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MAX4891ETJ-T中文资料

General Description

The MAX4890/MAX4891/MAX4892 high-speed analog switches meet the needs of 10/100/1000 Base-T appli-cations. These devices switch the signals from two interface transformers and connect the signals to a sin-gle 10/100/1000 Base-T Ethernet PHY, simplifying docking station design and reducing manufacturing costs. The MAX4890/MAX4891/MAX4892 can also route signals from a common interface transformer to two different boards in board-redundancy applications.The MAX4890/MAX4891/MAX4892 switches provide an extremely low capacitance and on-resistance to meet Ethernet insertion and return-loss specifications. The MAX4891/MAX4892 feature one and three built-in LED switches, respectively.

The MAX4890/MAX4891/MAX4892 are available in space-saving 32- and 36-lead TQFN packages, significantly reducing the required PC board area.These devices operate over the -40°C to +85°C tem-perature range.

Applications

Notebooks and Docking Stations

Servers and Routers with Ethernet Interfaces Board-Level Redundancy Protection SONET/SDH Signal Routing T3/E3 Redundancy Protection Video Switching

Features

?Single +3.0V to +3.6V Power-Supply Voltage ?Low On-Resistance (R ON ): 4?(typ), 6.5?(max)?Ultra-Low On-Capacitance (C ON ): 6.5pF (typ)?Low < 200ps Bit-to-Bit Skew ?-3dB Bandwidth: 1GHz

?Optimized Pin-Out for Easy Transformer and PHY Interface

?Built-In LED Switches for Switching Indicators to Docking Station

?Low 450μA (max) Quiescent Current

?Bidirectional 8 to 16 Multiplexer/Demultiplexer ?Space-Saving Packages

32-Pin, 5mm x 5mm, TQFN Package 36-Pin, 6mm x 6mm, TQFN Package

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

________________________________________________________________Maxim Integrated Products

Pin Configurations

Ordering Information

19-3577; Rev 1; 8/05

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/279629763.html,.

All devices are available in the -40°C to +85°C operation tem-perature range.

Typical Operating Circuit appears at end of data sheet.

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch

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.

V+……………………………………………………… -0.3V to +4V SEL (Note 1)………………………………….. -0.3V to (V+ +0.3V)A_, _B_, LED_, _LED_ .……………………… -0.3V to (V+ +0.3V)Continuous Current (A_ to _B_)......................................±120mA Continuous Current (LED_ to _LED_).…………………… ±30mA Peak Current (A_ to _B_)

(pulsed at 1ms, 10% duty cycle) ……………………. ±240mA

Continuous Power Dissipation (T A = +70°C)

32-Pin TQFN (derate 34.5mW/°C above +70°C) …….. 2.76W 36-Pin TQFN (derate 26.3mW/°C above +70°C) …….. 2.11W Operating Temperature Range …………………. -40°C to +85°C Junction Temperature.……………………………………. +150°C Storage Temperature Range .…………………. -65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C

ELECTRICAL CHARACTERISTICS

(V+ = +3V to +3.6V, T A = T MIN to T MAX , unless otherwise noted. Typical values are at V+ = 3.3V, T A = +25°C.) (Note 2)

Note 1:Signals on SEL, exceeding V+ or GND, are clamped by internal diodes. Limit forward-diode current to maximum current

rating.

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

_______________________________________________________________________________________3

ELECTRICAL CHARACTERISTICS (continued)

(V+ = +3V to +3.6V, T A = T MIN to T MAX , unless otherwise noted. Typical values are at V+ = 3.3V, T A = +25°C.) (Note 2)

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 4_______________________________________________________________________________________

Typical Operating Characteristics

(V+ = 3.3V, T A = +25°C, unless otherwise noted.)

3.0

3.23.63.43.8

4.0ON-RESISTANCE vs. V A_

V A_ (V)

R O N (?)

1.80.9

2.7

3.6

013

ON-RESISTANCE vs. V A_

V A_ (V)

R O N (?)

1.1

2.2

3.3

81012

161820

0.9

1.8

2.7

3.6

LED_ ON-RESISTANCE vs. V A_

V A_ (V)

R O N L E D (?)

064281012141618200

1.1

2.2

3.3LED_ ON-RESISTANCE vs. TEMPERATURE

V A_ (V)

R O N L E D (?)

40020010008006001600140012001800-4010-1535

6085LEAKAGE CURRENT vs. TEMPERATURE

TEMPERATURE (°C)

L E A K A G E C U R R E N T (p A )0

1005201525300 1.1

2.2

3.3

CHARGE INJECTION vs. V A_

M A X 4890 t o c 06

V A_ (V)

C H A R G E I N J E C T I O N (p C )

150

210190170230250270290310330350-40

-15

QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

M A X 4890 t o c 07

TEMPERATURE (°C)

Q U I E S C E N T S U P P L Y C U R R E N T (μA )

400200800600100012000

1.1

2.2

3.3

QUIESCENT SUPPLY CURRENT

vs. LOGIC LEVEL

M A X 4890 t o c 08

LOGIC LEVEL (V)

Q U I E S C E N T S U P P L Y C U R R E N T (μA )0

0.40.2

1.00.80.61.61.41.2

1.8

3.0

3.2

3.1

3.3

3.4

3.5

3.6

LOGIC THRESHOLD vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

L O G I C T H R E S H O L D (V )

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

_______________________________________________________________________________________5

25TURN-ON/-OFF TIME vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

t O N /t O F F (n s )

3.0

3.2

3.4

3.6

52015

2530-40

-15

TURN-ON/-OFF TIME vs. TEMPERATURE

TEMPERATURE (°C)

t O N /t O F F (n s )

100

150

200

250

3.0 3.3

3.6

RISE-/FALL-TIME PROPAGATION DELAY

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

O U T P U T R I S E /F A L L -T I M E D E L A Y (p s )

250200

150

100

50-40

-15

RISE-/FALL-TIME PROPAGATION DELAY

vs. TEMPERATURE

TEMPERATURE (°C)

O U T P U T R I S E -/F A L L -T I M E D E L A Y (p s

)

020

80100

PULSE SKEW vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

P U L S E S K E W (p s )

3.0

3.3

3.6

020

80100

-40

-15

PULSE SKEW vs. TEMPERATURE

TEMPERATURE (°C)

P U L S E S K E W (p

s )

-20

-10

203.0

3.3

3.6

OUTPUT SKEW vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

O U T P U T S K E W (p s )

100

-10

-20

-40

-15

OUTPUT SKEW vs. TEMPERATURE

TEMPERATURE (°C)

O U T P U T S K E W (p s )

DIFFERENTIAL INSERTION LOSS

vs. FREQUENCY

M A X 4890 t o c 18

FREQUENCY (MHz)

D I F F

E R E N T I A L I N S E R T I O N L O S S (d B )

-4-3-2-101-5

1100

Typical Operating Characteristics (continued)

(V+ = 3.3V, T A = +25°C, unless otherwise noted.)

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 6_______________________________________________________________________________________

DIFFERENTIAL RETURN LOSS

vs. FREQUENCY

M A X 4890 t o c 19

FREQUENCY (MHz)

D I F F

E R E N T I A L R E T U R N L O S S (d B )

-30

-20

-10

0-40

100

DIFFERENTIAL CROSSTALK

vs. FREQUENCY

FREQUENCY (MHz)

D I F F

E R E N T I A L C R O S S T A L K (d B )

-90

-80-70-60-50-40-30-20-100-100

100

SINGLE-ENDED OFF-ISOLATION

vs. FREQUENCY

FREQUENCY (MHz)

S I N G L E -E N D E D O F F -I S O L A T I O N (d B )

-90-80-70-60-50-40-30-20-100-100

1100

SINGLE-ENDED CROSSTALK

vs. FREQUENCY

FREQUENCY (MHz)

S I N G L E -E N D E D C R O S S T A L K (d B )

-90-80-70-60-50-40-30-20-100-100

100

SINGLE-ENDED INSERTION LOSS

vs. FREQUENCY

M A X 4890 t o c 23

FREQUENCY (MHz)

S I N G L E -E N D E D I N S E R T I O N L O S S (d B )

100

-4

-3

-2

-1

-5

1000

Typical Operating Characteristics (continued)

(V+ = 3.3V, T A = +25°C, unless otherwise noted.)

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

_______________________________________________________________________________________7

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 8_______________________________________________________________________________________

Test Circuits

Figure 1. Differential Insertion Loss

Figure 2. Differential Return Loss

Detailed Description

The MAX4890/MAX4891/MAX4892 are high-speed ana-log switches targeted for 10/100/1000 Base-T applica-tions. In a typical application, the MAX4890/MAX4891/MAX4892 switch the signals from two separate inter-face transformers and connect the signals to a single 10/100/1000 Base-T Ethernet PHY (see the Typical Operating Circuit ). This configuration simplifies docking station design by avoiding signal reflections associated with unterminated transmission lines in a T configura-tion. The MAX4891 and MAX4892 also include LED switches that allow the LED output signals to be routed to a docking station along with the Ethernet signals.See the Functional Diagrams.

The MAX4890/MAX4891/MAX4892 switches provide an extremely low capacitance and on-resistance to meet Ethernet insertion and return-loss specifica-tions. The MAX4891/MAX4892 feature one and three built-in LED switches, respectively.

The MAX4890/MAX4891/MAX4892 incorporate a unique architecture design utilizing only n-channel switches

within the main Ethernet switch, reducing I/O capaci-tance and channel resistance. An internal two-stage charge pump with a nominal output of 7.5V provides the high voltage needed to drive the gates of the n-channel switches, while maintaining a consistently low R ON throughout the input signal range. An internal bandgap reference set to 1.23V and an internal oscillator running at 2.5MHz provide proper charge-pump operation.Unlike other charge-pump circuits, the MAX4890/MAX4891/MAX4892 include internal flyback capacitors,reducing design time, board space, and cost.

Digital Control Inputs

The MAX4890/MAX4891/MAX4892 provide a single digital control SEL. SEL controls the switches as well as the LED switches as shown in Table 1.

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

Figure 3. Single-Ended Bandwidth, Crosstalk and Off-Isolation

M A X 4890/M A X 4891/M A X 4892

Analog Signal Levels

The on-resistance of the MAX4890/MAX4891/MAX4892is very low and stable as the analog input signals are swept from ground to V+ (see the Typical Operating Characteristics ). The switches are bidirectional, allow-ing A_ and _B_ to be configured as either inputs or out-puts.

ESD Protection

The MAX4890/MAX4891/MAX4892 are characterized using the Human Body Model for ±2kV of ESD protec-tion. Figure 8 shows the Human Body Model, and Figure 9 shows the current waveform the Human Body Model generates when discharged into a low-impedance load.This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device through a 1.5k ?resistor.

Applications Information

Typical Operating Circuit

The Typical Operating Circuit depicts the MAX4890/MAX4891/MAX4892 in a 10/100/1000 Base-T docking station application.

Line-Card Redundancy (Ethernet T3/E3)

Figure 10 shows the MAX4890/MAX4891/MAX4892 in a line-card redundancy configuration.

Power-Supply Sequencing and

Overvoltage Protection

Caution:Do not exceed the absolute maximum ratings.Stresses beyond the listed ratings may cause perma-nent damage to the device.

Proper power-supply sequencing is recommended for all CMOS devices. Always apply V+ before applying analog signals, especially if the analog signal is not current limited.

Layout

High-speed switches require proper layout and design procedures for optimum performance. Keep design-controlled-impedance printed circuit board traces as short as possible. Ensure that bypass capacitors are as close to the device as possible. Use large ground planes where possible.

10/100/1000 Base-T Ethernet LAN Switch 10______________________________________________________________________________________

Figure 4. Differential Crosstalk

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

______________________________________________________________________________________11

Figure 5. ENABLE and DISABLE Times Figure 6. Propagation Delay Times

Figure 7. Output Skew

Figure 8. Human Body ESD Test Model

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 12______________________________________________________________________________________

Figure 9. Human Body Model Current Waveform Figure 10. Typical Application for Line-Card Redundancy

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

______________________________________________________________________________________13

Typical Operating Circuit

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 14______________________________________________________________________________________

Functional Diagrams

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

______________________________________________________________________________________15

Functional Diagrams (continued)

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch 16______________________________________________________________________________________

Chip Information

TRANSISTOR COUNT: 948PROCESS:BiCMOS

Pin Configurations (continued)

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/279629763.html,/packages .)

M A X 4890/M A X 4891/M A X 4892

10/100/1000 Base-T Ethernet LAN Switch

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

18____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600?2005 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products, Inc.

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/279629763.html,/packages .)