AMD

7

Am7996

Figure 2 is an external component diagram showing

how to implement the transmit mode collision detect

levels recommended by IEEE 802.3. Figure 3 on the

following page shows how to implement the receive

mode

collision

detect

levels

recommended

by

IEEE 802.3. Receive mode collision detect threshold

levels of the Am7996 are implemented by adding R9,

R10 and C4. For the values of the components shown in

Figure 3, a nominal receive mode collision detect

threshold of –1.5 V, for a –1.404 V to –1.581 V window,

is achieved.

Notes:

1.

2.

D2 can be eliminated in Cheapernet (IEEE 802.3, 10BASE2) applications.

3.

Shown with SQE Test disabled.

4.

Discrete Power Supply or Hybrid-Hybrid DC-DC Converter Manufacturers include:

Ethernet (IEEE 802.3, 10BASE5)

Reliability: 2E12R9

Valor Electronics: PM1001

Cheapernet (IEEE 802.3, 10BASE2)

Reliability Inc: 2VP5U9

Valor Electronics: PM7102

5.

The capacitance of C3, Am7996 package, D3 and the printed circuit board should add up to 180 pF

± 20%.

6.

The capacitance of C1, Am7996 package and the printed circuit board should add up to 39 pF.

7.

Figure 2 used for production testing of all parameters that are tested.

07506E-5

COLL

RCV

XMT

1:1

1:1

1:1

Power (DTE)

(Note 3)

2

3

4

5

GND

–9 V

6

7

8

9

10

R1

40.2

Ω

1%

R3

174

Ω

9.09

Ω

1%

(Note 5)

1N4001

C3

180 pF

(Note 1)

9.09

Ω

1%

1N4150

D2

D1

CC

R6

24.9 k

Ω

1%

CL

(Note 6)

C1

39 pF

C2

0.1

µF

1%

1%

R4

1.1 k

Ω

Coax

Connector

1

20

19

18

17

16

15

14

13

12

11

MAU Power Supply

(Note 4)

R2

40.2

Ω

1%

1%

(75

µH)

PE64102/PE64107 (or equivalent)

VCC1

CI+

CI–

DI+

DI–

VCREF

SQE^TEST

DO+

DO–

VEE

COLL OSC

VCC2

VCOL

NC

RXT

Tap

Shield

VTX-

TXT

VTX+

NC

R5

75 k

Ω

(Note 1)

D3

(Note 2)

R8

Am7996

R7

Figure 2. Am7996 External Component Diagram for Transmit Mode Collision Detect