L7554 Low-Power SLIC
Data Sheet
March 1997
Electrical Characteristics
(continued)
Table 5. 2-Wire Port
Parameter
Tip or Ring Drive Current
= dc + Longitudinal + Signal Currents
Signal Current
Longitudinal Current Capability per Wire
1
dc Loop Current Limit
2
R
LOOP
= 100
Ω
Programmability Range
Accuracy (20 mA < I
LIM
< 40 mA)
Powerup Open Loop Voltage Levels
Common-mode Voltage
Differential Voltage:
V
BAT
= –48 V, Temperature = 25
°C
V
BAT
= –72 V, Temperature = 85
°C
(L7554BP)
Disconnect State
PT Resistance (V
BAT
< V
PT
< 0 V)
PR Resistance (V
BAT
< V
PR
< 0 V)
Ground Start State
PT Resistance
dc Feed Resistance (for I
LOOP
below regulation level)
Loop Resistance Range (–3.17 dBm overload into
600
Ω;
not including protection)
I
LOOP
= 20 mA at V
BAT
= –48 V
I
LOOP
= 20 mA at V
BAT
= –24 V
Longitudinal to Metallic Balance—IEEE
3
Std. 455
(See Figure 7.)
4
50 Hz to 1 kHz
1 kHz to 3 kHz
Metallic to Longitudinal Balance
200 Hz to 4 kHz
RFI Rejection (See Figure 8.)
5
0.5 Vrms, 50
Ω
Source, 30% AM Mod. 1 kHz
500 kHz to 100 MHz
Min
65
15
8.5
—
5
—
—
|V
BAT
+ 7.0|
|V
BAT
+ 10.0|
100
100
100
90
Typ
—
—
15
I
LIM
—
—
V
BAT
/2
|V
BAT
+ 6.5|
|V
BAT
+ 6.8|
143
133
143
113
Max
—
—
—
—
45
±12
—
|V
BAT
+ 6.0|
—
—
—
—
133
Unit
mA
mArms
mArms
mA
mA
%
V
V
V
kΩ
kΩ
kΩ
Ω
1900
700
—
—
—
—
Ω
Ω
64
60
46
75
70
—
—
—
—
dB
dB
dB
—
–55
–45
dBV
1. The longitudinal current is independent of dc loop current.
2. Current-limit I
LIM
is programmed by a resistor, R
PROG
, from pin I
PROG
to DCOUT. I
LIM
is specified at the loop resistance where current limiting
begins (see Figure 25). Select R
PROG
(kΩ) = 1.67 x I
LIM
(mA).
3.
IEEE
is a registered trademark of The Institute of Electrical and Electronics Engineers, Inc.
4. Longitudinal balance of circuit card will depend on loop series resistance matching (see Figures 23 and 24).
5. This parameter is not tested in production. It is guaranteed by design and device characterization.
8
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
