Datasheet

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General Description

The MAX3840 is a dual 2

2 asynchronous crosspoint

switch for SDH/SONET DWDM and other high-speed

data switching applications where serial data stream

loop-through and protection channel switching are

required. It is ideal for OC-48 systems with forward

error correction. A high-bandwidth, fully differential sig-

nal path minimizes jitter accumulation, crosstalk, and

signal skew. Each 2

2 crosspoint switch can fan out

and/or multiplex up to 2.7Gbps data and 2.7GHz clock

signals. All inputs and outputs are current mode logic

(CML) compatible and easily adaptable to interface

with an AC-coupled LVPECL signal. When not used,

each CML output stage can be powered down with an

enable control to conserve power. The typical power

consumption is 460mW with all outputs enabled.

The MAX3840 is compatible with the MAX3876

2.5Gbps clock and data recovery (CDR) circuit.

The MAX3840 is available in a 32-pin exposed-pad

QFN package (5mm

5mm footprint) and operates

from a +3.3V supply over a temperature range of -40°C

to +85°C.

________________________Applications

SDH/SONET and DWDM Transport Systems

Add-Drop Multiplexers

ATM Switch Cores

WDM Cross-Connects

High-Speed Backplanes

Features

♦ Single +3.3V Supply

♦ 460mW Power Consumption

♦ 2ps

RMS

Random Jitter

♦ 7ps

P-P

Deterministic Jitter

♦ Power-Down Feature for Deselected Outputs

♦ CML Inputs/Outputs

♦ 6ps Channel-to-Channel Skew

♦ 100ps Output Edge Speed

♦ 5mm

5mm 32 QFN or Thin QFN Package

MAX3840

+3.3V, 2.7Gbps Dual 2

2 Crosspoint Switch

________________________________________________________________ Maxim Integrated Products 1

MAX3866

TIA AND LA

MAX3876

CDR

MAX3840

CROSSPOINT

SWITCH

= 50Ω TRANSMISSION LINE

DATA

CLOCK

MAX3866

TIA AND LA

MAX3876

CDR

DATA

CLOCK

MAX3869

LASER

DRIVER

LASER

DRIVER

VCC = +3.3V

Typical Application Circuit

19-1854; Rev 5; 9/07

Ordering Information

PART

TEMP RANGE

PIN -

PA C K A G E

PK G

C O D E

MAX3840ETJ+

-40°C to +85°C

32 TQFN T3255-3

MAX3840EGJ

-40°C to +85°C

32 QFN G3255-1

Pin Configurations appear at end of data sheet.

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.

+Denotes a lead-free package.

Summary of content (8 pages)

PAGE 1
9-1854; Rev 5; 9/07 +3.3V, 2.7Gbps Dual 2 ✕ 2 Crosspoint Switch The MAX3840 is a dual 2 ✕ 2 asynchronous crosspoint switch for SDH/SONET DWDM and other high-speed data switching applications where serial data stream loop-through and protection channel switching are required. It is ideal for OC-48 systems with forward error correction. A high-bandwidth, fully differential signal path minimizes jitter accumulation, crosstalk, and signal skew.
PAGE 2
MAX3840 +3.3V, 2.7Gbps Dual 2 ✕ 2 Crosspoint Switch ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .............................................-0.5V to +5.0V Input Voltage (CML) .........................(VCC - 1.0) to (VCC + 0.5V) TTL Control Input Voltage...........................-0.5V to (VCC + 0.5V) Output Currents (CML) .......................................................22mA Continuous Power Dissipation (TA = +85°C) 32-Pin TQFN (derate 21.3mW/°C above +85°C) .................................1.
PAGE 3
+3.3V, 2.7Gbps Dual 2 ✕ 2 Crosspoint Switch (VCC = +3.0V to +3.6V, TA = -40°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS CML Input and Output Data Rate 2.7 Gbps CML Input and Output Clock Rate 2.
PAGE 4
✕ 2 Crosspoint Switch Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs.
PAGE 5
+3.3V, 2.7Gbps Dual 2 ✕ 2 Crosspoint Switch PIN NAME FUNCTION 1 ENB1 Channel B1 Output Enable, TTL Input. A TTL low input powers down B1 output stage. 2 DIB1+ Channel B1 Positive Signal Input, CML 3 DIB1- Channel B1 Negative Signal Input, CML 4 ENB0 Channel B0 Output Enable, TTL Input. A TTL low input powers down B0 output stage. 5 SELB0 Channel B0 Output Select, TTL Input. See Table 1.
PAGE 6
MAX3840 +3.3V, 2.7Gbps Dual 2 ✕ 2 Crosspoint Switch Table 1.
PAGE 7
+3.3V, 2.7Gbps Dual 2 Interfacing PECL Inputs and Outputs to the MAX3840 For information on interfacing with CML, refer to Maxim Application Note HFAN-01.0, Introduction to LVDS, PECL, and CML. 2 Crosspoint Switch Layout Techniques For best performance, use good high-frequency layout techniques, filter VCC supplies, and keep ground connections short. Use multiple vias where possible. Also, use controlled-impedance transmission lines to interface with the MAX3840 data inputs and outputs.
PAGE 8
✕ 2 Crosspoint Switch VCC SELA1 25 DOA1- DIA0+ 26 DOA1+ DIA0- 27 VCC SELA0 28 DOA0- ENA0 29 DOA0+ DIA1+ 30 VCC DIA1- 31 TOP VIEW GND ENA1 TOP VIEW 32 Pin Configurations 24 23 22 21 20 19 18 17 ENB1 1 24 GND SELA1 25 16 VCC DIB1+ 2 23 VCC DIA0+ 26 15 DOB1+ DIB1- 3 22 DOA0+ DIA0- 27 14 DOB1- ENB0 4 21 DOA0- SELA0 28 13 VCC SELB0 5 20 VCC ENA0 29 12 DOB0+ DIB0+ 6 19 DOA1+ DIA1+ 30 11 DOB0- DIB0- 7 18 DOA1- DIA1- 31 10 V