MAX3272A MAXIM [Maxim Integrated Products], MAX3272A Datasheet - Page 6

• Manufacturer Part Number: MAX3272A
• Description: +3.3V, 2.5Gbps Low-Power Limiting Amplifiers
• Manufacturer: MAXIM [Maxim Integrated Products]

+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
Figure 1. Power-Supply Current Measurement
Figure 2. Functional Diagram
6
CML SUPPLY CURRENT (I
_______________________________________________________________________________________
MAX3272A
MAX3272/
V
CC
IN+
IN-
I
CC
50Ω
CC
)
MAX3272A
MAX3272/
100Ω
50Ω
R
CONTROL
CORRECTION
TH
BUFFER
INPUT
CML
OFFSET
LEVEL
OPEN
SQUELCH
OPEN
POWER DETECTOR AND
I
TH
OUT
DETECTOR
POWER
LOS INDICATOR
CLOS
CAZ1
LOWPASS
FILTER
0.1µF
Figure 2 is a functional diagram of the MAX3272/
MAX3272A, comprising a CML input buffer, power
detector and loss-of- signal indicators, gain stage, offset-
correction loop, and CML output buffer.
The input buffer (Figure 3) provides 100Ω input imped-
ance between IN+ and IN-. DC-coupling the inputs is
not recommended; this prevents the DC offset-correc-
tion circuitry from functioning properly.
The MAX3272/MAX3272A are equipped with loss-of-sig-
nal (LOS) circuitry that indicates when the input signal is
below a programmable threshold, set by resistor R
the TH pin (see the Typical Operating Characteristics for
appropriate resistor selection). An averaging peak-
power detector compares the input signal amplitude
with this threshold and feeds the signal-detect informa-
tion to the LOS outputs, which are internally terminated
to 8kΩ (Figure 4).
CAZ2
CONTROL
Detailed Description
OUTPUT
BUFFER
TTL
TTL
CML
Loss-of-Signal Indicator
Power Detect and
CML Input Buffer
LOS
LOS
SQUELCH
OUT+
OUT-
LEVEL
OUTPOL
TH
at