The S3051 is an integrated limiting amplifier in-
tended for high-frequency fiber-optic applications.
The circuit connects to typical transimpedance am-
plifiers found within a fiber-optic link. The linear
signal output from a transimpedance amplifier can
contain significant amounts of noise, and may vary
in amplitude over time. The S3051 limiting amplifier
quantizes the signal, and outputs a voltage limited
waveform over a 38 dB input dynamic range.
At low signal levels, below 12 mVp-p, the circuit be-
haves as a linear amplifier. At higher levels the
device becomes a limiting amplifier.
2.5 GBPS LIMITING AMPLIFIER
The referred wideband input noise (160 µVrms) al-
lows for a less than 1E-9 Bit Error Rate for inputs
down to 2 mVp-p.
The S3051 is designed to allow adjustment of the
DC offset between the DIN+ and DIN– inputs. V+REF
can be used as a reference from which the required
offset can be subtracted to set the DC bias level at
DIN–. Similarly, V–REF can be used to set the DC
bias level at DIN+. (See Application Information).
If no adjustment is made to the input DC bias level,
two resistors can be connected in a negative feed-
back configuration in order to cancel any DC offset
at the input. This will minimize the pulse width distor-
tion. (See separate S3051 Limiting Amplifier
Figure 2. Functional Block Diagram
NC ..... No Connect
13 14 15 16
VCC(GS1,GS2) VCC(GS1,SS2) GND(GS1,GS2) GND(GS1,GS2)
2 July 14, 1999 / Revision B