CS6704 Myson Technology, CS6704 Datasheet - Page 4

• Manufacturer Part Number: CS6704
• Description: 1.25Gbps Fiber-optic Pin Pre-amplifier With Agc
• Manufacturer: Myson Technology

CS6704
Preliminary
FUNCTIONAL DESCRIPTION
The CS6704 is a transimpedance pre-amplifier fabricated by BiCMOS process. The CS6704 consists of a
transimpedance amplifier, an AGC control block, an output buffer, a DC restore block, and a voltage regulator.
Transimpedance Amplifier
The transimpedance amplifier in CS6704 is a high gain, single ended amplifier with a feedback resistor. The
feedback resistor converts the input current to a voltage at the output node, and is controlled by the AGC control
block. The minimum differential output swing is 10mV with 50Ω load at -27dBm input.
AGC Control Block
The AGC control block is to prevent the output voltage swing from saturation. When the input optic power is lower
than -9.5dBm, the AGC function is disabled, and the transimpedance gain is 3.2kΩ.
Output Buffer
The single-ended output of transimpedance amplifier is converted to differential signal through output buffer. It is
able to drive either a 50Ω load or a high impedance load. The output swing will be smaller when the CS6704 is
terminated with a 50Ω load. For better noise rejection, the different output should be terminated symmetrically.
DC Restore Block
The DC restore block draws DC component of the input current, thus minimize the pulse width distortion of large
input current.
Voltage Regulator
In order to minimize the influence of power supply on noise performance, a voltage regulator is incorporated in
the CS6704.
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