HC-5509B Datasheet, PDF (6/10 Pages) Intersil Corporation – SLIC Subscriber Line Interface Circuit

HC-5509B3999-003
Pin Descriptions (Continued)
SOIC
SYMBOL
DESCRIPTION
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.
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
VFB
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
TF₂
Tip Feed - A low impedance analog output connected to the TIP terminal through a feed resistor. Functions
with the RF terminal to provide loop current, and to feed voice signals to the telephone set and to sink longitu-
dinal currents. Must be tied to TF₁.
NA
TF₁
Tie directly to TF₂ in the PLCC application.
26
RF₁
Ring Feed - A low impedance analog output connected to the RING terminal through a feed resistor. Functions
with the TF terminal to provide loop current, feed voice signals to the telephone set, and to sink longitudinal
currents. Tie directly to RF₂.
NA
RF₂
Tie directly to RF₁ in the PLCC application.
27
VB-
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 terminal.
NC
No internal connection.
NOTE:
1. All grounds (AG, BG, 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.
6