HC55143IM Intersil, HC55143IM Datasheet - Page 25

• Manufacturer Part Number: HC55143IM
• Description: IC SLIC UNIVERSAL LP 32-PLCC
• Manufacturer: Intersil
• Series: UniSLIC14r

Specifications of HC55143IM

• Function: Subscriber Line Interface Concept (SLIC)
• Number Of Circuits: 1
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 2.25mA
• Power (watts): 1.4W
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-PLCC
• Includes: Battery Tracking Anti-Clipping, Loop and Ground Key Detection, Ring Control
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Interface: -

Overload Levels and Silent Polarity Reversal
The pulse metering signal and voice are simultaneously
transmitted, and therefore require additional overhead to
prevent distortion of the signal. Reference section “Off hook
Overhead Voltage” to account for the additional pulse
metering signal requirements.
Most of the SLICs in the UniSLIC14 family feature full
polarity reversal. Full polarity reversal means that the SLIC
can transmit, determine the status of the line (on hook and
off hook) and provide “silent” polarity reversal. Reference
Equation 39 to program the polarity reversal time.
Interface to Dual and Single Supply
CODECs
Great care has been taken to minimize the number of external
components required with the UniSLIC14 family while still
providing the maximum flexibility. Figures 24A, 24B) shows
the connection of the UniSLIC14 to both a dual supply
CODEC/Filter and a single supply DSP CODEC/Filter.
To eliminate the DC blocking capacitors between the SLIC
and the CODEC/Filter when using a dual supply
CODEC/Filter, both the receive and transmit leads of the
SLIC are referenced to ground. This leads to a very simple
SLIC to CODEC/Filter interface, as shown in Figure 24A.
When using a single supply DSP CODEC/Filter the output
and input of the CODEC/Filter are no longer referenced to
ground. To achieve maximum voltage swing with a single
supply, both the output and input of the CODEC/Filter are
referenced to its own V
capacitors are once again required. By using the PTG pin of
the UniSLIC14 and the externally supplied V
FIGURE 23. PULSE METERING WITH TRANSHYBRID
5
I
X
500K
500K
BALANCE
RA
RB
HC55120, HC55121, HC55130, HC55140, HC55142, HC55143, HC55150
OUTPUT BUFFER
I
X
CC
125K
UniSLIC14
+
-
A = 1
/2 reference. Thus, DC blocking
25
V
V
PTG
SPM
TX
150pF
C added to
bottom of
board
R added to
bottom of
board
30.1K
CC
V
/2 reference
TX
+
-
V
ttx
+
-
of the CODEC/Filter, one of the DC blocking capacitors can
be eliminated (Figure 24B).
Power Management
The UniSLIC14 family provides two distinct power
management capabilities:
Power Sharing and Battery Selection
Power Sharing
Power sharing is a method of redistributing the power away
from the SLIC in short loop applications. The total system
power is the same, but the die temperature of the SLIC is
much lower. Power sharing becomes important if the
application has a single battery supply (-48V on hook
requirements for faxes and modems) and the possibility of
high loop currents (reference Figure 25). This technique
would prevent the SLIC from getting too hot and thermally
shutting down on short loops.
The power dissipation in the SLIC is the sum of the smaller
quiescent supply power and the much larger power that
results from the loop current. The power that results from the
loop current is the loop current times the voltage across the
SLIC. The power sharing resistor (R
across the SLIC, and thereby the on-chip power dissipation.
The voltage across the SLIC is reduced by the voltage drop
across R
loop current and the negative supply.
A mathematical verification follows:
FIGURE 24. INTERFACE TO DUAL AND SINGLE SUPPLY
500K
500K
UniSLIC14
UniSLIC14
PS
+
+
-
-
A = 1
A = 1
. This occurs because R
CODECs
V
V
V
V
PTG
RX
RX
TX
TX
FIGURE 24A.
FIGURE 24B.
V
V
V
OUT
REF
OUT
V
IN
PS
PS
+
SINGLE SUPPLY
) reduces the voltage
-
CODEC/FILTER
DUAL SUPPLY
CODEC/FILTER
is in series with the
DSP
June 1, 2006
FN4659.13
5V
GND
-5V
5V
GND