of the AD6688 between the DDC modes is selectable via SPI-programmable profiles.
In addition to the DDC blocks, the AD6688 has several functions that simplify the automatic gain control (AGC) function in a communications receiver. The programmable threshold detector allows monitoring of the incoming signal power using the fast detect control bits in Register 0x0245 of the ADC. If the input signal level exceeds the programmable threshold, the fast detect indicator goes high. Because this threshold indicator has low latency, the user can quickly turn down the system gain to avoid an overrange condition at the ADC input. Besides the fast detect outputs, the AD6688 also offers signal monitoring capability. The signal monitoring block provides additional information about the signal being digitized by the ADC.
The user can configure the Subclass 1 JESD204B-based high speed serialized output in a variety of one-lane, two-lane, four-lane, six-lane, and eight-lane configurations, depending on the DDC configuration and the acceptable lane rate of the receiving logic device. Multidevice synchronization is supported through the SYSREF± and SYNCINB± input pins.
The AD6688 has flexible power-down options that allow significant power savings when desired. All of these features can be programmed using a 3-wire serial port interface (SPI).The AD6688 is available in a Pb-free, 196-ball BGA specified over the −40°C to +85°C ambient temperature range.
- Wide full power bandwidth supports IF sampling of signals up to 9GHz (-3dB point).
- Four Integrated wide-band decimation filter and NCO blocks supporting multi-band receivers.
- Fast NCO switching enabled through GPIO pins.
- Flexible SPI interface controls various product features and functions to meet specific system requirements.
- Programmable fast overrange detection and signal monitoring.
- On-chip temperature dioide for system thermal management.
- 12mm x 12mm 196-Lead BGA
- Diversity multiband, multimode digital receivers
- 3G/4G, TD-SCDMA, W-CDMA, GSM, LTE, LTE-A
- DOCSIS 3.0 CMTS upstream receive paths
- HFC digital reverse path receivers
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
The AD6688-3000EBZ supports the AD6688-3000, a 14-bit, 3GSPS dual analog-to-digital converter (ADC). The device has an on-chip buffer and a sample-and-hold circuit designed for low power, small size, and ease of use. This device is designed support direct RF sampling analog signals of up to 5 GHz. The 3 dB bandwidth of the ADC input is greater than 9 GHz. The AD6688 is optimized for wide input bandwidth, high sampling rate, excellent linearity, and low power in a small package.
This reference design provides all of the support circuitry required to operate the ADC in its various modes and configurations. It is designed to interface directly with the ADS7-V2EBZ data capture card, allowing users to download captured data for analysis. The device control and subsequent data analyses can now be done using the ACE software package.
Tools & Simulations
This command line executable tool generates a Verilog module which implements the JESD204 receive transport layer. The user specifies in a configuration file one or more modes to be supported by the transport layer module. These modes are defined as a set of JESD204 parameter values: L, M, F, S, N', and CF. The transport layer converts JESD204 lane data output from a JESD204 link layer IP to a data bus with a fixed width, containing interleaved virtual converter samples. Both JESD204B and JESD204C link layers are supported.
The JESD204x Frame Mapping Table Generator tool consists of two Windows executables that will allow the user to input any valid combination of JESD204x parameters (L, M, F, S, NP) in order to output a .csv file that illustrates the frame mapping of the JESD204x mode in table format. There is an executable that allows the user to input a single JESD204x mode and another, that allows the user to input the parameters for multiple JESD204x modes in a specified .csv format in order to output a .csv file that illustrates the frame mapping of each of the JESD204x modes that were input into separate tables.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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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.