SP Amp Transimpedance Amp Single DIE

The MAX3665 low-power transimpedance preamplifier for 622Mbps SDH/SONET applications consumes only 70mW at VCC = 3.3V. Operating from a single +3.3V or +5.0V supply, it converts a small photodiode current to a measurable differential voltage. A DC cancellation circuit provides a true differential output swing over a wide range of input current levels, thus reducing pulse-width distortion. The differential outputs are back-terminated with 50O per side. The overall transimpedance gain is nominally 8kO. For input signal levels beyond approximately 50µAp-p, the amplifier will limit the output swing to 250mV. The MAX3665"s low 55nA input noise provides a typical sensitivity of -33.2dBm in 1300nm, 622Mbps receivers. The MAX3665 is designed to be used in conjunction with the MAX3676 clock recovery and data retiming IC with limiting amplifier. Together they form a complete 3.3V or 5.0V 622Mbps SDH/SONET receiver. In die form, the MAX3665 is designed to fit on a header with a PIN diode. It includes a filter connection that provides positive bias for the photodiode through a 1.5kO resistor to VCC. The device is available in an 8-pin µMAX package.

• +3.3V or +5.0V Single-Supply Operation
• 55nA_RMS Input-Referred Noise
• 70mW Power Consumption at V_CC = 3.3V
• 8kO Gain
• 450µA Peak Input Current
• 260ps (max) Deterministic Jitter
• Differential Output Drives 100OLoad
• 470MHz Bandwidth