MAX3746ETE Maxim Integrated Products, MAX3746ETE Datasheet - Page 9

• Manufacturer Part Number: MAX3746ETE
• Description: Limiting Amplifiers 622Mbps to 3.2Gbps
• Manufacturer: Maxim Integrated Products

Specifications of MAX3746ETE

• Operating Supply Voltage: 3.3 V
• Supply Current: 35 mA
• Operating Temperature Range: + 85 C
• Package / Case: TQFN EP
• Mounting Style: SMD/SMT
• Number Of Channels: 1
• Power Dissipation: 1400 mW
• Lead Free Status / Rohs Status: No

Figure 5. LOS Output Circuit
External resistor, R
threshold. See the LOS Threshold vs. R
Typical Operating Characteristics to select the appro-
priate resistor.
When AC coupling is desired, coupling capacitors C
and C
er’s deterministic jitter. Jitter is decreased as the input
low-frequency cutoff (f
For ATM/SONET or other applications using scrambled
NRZ data, select (C
f
other applications using 8B/10B data coding, select
(C
Refer to Application Note HFAN-1.1, Choosing AC-
Coupling Capacitors .
The SFF-8472 Digital Diagnostic specification requires
monitoring of input receive power. The MAX3746 and
MAX3744 receiver chipset allows for the monitoring of
the average receive power by measuring the average
DC current of the photodiode.
The MAX3744/MAX3724 preamp measures the aver-
age photodiode current and provides the information to
the output common mode. The MAX3746 RSSI detect
block senses the common-mode DC level of input sig-
nals. IN+ and IN- provide a ground-referenced output
signal (RSSI) proportional to the photodiode current.
IN
IN
< 32kHz. For Fibre Channel, Gigabit Ethernet, or
, C
OUT
OUT
Program the LOS Assert Threshold
should be selected to minimize the receiv-
) ≥ 0.01µF, which provides f
Select the Coupling Capacitor
f
IN
_______________________________________________________________________________________
= 1 / [2π(50)(C
IN
TH,
GND
V
IN
, C
CC
) is decreased.
programs the loss-of-signal
OUT
Design Procedure
RSSI Implementation
) ≥ 0.1µF, which provides
IN
)]
Low-Power, 622Mbps to 3.2Gbps
TH
IN
ESD
STRUCTURE
graph in the
< 320kHz.
LOS
IN
Table 1. Logic Table for Polarity and CML
Output-Level Settings
The advantage of this implementation is that it allows
the TIA to be packaged in a low-cost, conventional 4-
pin TO-46 header.
The MAX3746 RSSI output is connected to an analog
input channel of the DS1858/DS1859 SFP controller to
convert the analog information into a 16-bit word. The
DS1858/DS1859 provide the receive-power information
to the host board of the optical receiver through a 2-
wire interface. The DS1859 allows for internal calibra-
tion of the receive power monitor.
The MAX3744/MAX3724 and the MAX3746 have been
optimized to achieve RSSI stability of 2.5dB within the
6µA to 500µA range of average input photodiode cur-
rent. To achieve the best accuracy, MAXIM recom-
mends receive-power calibration at the low end (6µA)
and the high end (500µA) of the required range. See
the RSSI Current Gain graph in the Typical Operating
Characteristics .
For best use of the RSSI monitor, capacitor C1 and
resistor R1 shown in the first Typical Application Circuit
need to be placed as close as possible to the Dallas
diagnostic monitor with the ground of C1 and R1 the
same as the DS1858/DS1859 ground. Capacitor C1
suppresses system noise on the RSSI signal. R1 = 3kΩ
and C1 = 0.1µF is recommended.
The MAX3746 has been designed for better EMI perfor-
mance. To help reduce EMI, special care has been
taken to produce symmetrical signal outputs. See the
eye diagram of the single-ended output in the Typical
Operating Characteristics .
TRANSISTOR COUNT: 1385
PROCESS: SiGe Bipolar
30kΩ to GND
Connecting to the Dallas DS1858/DS1859
OUTPOL
Open
GND
V
CC
Limiting Amplifier
N oni nver ti ng outp ut w i th ful l C M L outp ut l evel
N oni nver ti ng outp ut w i th r ed uced C M L outp ut
l evel
Inverting output with reduced CML output
level
Inverting output with full CML output level
DESCRIPTION
Chip Information
EMI Performance
9