19-0406; Rev 2; 2/08
KIT
ATION
EVALU
E
BL
AVAILA
1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables
General Description
The MAX3787 is a 1Gbps to 12.5Gbps equalization
network that compensates for transmission medium loss-
es encountered with FR4 and cables. The equalization
network is composed entirely of passive components
and functions equally well for 8b/10b or scrambled sig-
nals. It is packaged in a small 1.5mm x 1.5mm chip-
scale package (UCSP™) that can be placed anywhere
along the transmission medium to increase jitter margin
for high-speed interconnects. Roughly the size of two
0603 components, the MAX3787 easily provides place-
ment and routing flexibility.
At 8.5Gbps, the MAX3787 compensates for spans up to
18in of FR4 and 7m of cable. At 12.5Gbps, the MAX3787
compensates for spans up to 12in of FR4 and 3m of
cable. Input and output impedance is 100Ω differential.
The MAX3787 requires no power and operates over a
-40°C to +125°C temperature range.
♦
No Power Supply Required
♦
Small 1.5mm x 1.5mm Chip-Scale Package
♦
Passive Equalization Reduces ISI
♦
Operates from 1Gbps to 12.5Gbps
♦
Extends Board Link
♦
Extends Cable Link
♦
Coding Independent, 8b/10b or Scrambled
Features
MAX3787
Ordering Information
PART
MAX3787ABL
MAX3787AWL+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
PIN-
PACKAGE
4 UCSP
4 WLP
PKG
CODE
B9-7
W91B1+3
+Denotes
a lead-free package.
Applications
Backplane Interconnect Compensation
Cable Interconnect Compensation
Chip-to-Chip Link Extensions
Ethernet and Fibre-Channel Serial Modules
Chassis Life Extension
B
A
IN+
Pin Configuration
TOP VIEW
1
2
3
OUT+
MAX3787
C
IN-
OUT-
UCSP is a trademark of Maxim Integrated Products, Inc.
UCSP/WLP
Typical Application Circuits
LINE CARD
IN+
IN-
ALL PASSIVE BACKPLANE INTERCONNECT
OUT+
OUT-
100Ω FR4
Rx (100Ω)
SWITCH CARD
(100Ω)
Tx
MAX3787
(100Ω)
Rx
OUT+
OUT-
MAX3787
IN+
IN-
100Ω FR4
Tx (100Ω)
Typical Application Circuits continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables
MAX3787
ABSOLUTE MAXIMUM RATINGS
Voltage between (IN+ and OUT+) or (IN- and OUT-) ..............+2V
Voltage between (IN+ and IN-) or (OUT+ and OUT-) ..............+4V
Voltage between (IN+ and OUT-) or (IN- and OUT+) ..............+4V
Continuous Power Dissipation (T
A
= +70°C)
4-Bump UCSP (derate 3.0mW/°C above +70°C) .........238mW
Operating Junction Temperature........................................+150°C
Storage Ambient Temperature Range .................-55°C to +150°C
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.
OPERATING CONDITIONS
PARAMETER
Operating Ambient Temperature
Bit Rate
CID Tolerance
SYMBOL
T
A
NRZ data
Consecutive identical digits
CONDITIONS
MIN
-40
1
TYP
+25
MAX
+125
12.5
100
UNITS
°C
Gbps
Bits
ELECTRICAL CHARACTERISTICS
(Specifications guaranteed over specified operating conditions. Typical values measured at T
A
= +25°C.)
PARAMETER
Supply Current
Input Swing
Compensation
Input Impedance
Output Impedance
Through Response
Input Return Loss
Output Return Loss
Resistance IN+ to IN- and OUT+
to OUT-
Resistance IN+ to OUT+ and
IN- to OUT-
Resistance IN+ to OUT- and
IN- to OUT+
DC Gain (OUT/IN)
Residual Deterministic Jitter
(Table 1, Notes 1, 2)
Measured differentially at point A in Figure 1
5GHz relative to 100MHz
Differential, Z
LOAD
= 100Ω
Differential, Z
SOURCE
= 100Ω
Relative to ideal load, see Figure 2 for setup
100MHz to 6GHz
100MHz to 6GHz
No load, high impedance on all ports
No load, high impedance on all ports
No load, high impedance on all ports
Z
LOAD
= 100Ω
3.125Gbps and 6.25Gbps, 18in of 6mil
microstrip FR4
8.5Gbps, 10.0Gbps, and 12.5Gbps,
18in of 6mil microstrip FR4
112
32
112
0.5
0.05
UI
0.10
6
100
100
See Figure 3 for limits
15
15
152
44
152
dB
dB
Ω
Ω
Ω
SYMBOL
CONDITIONS
MIN
TYP
0.0
3600
MAX
UNITS
mA
mV
P-P
dB
Ω
Ω
Note 1:
Signal applied differentially at point A as shown in Figure 1. The deterministic jitter at point B is from media-induced loss,
not from clock-source modulation. Deterministic jitter is measured at the 50% vertical level of the signal at point C.
Note 2:
Difference in deterministic jitter between reference points A and C in Figure 1. Stress pattern: 2
7
PRBS, 100 zeros, 1, 0, 1, 0,
27 PRBS, 100 ones, 0, 1, 0, 1.
2
_______________________________________________________________________________________
1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables
MAX3787
FR4 TEST BOARD
SIGNAL SOURCE
0in
≤
L
≤
18in
ROGERS 4350 BOARD
OSCILLOSCOPE
MAX3787
SEE TABLE 1 FOR PCB PARAMETERS.
A
B
C
REPRESENTS EDGE-MOUNTED SMA CONNECTOR.
Figure 1. Residual Deterministic Jitter Test Circuit
ROGERS 4350 BOARD
VNA SOURCE
VNA DETECTOR
1in DUAL 50Ω
MICROSTRIP LINE
1in DUAL 50Ω
MICROSTRIP LINE
MAX3787
REPRESENTS EDGE-MOUNTED SMA CONNECTOR.
Figure 2. Frequency Response Test Circuit Using Vector Network Analyzer (VNA)
_______________________________________________________________________________________
3
1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables
MAX3787
FREQUENCY
100MHz
200MHz
300MHz
500MHz
1.0GHz
2.0GHz
3.0GHz
4.0GHz
5.0GHz
5.5GHz
6.0GHz
6.5GHz
7.0GHz
7.5GHz
8.0GHz
8.5GHz
9.0GHz
9.5GHz
10.0GHz
MIN
(dB)
-8.2
-7.9
-7.5
-6.8
-5.5
-4.2
-3.1
-2.3
-2.1
-2.4
-2.9
—
—
—
—
—
—
—
—
TYP
(dB)
-7.4
-7.0
-6.6
-6.0
-4.8
-3.2
-2.2
-1.5
-1.3
-1.6
-2.1
-2.6
-3.1
-3.6
-4.1
-4.7
-5.5
-7.0
-9.0
MAX
(dB)
-6.8
-6.4
-6.0
-5.3
S21 (dB)
0
-1
-2
-3
MAX
-4
-5
-6
-7
-8
-9
0
1
2
3
4
5
6
7
8
9
10
FREQUENCY (GHz)
MIN
TYP
THROUGH-RESPONSE LIMITS
(RELATIVE TO IDEAL LOAD)
-4.2
-2.5
-1.5
-0.8
-0.5
-0.6
-1.1
—
—
—
—
—
—
—
—
Figure 3. Through Response Limits
Table 1. PCB Assumptions (Board Material is FR4)
PARAMETER
Transmission Line
Relative Permittivity at 1GHz
Loss Tangent
Metal Thickness
Impedance
FR4 or similar
FR4 or similar
1oz copper
Differential
90
CONDITIONS
Edge-coupled microstrip line
MIN
TYP
6
4.0
0.02
1.4
100
110
MAX
UNITS
mil
—
—
mil
Ω
4
_______________________________________________________________________________________
1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted. All measurements were done with 1V
P-P
at the source. Stress pattern: 2
7
PRBS, 100 zeros, 1, 0, 1,
0, 2
7
PRBS, 100 ones, 0, 1, 0, 1. Residual deterministic jitter graphs were measured using Tektronix’s FrameScan
®
. Deterministic jitter of
the system was subtracted from the measured value. Eye diagrams acquired by FrameScan include deterministic jitter of the system
(approximately 9ps) but not random jitter. Twin-ax cable: Amphenol Spectra-Strip
®
Skewclear
®
100Ω 24AWG.)
VERTICAL EYE OPENING vs. LENGTH
(4.25Gbps, STRESS PATTERN)
MAX3787toc01
MAX3787
VERTICAL EYE OPENING vs. LENGTH
(8.5Gbps, STRESS PATTERN)
MAX3787toc02
VERTICAL EYE OPENING vs. LENGTH
(10.3125Gbps, STRESS PATTERN)
800
VERTICAL EYE OPENING (mV
P-P
)
700
600
500
400
300
200
100
0
WITH EQUALIZER
WITHOUT EQUALIZER
MAX3787toc03
1000
900
VERTICAL EYE OPENING (mV
P-P
)
800
700
600
500
400
300
200
100
0
0
5
WITH EQUALIZER
WITHOUT EQUALIZER
900
800
VERTICAL EYE OPENING (mV
P-P
)
700
600
500
400
300
200
100
0
WITH EQUALIZER
WITHOUT EQUALIZER
900
10 15 20 25 30 35 40 45 50
FR4 BOARD LENGTH (in)
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
FR4 BOARD LENGTH (in)
FR4 BOARD LENGTH (in)
EYE DIAGRAM OF UNEQUALIZED SIGNAL
(18in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc04
EYE DIAGRAM OF EQUALIZED SIGNAL
(18in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc05
EYE DIAGRAM OF EQUALIZED SIGNAL (ZOOM)
(18in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc06
120mV/div
120mV/div
50mV/div
14ps/div
14ps/div
14ps/div
EYE DIAGRAM OF UNEQUALIZED SIGNAL
(12in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc07
EYE DIAGRAM OF EQUALIZED SIGNAL
(12in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc08
EYE DIAGRAM OF EQUALIZED SIGNAL (ZOOM)
(12in FR4, 12.5Gbps, STRESS PATTERN)
MAX3787toc09
120mV/div
120mV/div
60mV/div
14ps/div
14ps/div
14ps/div
FrameScan is a registered trademark of Tektronix.
Spectra-Strip and Skewclear are registered trademarks of Amphenol.
_______________________________________________________________________________________
5
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