HC5515_06 Datasheet, PDF (17/20 Pages) Intersil Corporation – ITU CO/PABX SLIC with Low Power Standby

HC5515
Pin Descriptions (Continued)
PLCC SYMBOL
DESCRIPTION
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
R_DC
DC feed current programming resistor pin. Constant current feed is programmed by resistors R_DC1 and R_DC2
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
V_EE
-5V power supply.
19
V_TX
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 C_HP. C_HP is required to properly separate the ring AC current from the DC
loop current. The other end of C_HP is connected to HPT.
21
HPT
TIP side of AC/DC separation capacitor C_HP. C_HP is required to properly separate the tip AC current from the DC loop
current. The other end of C_HP is connected to HPR.
22
RD
Loop current programming resistor. Resistor R_D sets the trigger level for the loop current detect circuit. A filter capacitor
C_D is also connected between this pin and V_EE.
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
TIP_SENSE 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.
17
FN4235.6
June 6, 2006