HC5503T_04 Datasheet, PDF (4/6 Pages) Intersil Corporation – Balanced PBX / Key System SLIC, Subscriber Line Interface Circuit

HC5503T
Pin Descriptions
24 PIN
SOIC
1
SYMBOL
DESCRIPTION
TIP An analog input connected to the TIP (more positive) side of the subscriber loop through a 150Ω feed resistor. Functions
with the Ring terminal to receive voice signals from the telephone and for loop
monitoring purposes.
2
RING An analog input connected to the RING (more negative) side of the subscriber loop through a 150Ω feed resistor.
Functions with the Tip terminal to receive voice signals from the telephone and for loop monitoring purposes.
3
V_CC Positive Voltage Source - Most positive supply. V_CC is typically 5V.
4
N/C No Connect. For proper operation this pin should be left floating.
5
C₁
Capacitor - An external capacitor to be connected between this terminal and analog ground. Required for proper
operation of the voice band hybrid. Typical value is 0.3µF, 30V.
6
DGND Digital Ground - To be connected to zero potential and serves as a reference for all digital inputs and outputs on the SLIC
microcircuit.
7
RS
This pin should be tied to 5V.
8
N/C No Connect. For proper operation this pin should be left floating.
9
TF
Tip Feed - A low impedance analog output connected to the TIP terminal through a 150Ω feed resistor. Provides voice
signals to the telephone set and sink longitudinal current.
10
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 signals to the telephone set, and sink longitudinal current.
11
V_BAT Negative Voltage Source - Most negative supply. V_BAT has an operational range of -24V to -58V.
Frequently referred to as “battery”.
12
BGND Battery Ground - To be connected to zero potential. All loop current and some quiescent current flows into this ground
terminal.
13
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.
14
N/C No Connect. For proper operation this pin should be left floating.
15
N/C No Connect. For proper operation this pin should be left floating.
16
N/C No Connect. For proper operation this pin should be left floating.
17
N/C No Connect. For proper operation this pin should be left floating.
18
T1
Used during production testing. For proper operation this pin should be connected to pin T2.
19
T2
Used during production testing. For proper operation this pin should be connected to pin T1.
20
T3
Used during production testing. For proper operation this pin should be connected to Analog Ground pin AGND.
21
RX
Receive Input - A high impedance analog input which is internally biased. Capacitive coupling to this input is required.
AC signals appearing at this input differentially drive the Tip feed and Ring feed terminals, which in turn drive tip and ring
through 300Ω of feed resistance on each side of the line.
22
N/C No Connect. For proper operation this pin should be left floating.
23
AGND Analog Ground - To be connected to zero potential and serves as a reference for the transmit output (TX) and receive
input (RX) terminals.
24
TX
Transmit Output - A low impedance analog output which represents the differential voltage across Tip and Ring. This
output is unbalanced and referenced to analog ground. Since the DC level of this output varies with loop current,
capacitive coupling to the next stage is essential.
NOTE: All grounds (AGND, BGND, and DGND) must be applied before V_CC or V_BAT. Failure to do so may result in premature failure of the part. If
a user wishes to run separate grounds off a line card, the AG must be applied first.
4