622Mbps, Ultra-Low-Power, 3.3V

Transimpedance Preamplifier for SDH/SONET

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9

INREF1 and INREF2

Connect INREF1 and INREF2 as close to the AC

ground of the photodetector diode as possible. The

photodetector AC ground is usually the ground of the

filter capacitor from the photodetector anode. The total

loop (from INREF1/INREF2, through the bypass capaci-

tor and the diode, and back to IN) should be no more

than 2 cm. long.

Wire Bonding

For high current density and reliable operation, the

MAX3664 uses gold metallization. Make connections to

the die with gold wire only, and use ball bonding tech-

niques (wedge bonding is not recommended). Die-pad

size is 4 mils square, with a 6 mil pitch. Die thickness is

12 mils.

Use good high-frequency design and layout tech-

niques. The use of a multilayer circuit board with sepa-

ground plane with the shortest possible traces.

FILTER

CAP

OUT+

OUT-

OUT+

OUT-

IN

COMP

PIN DIODE

Figure 4. Suggested Layout for TO-46 Header