Rainbow Electronics MAX3746 User Manual
General Description
The MAX3746 multirate limiting amplifier functions as a
data quantizer for SONET, Fibre-Channel, and Gigabit
Ethernet optical receivers. The amplifier accepts a wide
range of input voltages and provides selectable-level,
current-mode logic (CML) output voltages with controlled edge speeds. A received-signal-strength indicator (RSSI) is available when the MAX3746 is
DC-coupled to the MAX3744/MAX3724 SFP transimpedance amplifier (TIA). A receiver consisting of the
MAX3744/MAX3724 and the MAX3746 can provide up
to 19dB RSSI dynamic range. Additional features
include a programmable loss-of-signal (LOS) detect, an
optional disable function (DISABLE), and an
output-signal polarity reversal (OUTPOL). Output disable can be used to implement squelch.
The combination of the MAX3746 and the MAX3744/
MAX3724 allows for the implementation of all the smallform-factor SFF-8472 digital diagnostic specifications
using a standard 4-pin TO-46 header.
The MAX3746 is pin-for-pin compatible with the
MAX3748A limiting amplifier and consumes 30% less
power. The MAX3746 is packaged in a 3mm x 3mm,
16-pin QFN package.
Applications
Gigabit Ethernet SFF/SFP Transceiver Modules
Fibre-Channel SFF/SFP Transceiver Modules
Multirate OC-12 to OC48-FEC SFF/SFP
Transceiver Modules
Features
♦ SFP Reference Design Available
♦ Low 115mW Power Consumption
♦ 16-Pin QFN Package with 3mm x 3mm Footprint
♦ 70ps Rise and Fall Time
♦ Loss-of-Signal with Programmable Threshold
♦ RSSI Interface (with MAX3744/MAX3724 TIA)
♦ Output Disable
♦ Polarity Select
♦ 8.4ps
P-P
Deterministic Jitter (3.2Gbps)
♦ Improved EMI Performance
♦ Selectable CML Output levels
♦ Pin Compatible with MAX3748A
MAX3746
Low-Power, 622Mbps to 3.2Gbps
Limiting Amplifier
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3386; Rev 0; 8/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Typical Operating Circuits continued at end of data sheet.
Pin Configuration appears at end of data sheet.
MAX3746
MAX3744 TIA
DS1859
3-INPUT DIAGNOSTIC
MONITOR
R1
3kΩ
C1
0.1µF
IN+
IN-
RSSI TH DISABLE LOS
OUTPOL V
CC
GND
4.7kΩ TO 10kΩ
LOS
2.97V TO 3.6V
OUT+
50Ω
0.1µF
OUT-
50Ω
0.1µF
SERDES
RTH = 14kΩ
SUPPLY FILTER HOST FILTER
V
CC
_RX
4-PIN TO HEADER
HOST BOARDSFP OPTICAL RECEIVER
Typical Operating Circuits
PART TEMP RANGE PIN-PACKAGE PKG CODE
MAX3746ETE -40°C to +85°C 16 QFN T1633F-3
MAX3746
Low-Power, 622Mbps to 3.2Gbps
Limiting Amplifier
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Power-Supply Voltage (VCC).................................-0.5V to +4.5V
Voltage at IN+, IN- ..........................(V
CC
- 2.4V) to (VCC+ 0.5V)
Voltage at DISABLE, OUTPOL, RSSI,
LOS, TH...................................................-0.5V to (V
CC
+ 0.5V)
Current into LOS.....................................................1mA to +9mA
Differential Input Voltage (IN+ - IN-) .....................................2.5V
Continuous Current at CML Outputs
(OUT+, OUT-) ................................................-25mA to +25mA
Continuous Power Dissipation (T
A
= + 70°C)
16-Pin QFN (derate 17.7mW above +70°C) .....................1.4W
Operating Junction Temperature Range (T
J
)....-55°C to +150°C
Storage Ambient Temperature Range (Ts) .......-55°C to +150°C
ELECTRICAL CHARACTERISTICS
(VCC= +2.97V to +3.63V, CML output load is 50Ω to VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC=
+3.3V, T
A
= +25°C, unless otherwise specified. The data input transition time is controlled by 4th-order Bessel filter with f
-3dB
= 0.75 x
2.667GHz for all data rates of 2.667Gbps and below, and with f
-3dB
= 0.75 x 3.2GHz for a data rate of 3.2Gbps.)
Single-Ended Input Resistance R
Input Return Loss
Input Sensitivity V
Input Overload V
Single-Ended Output Resistance R
Output Return Loss diff S
CML Differential Output Voltage
Differential Output Signal when
Disabled
Deterministic Jitter
(Note 3)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Single ended to V
IN
se S
diff S
IN-MIN
IN-MAX
OUT
S i ng l e end ed , f < 3GH z, D U T i s p ow er ed on 14
11
Differential, f < 3GHz, DUT is powered on 15
11
(Note 1) 2 4 mV
(Note 1) 1200 mV
Single ended to V
Differential, f < 3GHz, DUT is powered on 20 dB
22
4mV
< V
P-P
OUTPOL connected to V
4mV
< V
P-P
OUTPOL open or connected to 30kΩ
CC
CC
< 1200mV
IN
< 1200mV
IN
P-P
CC
P-P
,
or GND
,
42 50 58 Ω
42 50 58 Ω
600 800 1000
400 500 600
Outputs AC-coupled,
V
applied to input (Note 2)
IN-MAX
10 mV
K28.5 pattern at 3.2Gbps (Note 2) 8.4 18
K28.5 pattern at 3.2Gbps at TA = +100°C 10.2
23
2
- 1 PRBS equivalent at 2.7Gbps (Note 2) 11.6 23
23
2
DJ
- 1 PRBS equivalent pattern at 2.7Gbps
= +100°C
at T
A
K28.5 pattern at 2.1Gbps 8 20
13.1
K28.5 pattern at 2.1Gbps at TA = +100°C 9.7
223 - 1 PRBS equivalent pattern at 622Mbps
(Note 2)
23
2
- 1 PRBS equivalent pattern at 622Mbps
at T
= +100°C
A
42.5 69
47.8
dB
P-P
P-P
mV
P-P
P-P
ps
P-P
MAX3746
Low-Power, 622Mbps to 3.2Gbps
Limiting Amplifier
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +2.97V to +3.63V, CML output load is 50Ω to VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC=
3.3V, T
A
= +25°C, unless otherwise specified. The data input transition time is controlled by 4th-order Bessel filter with f
-3dB
= 0.75 x
2.667GHz for all data rates of 2.667Gbps and below, and with f
-3dB
= 0.75 x 3.2GHz for a data rate of 3.2Gbps.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Random Jitter Input = 4mV
P-P
(Notes 2, 4) 3 7
ps
RMS
Data Output Transition
Time
4mV
P-P
< V
INP-P
< 1200mV
P-P
,
20% to 80% (Note 2)
70 114 ps
Input-ReferredNoise (Note 2) 150
µV
RMS
Low-Frequency Cutoff 20 kHz
Includes the CML output current; OUTPOL
connected to V
CC
or GND
35
Includes the CML output current; OUTPOL
open or connected to 30kΩ to GND
29 35
Power-Supply Current I
CC
Excludes the CML output current and the
CM_RSSI circuitry; OUTPOL connected to
V
CC
or GND (Note 5)
20 25
mA
Power-Supply Noise Rejection PSNR f < 2MHz 40 dB
LOSS-OF-SIGNAL (Notes 2, 6)
LOS Hysteresis 10 log (V
DEASSERT
/ V
ASSERT
)
2.2 dB
LOS Assert/Deassert Time (Note 7) 2.3 50 µs
Low LOS Assert Level RTH = 2kΩ 2.6 4 6.4
mV
P-P
Low LOS Deassert Level RTH = 2kΩ 6 9.6
mV
P-P
Medium LOS Assert Level RTH = 14kΩ
28
mV
P-P
Medium LOS Deassert Level RTH = 14kΩ 42
mV
P-P
High LOS Assert Level RTH = 25kΩ 36 50
mV
P-P
High LOS Deassert Level RTH = 25kΩ 84
mV
P-P
CM_RSSI SPECIFICATION
RSSI Current Gain A
RSSIIRSSI
/ I
CM_RSSI
(Note 8)
V
CM
to I
RSSI
3dB Bandwidth 40 kHz
Input-Referred RSSI Current
Stability
I
RSS
I
ARSS
I
Input < 6.6mA, 0V ≤ V
RSSI
≤ 2.5V (Note 9) -40
µA
RSSI Output Compliance Voltage
V
RSSI
0 2.0 V
TTL/CMOS I/O
LOS Output High Voltage V
OH
R
LOS
= 4.7kΩ to 10kΩ to Vcc_host (3V) 2.4 V
LOS Output Low Voltage V
OL
R
LOS
= 4.7kΩ to 10kΩ to Vcc_host (3.6V) 0.4 V
1.25
19.6
0.031
41.5
31.8
54.7
54.3
114
+36
Typical Operating Characteristics
(VCC= +3.3V, TA = +25°C, unless otherwise noted.)
MAX3746
Low-Power, 622Mbps to 3.2Gbps
Limiting Amplifier
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +2.97V to +3.63V, CML output load is 50Ω to VCC, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC=
+3.3V, T
A
= +25°C, unless otherwise specified. The data input transition time is controlled by 4th-order Bessel filter with f
-3dB
= 0.75 x
2.667GHz for all data rates of 2.667Gbps and below, and with f
-3dB
= 0.75 x 3.2GHz for a data rate of 3.2Gbps.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DISABLE Input High V
IH
2.0 V
DISABLE Input Low V
IL
0.8 V
DISABLE Input Current R
LOS
= 4.7kΩ to 10kΩ to Vcc_host 10 µA
Note 1: Between sensitivity and overload, all AC specifications are met.
Note 2: Guaranteed by design and characterization.
Note 3: The deterministic jitter caused by the filter is not included in the DJ generation specification.
Note 4: Random jitter was measured without using a filter at the input.
Note 5: The supply current measurement excludes the CML output currents by connecting the CML outputs to a separate V
CC
. (See
Figure 1.)
Note 6: Hysteresis is calculated as 10 log (V
DEASSERT
/ V
ASSERT
). Unless otherwise specified, the data rate for all LOS detect speci-
fications varies from 622Mbps up to 3.2Gbps, and the patterns are 1010 or 2
23
- 1 PRBS.
Note 7: The signal is switched between two amplitudes, Signal_On and Signal _Off as shown in Figure 2.
Note 8: I
CM_RSSI
is the input common-mode current. I
RSSI
is the current at the RSSI output.
Note 9: Stability is defined as the variation over temperature and power supply with respect to the typical gain of the part.
SUPPLY CURRENT
vs. TEMPERATURE
MAX3746 toc01
TEMPERATURE (°C)
CURRENT (mA)
908060 70-10 0 10 20 30 40 50-30-20
10
20
30
40
50
60
70
80
90
100
0
-40 100
CML OUTPUTS INCLUDED
CML OUTPUTS NOT INCLUDED
OUTPOL = V
CC
TRANSFER FUNCTION
MAX3746 toc02
DIFFERENTIAL INPUT (mV
P-P
)
DIFFERENTIAL OUTPUT (mV
P-P
)
54321
100
200
300
400
500
600
700
800
900
0
06
OUTPOL = V
CC
RANDOM JITTER vs. TEMPERATURE
(INPUT LEVEL 10mV
P-P
)
MAX3746 toc03
TEMPERATURE (°C)
RANDOM JITTER (ps
RMS
)
908060 70-10 0 10 20 30 40 50-30-20
1
2
3
4
5
6
7
8
9
10
0
-40 100
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