HC5515 Intersil Corporation, HC5515 Datasheet - Page 13

• Manufacturer Part Number: HC5515
• Description: ITU CO/PABX SLIC with Low Power Standby
• Manufacturer: Intersil Corporation

Ringing State (C1 = 1, C2 = 0)
The ring relay driver and the ring trip detector are activated.
Both the tip and ring line drive amplifiers are powered down.
Both tip and ring are disconnected from the line via the
external ring relay.
Standby State (C1 = 1, C2 = 1)
Both the tip and ring line drive amplifiers are powered down.
Internal resistors are connected between tip to ground and ring
to V
The loop current and ground key detectors are both active, E0
determines if the detector is gated to the DET output.
AC Transmission Circuit Stability
To ensure stability of the AC transmission feedback loop two
compensation capacitors C
Figure 20 (Application Circuit) illustrates their use.
Recommended value is 2200pF.
AC-DC Separation Capacitor, C
The high pass filter capacitor connected between pins HPT
and HPR provides the separation between circuits sensing
tip to ring DC conditions and circuits processing AC signals.
A 10nf C
3dB break point at 48Hz. Where:
where R
Thermal Shutdown Protection
The HC5515’s thermal shutdown protection is invoked if a
fault condition on the tip or ring causes the temperature of
the die to exceed 160
a high impedance state and will remain there until the
temperature of the die cools down by about 20
will return back to its normal operating mode, providing the
fault condition has been removed.
SLIC Operating States
f
3dB
BAT
E0
0
0
0
0
1
1
1
1
=
---------------------------------------------------- -
to allow loop current detect in an off-hook condition.
2
HP
HP
= 330k .
will position the low end frequency response
R
1
HP
C1
0
0
1
1
0
0
1
1
C
o
HP
C. If this happens, the SLIC goes into
TC
C2
0
1
0
1
0
1
0
1
67
and C
Open Circuit
Active
Ringing
Standby
Open Circuit
Active
Ringing
Standby
RC
SLIC OPERATING STATE
are required.
HP
o
C. The SLIC
TABLE 1. LOGIC TRUTH TABLE
(EQ. 28)
HC5515
No Active Detector
Loop Current Detector
Ring Trip Detector
Loop Current Detector
No Active Detector
Loop Current Detector
Ring Trip Detector
Loop Current Detector
Surge Voltage Protection
The HC5515 must be protected against surge voltages and
power crosses. Refer to “Maximum Ratings” TIPX and
RINGX terminals for maximum allowable transient tip and
ring voltages. The protection circuit shown in Figure 20
utilizes diodes together with a clamping device to protect tip
and ring against high voltage transients.
Positive transients on tip or ring are clamped to within a
couple of volts above ground via diodes D
normal operating conditions D
and out of the circuit.
Negative transients on tip and ring are clamped to within a
couple of volts below ground via diodes D
help of a Surgector. The Surgector is required to block
conduction through diodes D
operating conditions and allows negative surges to be
returned to system ground.
The fuse resistors (R
nondestructive power dissipaters during surge and fuses
when the line in exposed to a power cross.
Power-Up Sequence
The HC5515 has no required power-up sequence. This is a
result of the Dielectrically Isolated (DI) process used in the
fabrication of the part. By using the DI process, care is no
longer required to insure that the substrate be kept at the
most negative potential as with junction isolated ICs.
Printed Circuit Board Layout
Care in the printed circuit board layout is essential for proper
operation. All connections to the RSN pin should be made as
close to the device pin as possible, to limit the interference
that might be injected into the RSN terminal. It is good
practice to surround the RSN pin with a ground plane.
The analog and digital grounds should be tied together at
the device.
ACTIVE DETECTOR
F
) serve a dual purpose of being
3
1
and D
and D
Logic Level High
Loop Current Status
Ring Trip Status
Loop Current Status
Logic Level High
4
2
under normal
are reverse biased
DET OUTPUT
1
3
and D
and D
2
4
. Under
with the