MAX3864ESA-T Maxim Integrated, MAX3864ESA-T Datasheet - Page 5

• Manufacturer Part Number: MAX3864ESA-T
• Description: Transimpedance Amplifiers
• Manufacturer: Maxim Integrated

For optimum supply-noise rejection, the MAX3864
should be terminated with a differential load. If a single-
ended output is required, the unused output should be
terminated with 50Ω to V
a DC-coupled, 50Ω grounded load.
The MAX3864 includes a one-pole lowpass filter that
limits the circuit bandwidth and improves noise perfor-
mance.
The DC cancellation circuit uses low-frequency feed-
back to remove the DC component of the input signal
(Figure 3). This feature centers the input signal within the
Figure 1. Functional Diagram
Figure 2. Limited Output
AMPLITUDE
2.5Gbps, +3V to +5.5V, Wide Dynamic Range
FILTER
IN
_______________________________________________________________________________________
V
CC
CC
DC Cancellation Circuit
750Ω
. The MAX3864 will not drive
R
F
TIME
OUTPUT (SMALL SIGNALS)
OUTPUT (LARGE SIGNALS)
= 1kΩ
Output Filter
TRANSIMPEDANCE
DISABLE
AMPLIFIER
Transimpedance Preamplifier
LOWPASS FILTER
AMPLIFIER
VOLTAGE
transimpedance amplifier’s linear range, thereby reduc-
ing pulse-width distortion (PWD) on large input signals.
The DC cancellation circuit is internally compensated
and therefore does not require external capacitors. This
circuit minimizes PWD for data sequences that exhibit a
50% duty cycle and mark density. A duty cycle or mark
density significantly different from 50% causes the
MAX3864 to generate PWD.
DC cancellation current is drawn from the input and
creates noise. For low-level signals with little or no DC
component, this is not a problem. Amplifier noise will
increase for signals with significant DC component (see
Typical Operating Characteristics).
Figure 3. DC Cancellation Effect on Input
DC CANCELLATION
CIRCUIT
AMPLITUDE
OUTPUT
BUFFER
INPUT (AFTER DC CANCELLATION)
50Ω
50Ω
MAX3864
INPUT FROM PHOTODIODE
OUTPUT
FILTER
OUT+
OUT-
GND
V
CC
TIME
5