MAXIM MAX3787 User Manual

General Description

The MAX3787 is a 1Gbps to 12.5Gbps equalization
network that compensates for transmission medium loss­es encountered with FR4 and cables. The equalization
network is composed entirely of passive components
and functions equally well for 8b/10b or scrambled sig­nals. It is packaged in a small 1.5mm x 1.5mm chip­scale 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 place­ment 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.

Applications

Backplane Interconnect Compensation

Cable Interconnect Compensation

Chip-to-Chip Link Extensions

Ethernet and Fibre-Channel Serial Modules

Chassis Life Extension

Features

♦ 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

MAX3787

1Gbps to 12.5Gbps

Passive Equalizer for Backplanes and Cables

________________________________________________________________

Maxim Integrated Products

1

19-0406; Rev 2; 2/08

EVALUATION KIT

AVAILABLE

Pin Configuration

Ordering Information

UCSP is a trademark of Maxim Integrated Products, Inc.

Typical Application Circuits continued at end of data sheet.

Typical Application Circuits

+

Denotes a lead-free package.

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.

PART TEMP RANGE

MAX3787ABL -40°C to +125°C 4 UCSP B9-7

MAX3787AWL+ -40°C to +125°C 4 WLP W91B1+3

PIN­PACKAGE

PKG

CODE

TOP VIEW

A

B

21

3

IN+

MAX3787

OUT+

C

IN- OUT-

UCSP/WLP

LINE CARD

Tx(100Ω) (100Ω)

(100Ω)

Rx

IN- OUT-

OUT- IN-

ALL PASSIVE BACKPLANE INTERCONNECT

OUT+IN+

MAX3787

IN+OUT+

MAX3787

100Ω FR4

100Ω FR4

SWITCH CARD

Rx

(100Ω)

Tx

MAX3787

2 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

(Specifications guaranteed over specified operating conditions. Typical values measured at TA = +25°C.)

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.

1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables

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.

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

OPERATING CONDITIONS

Operating Ambient Temperature

Bit Rate NRZ data 1 12.5 Gbps

CID Tolerance Consecutive identical digits 100 Bits

Supply Current 0.0 mA

PARAMETER SYM B O L CONDITIONS MIN TYP MAX UNITS

T

A

PARAMETER SYM B O L CONDITIONS MIN TYP MAX UNITS

-40 +25 +125 °C

Input Swing Measured differentially at point A in Figure 1 3600 mV

Compensation 5GHz relative to 100MHz 6 dB

Input Impedance Differential, Z

Output Impedance Differential, Z

Through Response Relative to ideal load, see Figure 2 for setup See Figure 3 for limits

Input Return Loss 100MHz to 6GHz 15 dB

Output Return Loss 100MHz to 6GHz 15 dB

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) Z

Residual Deterministic Jitter
(Table 1, Notes 1, 2)

No load, high impedance on all ports 112 152 Ω

No load, high impedance on all ports 32 44 Ω

No load, high impedance on all ports 112 152 Ω

= 100Ω 0.5

LOAD

3.125Gbps and 6.25Gbps, 18in of 6mil
microstrip FR4

8.5Gbps, 10.0Gbps, and 12.5Gbps,
18in of 6mil microstrip FR4

= 100Ω 100 Ω

LOAD

= 100Ω 100 Ω

SOURCE

0.05

0.10

P-P

UI

MAX3787

Figure 1. Residual Deterministic Jitter Test Circuit

Figure 2. Frequency Response Test Circuit Using Vector Network Analyzer (VNA)

1Gbps to 12.5Gbps

Passive Equalizer for Backplanes and Cables

_______________________________________________________________________________________ 3

FR4 TEST BOARD

SIGNAL SOURCE

A

VNA SOURCE

1in DUAL 50Ω

MICROSTRIP LINE

0in ≤ L ≤ 18in

SEE TABLE 1 FOR PCB PARAMETERS.

REPRESENTS EDGE-MOUNTED SMA CONNECTOR.

ROGERS 4350 BOARD

MAX3787

B

1in DUAL 50Ω

MICROSTRIP LINE

ROGERS 4350 BOARD

OSCILLOSCOPE

MAX3787

C

VNA DETECTOR

REPRESENTS EDGE-MOUNTED SMA CONNECTOR.

MAX3787

4 _______________________________________________________________________________________

1Gbps to 12.5Gbps
Passive Equalizer for Backplanes and Cables

Figure 3. Through Response Limits

Table 1. PCB Assumptions (Board Material is FR4)

FREQUENCY

100MHz -8.2 -7.4 -6.8

200MHz -7.9 -7.0 -6.4

300MHz -7.5 -6.6 -6.0

500MHz -6.8 -6.0 -5.3

1.0GHz -5.5 -4.8 -4.2

2.0GHz -4.2 -3.2 -2.5

3.0GHz -3.1 -2.2 -1.5

4.0GHz -2.3 -1.5 -0.8

5.0GHz -2.1 -1.3 -0.5

5.5GHz -2.4 -1.6 -0.6

6.0GHz -2.9 -2.1 -1.1

6.5GHz — -2.6 —

7.0GHz — -3.1 —

7.5GHz — -3.6 —

8.0GHz — -4.1 —

8.5GHz — -4.7 —

9.0GHz — -5.5 —

9.5GHz — -7.0 —

10.0GHz — -9.0 —

MIN
(dB)

TYP
(dB)

MAX

(dB)

THROUGH-RESPONSE LIMITS

(RELATIVE TO IDEAL LOAD)

0

-1

-2

-3

-4

S21 (dB)

-5

-6

-7

-8

-9
010

MAX

TYP

MIN

986723451

FREQUENCY (GHz)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Transmission Line Edge-coupled microstrip line 6 mil

Relative Permittivity at 1GHz FR4 or similar 4.0 —

Loss Tangent FR4 or similar 0.02 —

Metal Thickness 1oz copper 1.4 mil

Impedance Differential 90 100 110 Ω

MAX3787

1Gbps to 12.5Gbps

Passive Equalizer for Backplanes and Cables

_______________________________________________________________________________________

5

Typical Operating Characteristics

(TA= +25°C, unless otherwise noted. All measurements were done with 1V

P-P

at the source. Stress pattern: 27PRBS, 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.)

FrameScan is a registered trademark of Tektronix.
Spectra-Strip and Skewclear are registered trademarks of Amphenol.

VERTICAL EYE OPENING vs. LENGTH

(4.25Gbps, STRESS PATTERN)

1000

900

)

800

P-P

700

600

500

400

300

VERTICAL EYE OPENING (mV

200

100

WITHOUT EQUALIZER

WITH EQUALIZER

0

01015205 253035 4540 50

FR4 BOARD LENGTH (in)

EYE DIAGRAM OF UNEQUALIZED SIGNAL

(18in FR4, 12.5Gbps, STRESS PATTERN)

MAX3787toc01

MAX3787toc04

VERTICAL EYE OPENING vs. LENGTH

(8.5Gbps, STRESS PATTERN)

900

800

)

P-P

700

600

500

400

300

200

VERTICAL EYE OPENING (mV

100

0

WITHOUT EQUALIZER

01015205 25303540

FR4 BOARD LENGTH (in)

EYE DIAGRAM OF EQUALIZED SIGNAL

(18in FR4, 12.5Gbps, STRESS PATTERN)

VERTICAL EYE OPENING vs. LENGTH

(10.3125Gbps, STRESS PATTERN)

900

800

)

MAX3787toc02

P-P

WITH EQUALIZER

700

600

500

400

300

200

VERTICAL EYE OPENING (mV

100

WITHOUT EQUALIZER

WITH EQUALIZER

0

01015205 25303540

FR4 BOARD LENGTH (in)

EYE DIAGRAM OF EQUALIZED SIGNAL (ZOOM)

(18in FR4, 12.5Gbps, STRESS PATTERN)

MAX3787toc05

MAX3787toc03

MAX3787toc06

120mV/div

14ps/div

EYE DIAGRAM OF UNEQUALIZED SIGNAL

(12in FR4, 12.5Gbps, STRESS PATTERN)

120mV/div

14ps/div

120mV/div

14ps/div

EYE DIAGRAM OF EQUALIZED SIGNAL

(12in FR4, 12.5Gbps, STRESS PATTERN)

MAX3787toc07

120mV/div

14ps/div

50mV/div

14ps/div

EYE DIAGRAM OF EQUALIZED SIGNAL (ZOOM)

(12in FR4, 12.5Gbps, STRESS PATTERN)

MAX3787toc08

60mV/div

14ps/div

MAX3787toc09