02011-BRF-001-A Datasheet, PDF (1/2 Pages) M/A-COM Technology Solutions, Inc. – 622Mbps Transimpedance Amplifier with AGC

®
622Mbps Transimpedance Amplifier with AGC
M02011
Low-power, high-sensitivity, 622Mbps transimped- _{> K E Y F E A T U R E S}
ance amplifier fabricated in sub-micron CMOS
> Typical -34 dBm sensitivity, > Maximum jitter of 100 ps p-p
The M02011 transimpedance amplifier (TIA) with automatic
gain control (AGC) is fabricated in sub-micron CMOS for
high performance. With typical transimpedance of 66k ohms
differential and input-referred noise of 56na, sensitivities
of -34 dbm are achievable. With an input overload capability
greater than 6ma p-p, the AGC allows more than 40 dB of
dynamic range, providing a low-cost solution for longer-
> +6 dBm saturation at 622
Mbps
> Bandwidth 600 Mhz (typical)
> Input-referred noise of
56na (typical)
> Overload of 8ma p-p
> Typical differential transim-
pedance: 66kΩ
> Differential 100Ω output
impedance
> Operates on a single 3.3V
supply
> Monitor output
> AGC provides dynamic
range of more than 40 dB
reach 622Mbps APON, BPON and OC-12 systems.
For optimum system performance, the M02011 die should be
mounted with a silicon or InGaAs PIN photodetector inside a
lensed TO-Can or other optical sub-assembly.
Transimpedance Amplifier (TIA)
The TIA consists of a high gain single-ended CMOS amplifier
with a feedback resistor. The feedback creates a virtual low
impedance at the input, and nearly all of the input current
passes through the feedback resistor, defining the voltage
at the output. Advanced CMOS design techniques are
employed to maintain the stability of this stage across all
input conditions. An on-chip low dropout linear regulator has
been incorporated into the design to give excellent noise
rejection up to several MHz. Higher frequency power supply
noise is removed by the external 470 pF decoupling capac-
itor connected to PINK.
The circuit is intended to be configured for use with PIN
photodiodes in the “grounded cathode” configuration with
the anode connected to the input of the TIA and the
cathode connected to the PINK terminal. The PINK terminal
provides a ~2.6V reverse DC bias to reduce the photodiode
capacitance. Operation with an external bias supply to a
higher potential than 2.6V is possible, as required by
avalanche photodiodes.
Automatic Gain Control (AGC)
The M02011 has been designed to operate over the input
range of +6 dBm to –34 dBm @ 622Mbps. The AGC operates
on signals greater than ~ 3.5ua p-p. The AGC pad allows the
AGC to be disabled during photodiode alignment by
grounding the pad through a low impedance. The AGC
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