hc55171b Intersil Corporation, hc55171b Datasheet - Page 9

• Manufacturer Part Number: hc55171b
• Description: Low Cost 5 Ren Ringing Slic For Isdn Modem/ta And Wl
• Manufacturer: Intersil Corporation

Pin Descriptions
PLCC
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
1
2
3
4
5
6
7
8
9
RING SENSE 1 An analog input connected to the RING (more negative) side of the subscriber loop through a feed resistor.
RING SENSE 2 This is an internal sense mode that must be tied to RING SENSE 1 for proper SLIC operation.
TIP SENSE
SYMBOL
AGND
BGND
V
OUT1
V
V
RDO
SHD
I
V
RTD
ALM
V
TST
-IN1
V
RDI
LMT
RING
RTI
RS
NU
NU
RF
F1
F0
TF
REF
BAT
CC
RX
TX
Analog Ground - Serves as a reference for the transmit output and receive input terminals.
Positive Voltage Source - Most Positive Supply.
An external voltage connected to this pin will override the internal V
Power Denial - An active low TTL compatible logic control input. When enabled, the output of the ring amplifier
will ramp close to the output voltage of the tip amplifier.
TTL compatible logic control input that must be tied high for proper SLIC operation.
TTL compatible logic control input that must be tied high for proper SLIC operation.
Switch Hook Detection - An active low TTL compatible logic output. Indicates an off-hook condition.
Ring Trip Detection - An active low TTL compatible logic output. Indicates an off-hook condition when the
phone is ringing.
A TTL logic input. A low on this pin will keep the SLIC in a power down mode. The TST pin in conjunction with
the ALM pin can provide thermal shutdown protection for the SLIC. Thermal shutdown is implemented by a
system controller that monitors the ALM pin. When the ALM pin is active (low) the system controller issues a
command to the TST pin (low) to power down the SLIC. The timing of the thermal recovery is controlled by
the system controller.
A TTL compatible active low output which responds to the thermal detector circuit when a safe operating die
temperature has been exceeded.
Loop Current Limit - Voltage on this pin sets the short loop current limiting conditions.
The analog output of the spare operational amplifier.
to AGND.
An analog input connected to the TIP (more positive) side of the subscriber loop through a feed resistor.
Functions with the RING terminal to receive voice signals and for loop monitoring purpose.
Functions with the TIP terminal to receive voice signals and for loop monitoring purposes.
Receive Input, 4-Wire Side - A high impedance analog input. AC signals appearing at this input drive the Tip
Feed and Ring Feed amplifiers deferentially.
Not used in this application. This pin should be left floating.
Transmit Output, 4-Wire Side - A low impedance analog output which represents the differential voltage across
TIP and RING. Since the DC level of this output varies with loop current, capacitive coupling to the next stage
is necessary.
TTL compatible input to drive the uncommitted relay driver.
This is the output of the uncommitted relay driver.
Battery Ground - All loop current and some quiescent current flows into this terminal.
Not used in this application. This pin should be either grounded or left floating.
Ring signal input.
This is the output of the tip amplifier.
This is the output of the ring amplifier.
The negative battery source.
Ring Trip Input - This pin is connected to the external negative peak detector output for ring trip detection.
The inverting analog input of the spare operational amplifier. The non-inverting input is internally connected
71
HC55171B
DESCRIPTION
BAT
/2 reference.