TNETE2201

1.25-GIGABIT ETHERNET TRANSCEIVER

SLLS267D – JUNE 1997 – REVISED FEBRUARY 1999

6

POST OFFICE BOX 655303

Terminal Functions (Continued)

TERMINAL

DESCRIPTION

NAME

NO.

TYPE

DESCRIPTION

POWER

VCC_A

20,28,29,53

55,57,59,60

63

Supply

Analog power. VCC_A provides a supply reference voltage for the high-speed analog circuits.

VCC_CMOS

5,10,23,

Supply

Digital PECL logic power. VCC_CMOS provides an isolated low-noise power supply for the logic

circuits.

VCC_RX

50

Supply

Receiver power. VCC_RX provides a low-noise supply reference voltage for the receiver high-speed

analog circuits.

VCC_TTL

42,37

Supply

TTL power. VCC_TTL provides a supply reference voltage for the receiver TTL circuits.

VCC_TX

18

Supply

Transmitter power. VCC_TX provides a low-noise supply reference voltage for the transmitter

high-speed analog circuits.

GROUND

GND_A

21,32,56,64

Ground

Analog ground. GND_A provides a ground reference for the high-speed analog circuits.

GND_CMOS

1,14,

25,58

Ground

Digital PECL logic ground. GND_CMOS provides an isolated low-noise ground for the logic circuits.

GND_RX

51

Ground

Receiver ground. GND_RX provides a ground reference for the receiver circuits.

GND_TTL

33,46

Ground

TTL circuit ground. GND_TTL provides a ground for TTL interface circuits.

GND_TX

15

Ground

Transmitter ground. GND_TX provides a ground reference for the transmitter circuits.

MISCELLANEOUS

RESERVED

26

Reserved. Internally pulled to GND, leave open or assert low.

detailed description

data transmission

The transmitter registers incoming 10-bit-wide data words (8b/10b encoded data, TD0..TD9) on the rising edge

of REFCLK (125 MHz). The reference clock is also used by the serializer, which multiplies the clock by a factor

of 10 providing a 1.25 Gbaud signal that is fed to the shift register. The data is then transmitted differentially at

PECL voltage levels. The 8b/10b encoded data is transmitted sequentially bit 0 through 9.

transmission latency

The data transmission latency of the TNETE2201 is defined as the delay from the initial 10-bit word load to the

serial transmission of bit 9. The typical transmission latency is 9 ns.

data reception

The receiver of the TNETE2201 deserializes 1.25 Gbps differential serial data. The 8b/10b data (or equivalent)

is retimed based on an extracted clock from the serial data. The serial data is then aligned to the 10-bit word

boundaries and presented to the protocol controller along with two receive byte clocks (RBC0, RBC1). RBC0

and RBC1 are 180 degrees out of phase and are generated by dividing down the recovered 1.25 Gbps

(625 MHz) clock by 10 providing for two 62.5-MHz signals. The receiver presents the protocol device byte 0 of

the received data valid on the rising edge of RBC1.

NOTE:

This allows the option of byte alignment without the use of the synchronous detection

(SYNC) function by the protocol device.

The receiver PLL can lock to the incoming 1.25 GHz data without the need for a lock-to-reference preset. The

received serial data rate (RX+ and RX–) should be 1.25 Gbps

±0.01% (100 ppm) for proper operation.