2-286

MH89626C

Preliminary Information

Figure 2 - Pin Connections

Pin Description

Pin #

Name

Description

1TIP

Tip Lead: Connects to the TIP lead of the telephone line.

2

RING

Ring Lead: Connects to the Ring lead of the telephone line.

3RF

Ring Feed.

4TF

Tip Feed.

5

LGND

Ground.

Battery Supply Voltage: Normally -48V.

7RF1

Ring Feed 1: Ringing input.

8RF2

Ring Feed 2: Ringing output.

Negative Supply Voltage. (-5V).

10

AGND

Analog Ground: Analog and Digital Ground. Connects to system ground.

11

Positive Supply Voltage. (+5V).

12

IC

Internal Connection.

13

VAC

components, can be applied to this pin to reduce longitudinal noise on TIP and RING. To

implement this feature, connect a 0.1

µF 100V capacitor from V

from VAC to AGND. This pin must be tied to AGND when not used.

14

IC

Internal Connection.

15

CS

Chip Select (Input): A TTL compatible digital input to enable the SDi to control all the

functions of the driver.

16

SHK

Switch Hook Detect (Output): A logic low indicates an off-hook condition.

17

LED

LED Drive (Output).: Drives an LED directly through an internal 2.2k

Ω resistor. A logic low

indicates an off-hook condition.

18

LCA

Loop Current Adjust (input): If this pin is left open, the constant current will be set at

VREF

D1

C2i

Do

F1i

IC

IC

IC

GS

IC

SD7

SD6

SD5

IC

VRLY

RGND

RD2

RD3

RD1

TIP

RING

RF

TF

LPND

VBat

RF1

RF2

VEE

AGND

VDD

IC

VAC

IC

CS

SHK

LED

LCA

SD1

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

20