4-29

HC55142

(28 LEAD SOIC)

TOP VIEW

HC55150

(28 LEAD SOIC)

TOP VIEW

ZT

PTG

RRLY

CH

RING

BGND

TIP

VBH

VBL

RDC_RAC

CDC

DT

DR

CRT_REV_LVM

AGND

SPM

VRX

RSYNC_REV

ILIM

RD

SHD

C1

C2

C3

GKD_LVM

VTX

ROH

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

ZT

PTG

RRLY

CH

RING

BGND

TIP

VBH

VBL

RDC_RAC

CDC

DT

DR

CRT_REV_LVM

AGND

SPM

VRX

RSYNC_REV

ILIM

RD

SHD

C1

C2

C3

LVM

VTX

ROH

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Pin Descriptions

28

PIN

PLCC

32

PIN

PLCC

28

PIN

SOIC

SYMBOL

DESCRIPTION

1

1

2

PTG

Programmable Transmit Gain - The 2-wire to 4-wire transmission gain is 0dB if this pin is left floating

and -6.02dB if tied to ground. The -6.02dB gain option is useful in systems where Pulse Metering is

used. See Figure 23.

2

2

3

RRLY

Ring Relay Driver Output - The relay coil may be connected to a maximum of 14V.

3

3

4

CH

AC/DC Separation Capacitor - CH is required to properly process the AC current from the DC loop

current. Recommended value 0.1

µF.

4

4

1

ZT

2-Wire Impedance Matching Pin - Impedance matching of the 2-wire side is accomplished by placing

an impedance between the ZT pin and ground. See Equation 32.

5

5

5

RING

6

6

6

BGND

Battery ground.

7

7

7

TIP

888

High Battery Supply (negative with respect to GND).

999

Low Battery Supply (negative with respect to GND, magnitude

10

10

10

RDC_RAC

Resistive Feed/Anti Clipping - Performs anti clipping function on constant current application and sets

the slope of the resistive feed curve for constant voltage applications.

11

11

14

CRT_REV

_LVM

Ring Trip, Soft Polarity Reversal and Line Voltage Measurement - A capacitor when placed between the

CRT_REV_LVM pin and +5V performs 3 mutually exclusive functions. When the SLIC is configured in the

Ringing mode it provides filtering of the ringing signal to prevent false detect. When the SLIC is transitioning

between the Forward Active State and Reverse Active State it provides Soft Polarity Reversal and performs

charge storage in the Line Voltage Measurement State. Recommended value 0.47

µF.

12

12

11

CDC

Filter Capacitor- The CDC Capacitor removes the VF signals from the battery feed control loop.

13

13

12

DT

Tip side of Ring Trip Detector - Ring trip detection is accomplished by connecting an external network

to a detector in the SLIC with inputs DT and DR. Ring trip occurs when the voltage on DT is more

negative than the voltage on DR.

14

14

13

DR

Ring Side of Ring Trip Detector - Ring trip detection is accomplished by connecting an external

network to a detector in the SLIC with inputs DT and DR. Ring trip occurs when the voltage on DR is

more positive than the voltage on DT.

-

15

-

C5

Activates Test Relay TRLY2.

HC55120, HC55121, HC55130, HC55131, HC55140, HC55141, HC55142, HC55143, HC55150, HC55151