MAX3746 Maxim Integrated Products, MAX3746 Datasheet - Page 8
MAX3746
Manufacturer Part Number
MAX3746
Description
Limiting Amplifier
Manufacturer
Maxim Integrated Products
Datasheet
1.MAX3746.pdf
(13 pages)
The MAX3746 is equipped with multirate LOS circuitry
that indicates when the input signal is below a pro-
grammable threshold, set by resistor R
(see the Typical Operating Characteristics for appropri-
ate resistor sizing). An averaging RMS power detector
compares the input signal amplitude with this threshold
and feeds the signal-detect information to the open-col-
lector LOS output.
To prevent LOS chatter in the region of the pro-
grammed threshold, approximately 2dB of hysteresis is
built into the LOS assert/deassert function. Once
Low-Power, 622Mbps to 3.2Gbps
Limiting Amplifier
Figure 1. Power-Supply Current Measurement
Figure 3. CML Input Buffer
8
IN+
IN-
Power Detect and Loss-of-Signal Indicator
0.25pF
0.25pF
_______________________________________________________________________________________
STRUCTURES
ESD
V
CC
MAX3746
I
CC
(SUPPLY CURRENT)
50Ω
50Ω
50Ω
V
CC
R
50Ω
TH
TH
I
OUTPUT CURRENT)
OUT
at the TH pin
(CML
asserted, the LOS is not deasserted until the input
amplitude rises to the required level (V
Figures 2 and 5.)
The MAX3746HETE is a MAX3746 in a hybrid lead-free
package. It is a hybrid part, which contains high-lead
bumps inside a lead-free thin QFN package. The part is
not 100% lead free; however, the high-lead solder in
the internal portion of the part does meet the RoHS
exemption for high-lead solders. For more information,
visit www.maxim-ic.com/emmi.
Figure 2. LOS Assert Threshold Set 1dB Below the Minimum by
Receiver Sensitivity for Selected R
Figure 4. CML Output Buffer
I1 = f (OUTPOL, DISABLE)
DISABLE
DATA
0V
V
IN
1dB
6dB
Q3
POWER-DETECT WINDOW
Q4
MAX DEASSERT LEVEL
I2 = f (OUTPOL, DISABLE)
MIN ASSERT LEVEL
SIGNAL OFF
Hybrid Lead-Free Package
SIGNAL ON
50Ω
Q1
TH
V
CC
Q2
50Ω
DEASSERT
TIME
STRUCTURES
). (See
ESD
OUT+
OUT-