LXT381 — Octal E1 Line Interface

8

Datasheet

14

F3

GND

S

Ground. This pin must be connected to Ground.

15

F4

GND

S

Ground. This pin must be connected to Ground.

16

G3

GND

S

Ground. This pin must be connected to Ground.

17

G1

VCCIO0

S

Power (I/O).

18

G4

GNDIO0

S

Ground (I/O).

19

H1

VCC0

S

Power (Core).

20

H4

GND0

S

Ground (Core).

21

22

23

24

25

26

27

28

G2

H3

H2

J4

J3

J2

J1

K1

LOOP0

LOOP1

LOOP2

LOOP3

LOOP4

LOOP5

LOOP6

LOOP7

DI

DI

DI

DI

DI

DI

DI

DI

Loopback Mode Select/Parallel Databus Input & Output. These pins

are inputs that select the loopback mode for transceiver ports 0-7

respectively as follows:

Normal operation (no loopback) is selected when pin is left open

(unconnected).

Remote loopback mode is selected when pin is Low. In this mode, data on

TPOS and TNEG is ignored and data received on RTIP and RRING is

looped around and retransmitted on TTIP and TRING.

Analog local loopback mode is selected when pin is High. In this mode,

data received on RTIP and RRING is ignored and data transmitted on TTIP

and TRING is internally looped around and routed back to the receive

inputs.

Note: When these inputs are left open, they stay in a high impedance

state. Therefore, the layout design should not route signals with fast

transitions near the LOOP pins. This practice will minimize

capacitive coupling.

29

L1

TCLK1

DI

Transmit Clock Input.

30

31

L2

L3

TPOS1

TNEG1

DI

DI

Transmit Positive Data Input.

Transmit Negative Data Input.

32

M1

RCLK1

DO

Receive Clock Output.

33

34

M2

M3

RPOS1

RNEG1

DO

DO

Receive Positive Data Output.

Receive Negative Data Output.

35

K3

ALOS1

DO

Analog Loss of Signal Output.

36

N1

TCLK0

DI

Transmit Clock Input.

37

38

N2

N3

TPOS0

TNEG0

DI

DI

Transmit Positive Data Input.

Transmit Negative Data Input.

39

P1

RCLK0

DO

Receive Clock Output.

40

41

P2

P3

RPOS0

RNEG0

DO

DO

Receive Positive Data.

Receive Negative Data.

42

K4

ALOS0

DO

Analog Loss of Signal Output.

43

K2

GND

S

Ground. This pin must be connected to Ground.

44

N4, P4

TVCC0

S

Transmit Driver Power Supply. Power supply pin for the output driver.

Table 1.

LXT381 Pin Description (Continued)

Pin #

LQFP

Pin #

PBGA

Symbol

Description

1. DI: Digital Input; DO: Digital Output; DI/O: Digital Bidirectional Port; AI: Analog Input; AO: Analog Output S: Power Supply;

N.C.: Not

Connected.