LUCL8574DP-D AGERE [Agere Systems], LUCL8574DP-D Datasheet - Page 16

• Manufacturer Part Number: LUCL8574DP-D
• Description: L8574D Resistive Subscriber Line Interface Circuit(SLIC), Ring Relay,and Protector(SRP)for Long Loop and TR-57 Applications
• Manufacturer: AGERE [Agere Systems]

L8574D Resistive Subscriber Line Interface Circuit (SLIC), Ring
Relay, and Protector (SRP) for Long Loop and TR-57 Applications
Electrical Characteristics
Switch Characteristics
Figure 3. Switch On-State V-I Characteristics SW1
16
16
Figure 4. Switch On-State V-I Characteristics SW3
–V
max
CURRENT
LIMITING
2/3 R
ON
and SW2
R
–1.5 V
ON
+I
–V
LIMIT
OS
I
I
SW
SW
R
+V
–I
ON
+1.5 V
OS
LIMIT
(continued)
R
ON
(continued)
2/3 R
CURRENT
LIMITING
ON
+V
max
12-3332 (F)
12-3333 (F)
V
V
SW
SW
Operating States
The L8574 has eight operating states. These states are
selected using three logic input bits, B0—B2, according
to the truth table shown in Table 14. Logic input B3
operates a relay driver independent of the state of bits
B0—B2. Data on the parallel data bus, B0—B3, is
loaded into a 4-bit latch on the L8574 on the low-to-
high transition of the channel select lead CS. Changes
in the data at inputs B0—B3 do not affect the L8574
while CS is either low or high. A low on channel enable
lead CE asynchronously resets the 4-bit latch to 1111
(scan state with the relay driver off) and disables the
channel select lead CS (i.e., CS is prevented from load-
ing any data into the 4-bit latch). A high on CE enables
CS. State transitions and delays between transitions
are left to the discretion of the user since, except for
fault conditions described later, the state of the L8574
depends only on the external control provided through
the logic interface.
Table 14. Input State Coding
Scan State
CE B3 B2 B1 B0
0
1
1
1
1
1
1
1
1
1
1
Normal on-hook supervision state.
The receive transmission path is powered down; the
transmit path is powered up.
The battery feed is connected to the high battery
supply (V
The current limiter is powered down and disabled.
SW1 is closed; SW2 and SW3 are open.
NSTAT reflects the status of the switchhook detector.
X
X
X
X
X
X
X
X
X
0
1
X
X
X
1
1
1
1
0
0
0
0
BAT1
).
X
1
1
0
0
1
1
0
0
X
X
X Scan state with relay driver off
X Relay driver output (RDO) is
X Relay driver output (RDO) is
1
0
1
0
1
0
1
0
Scan
Disconnect
Alternative talk—SW1 closed
Talk—SW1 open
Scan current limit
Ringing
On-hook transmission
Intermediate talk
low (relay active)
high (relay not active)
Lucent Technologies Inc.
State
October 1998
Data Sheet