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General Description

The MAX4888A/MAX4889A high-speed passive switches

route PCI Express

(PCIe) data between two possible

destinations. The MAX4888A is a quad single-pole/dou-

ble-throw (4 x SPDT) switch ideally suited for switching

two half lanes of PCIe data between two destinations. The

MAX4889A is an octal single-pole/double-throw (8 x

SPDT) switch ideal for switching four half lanes of PCIe

data between four destinations. The MAX4888A/

MAX4889A feature a single digital control input (SEL) to

switch signal paths.

The MAX4888A/MAX4889A are fully specified to oper-

ate from a single +3.0V to +3.6V power supply

††

. The

MAX4888A is available in a 3.5mm x 5.5mm, 28-pin

TQFN package. The MAX4889A is available in a 3.5mm

x 9.0mm, 42-pin TQFN package. Both devices operate

over the -40°C to +85°C temperature range.

Features

♦ Single +3.0V to +3.6V Power-Supply Voltage

♦ Low Same-Pair Skew of 7ps

♦ Low 120µA (Max) Quiescent Current

♦ Supports PCIe Gen I and Gen || Data Rates

♦ Flow-Through Pin Configuration for Ease of

Layout

♦ Industry-Compatible Pinout

♦ Lead-Free Packaging

Applications

Desktop Computers

Servers/Storage Area Networks

Laptops

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

________________________________________________________________

Maxim Integrated Products

MAX4888A

TOP VIEW

TQFN

V+

GND

*EP

V+

GND

V+

GND

V+

GND

12345678910

24 23 22 21 20 19 18 17 16 15

GND

N.C.

V+

COM2-

COM2+

COM1-

COM1+

N.C.

SEL

GND

NO2-

NO2+

NO1-

NO1+

V+

GND

NC2-

NC2+

NC1-

NC1+

MAX4889A

TQFN

V+

GND

V+

GND

V+

GND

V+

GND

1234567891011121314151617

38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22

COM3-

V+

GND

COM4+

COM4-

GND

COM3+

GND

SEL

V+

COM2-

COM2+

V+

GND

COM1-

COM1+

GND

NC4+

NC4-

NO3+

NO3-

NO4+

NO4-

NC3-

NC3+

V+

NO2-

NO2+

NO1-

NO1+

NC2-

NC2+

NC1-

NC1+

*CONNECT EXPOSED PADDLE TO GROUND.

*EP

Pin Configurations

19-0770; Rev 2; 5/09

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.

EVALUATION KIT

AVAILABLE

Typical Application Circuit appears at end of data sheet.

††

Contact factory if operating at +2.5V or +1.8V.

PCI Express is a registered trademark of PCI-SIG Corp.

PART TEMP RANGE PIN-PACKAGE CONFIGURATION

MAX4888AETI+ -40°C to +85°C 28 TQFN-EP* Two Half Lanes

MAX4889AETO+ -40°C to +85°C 42 TQFN-EP* Four Half Lanes

Ordering Information/Selector Guide

Denotes lead(Pb)-free/RoHS-compliant package.

EP = Exposed paddle.

Summary of content (14 pages)

PAGE 1
9-0770; Rev 2; 5/09 KIT ATION EVALU E L B AVAILA 5.0Gbps PCI Express Passive Switches Features The MAX4888A/MAX4889A high-speed passive switches route PCI Express® (PCIe) data between two possible destinations. The MAX4888A is a quad single-pole/double-throw (4 x SPDT) switch ideally suited for switching two half lanes of PCIe data between two destinations. The MAX4889A is an octal single-pole/double-throw (8 x SPDT) switch ideal for switching four half lanes of PCIe data between four destinations.
PAGE 2
MAX4888A/MAX4889A 5.0Gbps PCI Express Passive Switches ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND, unless otherwise noted.) V+ .............................................................................-0.3V to +4V SEL, COM__, NO__, NC__ (Note 1) .............-0.3V to (V+ + 0.3V) | COM__ - NO__ |, | COM__ - NC__ | (Note 1).................0 to +2V Continuous Current (COM_ to NO__/NC__) .....................±70mA Peak Current (COM__ to NO__/NC__) (pulsed at 1ms, 10% duty cycle)..............
PAGE 3
5.0Gbps PCI Express Passive Switches (V+ = +3.0V to +3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA = +25°C.) (Note 2) PARAMETER SYMBOL DYNAMIC Turn-On Time tON Turn-Off Time t OFF Propagation Delay t PD CONDITIONS TYP MAX UNITS VNO_ or VNC_ = +1.0V, RL = 50 , Figure 1 90 250 ns VNO_ or VNC_ = +1.
PAGE 4
Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) ON-RESISTANCE vs. VCOM_ (V+ = +1.8V) 8.0 12 7.5 7.0 6.5 14 8 TA = +85°C 12 6 10 TA = -40°C 4 TA = +25°C 8 6 4 V+ = +3.3V 2 2 5.5 5.0 0 0 -0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 VCOM_ (V) -0.1 ON-RESISTANCE vs. VCOM_ (V+ = +3.3V) 10 0.2 0.3 VCOM_ (V) 0.4 0.5 -0.1 0.6 8 6 4 70 60 V+ = +3.3V 40 V+ = +2.5V 20 10 TA = -40°C 0 0.5 0.7 VCOM_ (V) -15 1.1 1.0 VIH tON/tOFF (ns) 1.3 0.9 0.8 VIL 0.
PAGE 5
.0Gbps PCI Express Passive Switches VCOM_+ VCOM_- VCOM_- EYE DIAGRAM (V+ = +2.5V, f = 2.5GHz, 600mVP-P PRBS SIGNAL, RS = RL = 50Ω)†† MAX4888A/89A toc12 MAX4888A/89A toc11 EYE DIAGRAM (V+ = +1.8V, f = 2.5GHz, 600mVP-P PRBS SIGNAL, RS = RL = 50Ω)†† 50mV/div VCOM_+ 50mV/div VCOM_- *PRBS = PSEUDORANDOM BIT SEQUENCE † = GEN 1, 2.5Gbps; U1 = 400ps *PRBS = PSEUDORANDOM BIT SEQUENCE † = GEN 1, 2.5Gbps; U1 = 400ps *PRBS = PSEUDORANDOM BIT SEQUENCE † = GEN 1, 2.
PAGE 6
5.0Gbps PCI Express Passive Switches MAX4888A/MAX4889A Pin Description PIN MAX4888A MAX4889A 1, 10, 12, 14, 1, 4, 10, 14, 17, 20, 25, 27 19, 21, 39, 41 6 NAME GND 2 3, 9 4 5 6 7 9 — 2 3 6 7 SEL N.C. COM1+ COM1COM2+ COM2- 8, 11, 13, 19, 26, 28 5, 8, 13, 18, 20, 30, 40, 42 V+ FUNCTION Ground Digital Control Input No Connection. Not internally connected. Analog Switch 1. Common Positive Terminal. Analog Switch 1. Common Negative Terminal. Analog Switch 2. Common Positive Terminal. Analog Switch 2.
PAGE 7
5.0Gbps PCI Express Passive Switches MAX4888A/MAX4889A +3.3V V+ COM_ NO_ OR NC_ VN_ LOGIC INPUT 50% VIL VOUT RL t OFF CL SEL VOUT GND LOGIC INPUT t r < 5ns t f < 5ns VIH SWITCH OUTPUT 0.9 x V0UT 0.9 x VOUT 0V t ON CL INCLUDES FIXTURE AND STRAY CAPACITANCE. RL VOUT = VN_ RL + RON ( ) VN_ = VNO_ OR VNC_ Figure 1.
PAGE 8
5.0Gbps PCI Express Passive Switches MAX4888A/MAX4889A Test Circuits/Timing Diagrams (continued) +3.3V V+ RS IN+ MAX4888A/MAX4889A NO_+ OR NC_+ COM_+ OUT+ RISE-TIME PROPAGATION DELAY = tPLHX OR tPLHY FALL-TIME PROPAGATION DELAY = tPHLX OR tPHLY RL RS IN- NO_- OR NC_- COM_- tSK1 = DIFFERENCE IN PROPAGATION DELAY (RISE-FALL) BETWEEN ANY TWO PAIRS tSK2 = | tPLHX - tPHLY | OR | tPHLX - tPLHY | BETWEEN TWO LINES ON THE SAME PAIR OUTRL SEL tINFALL tINRISE +1.
PAGE 9
5.0Gbps PCI Express Passive Switches +3.3V 0.1μF OFF-ISOLATION = 20log NETWORK ANALYZER 0V OR V+ V+ SEL NC_ 50Ω VIN COM_ V ON-LOSS = 20log OUT VIN 50Ω MAX4888A/MAX4889A VOUT NO_ 50Ω MEAS REF 50Ω VOUT VIN V CROSSTALK = 20log OUT VIN 50Ω GND MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS. OFF-ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINAL ON EACH SWITCH. ON-LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_ TERMINAL ON EACH SWITCH.
PAGE 10
5.
PAGE 11
5.0Gbps PCI Express Passive Switches PCIe Switching The MAX4888A/MAX4889A primary applications are aimed at reallocating PCIe lanes (see Figure 5). For example, in graphics applications, several manufacturers have found that it is possible to improve performance by a factor of nearly two by splitting a single 16-lane PCIe bus into two 8-lane buses. Two of the more prominent examples are SLI™ (Scaled Link Interface) and CrossFire™.
PAGE 12
5.
PAGE 13
5.0Gbps PCI Express Passive Switches PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 28 TQFN-EP T283555-1 21-0184 42 TQFN-EP T423590M-1 21-0181 ______________________________________________________________________________________ 13 MAX4888A/MAX4889A Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
PAGE 14
MAX4888A/MAX4889A 5.0Gbps PCI Express Passive Switches Revision History REVISION NUMBER REVISION DATE 0 4/07 Initial release 2 5/09 Updated voltage range, style edits. DESCRIPTION PAGES CHANGED — 1, 2, 3, 5–9, 13, 14 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.