OverviewAll product unitsProduct unitPassive ComponentsProduct groupSignal & CommunicationsProduct familyFiltered ConnectorsProduct seriesWE-RJ45 LAN Transformer

WE-RJ45 LAN Transformer

WE-LAN RJ45 LAN Transformer. RJ45 Connector with integrated transformer / common mode choke. Available in SMT, THT and THT with USB. Compatible to Industrial Ethernet systems like EtherCAT or Profinet.

Characteristics

  • RJ45 Connector with integrated transformer / common mode choke
  • Power over Ethernet up to 50 Watt and speeds up to 10 Gbit/s
  • Available in SMT, THT and THT with USB
  • Compliant with standards: IEEE 802.3u, IEEE 802.3ab, IEEE 802.3af, IEEE 802.3at and upcoming IEE 802.3bt
  • Improved Common Mode Rejection (CMRR) due to additional NiZn cores

Reference Designs

  • RD022 GB PoE+-Ethernet-USB“ adapter for industrial use with an EMC perspective
  • RD016 Reference Design Gigabit Ethernet Front End
  • RD041 Design of a Single Pair Ethernet System with Power over Data Lines (SPoE)

Applications

  • Suitable for industrial temperatures from –40 °C up to +85 °C
  • Compatible to Industrial Ethernet systems like EtherCAT or Profinet
  • Compliant with most IC’s for Ethernet applications such as Microchip, Broadcom, Marvell
  • Hubs, Routers, Switches, IP cameras, IoT applications

Products

All
10/100BASE-T
1000BASE-T
Order Code Data­sheet Simu­lation Downloads StatusData ratePoEPortsTabImproved CMRROperating TemperatureLEDPHY Chip ModeMountShield TabsDesign Kit Samples
7499051002SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 2x1 Up/Down No -40 °C up to +85 °C current & voltage THT Yes
7499031120ASPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1x4 Down No -40 °C up to +85 °C yellow-green current & voltage THT Yes
74980111211SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow-green current & voltage SMT Yes749945
7498011001ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Down No 0 °C up to +70 °C current & voltage SMT Yes
7498011008SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Down No -40 °C up to +85 °C current & voltage SMT Yes
7499210001ASPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T PoE 1 Up No -40 °C up to +85 °C No LED current & voltage THT No
74990100011ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C No LED current & voltage THT No749945
74990101210SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C green-yellow current & voltage THT No749945
74990111217SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow-green current & voltage THT Yes
7499211125SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T PoE 1 Up No -40 °C up to +85 °C yellow-green current & voltage THT Yes
7499410221SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T PoE+ 1 Vertical No -40 °C up to +85 °C green-green current THT No
7498210002SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T PoE+ 1 Down No -40 °C up to +85 °C current & voltage SMT No
7498210003SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T PoE 1 Up No -40 °C up to +85 °C current & voltage SMT Yes
7498210220ASPEC
6 files PTN i| Production will be discontinued. Expected lifetime: <2 years. 10/100BASE-T PoE 1 Up No -40 °C up to +85 °C green-green current & voltage SMT No
7499021002ASPEC
5 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1x2 Down No -40 °C up to +85 °C current & voltage THT Yes
7497011611ASPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C green/orange-yellow current & voltage THT Yes
7499010003ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C current & voltage THT No
74990101241SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C green-yellow current & voltage THT No
7498011122ARSPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow-green current & voltage SMT Yes
7498010210ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Up No -40 °C up to +85 °C green-yellow current & voltage SMT Yes
74990214400SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1x2 Up No -40 °C up to +85 °C yellow-green current & voltage THT Yes
7499011448SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 10/100BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C yellow/green-yellow/green current & voltage THT Yes
7499021125SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x2 Down No -40 °C up to +85 °C yellow-green current & voltage THT Yes749945
7498011211SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1 Down Yes -40 °C up to +85 °C green-yellow current & voltage SMT Yes
74990111215ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down Yes 0 °C up to +70 °C yellow-green current & voltage THT Yes
7499210124ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Up No -40 °C up to +85 °C yellow-green current & voltage THT No
7499211121ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Down No -40 °C up to +85 °C yellow-green current & voltage THT Yes
7499211122ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Down No 0 °C up to +70 °C yellow-green current THT Yes749945
7499210121ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Down No -40 °C up to +85 °C yellow-green current & voltage THT No
7499211002ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Down No -40 °C up to +85 °C No LED current THT Yes
7499211123ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE 1x1 Down Yes 0 °C up to +70 °C yellow-green current THT Yes749945
7499411122ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE+ 1 Up Yes 0 °C up to +70 °C yellow-green current & voltage THT Yes
74990112116ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C green-yellow current & voltage THT Yes
7499010121ASPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C yellow-green current & voltage THT No
74990110030SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C current & voltage THT Yes
7499010001ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C current & voltage THT No
7499011222ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C green-green current & voltage THT Yes
7499011121ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C yellow-green current & voltage THT Yes749945
7499010211ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No 0 °C up to +70 °C green-yellow current & voltage THT No
7499011001ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C No LED current & voltage THT Yes
7499010441SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C green/yellow - green/yellow current & voltage THT No
7499210123ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE (up to 350 mA) 1x1 Vertical No -40 °C up to +85 °C green-yellow current & voltage THT No
7499410213SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX PoE+ 1x1 Down No -40 °C up to +85 °C green-yellow current THT No
7499011441ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C green/yellow - green/yellow current & voltage THT Yes
74990101212SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Up No -40 °C up to +85 °C yellow-green current & voltage THT No
74990111211SPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C yellow-green current & voltage THT Yes
7499010126ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Vertical No -40 °C up to +85 °C green-yellow current & voltage THT No
74990100040SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 100BASE-TX non-PoE 1x1 Down No -40 °C up to +85 °C No LED current & voltage THT No
7499151120SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 2x1 Up/Down No -40 °C up to +85 °C yellow-green current THT Yes
7497111611ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No 0 °C up to +70 °C green/orange-yellow current THT Yes
7497110616SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow/green-green current THT No749945
7499111614ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up Yes -40 °C up to +85 °C green/orange-yellow current & voltage THT Yes749945
7499511440SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T PoE+ 1 Up No -40 °C up to +85 °C green/yellow - green/yellow current & voltage THT Yes749945
7499511611ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T PoE+ 1 Up Yes 0 °C up to +70 °C green/orange-yellow current & voltage THT Yes749945
7499111221ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No 0 °C up to +70 °C green-green current & voltage THT Yes
7499111000ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No 0 °C up to +70 °C current & voltage THT Yes
7499110124SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Up No -40 °C up to +85 °C green-yellow/green current THT No
7499111446SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Down No -40 °C up to +85 °C green/yellow - green/yellow current THT Yes
7499111121ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Down No -40 °C up to +85 °C yellow-green current THT Yes
7499110122SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Down No 0 °C up to +70 °C yellow-green current THT No
7499110123SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C green-yellow current THT No749945
7499111447SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C green/yellow - green/yellow current THT Yes749945
7499111001ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Down No -40 °C up to +85 °C No LED current THT Yes
7499121211SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x2 Down No -40 °C up to +85 °C green-yellow current THT Yes
7498111001ASPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C No LED current SMT Yes
7499110120ASPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x1 Vertical No -40 °C up to +85 °C green-yellow current THT No
7499511002ASPEC
7 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T PoE+ 1 Up Yes -40 °C up to +85 °C No LED current & voltage THT Yes
7498111120ARSPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow-green current SMT Yes
7499311614SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T PoE 1 Up No -40 °C up to +85 °C green/orange-green current & voltage THT Yes
7499511420SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T 4PPoE 1 Up No -40 °C up to +85 °C green/yellow-green current & voltage THT Yes
7499111615SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C green/orange-yellow current & voltage THT Yes
74991104402SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C yellow/green-yellow/green current THT No
74991114410SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C yellow/green-yellow/green current THT Yes
74991114412SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow/green-yellow/green voltage THT Yes
74991104404SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Up No -40 °C up to +85 °C yellow/green-yellow/green voltage THT No
74991114411SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Down No -40 °C up to +85 °C yellow/green-yellow/green voltage THT Yes
74991104403SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T 1 Down No -40 °C up to +85 °C yellow/green-yellow/green voltage THT No
74981104402SPEC
6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1 Vertical No -40 °C up to +85 °C yellow/green-yellow/green voltage THT No
74991214400SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x2 Down No -40 °C up to +85 °C yellow/green-yellow/green voltage THT Yes
74991204400SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

6 files Active i| Production is active. Expected lifetime: >10 years. 1000BASE-T non-PoE 1x2 Down No -40 °C up to +85 °C yellow/green-yellow/green voltage THT No
Order Code Data­sheet Simu­lation
7499051002SPEC
7499031120ASPEC
74980111211SPEC
7498011001ASPEC
7498011008SPEC
7499210001ASPEC
74990100011ASPEC
74990101210SPEC
74990111217SPEC
7499211125SPEC
7499410221SPEC
7498210002SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

7498210003SPEC
7498210220ASPEC
7499021002ASPEC
7497011611ASPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

7499010003ASPEC
74990101241SPEC
7498011122ARSPEC
7498010210ASPEC
74990214400SPEC
7499011448SPEC
7499021125SPEC
7498011211SPEC
74990111215ASPEC
7499210124ASPEC
7499211121ASPEC
7499211122ASPEC
7499210121ASPEC
7499211002ASPEC
7499211123ASPEC
7499411122ASPEC
74990112116ASPEC
7499010121ASPEC
74990110030SPEC
7499010001ASPEC
7499011222ASPEC
7499011121ASPEC
7499010211ASPEC
7499011001ASPEC
7499010441SPEC
7499210123ASPEC
7499410213SPEC
7499011441ASPEC
74990101212SPEC
74990111211SPEC
7499010126ASPEC
74990100040SPEC
7499151120SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

7497111611ASPEC
7497110616SPEC
7499111614ASPEC
7499511440SPEC
7499511611ASPEC
7499111221ASPEC
7499111000ASPEC
7499110124SPEC
7499111446SPEC
7499111121ASPEC
7499110122SPEC
7499110123SPEC
7499111447SPEC
7499111001ASPEC
7499121211SPEC
7498111001ASPEC
7499110120ASPEC
7499511002ASPEC
7498111120ARSPEC
7499311614SPEC
7499511420SPEC
7499111615SPEC
74991104402SPEC
74991114410SPEC
74991114412SPEC
74991104404SPEC
74991114411SPEC
74991104403SPEC
74981104402SPEC
74991214400SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

74991204400SPEC

PCN pending

Due to a pending PCN, a modification of the component will be implemented soon. Please find the PCN below. If you have further questions please get in contact with our sales staff.

Samples
Order Code Data­sheet Simu­lation Downloads StatusData ratePoEPortsTabImproved CMRROperating TemperatureLEDPHY Chip ModeMountShield TabsDesign Kit Samples

WE-RJ45 LAN

The RJ45 connector with magnetics can be quickly and easily implemented in an ethernet interface, with the integrated transformer and filter design ensuring compliance to IEEE 802.3 and IEC 62368-1 (old: IEC 60950-1) standards. For valuable board space savings, the design is 50% more compact than a discrete magnetics solution.

The filter design consists of a transformer, at least one common mode choke per channel and Bob Smith termination. Components with additional common mode chokes are available for even better common mode rejection.

Still questions about the application?

Which socket is suitable for current/voltage controlled PHYs?

The data sheet of the PHY indicates whether it is current or voltage controlled, which is an important criterion for selecting the transformer jack.

For a voltage controlled PHY, the LAN transformer is wired directly to the terminals of the PHY chip. The current mode PHY has a VDDA pin for power supply, the voltage mode PHY has no VDDA pin. Therefore the current in current mode PHYs flows via the LAN transformer pins.

Looking for the right jack for your interface? With REDEXPERT, our precise simulation platform, you can find it quickly and easily.

What has to be considered with PoE (Power over Ethernet)?

In addition to data transmission, PoE also realizes the power supply via the Ethernet interface, which means that no additional power supply cable is required. According to the IEEE 802.3 standard, the energy supplier is called Power Source Equipment (PSE) and the consumer Powered Device (PD).

To avoid incorrect polarity (reverse polarity) on the part of the PD, a diode bridge is necessary. Würth Elektronik offers components that already contain this (left) or that have connections that enable an external connection (right).

REDEXPERT allows to filter the RJ45 LAN jacks with magnetics according to the application on the side of the PD or the PD and the PSE.

How to connect RJ45 to the PHY-Chip?

1 WE-RJ45 LAN Connector with Magnetics: This is a ready-made module in which the Ethernet jack, the transformer and the Bob Smith termination are integrated. This provides the safety-relevant galvanic isolation as well as impedance matching and protects against transient interference and common mode noise.

2 Shield connection: For plastic housings, the capacitors are used to connect the Ethernet jack shield and thus the cable shield to the board ground (GND). For metal housings, it is recommended not to assemble the capacitors, but to connect the GND directly to the housing via screw connection.

3 Controller: Two TVS diode arrays are used to limit the interface-side transient noise to the PHY against GND. An EEPROM is connected to the controller for the on-board software and the signal section is clocked with a 25 MHz crystal.

More information about the circuit design and layout can be found in our reference design Gigabit-Ethernet Front-End.

What does a standard Ethernet interface look like?

1. Bob Smith Termination: To reduce common mode current and susceptibility to interference from unused wire pairs on the RJ45 connector

2. Common Mode Chokes: Improve EMC by attenuating common-mode interference

3. Signal Transformer: Provides galvanic isolation between PHY chip and RJ45 jack, protects against transients, and matches the impedance to the internal logic and to balanced wire pairs

4. MLCC Capacitors: Contribute to common mode rejection by RF-connecting the center taps of the transformers to ground (GND)

5. TVS-Dioden-Array: Limits interface transients to the PHY against GND.

Part 1, 2, 3 and 4 are already integrated in the WE-RJ45 LAN connector with magnetics. More information on the Ethernet interface can be found in our Application Guide.

PoE Power classes according to IEEE 802.3
*) for powers above 30 W, there were/are several suppliers that came onto the market with different implementations and names (UPoE, 4PPoE, PoE++, ...). These are not compatible with each other. Only with 802.3bt is there a general standard again with Hi-PoE (High Power PoE).
*) for powers above 30 W, there were/are several suppliers that came onto the market with different implementations and names (UPoE, 4PPoE, PoE++, ...). These are not compatible with each other. Only with 802.3bt is there a general standard again with Hi-PoE (High Power PoE).

Assortments

Articles from this product series can be found in the following assortments:

Videos

Würth Elektronik Webinar: EMI issues and EMC Certification