HC55120CM INTERSIL [Intersil Corporation], HC55120CM Datasheet - Page 30

• Manufacturer Part Number: HC55120CM
• Description: Low Power Universal SLIC Family
• Manufacturer: INTERSIL [Intersil Corporation]

Pin Descriptions
HC55120, HC55121, HC55130, HC55131, HC55140, HC55141, HC55142, HC55143, HC55150, HC55151
PLCC
PIN
28
15
16
17
18
19
20
21
22
23
24
25
26
27
28
-
-
-
PLCC
PIN
32
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
SOIC
PIN
28
16
17
18
19
15
20
21
22
23
24
28
25
26
27
-
-
-
(Continued)
RSYNC_REV
4-30
GKD_LVM
SYMBOL
TRLY2
TRLY1
AGND
ROH
SPM
SHD
VRX
V
ILIM
VTX
RD
C4
C3
C2
C1
CC
Activates Test Relay TRLY1.
TTL Compatible Logic Input. The logic states of C1, C2 and C3 determine the operating states of the
SLIC. Reference Table 1 for details.
TTL Compatible Logic Input. The logic states of C1, C2 and C3 determine the operating states of the
SLIC. Reference Table 1 for details.
TTL Compatible Logic Input. The logic states of C1, C2 and C3 determine the operating states of the
SLIC. Reference Table 1 for details.
Switch Hook Detect - Active during off hook, ground key and loopback. Reference Table 1 for details.
Ground Key Detector and Line Voltage Measurement - Reference Table 1 for details.
5V Supply.
Loop Current Threshold Programming Pin - A resistor between this pin and ground will determine the
trigger level for the loop current detect circuit. See Equation 7.
Off Hook Overload Setting Resistor - Used to set combined overhead for voice and pulse metering
signals. See Equation 10.
Current Limit Programming Pin - A resistor between this pin and ground will determine the constant
current limit of the feed curve. See Equation 11.
Ring Synchronization Input and Reversal Time Setting. A resistor between this pin and GND
determines the polarity reversal time. Synchronization of the closing of the relay at zero voltage is
achieved via a ring sync pulse (5V to 0V) synchronized to the ring signal zero voltage crossing
(Reference Figure 18).
Analog ground
Receive Input - Ground referenced 4-wire side.
Pulse Metering Signal Input. If pulse metering is not used, then this pin should be grounded as close
to the device pin as possible.
Transmit Output - Ground referenced 4-wire side.
Test Relay Driver 2.
Test Relay Driver 1.
DESCRIPTION