RX40 - An 80 Mbit/s optical receiver


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Welcome to the RX40 project web page! This page contains information on the RX40 ASIC, a custom-developed receiver for the CMS tracker digital optical link.

Main features

The CMS tracker control system will use approximately 1000 digital optical links for the transmission of timing, trigger and control signals. These digital signals, transmitted serially at a bitrate of 40 Mbit/s (80 Mbit/s for the clock signal), will be converted into electrical signals by a PIN photodiode at the receiver end. An IC, coupled to the photodiode, will then amplify the signal and transfer it in LVDS logic to the other circuit s along the control chain. As one of the transmission channel ends will sit inside the CMS detector, hence in a radiation environment, its components nee to be radiation tolerant.

RX40 has been developed to this purpose in a commercial quarter micron technology using radiation-tolerant design practices. The main feature of the ASIC are:

 

2 x 2 mm die size

2 identical receiver channels on chip

package: LPCC 32 (5 x 5 mm)

0.25 µm commercial CMOS technology with radiation tolerant layout practices

Automatic Gain Control to cope with AC signals from 10 to more than 500 µA

DC coupling to the PIN photodiode

Baseline DC current capability up to 500 µA

Bandwidth larger than 80 MHz

LVDS output signals

Detection of reset code transmitted on the line with enabling of reset output flag

 

 

Last modified: 08 October 2001