Data Sheet
March 1997
L7554 Low-Power SLIC
Electrical Characteristics (continued)
Table 5. 2-Wire Port
Parameter
Min
Typ
Max
Unit
Tip or Ring Drive Current
= dc + Longitudinal + Signal Currents
—
—
15
—
—
—
65
15
mA
Signal Current
mArms
mArms
Longitudinal Current Capability per Wire1
8.5
dc Loop Current Limit2
RLOOP = 100 Ω
Programmability Range
Accuracy (20 mA < ILIM < 40 mA)
—
5
—
ILIM
—
—
—
45
±12
mA
mA
%
Powerup Open Loop Voltage Levels
Common-mode Voltage
—
VBAT/2
—
V
Differential Voltage:
VBAT = –48 V, Temperature = 25 °C
VBAT = –72 V, Temperature = 85 °C (L7554BP)
|VBAT + 7.0| |VBAT + 6.5| |VBAT + 6.0|
V
V
|VBAT + 10.0| |VBAT + 6.8|
—
Disconnect State
PT Resistance (VBAT < VPT < 0 V)
PR Resistance (VBAT < VPR < 0 V)
143
133
—
—
100
100
kΩ
kΩ
Ground Start State
PT Resistance
143
113
—
100
90
kΩ
dc Feed Resistance (for ILOOP below regulation level)
133
Ω
Loop Resistance Range (–3.17 dBm overload into
600 Ω; not including protection)
ILOOP = 20 mA at VBAT = –48 V
—
—
—
—
1900
700
Ω
Ω
ILOOP = 20 mA at VBAT = –24 V
Longitudinal to Metallic Balance—IEEE 3 Std. 455
(See Figure 7.)4
50 Hz to 1 kHz
—
—
64
60
75
70
dB
dB
1 kHz to 3 kHz
Metallic to Longitudinal Balance
200 Hz to 4 kHz
—
—
46
—
dB
RFI Rejection (See Figure 8.)5
0.5 Vrms, 50 Ω Source, 30% AM Mod. 1 kHz
500 kHz to 100 MHz
–55
–45
dBV
1. The longitudinal current is independent of dc loop current.
2. Current-limit ILIM is programmed by a resistor, RPROG, from pin IPROG to DCOUT. ILIM is specified at the loop resistance where current limiting
begins (see Figure 25). Select RPROG (kΩ) = 1.67 x ILIM (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 ]
