ATA7601
Packaging
The ATA7601D1 is provided as bare die. For optimum performance, the die should be packaged in a
hermetic enclosure and a low inductance ground plane should be made available for power supply
bypassing and ground bonds. The bond wire from the photodetector to IIN should be made as short as
possible. As the inductance of this connection increases beyond 1nH, more gain peaking will occur
and the group delay performance will degrade.
Output Connections
The ATA7601D1 provides a differential output that must be AC coupled to the next stage of the receiver
as the output buffer is not designed to drive a DC coupled 50W load. For single-ended applications,
one output of the ATA7601D1 must be AC terminated to a 50W load.
CEXT Connection
In order to achieve the desired low frequency cutoff, an external capacitor is required. A low inductance
surface mount chip capacitor or MIM capacitor is recommended.
Sensitivity Measurement
The typical sensitivity, as specified in the AC characteristics, is 19.5dBm. This was measured at a
BER of 10-10 with a 10Gb/s, 223-1 PRBS, using a lensed single mode fiber with the photodetector and
TIA in an open test fixture under the following conditions:
Photodetector active area: 32mm
Photodetector capacitance: 0.2pF
Photodetector responsivity: 0.85A/W
Lensed fiber beam width: 13mm (86.5% of contained power)
Lensed fiber focal distance: 3mm
When the photodetector and TIA are packaged in a hermetic enclosure, with the fiber optimally aligned
to the active area of the photodiode, an improvement in sensitivity should be observed.
Device Modeling and Simulation
S-parameter files of the TIA are available on the Anadigics web site ( http://www.anadigics.com) or upon
request. Also included on the web-site is a virtual sample. This is an encrypted model of the TIA that
can be downloaded into the ADS simulation environment.
Preliminary Data Sheet - Revision 1
03/01
7
ANADIGICS [ ANADIGICS, INC ]
