HC-5502B1 Datasheet, PDF (5/12 Pages) Intersil Corporation – SLIC Subscriber Line Interface Circuit

HC-5502B1
Pin Descriptions
28 PIN
PLCC
2
3
4
5
6
7
9
10
11
12
13
14
16
17
18
19
20
21
23
24
25
24 PIN
DIP/SOIC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
SYMBOL
DESCRIPTION
TIP
An analog input connected to the TIP (more positive) side of the subscriber loop through a 150Ω feed
resistor and a ring relay contact. Functions with the Ring terminal to receive voice signals from the tele-
phone and for loop monitoring process.
RING
An analog input connected to the RING (more negative) side of the subscriber loop through a 150Ω feed
resistor and a ring relay contact. Functions with the Tip terminal to receive voice signals from the tele-
phone and for loop monitoring purposes.
V_B+ Positive Voltage Source - Most positive supply. V_B+ is typically 12V or 5V.
C₁
Capacitor #1 - Optional Capacitor used to improve power supply rejection. This pin should be left open if un-
used.
C₃
Capacitor #3 - An external capacitor to be connected between this terminal and analog ground. Required
for proper operation of the loop current limiting function, and for filtering V_B- supply. Typical value is 0.3µF,
30V.
DG
Digital Ground - To be connected to zero potential and serves as a reference for all digital inputs and out-
puts on the SLIC.
RS
Ring Synchronization Input - A TTL - Compatible Clock Input. The clock should be arranged such that a
positive transition occurs on the negative going zero crossing of the ring voltage source, ensuring that the
ring relay is activated and deactivated when the instantaneous ring voltage is near zero. If synchronization
is not required, tie to 5V.
RD
Relay Driver - A low active open collector logic output. When enabled, the external ring relay is energized.
TF
Tip Feed - A low impedance analog output connected to the TIP terminal through a 150Ω feed resistor.
Functions with the RF terminal to provide loop current, feed voice signals to the telephone set, and sink
longitudinal current.
RF
Ring Feed - A low impedance analog output connected to the RING terminal through a 150Ω feed resistor.
Functions with the TF terminal to provide loop current, feed voice signal to the telephone set, and sink
longitudinal current.
V_B-
Negative Voltage Source - Most negative supply. V_B- is typically -48V with an operational range of -42V
to -58V. Frequently referred to as “battery”.
BG
Battery Ground - To be connected to zero potential. All loop current and some quiescent current flows into
this ground terminal.
SHD
Switch Hook Detection - A Low Active LS TTL - Compatible Logic Output. This output is enabled for loop
currents exceeding 10mA and disabled for loop currents less than 5mA.
GKD
Ground Key Detection - A Low Active LS TTL - Compatible Logic Output. This output is enabled if the DC
current into the ring lead exceeds the DC current out of the tip lead by more than 20mA, and disabled if
this current difference is less than 10mA.
PD
Power Denial - A Low Active TTL - Compatible Logic Input. When enabled the switch hook detect (SHD)
and ground key detect (GKD) are not necessarily valid, and the relay driver (RD) output is disabled.
RC
Ring Command - A Low Active TTL - Compatible Logic Input. When enabled, the relay driver (RD) output
goes low on the next rising edge of the ring sync (RS) input, as long as the SLIC is not in the power denial
state (PD = 0) or the subscriber is not already off- hook (SHD = 0).
C₂
Capacitor #2 - An external capacitor to be connected between this terminal and digital ground. Prevents
false ground key indications from occurring during ring trip detection. Typical value is 0.15µF, 10V. This
capacitor is not used if ground key function is not required.
OUT The analog output of the spare operational amplifier.
-IN
The inverting analog input of the spare operational amplifier.
+IN The non-inverting analog input of the spare operational amplifier.
RX
Receive Input, Four Wire Side - A high impedance analog input which is internally biased. Capacitive cou-
pling to this input is required. AC signals appearing at this input differentially drive the Tip feed and Ring
feed amplifiers, which in turn drive tip and ring through 300Ω of feed resistance on each side of the line.
4-5