7

MB86961A

Figure 2. LAN Adapter Board Application - Auto Port Select with External Loopback Control

NS8390

Back-End Controller

Interface

Loopback Enable

Programming

Options

Remote Status

TXD

TXE

TXC

RXC

RXD

CPS

COL

+5 V

Line Status

+

1

µF TANT 0.1 µF

TXD

TEN

TCLK

RCLK

RXD

CD

COL

LBK

PAUI

AUTOSEL

MD0

MD1

NTH

UTP

LI

RIAB

RLD

RCMPT

JAB

PLR

LEDC/XLBK

LEDR

LEDL

LEDT/PDN

VCC1

VCC2

CLK1

20 pF

20 MHz

CLK0

20 pF

1

TPOPB

TPOPA

TPONA

TPONB

TPIP

TPIN

CIN

CIP

DON

DOP

DIN

DIP

RBIAS

GND1

GND2

3

2

1

2

3

4

5

6

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

3

2

1

75

Ω ±1%

37.5

Ω ±1%

50

Ω ±1%

12.4 K

Ω ±1%

78

Ω

1:

2

1:1

18pF

RJ45

+12 V

Fuse

To 10Base-T

D-Connector

to AUI Drop Cable

Twisted-Pair Network

78

Ω

78

Ω

50

Ω ±1%

0.1

µF

37.5

Ω ±1%

75

Ω ±1%

Suitable crystals includes: MTRON Industries, Inc. MP-1 and MP-2, and Ecliptek ECSM20.000M

Suitable TP transformers include: Fil-Mag 23Z128 and SM23Z128, Valor PT4069, and Pulse

Engineering PE-65745, PE-65454 and PE-68048

Suitable AUI transformers include: Fil-Mag 23Z90 and SM23Z90, and Valor LT6030

MB86961A