MAXIM MAX3841 User Manual

General Description

The MAX3841 is a low-power, 12.5Gbps 2 × 2 cross­point switch IC for high-speed serial data loopback,
redundancy, and switching applications. The MAX3841
current-mode logic (CML) inputs and outputs have iso­lated VCCconnections to enable DC-coupled interfaces
to 1.8V, 2.5V, or 3.3V CML ICs. Fully differential signal
paths and Maxim’s second-generation SiGe technology
provide optimum signal integrity, minimizing jitter,
crosstalk, and signal skew. The MAX3841 is ideal for
serial OC-192 and 10GbE optical module, line card,
switch fabric, and similar applications.

The MAX3841 has 150mV

P-P

minimum differential input

sensitivity, and 500mV

P-P

nominal differential output
swing. Unused outputs can be powered down individu­ally to conserve power. In addition to functioning as a 2
× 2 switch, the MAX3841 can be configured as a 2:1
multiplexer, 1:2 buffer, or dual 1:1 buffer. The MAX3841
is available in a 4mm × 4mm 24-pin thin QFN package,
and consumes only 215mW with both outputs enabled.

Applications

OC-192, 10GbE Switch/Line Cards

OC-192, 10GbE Optical Modules

System Redundancy/Self Test

Clock Fanout

Features

♦ Up to 12.5Gbps Operation

♦ Less Than 10ps

P-P

Deterministic Jitter

♦ Less Than 0.7ps

RMS

Random Jitter

♦ 1.8V, 2.5V, and 3.3V DC-Coupled CML I/O

♦ Independent Output Power-Down

♦ 4mm × 4mm Thin QFN Package

♦ -40°C to +85°C Operation

♦ +3.3V Core Supply

♦ 215mW Power Consumption (Excluding

Termination Currents)

MAX3841

12.5Gbps CML 2 ×2 Crosspoint Switch

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

MAX3841

10Gbps

SERIAL
OPTICAL
MODULE

SDI+

SDI-

SDO+

SDO-

OUT1+

OUT1-

IN1+

IN1-

SEL1 SEL2 ENO1 ENO2

LOOPBACK

3.3V

V

CCVCC1OUT

VCC1IN

2.5V

2.5V

2.5V

IN2+

IN2-

OUT2+

OUT2-

SDO+

SDO-

SDI+

SDI-

VCC2IN

VCC2OUT

1.8V

1.8V

GND

10Gbps

CDR/SERDES

ASIC

3.3V

1.8V

Typical Application Circuit

19-2905; Rev 1; 3/09

EVALUATION KIT

AVAILABLE

Pin Configuration appears at end of data sheet.

+

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

*

EP = Exposed pad.

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 PIN-PACKAGE

MAX3841ETG -40°C to +85°C 24 Thin QFN-EP*

MAX3841ETG+ -40°C to +85°C 24 Thin QFN-EP*

MAX3841

12.5Gbps CML 2 ×2 Crosspoint Switch

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.0V to +3.6V, VCC_IN = +1.71V to VCC, VCC_OUT = +1.71V to VCC, TA= -40°C to +85°C. Typical values are at VCC=
+3.3V, VCC_IN = VCC_OUT = 1.8V, T

A

= +25°C, unless otherwise noted.)

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.

Note 1: Guaranteed by design and characterization.
Note 2: Differential swing is defined as V

IN

= (IN_+) - (IN_-) and V

OUT

= (OUT_+) - (OUT_-). See Figure 1.

Note 3: Measured using a 0000011111 pattern at 12.5Gbps, and V

IN

= 400mV

P-P

differential.

Note 4: Measured at 9.953Gbps using a pattern of 100 ones, 2

7

- 1 PRBS, 100 zeros, 27 - 1 PRBS, and at 12.5Gbps using a ±K28.5

pattern. VCC_IN = VCC_OUT = 1.8V, and V

IN

= 400mV

P-P

differential.

Note 5: Refer to Application Note 1181:

HFAN-04.5.1: Measuring Random Jitter on a Digital Sampling Oscilloscope

.

Supply Voltage, V

CC

..............................................-0.5V to +4.0V

CML Supply Voltage (VCC_IN, VCC_OUT)...........-0.5V to +4.0V

Continuous Output Current (OUT1±, OUT2±)...................±25mA

CML Input Voltage (IN1±, IN2±)...........-0.5V to (VCC_IN + 0.5V)

LVCMOS Input Voltage (SEL1, SEL2,

ENO1, ENO2) .........................................-0.5V to (V

CC

+ 0.5V)

Continuous Power Dissipation (T

A

= +85°C)
24-Pin Thin QFN (derate 20.8mW/°C

above +85°C).............................................................1352mW

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

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

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

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Core Supply Current ICC Excluding CML termination currents 65 90 mA

Data Rate (Note 1) 0 12.5 Gbps

CML Input Differential VIN AC-coupled or DC-coupled (Note 2) 150 1200 mV

CML Input Common Mode DC-coupled VCC_IN - 0.3 VCC_IN V

CML Input Termination Single ended 42.5 50 57.5 

CML Input Return Los s Up to 10GHz 12 dB

CML Output Differential V

CML Output Terminat ion Single ended 42.5 50 57.5 

CML Output Tran sition Time tR, tF 20% to 80% (Notes 1, 3) 30 ps

Determin istic Jitter (Notes 1, 4) 10 ps

Random Jitter VIN = 150mV

Propagation Delay Any input to output (Note 1) 100 140 ps

Channel-to-Channel Skew (Note 1) 12 ps

Output Duty-Cycle Skew 50% input duty c yc le (Notes 1, 3) 8 ps

LVCMOS Input Current IIH, IIL -10 +10 μA

LVCMOS Input High Voltage VIH 1.7 V

LVCMOS Input Low Voltage VIL 0.7 V

(Note 2) 400 500 600 mV

OUT

(Notes 1, 5) 0.3 0.7 ps

P-P

P-P

P-P

P-P

RMS

MAX3841

12.5Gbps CML 2 ×2 Crosspoint Switch

_______________________________________________________________________________________

3

Typical Operating Characteristics

(VCC= 3.3V, VCC_IN, VCC_OUT = 1.8V, VIN= 500mV

P-P

, TA= +25°C, unless otherwise noted.)

CORE SUPPLY CURRENT vs. TEMPERATURE

(EXCLUDES CML I/O CURRENTS)

140

130

120

110

100

90

80

70

SUPPLY CURRENT (mA)

60

50

40

-40 85

0 OUTPUTS ENABLE

1 OUTPUT ENABLE

2 OUTPUTS ENABLE

TEMPERATURE (°C)

OUTPUT EYE DIAGRAM

(10.7Gbps, 2

23

- 1 PRBS)

603510-15

MAX3841 toc04

140

130

MAX3841 toc01

120

110

100

90

80

70

SUPPLY CURRENT (mA)

60

50

40

SUPPLY CURRENT vs. TEMPERATURE

(CORE PLUS CML I/O CURRENTS)

2 OUTPUTS ENABLE

1 OUTPUT ENABLE

0 OUTPUTS ENABLE

CML INPUTS AND OUTPUTS AC-COUPLED

-40 85
TEMPERATURE (°C)

OUTPUT EYE DIAGRAM

(6.25Gbps, 2

23

- 1 PRBS)

603510-15

MAX3841 toc05

MAX3841 toc02

60mV/div

OUTPUT EYE DIAGRAM

(12.5Gbps, 2

OUTPUT EYE DIAGRAM

(622Mbps, 2

23

14ps/div

23

- 1 PRBS)

- 1 PRBS)

MAX3841 toc03

MAX3841 toc06

60mV/div

16ps/div

DETERMINISTIC JITTER

vs. TEMPERATURE

16

14

12

10

8

6

DETERMINISTIC JITTER (ps)

4

2

±K28.5 AT 12.5Gbps

0

-40 85

27 - 1 PRBS + 100CIDs

TEMPERATURE (°C)

AT 10.7Gbps

6035-15 10

60mV/div

550

540

)

MAX3841 toc07

530

P-P

520

510

500

490

480

DIFFERENTIAL OUTPUT (mV

470

460

450

-40 85

28ps/div

DIFFERENTIAL OUTPUT SWING

vs. TEMPERATURE

603510-15

TEMPERATURE (°C)

60mV/div

MAX3841 toc08

IN1

OUT1

270ps/div

PROPAGATION DELAY

100ps/div

MAX3841 toc09