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Preliminary Data Sheet - Revision 1

03/01

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 I

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.

C

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

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

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.

ATA7601