HC5503PRI Datasheet, PDF (5/8 Pages) Intersil Corporation – Low Cost SLIC For Large Telecom Switches

HC5503PRI
Pin Descriptions (Continued)
24 PIN
DIP/SOIC SYMBOL
DESCRIPTION
15
PD Power Denial - A low active TTL - Compatible logic input. When enabled, the ring feed voltage collapses to the tip feed
voltage (~4V). The DC feed is disabled, but the AC transmission is maintained. The switch hook detect (SHD) is not
necessarily valid, and the relay driver (RD) output is disabled.
16
RC 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 (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).
17
NC Leave disconnected.
18
OUT The analog output of the spare operational amplifier.
19
-IN The inverting analog input of the spare operational amplifier.
20
+IN The non-inverting analog input of the spare operational amplifier.
21
RX 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 differentially drive the Tip feed and Ring feed terminals.
22
C₂
Capacitor #2 - An external capacitor to be connected between this terminal and analog ground. This capacitor is
required for the proper operation of ring trip detection. Recommended value 0.82µF ±10% 10V non-polarized.
23
AG 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, Four Wire Side - A low impedance analog output proportional to the loop current. 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.
NC No internal connection.
NOTE: All grounds (AG, BG, and DG) must be applied before V_B+ or V_B-. 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.
Functional Diagram
RS
RING SYNC
RC
RING COMMAND
RD
TIP
1/2 RING
R_P
TIP
RELAY
R_S
2-WIRE
TF
LOOP
V_B-
SECONDARY
PROTECTION
V_B-
RING
RING
VOLTAGE
V_B-
1/2 RING
RELAY
BG
RF
RFS
R_S
R_P
RING
PD
POWER DENIAL
R_S: 100Ω; 1/2W to 2W depending on surge requirements
R_P: 50Ω; 1/2W to 2W depending on surge requirements
RING
CONTROL
RING
TRIP
LOOP
MONITORING
SHD _{SWITCH HOOK}
DETECTION
DIFF
AMP
+
TX TRANSMIT
OUTPUT
BATTERY
FEED
LOOP
CURRENT
LIMITER
+1
LINE
DRIVERS
-1
SLIC MICROCIRCUIT
+
OP
AMP
OUT
+IN
-IN
RX _RECEIVE
INPUT
5
FN6101.0