March 2000
PBL 386 40/2
Subscriber Line
Interface Circuit
Description
The PBL 386 40/2 Subscriber Line Interface Circuit (SLIC) is a 90 V bipolar integrated
circuit for use in Digital Loop Carrier, FITL and other telecommunications equipment.
The PBL 386 40/2 has been optimized for low total line interface cost and a high
degree of flexibility in different applications.
The PBL 386 40/2 emulates resistive loop feed, programmable between 2x50
Ω
and 2x900
Ω,
with short loop current limiting adjustable to max 45 mA. In the current
limited region the loop feed is nearly constant current with a slight slope correspond-
ing to 2x30 kΩ.
A second, lower battery voltage may be connected to the device to reduce short
loop power dissipation. The SLIC automatically switches between the two battery
supply voltages without need for external components or external control.
The SLIC incorporates loop current, ground key and ring trip detection functions.
The PBL 386 40/2 is compatible with both loop and ground start signaling.
Two- to four-wire and four- to two-wire voice frequency (VF) signal conversion is
accomplished by the SLIC in conjunction with either a conventional CODEC/filter or
with a programmable CODEC/filter, e.g. SLAC, SiCoFi, Combo II. The programmable
two-wire impedance, complex or real, is set by a simple external network.
Longitudinal voltages are suppressed by a feedback loop in the SLIC and the
longitudinal balance specifications meet the DLC requirements.
The PBL 386 40/2 package options are 24-pin SSOP package, 24-pin SOIC and
28-pin PLCC.
Key Features
• 24-pin SSOP package
• High and low battery with automatic
switching
• 65 mW on-hook power dissipation in
active state
• On-hook transmission
• Long loop battery feed tracks Vbat for
maximum line voltage
• Only +5 V feed in addition to battery
• Selectable transmit gain (1x or 0.5x)
• No power-up sequence
• Programmable signal headroom
• 43V open loop voltage @ -48V battery
feed
• Constant loop voltage for line leakage
<5 mA (RLeak ~ >10 kΩ @ -48V)
• Full longitudinal current capability
during on-hook state
• Analog over temperature protection
permits transmission while the
protection circuit is active
• Line voltage measurement
Ring Relay
Driver
RRLY
• Polarity reversal
• Ground key detector
• Tip open state with ring ground
detector
• -40°C to +85°C ambient temperature
range
DT
DR
TIPX
RINGX
HP
Ring Trip
Comparator
Input
Decoder
and
Control
C1
C2
C3
DET
Ground Key
Detector
VCC
38
VBAT2
VBAT
Off-hook
Detector
PLD
REF
PBL
AGND
BGND
VF Signal
Transmission
VTX
RSN
386
40/2
24-pin SOIC, 24-pin SSOP, 28-pin PLCC
PTG
Figure 1. Block diagram.
1
38 PB
6 L
40
/2
LP
P
B
L
6
40
Two-wire
Interface
Line Feed
Controller
and
Longitudinal
Signal
Suppression
POV
PSG
PLC
/2
PBL 386 40/2
Maximum Ratings
Parameter
Symbol
Min
Max
Unit
Temperature, Humidity
Storage temperature range
Operating temperature range
Operating junction temperature range, Note 1
Power supply,
-40°C
≤
T
Amb
≤
+85°C
V
CC
with respect to A/BGND
V
Bat2
with respect to A/BGND
V
Bat
with respect to A/BGND, continuous
V
Bat
with respect to A/BGND, 10 ms
Power dissipation
Continuous power dissipation at T
Amb
≤
+85
°C
Ground
Voltage between AGND and BGND
Relay Driver
Ring relay supply voltage
Ring trip comparator
Input voltage
Input current
Digital inputs, outputs
(C1, C2, C3, DET)
Input voltage
Output voltage
TIPX and RINGX terminals,
-40°C < T
Amb
< +85°C, V
Bat
= -50V
Maximum supplied TIPX or RINGX current
TIPX or RINGX voltage, continuous (referenced to AGND), Note 2
TIPX or RINGX, pulse < 10 ms, t
Rep
> 10 s, Note 2
TIPX or RINGX, pulse < 1
µs,
t
Rep
> 10 s, Note 2
TIPX or RINGX, pulse < 250 ns, t
Rep
> 10 s, Notes 2 & 3
T
Stg
T
Amb
T
J
V
CC
V
Bat2
V
Bat
V
Bat
P
D
V
G
-55
-40
-40
-0.4
V
Bat
-75
-80
+150
+110
+140
6.5
0.4
0.4
0.4
1.5
°C
°C
°C
V
V
V
V
W
V
-0.3
+0.3
BGND+14 V
V
DT
, V
DR
I
DT
, I
DR
V
ID
V
OD
I
TIPX
, I
RINGX
V
TA
, V
RA
V
TA
, V
RA
V
TA
, V
RA
V
TA
, V
RA
V
Bat
-5
-0.4
-0.4
AGND
5
V
CC
V
CC
+100
2
5
10
15
V
mA
V
V
-100
-80
V
Bat
-10
V
Bat
-25
V
Bat
-35
mA
V
V
V
V
Recommended Operating Condition
Parameter
Symbol
Min
Max
Unit
Ambient temperature
V
CC
with respect to AGND
V
Bat
with respect to AGND
AGND with respect to BGND
T
Amb
V
CC
V
Bat
V
G
-40
4.75
-58
-100
+85
5.25
-8
100
°C
V
V
mV
Notes
1.
2.
3.
The circuit includes thermal protection. Operation at or above 140°C junction temperature may degrade device reliability.
With the diodes D
VB
and D
VB2
included, see figure 12.
R
F1
and R
F2
≥
20
Ω
is also required. Pulse is applied to TIP and RING outside R
F1
and R
F2
.
2
PBL 386 40/2
Electrical Characteristics
-40
°C ≤
T
Amb
≤
+85
°C,
PTG = open (see pin description), V
CC
= +5V
±5
%, V
Bat
= -58V to -40V, V
Bat2
=-32V, R
LC
=32.4 kΩ,
I
L
= 27 mA. R
L
= 600
Ω,
R
F1
=R
F2
=0, R
Ref
= 49.9 kΩ, C
HP
= 47nF, C
LP
=0.15
µF,
R
T
= 120 kΩ, R
SG
= 0 kΩ, R
RX
= 60 kΩ,
R
R
= 52.3 kΩ, R
OV
=∞ unless otherwise specified. Current definition: current is positive if flowing into a pin.
Parameter
Ref
fig
Conditions
Min
Typ
Max
Unit
Two-wire port
Overhead voltage, V
TRO
,I
Ldc
> 18mA
On-Hook, I
Ldc
< 5mA
Input impedance, Z
TR
Longitudinal impedance, Z
LOT
, Z
LOR
Longitudinal current limit, I
LOT
, I
LOR
Longitudinal to metallic balance, B
LM
2
Active state
1% THD, R
OV
=
∞
Note 1
Note 2
0 < f < 100 Hz
active state
IEEE standard 455-1985, Z
TRX
=736Ω
Normal polarity:
0.2 kHz < f < 1.0 kHz, T
amb
0-70°C
1.0 kHz < f < 3.4 kHz, T
amb
0-70°C
0.2 kHz < f < 1.0 kHz, T
amb
-40-85°C
1.0 kHz < f < 3.4 kHz, T
amb
-40-85°C
Reverse polarity:
0.2 kHz < f < 1.0 kHz, T
amb
0-70°C
1.0 kHz < f < 3.4 kHz, T
amb
0-70°C
0.2 kHz < f < 1.0 kHz, T
amb
-40-85°C
1.0 kHz < f < 3.4 kHz, T
amb
-40-85°C
Normal polarity:
0.2 kHz < f < 1.0 kHz, T
amb
0-70°C
1.0 kHz < f < 3.4 kHz, T
amb
0-70°C
0.2 kHz
≤
f
≤
1.0 kHz, T
amb
-40-85°C
1.0 kHz < f < 3.4 kHz, T
amb
-40-85°C
Reverse polarity:
0.2 kHz < f < 1.0 kHz, T
amb
0-70°C
1.0 kHz < f < 3.4 kHz, T
amb
0-70°C
0.2 kHz < f < 1.0 kHz, T
amb
-40-85°C
1.0 kHz < f < 3.4 kHz, T
amb
-40-85°C
0.2 kHz < f < 3.4 kHz
2.7
1.1
Z
T
/200
20
28
35
V
Peak
V
Peak
Ω/wire
mA
rms
/wire
63
60
60
55
59
55
55
55
63
60
60
55
59
55
55
55
40
66
66
66
66
66
66
66
66
66
66
66
66
66
66
66
66
50
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
Longitudinal to metallic balance, B
LME
Longitudinal to four wire balance B
LFE
B
LME
= 20 · Log E
Lo
V
TR
B
LFE
= 20 · Log E
Lo
V
TX
3
3
Metallic to longitudinal balance, B
MLE
V
TR
B
MLE
= 20 · Log
; E
RX
= 0
V
Lo
4
Figure 2. Overhead voltage, V
TRO
, two-
wire port
1
<< R
L
, R
L
= 600
Ω
ωC
R
T
= 120 kΩ, R
RX
= 60 kΩ
R
L
V
TRO
C
TIPX
VTX
I
LDC
PBL 386 40/2
RINGX
RSN
R
T
E
RX
R
RX
Figure 3. Longitudinal to metallic (B
LME
)
and Longitudinal to four-wire (B
LFE
)
balance
1
ωC
<< 150
Ω,
R
LR
=R
LT
=R
L
/2=300Ω
R
T
= 120 kΩ, R
RX
= 60 kΩ
TIPX
E
Lo
C
R
LT
V
TR
R
LR
RINGX
VTX
PBL 386 40/2
RSN
R
T
V
TX
R
RX
3
PBL 386 40/2
Ref
fig
Parameter
Conditions
Min
Typ
Max
Unit
Four-wire to longitudinal balance, B
FLE
4
0.2 kHz < f < 3.4 kHz
E
B
FLE
= 20 · Log
RX
V
Lo
r = 20 · Log
|Z
TR
+ Z
L
|
|Z
TR
- Z
L
|
40
50
dB
Two-wire return loss, r
TIPX idle voltage, V
Ti
RINGX idle voltage, V
Ri
V
TR
Four-wire transmit port
(VTX)
Overhead voltage, V
TXO
, I
L
> 18mA
On-hook, I
L
< 5mA
Output offset voltage,
∆V
TX
Output impedance, z
TX
Four-wire receive port
(RSN)
Receive summing node (RSN) DC voltage
Receive summing node (RSN) impedance
Receive summing node (RSN)
current (I
RSN
) to metallic loop current (I
L
)
gain,α
RSN
Frequency response
Two-wire to four-wire, g
2-4
6
5
0.2 kHz < f < 1.0 kHz
1.0 kHz < f < 3.4 kHz, Note 3
active, I
L
< 5 mA
active, I
L
< 5 mA
tip open, I
L
< 5 mA
active, I
L
< 5 mA
Load impedance > 20 kΩ,
1% THD, Note 4
30
20
35
22
- 1.3
V
Bat
+3.0
V
Bat
+3.0
V
Bat
+4.3
dB
dB
V
V
V
V
V
Peak
V
Peak
mV
Ω
V
Ω
ratio
2.7
1.1
-100
0.2 kHz < f < 3.4 kHz
I
RSN
= -55
µA
0.2 kHz < f < 3.4 kHz
0.3 kHz < f < 3.4 kHz
1.15
0
15
1.25
8
200
100
50
1.35
20
relative to 0 dBm, 1.0 kHz. E
RX
= 0 V
0.3 kHz < f < 3.4 kHz
f = 8.0 kHz, 12 kHz, 16 kHz
-0.20
-1.0
0.10
0.1
dB
dB
TIPX
C
V
Lo
R
LT
V
TR
R
LR
RINGX
VTX
Figure 4. Metallic to longitudinal and four-
wire to longitudinal balance
R
T
PBL 386 40/2
RSN
E
RX
1
<< 150
Ω,
R
LT
=R
LR
=R
L
/2 =300Ω
ωC
R
T
= 120 kΩ, R
RX
= 60 kΩ
R
RX
C
R
L
I
LDC
E
L
TIPX
VTX
Figure 5. Overhead voltage, V
TXO
, four-
wire transmit port
1
<< R
L
, R
L
= 600
Ω
ωC
R
T
= 120 kΩ, R
RX
= 60 kΩ
R
RX
PBL 386 40/2
RINGX
RSN
R
T
V
TXO
4
PBL 386 40/2
Ref
fig
Parameter
Conditions
Min
Typ
Max
Unit
Four-wire to two-wire, g
4-2
6
Four-wire to four-wire, g
4-4
Insertion loss
Two-wire to four-wire, G
2-4
6
relative to 0 dBm, 1.0 kHz. E
L
=0 V
0.3 kHz < f < 3.4 kHz
f = 8 kHz, 12 kHz,
16 kHz
relative to 0 dBm, 1.0 kHz, E
L
=0 V
0.3 kHz < f < 3.4 kHz
0 dBm, 1.0 kHz, Note 5
V
G
2-4
= 20 · Log
TX
; E
RX
= 0
V
TR
PTG = AGND
0 dBm, 1.0 kHz, Note 6
V
G
4-2
= 20 · Log
TR
; E
L
= 0
E
RX
Ref. -10 dBm, 1.0 kHz, Note 7
-40 dBm to + 3 dBm
-55 dBm to -40 dBm
Ref. -10 dBm, 1.0 kHz,
-40 dBm to + 3 dBm
-55 dBm to -40 dBm
C-message weighting
Psophometrical weighting
Note 8
-0.2
-1.0
-2.0
-0.2
0.1
0
0
0.1
dB
dB
dB
dB
6
-0.2
-6.22
-0.2
-6.02
0.2
-5.82
0.2
dB
dB
dB
Four-wire to two-wire, G
4-2
6
Gain tracking
Two-wire to four-wire
6
-0.1
-0.2
-0.1
-0.2
0.1
0.2
0.1
0.2
12
-78
dB
dB
dB
dB
dBrnC
dBmp
Four-wire to two-wire
6
Noise
Idle channel noise at two-wire
(TIPX-RINGX) or four-wire (VTX) output
Harmonic distortion
Two-wire to four-wire
Four-wire to two-wire
Battery Feed characteristics
Loop current, I
L
, in the current
limited region, reference A, B & C
Tip open state TIPX current, I
Leak
Tip open state RINGX current, I
LRTo
Tip open state RINGX voltage, V
RTo
Tip voltage (ground start)
13
7
7
7
7
6
0 dBm
0.3 kHz < f < 3.4 kHz
-67
-67
-50
-50
dB
dB
18mA
≤
I
L
≤
45 mA
S = closed; R = 7 kΩ, note 10
R
LRTo
= 0Ω, V
Bat
= -48V
R
LRTo
= 2.5 kΩ, V
Bat
= -48V
I
LRTo
< 23 mA
Active state, Tip lead open (S open),
Ring lead to ground through 150
Ω
0.92 I
L
I
L
I
L
17
V
Bat
+ 6
-2.2
1.08 I
L
-100
mA
µA
mA
mA
V
V
-4
C
Figure 6.
Frequency response, insertion loss,
gain tracking.
1
ωC
<< R
L
, R
L
= 600
Ω
TIPX
VTX
R
L
V
TR
E
L
I
LDC
PBL 386 40/2
RINGX
RSN
R
T
E
RX
V
TX
R
RX
R
T
= 120 kΩ, R
RX
= 60 kΩ
5
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