Preliminary
PBL 386 65/2
Ref
fig
Parameter
Conditions
Min
Typ
Max
Unit
Four-wire to longitudinal balance, BFLE
4
Active state
ERX
BFLE = 20 • Log
VLo
0.2 kHz < f < 3.4 kHz
40
dB
Two-wire return loss, r
|ZTR + ZL|
|ZTR - ZL|
r = 20 • Log
0.2 kHz < f < 0.5 kHz
0.5 kHz < f < 1.0 kHz
1.0 kHz < f < 3.4 kHz, Note 3
active, IL < 5 mA
active, IL < 5 mA
tip open, IL < 5 mA
active, IL < 5 mA
25
27
23
dB
dB
dB
V
V
V
TIPX idle voltage, VTi
RINGX idle voltage, VRi
RINGX idle voltage, VRi
VTR
- 1.5
VBat +2.7
VBat +3.0
VBat +4.2
V
Four-wire transmit port (VTX)
Overload level, VTXO, IL ≥ 10 mA
On hook IL ≤ 5 mA
Output offset voltage, ∆VTX
Output impedance, zTX
5
Load impedance > 20 kΩ,
1% THD, Note 4
1.55
0.7
-60
VPeak
VPeak
mV
Ω
60
20
0.2 kHz < f < 3.4 kHz
5
Four-wire receive port (RSN)
Receive summing node (RSN) dc voltage
Receive summing node (RSN) impedance
Receive summing node (RSN)
current (IRSN) to metallic loop current (IL)
gain,αRSN
I
RSN = 0 mA
-25
GND
10
+25
50
mV
Ω
0.2 kHz < f < 3.4 kHz
0.3 kHz < f < 3.4 kHz
400
ratio
Frequency response
Two-wire to four-wire, g2-4
6
relative to 0 dBm, 1.0 kHz. ERX = 0 V
0.3 kHz < f < 3.4 kHz
-0.15
-0.5
0.15
+0.1
dB
dB
f = 8.0 kHz, 12 kHz, 16 kHz
0
Figure 4. Metallic to longitudinal and
four-wire to longitudinal balance
TIPX
VTX
RLT
C
1
<< 150 Ω, RLT = RLR = RL /2=300Ω
ωC
VTR
RT
PBL 386 65/2
ERX
VLo
RLR
RINGX
RSN
RT = 120 kΩ, RRX = 120 kΩ
RRX
Figure 5. Overload level, VTXO, four-wire
transmit port
C
TIPX
VTX
RL
EL
1
<< RL, RL = 600 Ω
ωC
ILDC
RT
VTXO
PBL 386 65/2
RT = 120 kΩ, RRX = 120 kΩ
RINGX
RSN
RRX
4