HC5526

FN4151 Rev 8.00

Page 2 of 19

August 2003

Pin Descriptions

PLCC

SYMBOL

DESCRIPTION

1RINGSENSE Internally connected to output of RING power amplifier.

2

BGND

Battery Ground - To be connected to zero potential. All loop current and longitudinal current flow from this ground.

Internally separate from AGND but it is recommended that it is connected to the same potential as AGND.

4VCC

5V power supply.

5

RINGRLY

Ring relay driver output.

6VBAT

Battery supply voltage, -24V to -56V.

7RSG

Saturation guard programming resistor pin.

8

E1

TTL compatible logic input. The logic state of E1 in conjunction with the logic state of C1 determines which detector is

gated to the DET output.

9

E0

TTL compatible logic input. Enables the DET output when set to logic level zero and disables DET output when set to

a logic level one.

11

DET

Detector output. TTL compatible logic output. A zero logic level indicates that the selected detector was triggered (see

Truth Table for selection of Ground Key detector, Loop Current detector or the Ring Trip detector). The DET output is

an open collector with an internal pull-up of approximately 15k

 to VCC.

12

C2

TTL compatible logic input. The logic states of C1 and C2 determine the operating states (Open Circuit, Active, Ringing

or Standby) of the SLIC.

13

C1

TTL compatible logic input. The logic states of C1 and C2 determine the operating states (Open Circuit, Active, Ringing

or Standby) of the SLIC.

14

RDC

DC feed current programming resistor pin. Constant current feed is programmed by resistors RDC1 and RDC2

connected in series from this pin to the receive summing node (RSN). The resistor junction point is decoupled to AGND

to isolate the AC signal components.

15

AGND

Analog ground.

16

RSN

Receive Summing Node. The AC and DC current flowing into this pin establishes the metallic loop current that flows

between tip and ring. The magnitude of the metallic loop current is 1000 times greater than the current into the RSN

pin. The constant current programming resistors and the networks for program receive gain and 2-wire impedance all

connect to this pin.

18

VEE

-5V power supply.

19

VTX

Transmit audio output. This output is equivalent to the TIP to RING metallic voltage. The network for programming the

2-wire input impedance connects between this pin and RSN.

20

HPR

RING side of AC/DC separation capacitor CHP. CHP is required to properly separate the ring AC current from the DC

loop current. The other end of CHP is connected to HPT.

21

HPT

TIP side of AC/DC separation capacitor CHP. CHP is required to properly separate the tip AC current from the DC loop

current. The other end of CHP is connected to HPR.

22

RD

Loop current programming resistor. Resistor RD sets the trigger level for the loop current detect circuit. A filter capacitor

CD is also connected between this pin and VEE.

23

DT

Input to ring trip comparator. Ring trip detection is accomplished by connecting an external network to a comparator in

the SLIC with inputs DT and DR.

25

DR

Input to ring trip comparator. Ring trip detection is accomplished by connecting an external network to a comparator in

the SLIC with inputs DT and DR.

26

TIPSENSE

Internally connected to output of tip power amplifier.

27

TIPX

Output of tip power amplifier.

28

RINGX

Output of ring power amplifier.

3, 10, 17,

24

N/C

No internal connection.