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KSZ9131RNXC-TR: A Gigabyte Ethernet Transceiver with Support for RGMII

The support for RGMII and Gigabyte Ethernet transceiver are two remarkable features we think makes KSZ9131RNXC unique. Now, in this article, we will explain the functions of these concepts and how they come together to offer an improved functionality for the target applications.

Gigabyte Transceiver Function

KSZ9131RNXC’s core function is to be a gigabyte transceiver – a medium of establishing communication across different devices across a lengthy distance.

The communication-related connections are further enhanced with the support for the RGMII. We will get to this shortly in this article.

Real-Time Data Transmission

Data transfer speed is optimum, thanks to the real-time speed used here. KSZ9131RNXC is a triple-speed Gigabyte Ethernet transceiver, featuring the trio of:

  • 10BASE-T
  • 100BASE-TX
  • 1000BASE-TX

By leveraging this data transfer interface, KSZ9131RNXC potentially speeds things up, via the multi-standard support. The supported standards include CAT-5, CAT-6 and CAT-5e.

These standards also support the transmission and reception of data, including the additional support for the Unshielded Twisted Pair (UTP) cables.

KSZ9131RNXC Offers Several Diagnostic Features


Detecting and fixing some of the common problems associated with transceiver usage are also enabled on KSZ9131RNXC. It supports a wide range of diagnostic features, such as:

1. Data Path Verification

KSZ9131RNXC prevents inordinate transmission of data to paths where they aren’t needed. That is the idea behind the provision of the following to verify the digital and the analog data paths:

  • Local loopback
  • Remote function
  • Externa function

2. Fault Detection

KSZ9131RNXC detects faults, facilitates the debugging process and helps in fast-tracking product deployment via the fault detection capability.

It uses the Parametric NAND Tree Support to detect faults between the KSZ9131RNXC and the circuit board.

On the other hand, there is the LinkMD TDR-based cable diagnostic for identifying the faults with copper cabling in the transceiver.

The RGMII Connection

KSZ9131RNXC’s provision or support for the RGMII is to enable the seamless connection to the RGMII MACs in the Gigabyte Ethernet processors. The connection is also extended to the switches that enable fast data transfer up to 1000 Megabytes per second.

However, there is more to the use of an RGMII, especially in a Gigabyte Ethernet transceiver. According to Wikipedia, Reduced Gigabit Media-Independent Interface (RGMII) is a type of Media-Independent Interface (MII).

RGMII offers an additional reduction in the number of pins usable with the Gigabit Media-Independent Interface (GMII).

The reduction can put the RGMII’s pin count at 14, as opposed to the 27 used with the GMII. Also, the pin reduction is facilitated via the removal of the non-required, collision-indication signals and the halving of data lines at double speed.

Generally, MII’s are designed to facilitate the real-time connection of a Fast Ethernet, typically the one that can achieve up to 100 Mbit/per second with a Media Access Control (MAC) block; to a PHY chip.

Advantages of the RGMII

Here are some of the upsides to using the RGMII support on the KSZ9131RNXC:

3. Multi-PHY Chip Connection

KSZ9131RNXC can be used to establish a connection to a PHY chip in different ways. For example, it can be used to make a direct connection to the PHY chip on a Printed Circuit Board (PCB). It can also be used to make an indirect connection, through the MAC’s connection to an external PHY via a pluggable connector.

4. RGMII Supports Multiple Media Connections

KSZ9131RNXC’s RGMII can also be used to establish a connection to several media peripherals, such as fiber optic and twisted pair.

The amazing thing about this connection method is that the connection can be made without necessarily making any design-related changes to the MAC’s hardware.

5. Energy-Detect Power-Down Mode

KSZ9131RNXC can also detect the power-related options on the transceiver. Through the Energy-Detect Power-Down Mode, the transceiver takes note of the power iterations, especially when the cable is not attached.

Therefore, if the power supply is imbalanced, the mode would have to reduce the transceiver’s power consumption.

6. Pair Swap Corrections

KSZ9131RNXC also has a dedicated automated detector and pair swap corrector. The two come in handy when detecting and fixing anomalies relating to pair polarity, pair swap and pair skew.

There is also the Automatic MDI/MDI-X Crossover feature used to detect and correct the pair swaps at all the speeds of operation.

Single Supply Operation

Without enabling overt power supply to the transceiver, KSZ9131RNXC took care to regulate the process. It uses the On-Chip LDO Controller, which supports up to 3.3 volts of single supply operation.

The major requirement here is a single, external FET, which is then used to generate up to 1.2 volts to the Core.

Speed Negotiation

KSZ9131RNXC can also negotiate the transceiver’s speed, via the auto-negotiation process. It paves the way for the device to automatically select the best and highest link-up speed, which could be up to 1000 Megabytes per second (Mbps).

The feature also allows for the automatic selection of the ideal duplex, which could either be half or full.

KSZ9131RNXC’s Properties

These are the features or the attributes of this Gigabyte Ethernet transceiver:

Number of Receivers/Drivers4/4
Mounting StyleSurface-mounted
Receiver Hysteresis500 mV
Package/Case48-VFQFN Exposed Pad
Type of ProtocolGigabit Ethernet
Voltage SupplyBetween 1.71 volts and 3.63 volts
Type of Supported DuplexesHalf and Full
Operating TemperatureBetween 0˚C and 70˚C
Supported Data RatesBetween 10Mbps and 1000Mbps

KSZ9131RNXC’s Duplex

KSZ9131RNXC supports both the half and the full duplex options. According to TechTarget, “duplex” has to do with the mode of communication for signal transmission. The popular formats are half-duplex, full duplex and simplex mode.

The half-duplex has to do with the signal transmission and “data communication” mode that allows both parties to communicate – but not at the same time. Therefore, this duplex option only permits one part of the channel to communicate, after which the other will do the same.

The full duplex is the opposite of the former in the sense that it allows for simultaneous communications. Since this is a two-way communication channel and signal transmission model, it is possible for the involved channels to send and receive data at the same time.

Finally, the hallmark of KSZ9131RNXC’s performance is the MDC/MDIO management interface for the PHY register configuration.