7

NWK914D

Fig.6 Simplified 100BASE-TX system block diagram showing NWK914D external components

EXTERNAL REQUIREMENTS

The NWK914D requires a number of external components

for the device to function correctly and these are shown in

the simplified 100BASE-TX application circuit in Fig.6 and

the component value information given in Table 2.

Note that the values of R2, R5 and R6 vary depending

upon application. When using 1:1 magnetics, use the values

shown in the middle of Table 2 with note "1:1 magnetics".

When using 2:1 magnetics use the values shown in the last

two lines of Table 2. Please refer to the Transmit Line Driver

section on pages 3-4 for more information on these values.

For more detailed Application information please contact

your local Sales Office.

GLOSSARY OF TERMS AND ABREVIATIONS

MAC

Media Access Control

MLT-3

Multi Level Transmit -3 levels

NRZ

Non Return To Zero

NRZI

Non Return to Zero Inverse

PCS

Physical Coding Sublayer

PHY

PHYsical Layer

PLL

Phase Locked Loop

PMD

Physical Media Dependent

UTP

Unshielded Twisted Pair

RX

Receive

STP

Shielded Twisted Pair

TX

Transmit

UTP

Unshielded Twisted Pair

VCO

Voltage Controlled Oscillator

1K

Ω

100pF

6.2K

Ω

.01

µF

R6

R5

15

Ω

15

Ω

68

Ω

0.1

µF

Xtal Osc.

LFTA

LFTB TXREF

TXGND

TXOP

TXON

RXIP

RXIN

LFRB

LFRA

REFCLK

TDAT0-4

TXC

RXC

RDAT0-4

.033

µF

RJ45

5

5

PCS

or

MAC

(with

embedded

PCS)

1:1

NWK914D

M

A

G

N

E

T

I

C

S

R1

C1

R2

C2

See Table 2 for

these resistor values

CT

C4

R7

R9

R8

R3

C3

REF.

VALUE

TOL.

FUNC.

NOTES

C1

100pF

20%

loop fltr

C2

0.033

µF

20%

loop fltr

C3

.01

µF

20%

loop fltr

R1

1K

Ω

1%

loop fltr

R2

1300

Ω

1%

tx ref

1:1 magnetics

R3

6.2K

Ω

1%

loop fltr

R5,R6

50

Ω

1%

xmit

1:1 magnetics

R7,R8

15

Ω

1%

rcv pad

R9

68

Ω

1%

rcv pad

R2

2.6K

Ω

1%

tx ref

2:1 magnetics

R5,R6

200

Ω

1%

xmit

2:1 magnetics

CT on transformer connects directly to

2:1 magnetics

Table 2: External components

NWK914B

NWK914S

NWK914D

Base Line Wander Correction

-

improved to 100m

improved to 100m

TXREF resistor with 1:1 magnetics

620

Ω

680

Ω

1300

Ω

Table 3: Differences between NWK914B, NWK914S and NWK914D