General DescriptionGeneral DescriptionSFP28 Direct Attach Cables are compliant with SFF-8432 and SFF-8402 specifications. Various choices of wire gauge are available from 30 to 26 AWG with various choices of cable length (up to 5m). Features• Up to 25.78125 Gbps data rate

• Up to 5 meter transmission

• Hot-pluggable SFP 20PIN footprint

• Improved Pluggable Form Factor(IPF)

compliant for enhanced EMI/EMC

performance

• Compatible to SFP28 MSA

• Compatible to SFF-8402 and SFF-8432

• Temperature Range: 0~ 70 °C

• RoHS CompatibleBenefits• Cost-effective copper solution

• Lowest total system power solution

• Lowest total system EMI solution

• Optimized design for Signal Integrity

Applications

• 25G Ethernet

Product Description

• The SFP28 passive cable assemblies are high performance, cost effective I/O solutions for 25G Ethernet. SFP28 copper cables allow hardware manufactures to achieve high port density, configurability and utilization at a very low cost and reduced power budget High Speed CharacteristicsParameter

Symbol

Min

Typical

Max

Unit

Note

Differential Impedance

TDR

90

100

110

Ώ

Insertion loss

SDD21

-22.48

dB

At 12.8906 GHz

Differential Return Loss

SDD11

SDD22

See 1

dB

At 0.05 to 4.1 GHz

See 2

dB

At 4.1 to 19 GHz

Common-mode to common-mode output return loss

SCC11

SCC22

-2

dB

At 0.2 to 19 GHz

Differential to common-mode

return loss

SCD11

SCD22

See 3

dB

At 0.01 to 12.89 GHz

See 4

At 12.89 to 19 GHz

Differential to common Mode

Conversion Loss

SCD21-IL

-10

dB

At 0.01 to 12.89 GHz

See 5

At 12.89 to 15.7 GHz

-6.3

At 15.7 to 19 GHz

Notes:

1. Reflection Coefficient given by equation SDD11(dB) < -16.5 + 2 × SQRT(f ), with f in GHz

2. Reflection Coefficient given by equation SDD11(dB) < -10.66 + 14 × log10(f/5.5), with f in GHz

3. Reflection Coefficient given by equation SCD11(dB) < -22 + (20/25.78)*f, with f in GHz

4. Reflection Coefficient given by equation SCD11(dB) < -15 + (6/25.78)*f, with f in GHz

5. Reflection Coefficient given by equation SCD21(dB) < -27 + (29/22)*f, with f in GHz

Pin Descriptions

SFP28 Pin Function Definition

Pin

Logic

Symbol

Name/Description

Notes

1

VeeT

Transmitter Ground

2

LV-TTL-O

TX_Fault

N/A

1

3

LV-TTL-I

TX_DIS

Transmitter Disable

2

4

LV-TTL-I/O

SDA

Tow Wire Serial Data

5

LV-TTL-I

SCL

Tow Wire Serial Clock

6

MOD_DEF0

Module present, connect to VeeT

7

LV-TTL-I

RS0

N/A

1

8

LV-TTL-O

LOS

LOS of Signal

2

9

LV-TTL-I

RS1

N/A

1

10

VeeR

Reciever Ground

11

VeeR

Reciever Ground

12

CML-O

RD-

Reciever Data Inverted

13

CML-O

RD+

Reciever Data Non-Inverted

14

VeeR

Reciever Ground

15

VccR

Reciever Supply 3.3V

16

VccT

Transmitter Supply 3.3V

17

VeeT

Transmitter Ground

18

CML-I

TD+

Transmitter Data Non-Inverted

19

CML_I

TD-

Transmitter Data Inverted

20

VeeT

Transmitter Ground

1.

Signals not supported in SFP+ Copper pulled-downto VeeT with 30K ohms resistor

2.

Passive cable assemblies do not support

LOS and TX_DIS

Mechanical Specifications

The connector is compatible with the SFF-8432 specification.

Length (m)

Cable AWG

1

30

2

30

3

30/26

4

26

5

26

Regulatory Compliance Feature

Test Method

Performance

Electrostatic Discharge (ESD) to the Electrical Pins

MIL-STD-883C Method 3015.7

Class 1(>2000 Volts)

Electromagnetic Interference(EMI)

FCC Class B

Compliant with Standards

CENELEC EN55022 Class B

CISPR22 ITE Class B

RF Immunity(RFI)

IEC61000-4-3

Typically Show no Measurable Effect from a 10V/m Field Swept from 80 to 1000MHz

RoHS Compliance

RoHS Directive 2011/65/EU and it's Amendment Directives 6/6

RoHS 6/6 compliant

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