Rainbow Electronics MAX3805 User Manual

General Description

The MAX3805 is designed to provide up to 30in
(0.75m) reach on 6-mil differential FR-4 transmission
line, or up to 24ft (8m) on RG-188A/U type coaxial
cable, for PRBS data from 9.95Gbps to 10.7Gbps. The
MAX3805 adaptive equalizer reduces intersymbol inter­ference, resulting in 20ps residual jitter after equaliza­tion. An internal feedback network controls the
equalizer to automatically match frequency-dependent
skin effect and dielectric losses. The MAX3805 pro­vides LVCMOS-compatible output-enable and signal­detect functions.

The MAX3805 has separate supply connections for the
internal logic and I/O circuits. This allows the current­mode logic (CML) input and CML output to be connect­ed to isolated supplies for independent DC-coupled
interfaces to 1.8V, 2.5V, or 3.3V ICs. The MAX3805
comes in a very small 3mm x 3mm package and con­sumes only 135mW.

Applications

OC-192, 10GbE Switches and Routers

OC-192, 10GbE Serial Modules

High-Speed Signal Distribution

Features

♦ 3mm x 3mm Package

♦ Spans 30in (0.75m) of 6-mil FR-4

♦ Spans 24ft (8m) of Coax

♦ Automatic Receive Equalization to Reduce ISI

Caused by Path Losses

♦ Up to 10.7Gbps NRZ Data Operating Range

♦ Signal-Detect Output

♦ Output-Enable Control

♦ 135mW Power Consumption

♦ DC-Coupled Input and Output to Terminations as

Low as 1.65V

♦ Differential or Single-Ended Operation

♦ +3.3V Core Power Supply

MAX3805

10.7Gbps Adaptive Receive Equalizer

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-2936; Rev 0; 7/03

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 Circuit

Pin Configuration appears at end of data sheet.

PART TEMP RANGE

MAX3805ETE -40°C to +85°C 16 Thin QFN T1633F-3

PIN­PACKAGE

PACKAGE
CODE

LINE CARD SWITCH CARD

2.5V

+3.3V

10Gbps

CDR/SERDES

Tx

2

+3.3V

22

Rx

2.5V

SDO

V

CC2

MAX3805

SD EN

V

CC

FR-4 STRIPLINE

2

SDI

V

CC1

PC BOARD

BACKPLANE

V

CC1VCCVCC2

SDI

2

FR-4 STRIPLINE

MAX3805

SD EN

SDO

2

2

1.8V

10Gbps

SWITCH

Rx

2

Tx

1.8V

MAX3805

10.7Gbps Adaptive Receive Equalizer

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Pin 13 (HFPD) and pin 14 (LFPD) are not connected. Typical values are at VCC= +3.3V, V

CC1

= V

CC2

= 1.8V, TA= +25°C, unless

otherwise noted.) (Values at -40°C are guaranteed by design and characterization.)

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.

Supply Voltage (VCC) ............................................-0.5V to +4.0V

CML Supply Voltage

(V

CC1

, V

CC2

) ..........................................-0.5V to (VCC+ 0.5V)

Current at SDO±...............................................................±25mA

SDI±, EN, SD, HFPD, LFPD........................-0.5V to (V

CC

+ 0.5V)

Current at HFPD, LFPD ......................................................400µA

Continuous Power Dissipation (T

A

= +85°C)

16-Lead QFN-EP (derate 17.5mW/°C

above +85°C) ............................................................1398mW

Operating Ambient Temperature Range .............-40°C to +85°C

Storage Ambient Temperature Range...............-55°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

OPERATING CONDITIONS

Supply Voltage V

Input Termination Voltage V

Output Termination Voltage V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CC

CC1

CC2

3.0 3.3 3.6 V

1.65 V

1.65 V

CC

CC

Operating Ambient Temperature -40 +25 +85 °C

Supply Current I

CML Input Differential Voltage V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CC

VCC = V

AC-coupled or DC-coupled at transmission

IN

line input (Notes 1, 6)

CC1

= V

CC2

CML Input Common-Mode
Voltage

CML Input Resistance Differential 85 100 115 Ω

CML Input Return Loss 100MHz to 10GHz 10 dB

CML Output Differential Voltage V

OUT

V

= 1.65V to 3.6V 400 500 600 mV

CC2

CML Output Resistance Differential 85 100 115 Ω

CML Output Transition Time tr/t

20% to 80% (Notes 2, 6) 35 ps

f

CML Output Return Loss 100MHz to 5GHz 10 dB

Equalizer Time Constant 10 µs

Output Residual Jitter (Notes 3–6) 21 30 ps

Signal-Detect Assert PRBS2

Signal-Detect Deassert PRBS2

LVCMOS Input-High Leakage
Current

I

H

31

- 1 at 10.7Gbps (Note 1) 200 mV

31

- 1 at 10.7Gbps (Note 1) 220 mV

41 60 mA

400 1200 mV

1.3 V

CC1

+10 +60 µA

V

V

P-P

V

P-P

P-P

P-P

P-P

MAX3805

10.7Gbps Adaptive Receive Equalizer

_______________________________________________________________________________________ 3

Note 1: Differential input sensitivity is defined at the input to a transmission line with path length up to 30in.
Note 2: Measured using 10 ones and 10 zeros at 10.7Gbps.
Note 3: Residual jitter is the difference in total jitter between the signal at the input to the transmission line and the equalizer output.

Total residual jitter is DJ

P-P

+ 14.1 × RJ

RMS

.

Note 4: Measured at 10.7Gbps using a pattern of 100 ones, PRBS 2

10

- 1, 100 zeros, PRBS 2

10

- 1.

Note 5: V

IN

= 400mV

P-P

to 1200mV

P-P

, input path is 0 to 30in, 6-mil microstrip in FR-4, εr= 4.5, and tan δ = 0.02.

Note 6: Guaranteed by design and characterization.

ELECTRICAL CHARACTERISTICS (continued)

(Pin 13 (HFPD) and pin 14 (LFPD) are not connected. Typical values are at VCC= +3.3V, V

CC1

= V

CC2

= 1.8V, TA= +25°C, unless

otherwise noted.) (Values at -40°C are guaranteed by design and characterization.)

Typical Operating Characteristics

(VCC= 3.3V, V

CC1

= 1.8V, V

CC2

= 1.8V, and TA= +25°C, unless otherwise noted.)

EQUALIZER INPUT EYE AFTER 30in OF FR-4
(2

10

- 1PRBS WITH 100 CIDs AT 9.953Gbps)

MAX3805 toc01

20ps/div

65mV/div

EQUALIZER OUTPUT EYE AFTER 30in OF FR-4

(2

31

- 1PRBS AT 10.7Gbps)

MAX3805 toc03

20ps/div

65mV/div

LVCMOS Input-Low Leakage
Current

LVCMOS Input High V

LVCMOS Input Low V

LVCMOS Output High V

LVCMOS Output Low V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I

L

IH

IL

OH

IOH = 12.5µA 2.1 V

IOL = 0.5mA 0.2 V

OL

-30 +30 µA

1.5 V

0.5 V

EQUALIZER OUTPUT EYE AFTER 30in OF FR-4

10

- 1PRBS WITH 100 CIDs AT 9.953Gbps)

(2

MAX3805 toc02

65mV/div

20ps/div