Questions & Answers | ADSL Technology and AFE Application Notes | Glossary |
General Questions
1.1: What are the key technology benefits of the KeyWave™ AFE?
1.2: What are the primary applications?
1.3: What are the main features?
1.4: Are there any novel design techniques used in this device?
1.5: What is the process technology used?
1.6: What is the product availability?
1.1: What are the key technology benefits of the KeyWaveT AFE?
MB88626 is a stand-alone AFE supporting both full-rate and G.lite ADSL versions as well as analog echo cancellation. It is therefore available independently for use with a customer's DMT processor. The MB88626 design requires a minimum of external components with no active components other than the transmit line driver. Fujitsu's Triple Well technology ensures good isolation of digital and analog sections.
1.2: What are the primary applications?
- ADSL CPE modems (full rate with echo cancellation or G.lite/V.90 using second Rx channel)
- PC-NIC ADSL modem cards
- Integrated Access Devices (IADs)
- Set-Top Boxes (STBs)
- ATU-C configuration on ADSL line cards for DSLAMs (CO or MTU), DLCs, and MSAPs
- G.lite line card modules for CO DSLAM or DLC/MTU RAM
- Single-channel G.dmt or dual-channel G.lite at CO
- ADSL over ISDN FDM and echo cancelling systems
1.3: What are the main features?
The MB86626 AFE is a single device incorporating: ·
- Dual 15-bit, 4.4MSa/s ADCs for Rx path
- Dual 15-bit, 4.4MSa/s DACs for Tx path
- Support for analog echo cancellation at CPE
- Dual Tx/Rx architecture which supports dual G.lite at CO
- Configurable digital data interface · Integrated filters
- Programmable Rx and Tx channel gain (0 to +38 dB AGC range for Rx channel)
- VCXO control output
- Tx power control
- Low power consumption
- Support for both G.dmt and reduced rate G.lite at CO and RT
- On/Off hook detection comparator for G.lite
1.4: Are there any novel design techniques used in this device?
MSD's successive-approximation ADC is used in the MB86626 design. As compared to sigma-delta architecture, this technology represents an excellent speed vs. power trade-off with very low noise. The requirements on subsequent digital filtering are relaxed allowing for chip area and power economy.
Fujitsu's Triple Well technology ensures good isolation of digital and analog sections and all analog signal paths in the AFE are fully differential.
The MB86626 architecture results in a very low noise receive path. A differential trim network improves SNR by improving matching to varying impedance lines. This reduces the echo signal before the analog/digital echo cancellation is applied. Analog echo cancellation allows for a higher receive path gain at the first stage which in turn reduces noise contribution from subsequent stages.
1.5: What is the process technology used?
0.35m CMOS technology with Triple-Well.
1.6: What is the product availability?
The MB86626 KeyWaveT AFE is commercially available now. The order part number is MB86626PFV.
1.7: What product literature is available?
- Product Flyer
- Product Datasheet
- Includes basic applications information, e.g. PCB layout guidelines
- Development Kit Flyer
- Development Kit User Manual
- Includes full board schematics
1.8: Other questions and product information?
Send an e-mail to: msg.support@acg.fujitsu-fme.com
