HC-5509B_03 Datasheet, PDF (5/9 Pages) Intersil Corporation – ITU CO/Loop Carrier SLIC

HC-5509B
Pin Descriptions (Continued)
SOIC SYMBOL
DESCRIPTION
14
TIP An analog input connected to the TIP (more positive) side of the subscriber loop through a feed resistor and ring relay
contact. Functions with the RING terminal to receive voice signals from the telephone and for loop monitoring purpose.
15
RING An analog input connected to the RING (more negative) side of the subscriber loop through a feed resistor. Functions
with the TIP terminal to receive voice signals from the telephone and for loop monitoring purposes.
16
RFS Ring Feed Sense - Senses RING side of the loop for Ground Key Detection. During Ring injected ringing the ring signal
at this node is isolated from RF via the ring relay. For Tip injected ringing, the RF and RFS pins must be shorted.
17
V_RX Receive Input, 4-Wire Side - A high impedance analog input. AC signals appearing at this input drive the Tip Feed and
Ring Feed amplifiers differentially.
18
C₂
Capacitor #C₂ - An external capacitor to be connected between this terminal and ground. It prevents false ring trip
detection from occurring when longitudinal currents are induced onto the subscriber loop from power lines and other
noise sources. This capacitor should be nonpolarized.
19
V_TX Transmit Output, 4-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 2-Wire to 4-Wire conversion.
This output is referenced to analog ground. Since the DC level of this output varies with loop current, capacitive coupling
to the next stage is necessary.
20
PRI A TTL compatible input used to control PR. PRI active High = PR active low.
21
PR
An active low open collector output. Can be used to drive a Polarity Reversal Relay.
22
DG
Digital Ground - To be connected to zero potential. Serves as a reference for all digital inputs and outputs on the SLIC.
(Note 5)
23
RD
Ring Relay Driver - An active low open collector output. Used to drive a relay that switches ringing signals onto the 2-
Wire line.
24
V_FB Feedback input to the tip feed amplifier; may be used in conjunction with transmit output signal and the spare op amp
to accommodate 2-Wire line impedance matching.
25
TF
Tip Feed - A low impedance analog output connected to the TIP terminal through a feed resistor.
26
RF
Ring Feed - A low impedance analog output connected to the RING terminal through a feed resistor.
27
V_B-
The battery voltage source. The most negative supply.
28
BG
Battery Ground - To be connected to zero potential. All loop current and some quiescent current flows into this ground
(Note 5) terminal.
NOTE:
5. 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.
5