HC5503 Intersil Corporation, HC5503 Datasheet - Page 11

• Manufacturer Part Number: HC5503
• Description: Low Cost 24V SLIC For PABX/Key Systems
• Manufacturer: Intersil Corporation

Pin Descriptions
NOTE: All grounds (AG, BG, and DG) must be applied before V
wishes to run separate grounds off a line card, the AG must be applied first.
20, 21, 22,
1, 8, 15,
28 PIN
PLCC
23, 24
10
11
12
13
14
16
18
19
25
26
27
28
17
2
3
4
5
6
7
9
17, 18, 19,
DIP/SOIC
24 PIN
10
11
12
13
15
16
21
22
23
24
14
20
1
2
3
4
5
6
7
8
9
SYMBOL
RING
V
RFS
SHD
V
TIP
DG
RD
BG
RC
AG
NC
NC
RS
RF
PD
R
TX
C
TF
C
BAT
CC
11
1
X
2
An analog input connected to the TIP (more positive) side of the subscriber loop. Functions with the Ring
terminal to receive voice signals from the telephone and for loop monitoring purposes.
An analog input connected to the RING (more negative) side of the subscriber loop. Functions with the Tip
terminal to receive voice signals from the telephone and for loop monitoring purposes.
Senses ring side of loop for ring trip detection. During ringing, the ring signal is inserted into the line at this
node and RF is isolated from RFS via a relay.
Positive Voltage Source - Most positive supply. V
Capacitor #1 - 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
Digital Ground - To be connected to zero potential and serves as a reference for all digital inputs and out-
puts on the SLIC microcircuit.
Ring Synchronization Input - A TTL - compatible clock input. The clock should be arranged such that a pos-
itive pulse transition occurs on the zero crossing of the ring voltage source, as it appears at the RFS termi-
nal. For Tip side injected systems, the RS pulse should occur on the negative going zero crossing and for
Ring injected systems, on the positive going zero crossing. This ensures that the ring relay activates and
deactivates when the instantaneous ring voltage is near zero. If synchronization is not required, the pin
should be tied to 5V.
Relay Driver - A low active open collector logic output. When enabled, the external ring relay is energized.
Tip Feed - A low impedance analog output connected to the TIP terminal through a 150 feed resistor.
Functions with the RF terminal to provide loop current, feed voice signals to the telephone set, and sink
longitudinal current.
Ring Feed - A low impedance analog output connected to the RING terminal through a 150 feed resistor.
Functions with the TF terminal to provide loop current, feed voice signals to the telephone set, and sink
longitudinal current.
Negative Voltage Source - Most negative supply. V
Battery Ground - To be connected to zero potential. All loop current and some quiescent current flows into
this ground terminal.
Switch Hook Detection - A low active LS TTL - compatible logic output. This output is enabled for loop cur-
rents exceeding 10.5mA and disabled for loop currents less than 5mA.
Power Denial - A low active TTL - Compatible logic input. When enabled, the switch hook detect (SHD) is
not necessarily valid, and the relay driver (RD) output is disabled.
Ring Command - A low active TTL - Compatible logic input. When enabled, the relay driver (RD) output
goes low on the next high level of the ring sync (R
state (PD = 0) or the subscriber is not already off-hook (SHD = 0).
Receive Input, Four Wire Side - A high impedance analog input which is internally biased. Capacitive coupling
to this input is required. AC signals appearing at this input deferentially drive the Tip feed and Ring feed termi-
nals, which in turn drive tip and ring through 150 of feed resistance on each side of the line.
Capacitor #2 - An external capacitor to be connected between this terminal and analog ground. This ca-
pacitor prevents false ring trip detection from occurring when longitudinal currents are induced onto the
subscriber loop from nearby power lines and other noise sources. Recommended value is 1.0 F, 20V. This
capacitor should be nonpolarized.
Analog Ground - To be connected to zero potential and serves as a reference for the transmit output (TX)
and receive input (RX) terminals.
Transmit Output, Four Wire Side - A low impedance analog output which represents the differential voltage
across Tip and Ring. Transhybrid balancing must be performed beyond this output to completely implement two
to four wire conversion. 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.
Used during production testing. For proper operation of the SLIC, this pin should float.
No internal connection.
CC
HC5503
or V
BAT
. Failure to do so may result in premature failure of the part. If a user
DESCRIPTION
BAT
CC
S
) input, as long as the SLIC is not in the power denial
is typically -24V. Frequently referred to as “battery”.
is typically 5V.
BAT
. Typical value is 0.3 F, 16V.