60 Pin Descriptions

24-Pin DIP

28-Pin PCC

Name

IO

Description

1

1

COL

O

COLLISION DETECT OUTPUT

Generates an active high signal when

10 MHz collision signal is detected

2

2

RXD

O

RECEIVE DATA OUTPUT

NRZ data output from the PLL This signal

must be sampled on the rising edge of receive clock

3

3

CRS

O

CARRIER SENSE

Asserted on the first valid high-to-low transition on

data

4

4

RXC

O

RECEIVE CLOCK

The receive clock from the Manchester data after

the PLL has locked Remains active 5 bit times after deasserting CRS

5

5

SEL

I

MODE SELECT

67

GROUND PIN

7

10

LBK

I

LOOPBACK

When high the loopback mode is enabled

811

X1

I

CRYSTAL OR EXTERNAL OSCILLATOR INPUT

912

X2

O

CRYSTAL FEEDBACK OUTPUT

Used in crystal connections only

Connected to ground when using an external oscillator

10

13

TXD

I

TRANSMIT DATA INPUT

NRZ data input from the controller The

data is combined with the transmit clock to produce Manchester data

TXD is sampled on the rising edge of transmit clock

11

14

TXC

O

TRANSMIT CLOCK

The 10 MHz clock derived from the 20 MHz

oscillator

12

15

TXE

I

TRANSMIT ENABLE

The encoder begins operation when this input is

asserted high

13

16

O

TRANSMIT OUTPUT

Differential line driver which sends the encoded

data to the transceiver The outputs are source followers which require

14

17

270X pull-down resistors

15

6

NC

NO CONNECTION

compatible with the DP8391

16

18

NC

NO CONNECTION

17

19

TEST

I

FACTORY TEST INPUT

Used to check the chip’s internal functions

May be tied low or have a 001 mf bypass capacitor to ground (for

compatibility with the bipolar DP8391) during normal operation

18

20

POWER CONNECTION

19

21

22

23

20

24

NC

NO CONNECTION

21

25

I

RECEIVE INPUT

Differential receive input pair from the transceiver

22

26

23

27

I

COLLISION INPUT

Differential collision pair input from the

transceiver

24

28

5