PBL38650/2SHT [ERICSSON]

SLIC, Bipolar, PDSO24, SSOP-24;
PBL38650/2SHT
型号: PBL38650/2SHT
厂家: ERICSSON    ERICSSON
描述:

SLIC, Bipolar, PDSO24, SSOP-24

电信 光电二极管 电信集成电路
文件: 总16页 (文件大小:138K)
中文:  中文翻译
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June 1999  
PBL 386 50/2  
Subscriber Line  
Interface Circuit  
Description  
Key Features  
The PBL 386 50/2 Subscriber Line Interface Circuit (SLIC) is a 90 V bipolar integrated • 24-pin SSOP package  
circuit for use in Central Office Metering applications and other telecommunications  
equipment. The PBL 386 50/2 has been optimized for low total line interface cost and  
headroom for 2.2 Vrms metering  
a high degree of flexibility in different applications.  
• Programmable two-wire signal  
• High and low battery with automatic  
The PBL 386 50/2 emulates resistive loop feed, programmable between 2x50 Ω  
switching  
and 2x900 , with short loop current limiting adjustable to max 45 mA. In the current  
• Only +5 V feed in addition to battery  
limited region the loop feed is nearly constant current with a slight slope  
corresponding to 2x30k.  
• Selectable transmit gain (0.5x or 0.25x)  
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 50/2 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 Bellcore TR909 requirements.  
The PBL 386 50/2 package options are 24-pin SSOP, 24-pin SOIC or 28-pin PLCC.  
• 70 mW on-hook power dissipation in  
active state  
• On-hook transmission  
• Long loop battery feed tracks Vbat for  
maximum line voltage  
• No power-up sequence  
• 43V open loop voltage @  
-48V battery feed  
• Constant loop voltage for line leakage  
<5 mA (RLeak ~ >10 k@ -48V)  
• Full longitudinal current capability  
during on-hook state  
• Analog over temperature protection  
permits transmission while the  
protection circuit is active  
• Line voltage measurement  
• Polarity reversal  
Ring Relay  
RRLY  
Driver  
• Ground key detector  
DT  
C1  
Ring Trip  
Comparator  
• Tip open state with ring ground  
detector  
DR  
TIPX  
RINGX  
HP  
C2  
Input  
Decoder  
and  
C3  
Ground Key  
Detector  
Control  
DET  
POV  
PSG  
PLC  
Line Feed  
Controller  
and  
Longitudinal  
Signal  
VCC  
Two-wire  
Interface  
PBL 386 50/2  
PBL  
Suppression  
LP  
386 50/2  
VBAT2  
VBAT  
PLD  
REF  
Off-hook  
Detector  
PBL 386 50/2  
AGND  
BGND  
VTX  
RSN  
VF Signal  
Transmission  
24-pin SOIC, 24-pin SSOP, 28-pin PLCC  
PTG  
Figure 1. Block diagram.  
1
PBL 386 50/2  
Maximum Ratings  
Parameter  
Symbol  
Min  
Max  
Unit  
Temperature, Humidity  
Storage temperature range  
Operating temperature range  
Operating junction temperature range, Note 1  
TStg  
TAmb  
TJ  
-55  
-40  
-40  
+150  
+110  
+140  
°C  
°C  
°C  
Power supply, 0°C TAmb -70°C  
V
V
V
V
CC with respect to A/BGND  
Bat2 with respect to A/BGND  
Bat with respect to A/BGND, continuous  
Bat with respect to A/BGND, 10 ms  
VCC  
VBat2  
VBat  
VBat  
-0.4  
VBat  
-75  
-80  
6.5  
0.4  
0.4  
0.4  
V
V
V
V
Power dissipation  
Continuous power dissipation at TAmb +70 °C  
PD  
VG  
1.5  
0,3  
W
V
Ground  
Voltage between AGND and BGND  
Relay Driver  
-0,3  
Ring relay supply voltage  
BGND+14 V  
Ring trip comparator  
Input voltage  
Input current  
VDT, VDR  
IDT, IDR  
VBat  
-5  
AGND  
5
V
mA  
Digital inputs, outputs (C1, C2, C3, DET)  
Input voltage  
VID  
-0.4  
-0.4  
VCC  
VCC  
V
V
Output voltage  
VOD  
TIPX and RINGX terminals, 0°C < TAmb < +70°C, VBat = -50V  
Maximum supplied TIPX or RINGX current  
ITIPX, IRINGX -100  
+100  
2
mA  
V
TIPX or RINGX voltage, continuous (referenced to AGND), Note 2  
TIPX or RINGX, pulse < 10 ms, tRep > 10 s, Note 2  
TIPX or RINGX, pulse < 1 µs, tRep > 10 s, Note 2  
VTA, VRA  
VTA, VRA  
VTA, VRA  
VTA, VRA  
-80  
VBat -10  
VBat -25  
VBat -35  
5
V
10  
15  
V
TIPX or RINGX, pulse < 250 ns, tRep > 10 s, Notes 2 & 3  
V
Recommended Operating Condition  
Parameter  
Symbol  
Min  
Max  
Unit  
Ambient temperature  
TAmb  
VCC  
VBat  
VG  
0
+70  
5.25  
-8  
°C  
V
V
V
V
CC with respect to AGND  
Bat with respect to AGND  
4.75  
-65  
-100  
AGND with respect to BGND  
100  
mV  
Notes  
1. The circuit includes thermal protection. Operation at or above 140°C junction temperature may degrade device reliability.  
2. With the diodes DVB and DVB2 included, see figure 12.  
3.  
RF1 and RF2 20 is also required. Pulse is applied to TIP and RING outside RF1 and RF2.  
2
PBL 386 50/2  
Electrical Characteristics  
0 °C TAmb +70 °C, PTG = Open (see pin description), ROV = , VCC= +5V ±5 %, VBat= -58V to -40V, VBat2 = -32V, RLC=32.4 k, IL  
= 27 mA. RL = 600 , RF1= RF2= RP1= RP2=0, RRef = 49.9 k, CHP = 47 nF, CLP=0.15 µF, RT = 60 k, RSG = 0 k, RRX = 60 k, RR =  
11 kunless otherwise specified. Current definition: current is positive if flowing into a pin.  
Ref  
Parameter  
fig  
Conditions  
Min  
Typ  
Max  
Unit  
Two-wire port  
Overhead voltage, VTRO ,ILdc > 18mA  
2
Active state, ROV = ∞  
0.2 kHz < f < 3.4 kHz  
1% THD, Note 1  
f16kHz, ZLAC =200, Adj. by ROV  
Note 2  
0 < f < 100 Hz  
active state  
Normal polarity:  
0.2 kHz < f < 1.0 kHz  
1.0 kHz < f < 3.4 kHz  
Reverse polarity:  
0.2 kHz < f < 3.4 kHz  
2.7  
1.1  
VPeak  
On-Hook, ILdc < 5mA  
Over load level, metering  
Input impedance, ZTR  
Longitudinal impedance, ZLOT, ZLOR  
Longitudinal current limit, ILOT, ILOR  
Longitudinal to metallic balance, BLM  
(IEEE standard 455-1985, ZTRX=736)  
Longitudinal to metallic balance, BLME  
ELo  
VPeak  
VPeak  
5.0  
35  
ZT/200  
20  
/wire  
mArms /wire  
18  
55  
55  
dB  
dB  
3
3
BLME = 20 · Log  
55  
dB  
VTR  
Longitudinal to four-wire balance, BLFE  
Normal polarity:  
0.2 kHz < f < 1.0 kHz  
1.0 kHz < f < 3.4 kHz  
Reverse polarity:  
61  
61  
75  
70  
dB  
dB  
ELo  
BLFE = 20 · Log  
VTX  
0.2 kHz < f < 3.4 kHz  
0.2 kHz < f < 3.4 kHz  
61  
40  
68  
50  
dB  
dB  
Metallic to longitudinal balance, BMLE  
VTR  
4
BMLE = 20 · Log  
; ERX = 0  
VLo  
C
TIPX  
VTX  
Figure 2. Overhead voltage, VTRO, two-  
wire port  
RL  
VTRO  
ILDC  
RT  
PBL 386 50/2  
ERX  
RINGX  
RSN  
1
<< RL, RL= 600 Ω  
ωC  
RRX  
RT = 60 k, RRX = 60 kΩ  
VTX  
TIPX  
ELo  
RLT  
C
Figure 3. Longitudinal to metallic (BLME  
)
RT  
VTR  
PBL 386 50/2  
VTX  
and Longitudinal to four-wire (BLFE  
)
balance  
RLR  
1
RINGX  
RSN  
<< 150 , RLR =RLT =RL /2=300Ω  
ωC  
RRX  
RT = 60 k, RRX = 60 kΩ  
3
PBL 386 50/2  
Ref  
fig  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Four-wire to longitudinal balance, BFLE  
4
0.2 kHz < f < 3.4 kHz  
40  
50  
dB  
ERX  
BFLE = 20 · Log  
VLo  
Two-wire return loss, r  
|ZTR + ZL|  
r = 20 · Log  
|ZTR - ZL|  
0.2 kHz < f < 1.0 kHz  
1.0 kHz < f < 3.4 kHz, Note 3  
active, IL <5 mA  
27  
20  
35  
22  
- 1.3  
dB  
dB  
V
TIPX idle voltage, VTi  
RINGX idle voltage, VRi  
active, IL <5 mA  
tip open, IL <5 mA  
active, IL<5 mA  
VBat +3.0  
VBat +3.0  
VBat +4.3  
V
V
V
VTR  
Four-wire transmit port (VTX)  
Overhead voltage, VTXO, IL > 18mA  
5
Load impedance > 20 k,  
1.35  
VPeak  
1% THD, Note 4  
On-hook, IL < 5mA  
Output offset voltage, VTX  
Output impedance, zTX  
0.55  
-100  
VPeak  
mV  
0
15  
100  
50  
0.2 kHz < f < 3.4 kHz  
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 = -155 µA  
1.15  
1.25  
8
1.35  
20  
V
0.2 kHz < f < 3.4 kHz  
0.3 kHz < f < 3.4 kHz  
200  
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  
-0.20  
-1.0  
0.10  
0.1  
dB  
dB  
f = 8.0 kHz, 12 kHz, 16 kHz  
TIPX  
VTX  
RLT  
Figure 4. Metallic to longitudinal and four-  
wire to longitudinal balance  
C
VTR  
RT  
PBL 386 50/2  
ERX  
VLo  
RLR  
1
RINGX  
RSN  
<< 150 , RLT =RLR =RL /2 =300Ω  
ωC  
RRX  
RT = 60 k, RRX = 60 kΩ  
C
TIPX  
VTX  
Figure 5. Overhead voltage, VTXO, four-  
wire transmit port  
RL  
ILDC  
RT  
VTXO  
PBL 386 50/2  
1
EL  
<< RL, RL = 600 Ω  
ωC  
RINGX  
RSN  
RRX  
RT = 60 k, RRX = 60 kΩ  
4
PBL 386 50/2  
Ref  
fig  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Four-wire to two-wire, g4-2  
6
relative to 0 dBm, 1.0 kHz. EL=0 V  
0.3 kHz < f < 3.4 kHz  
f = 8 kHz, 12 kHz,  
-0.2  
-1.0  
-2.0  
0.1  
0
0
dB  
dB  
dB  
16 kHz  
Four-wire to four-wire, g4-4  
6
6
relative to 0 dBm, 1.0 kHz, EL=0 V  
0.3 kHz < f < 3.4 kHz  
-0.2  
0.1  
dB  
Insertion loss  
Two-wire to four-wire, G2-4  
0 dBm, 1.0 kHz, Note 5  
VTX  
G2-4 = 20 · Log  
; ERX = 0  
-6.22  
-6.02  
-5.82  
dB  
dB  
VTR  
PTG = AGND  
-12.24  
-12.04  
-11.84  
Four-wire to two-wire, G4-2  
6
0 dBm, 1.0 kHz, Note 6  
VTR  
G4-2 = 20 · Log  
; EL = 0  
-0.2  
0.2  
dB  
ERX  
Gain tracking  
Two-wire to four-wire  
6
6
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  
-0.1  
-0.2  
0.1  
0.2  
dB  
dB  
Four-wire to two-wire  
-0.1  
-0.2  
0.1  
0.2  
dB  
dB  
-55 dBm to -40 dBm  
Noise  
Idle channel noise at two-wire  
(TIPX-RINGX) or four-wire (VTX) output  
C-message weighting, 2 wire  
Psophometrical weighting, 2 wire  
C-message weighting, 4 wire  
Psophometrical weighting, 4 wire  
Note 8  
12  
-78  
6
dBrnC  
dBmp  
dBrnC  
dBmp  
-84  
Harmonic distortion  
Two-wire to four-wire  
Four-wire to two-wire  
6
0 dBm  
0.3 kHz < f < 3.4 kHz  
-67  
-67  
-50  
-50  
dB  
dB  
Battery feed characteristics  
Loop current, IL , in the current  
limited region, reference A, B & C  
13  
7
18mA IL 45 mA  
0.92 IL  
IL  
1.08 IL  
-150  
mA  
Tip open state TIPX current, ILeak  
Tip open state RINGX current, ILRTo  
S = closed; R = 7 k, Note 10  
RLRTo = 0, VBat = -48V  
RLRTo = 2.5 k, VBat = -48V  
ILRTo < 23 mA  
µA  
mA  
mA  
V
IL  
17  
Tip open state RINGX voltage, VRTo  
VBat +6  
C
Figure 6.  
TIPX  
VTX  
Frequency response, insertion loss,  
gain tracking.  
RL  
EL  
VTR  
ILDC  
RT  
PBL 386 50/2  
VTX  
ERX  
1
<< RL, RL = 600 Ω  
ωC  
RINGX  
RSN  
RRX  
RT = 60 k, RRX = 60 kΩ  
5
PBL 386 50/2  
Ref  
fig  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
Tip voltage (ground start)  
7
Active state, Tip lead open (S open), -4  
-2.2  
V
Ring lead to ground through 150 Ω  
Tip voltage (ground start)  
Active state, tip lead to -48 V  
through 7 k(S closed), Ring  
lead to ground through 150 Ω  
RL = 0Ω  
-6  
-2.4  
0
V
Open circuit state loop current, ILOC  
-100  
100  
µA  
Loop current detector  
Programmable threshold, ILTh  
active, active reverse  
500  
RLD  
,
ILTh  
=
0.85·ILTh ILTh  
0.85·ILTh ILTh  
1.15·ILTh mA  
1.15·ILTh mA  
RLD in k, ILTh 7 mA  
Tip open state  
500  
=
ILTh  
RLD  
Ground key detector  
Ground key detector threshold  
(ILTIPX and ILRINGX difference to trigger ground key det.)  
10  
16  
22  
mA  
Line voltage measurement  
Pulse width, tLVM  
Note 9  
5.5  
µs/V  
Ring trip comparator  
Offset voltage, VDTDR  
Input bias current, IB  
Input common mode range, VDT, VDR  
Ring relay driver  
Source resistance, RS = 0 Ω  
IB = (IDT + IDR)/2  
-20  
-200  
VBat+1  
0
-20  
20  
200  
-1  
mV  
nA  
V
Saturation voltage, VOL  
Off state leakage current, ILk  
Digital inputs (C1, C2, C3)  
Input low voltage, VIL  
Input high voltage, VIH  
Input low current, IIL  
Input high current, IIH  
Detector output (DET)  
Output low voltage  
IOL = 50 mA  
VOH = 12 V  
0.2  
0.5  
10  
V
µA  
0
2.5  
0.5  
VCC  
-50  
50  
V
V
µA  
µA  
VIL = 0.5  
VIH = 2.5 V  
I
OL = 0.5 mA  
0.7  
V
Internal pull-up resistor  
Power dissipation (VBat = -48V, VBat2 = -32V)  
P1  
15  
10  
kΩ  
Open circuit state, C1, C2, C3 = 0, 0, 0  
Active state, C1, C2, C3 = 0, 1, 0  
15  
85  
mW  
P2  
P3  
P4  
Longitudinal current = 0 mA, I L=0 mA (on-hook) 70  
mW  
mW  
mW  
RL = 300 (off-hook)  
RL = 800 (off-hook)  
730  
360  
Power supply currents (VBat = -48V)  
VCC current, ICC  
VBat current, IBat  
VCC current, ICC  
VBat current, IBat  
Open circuit state  
1.2  
-0.05  
2.8  
2.0  
4.0  
mA  
mA  
mA  
mA  
-0.1  
-1.5  
Active state  
On-hook, Long Current = 0 mA  
-1.1  
Power supply rejection ratios  
VCC to 2- or 4-wire port  
VBat to 2- or 4-wire port  
VBat2 to 2- or 4-wire port  
Active State  
f = 1 kHz Vn = 100mV  
30  
36  
40  
42  
45  
60  
dB  
dB  
dB  
Temperature guard  
Junction threshold temperature, TJG  
Thermal resistance  
145  
°C  
28-pin PLCC, θJP28plcc  
24-pin SOIC, θJP24soic  
24-pin SSOP, θJP24ssop  
39  
43  
55  
°C/W  
°C/W  
°C/W  
6
PBL 386 50/2  
R
S
TIPX  
VBExt  
PBL 386 50/2  
RLRTo  
RINGX  
Figure 7. Tipx voltage.  
Notes  
1. The overhead voltage can be adjusted with the ROV resistor  
for higher levels e.g. min 3.1 VPeak and is specified at the  
two-wire port with the signal source at the four-wire  
receive port.  
5. Pin PTG = Open sets transmit gain to nom. -6.02dB  
Pin PTG = AGND sets transmit gain to nom. -12.04 dB  
Secondary protection resistors RF and resistors RP impact  
the insertion loss as explained in the text, section  
Transmission. The specified insertion loss is for RF = RP = 0.  
6. The specified insertion loss tolerance does not include  
errors caused by external components.  
2. The two-wire impedance is programmable by selection of  
external component values according to:  
ZTRX = ZT/|G2-4S α RSN| where:  
7. The level is specified at the two-wire port.  
8. The two-wire idle noise is specified with the port  
terminated in 600 (RL) and with the four-wire receive  
port grounded (ERX = 0; see figure 6).  
ZTRX = impedance between the TIPX and RINGX  
terminals  
ZT = programming network between the VTX and RSN  
terminals  
The four-wire idle noise at VTX is specified with the two-  
wire port terminated in 600 (RL). The noise specification  
is referenced to a 600 programmed two-wire impedance  
level at VTX. The four-wire receive port is grounded  
(ERX = 0).  
G2-4S = transmit gain, nominally = 0.5 (or 0.25 see pin  
PTG)  
α
RSN = receive current gain, nominally = 200 (current  
defined as positive flowing into the receivesumm-  
ing node, RSN, and when flowing from ring to tip).  
9. Previous state must be active - loop or ground key  
detector.  
10. If |VBExt| |VBat + 2 V|, where VBat is the voltage at VBAT pin,  
the current ILeak is limited to 5mA.  
3. Higher return loss values can be achieved by adding a  
reactive component to RT, the two-wire terminating  
impedance programming resistance, e.g. by dividing RT  
into two equal halves and connecting a capacitor from the  
common point to ground.  
4. The overhead voltage can be adjusted with the ROV  
resistor for higher levels e.g. min 1.6 VPeak and is specified  
at the four-wire transmit port, VTX, with the signal source  
at the two-wire port. Note that the gain from the two-wire  
port to the four-wire transmit port is G2-4S = 0.5 (or 0.25 see  
pin PTG). The overhead voltage is dependent on G2-4S and  
POV setting.  
7
PBL 386 50/2  
1
2
24 VTX  
PTG  
RRLY  
HP  
23 AGND  
3
22  
21  
20  
RSN  
REF  
PLC  
POV  
5
6
25  
24  
23  
22  
21  
20  
19  
RINGX  
BGND  
TIPX  
NC  
RINGX  
BGND  
TIPX  
4
REF  
PLC  
POV  
PLD  
VCC  
NC  
5
24-pin SOIC  
and  
7
28-pin PLCC  
6
24-pin SSOP 19  
8
VBAT  
VBAT2  
PSG  
VBAT  
VBAT2  
PSG  
7
18 PLD  
17 VCC  
16 DET  
9
8
10  
11  
9
NC  
10  
15  
C1  
LP  
DT  
DR  
11  
12  
14 C2  
13  
C3  
Figure 8. Pin configuration, 24-pin SSOP, 24-pin SOIC and 28 pin PLCC package, top view.  
Pin Description  
Refer to figure 8.  
PLCC Symbol Description  
1
2
3
PTG  
RRLY  
HP  
Progr.Transmit Gain. Left open transmit gain = -6.02 dB, connected to AGND transmit gain = -12.04 dB.  
Ring Relay driver output. The relay coil may be connected to maximum +14V.  
Connection for High Pass filter capacitor, CHP. Other end of CHP connects to TIPX.  
4
5
NC  
RINGX  
No internal Connection  
The TIPX and RINGX pins connect to the tip and ring leads of the two-wire interface via overvoltage  
protection components and ring relay (and optional test relay).  
6
7
BGND  
TIPX  
Battery Ground, should be tied together with AGND.  
The TIPX and RINGX pins connect to the tip and ring leads of the two-wire interface via overvoltage  
protection components and ring relay (and optional test relay).  
8
VBAT  
VBAT2  
PSG  
Battery supply Voltage. Negative with respect to AGND.  
An optional second (2) Battery Voltage connects to this pin.  
9
10  
Programmable Saturation Guard. The resistive part of the DC feed characteristic is programmed by a  
resistor connected from this pin to VBAT.  
11  
12  
13  
NC  
LP  
DT  
No internal Connection  
Connection for Low Pass filter capacitor, CLP. Other end of CLP connects to VBAT.  
Input to the ring trip comparator. With DR more positive than DT the detector output, DET, is at logic level  
low, indicating off-hook condition. The external ring trip network connects to this input.  
14  
DR  
Input to the ring trip comparator. With DR more positive than DT the detector output, DET, is at logic  
level low, indicating off-hook condition. The external ring trip network connects to this input.  
8
PBL 386 50/2  
15  
16  
17  
C3  
C2  
C1  
C1, C2 and C3 are digital inputs (internal pull-up) controlling the SLIC operating states.  
Refer to section "Operating states" for details.  
}
18  
DET  
Detector output. Active low when indicating loop detection and ring trip, active high when indicating  
ground key detection.  
19  
20  
21  
NC  
No internal Connection  
VCC  
PLD  
+5 V power supply.  
Programmable Loop Detector threshold. The loop detection threshold is programmed by a resistor  
connected from this pin to AGND.  
22  
23  
POV  
PLC  
Programmable Overhead Voltage. If pin is left open: The overhead voltage is internally set to min 2.7 V in  
off-hook and min 1.1 V in On-hook. If a resistor is connected between this pin and AGND: the overhead  
voltage can be set to higher values.  
Prog. Line Current, the current limit,reference C in figure 13, is programmed by a resistor connected from  
this pin to AGND.  
24  
25  
26  
REF  
NC  
A Reference, 49.9 k, resistor should be connected from this pin to AGND.  
No internal Connection  
RSN  
Receive Summing Node. 200 times the AC-current flowing into this pin equals the metallic (transversal)  
AC-current flowing from RINGX to TIPX. Programming networks for two-wire impedance and receive gain  
connect to the receive summing node. A resistor should be connected from this pin to AGND.  
27  
28  
AGND  
VTX  
Analog Ground, should be tied together with BGND.  
Transmit vf output. The AC voltage difference between TIPX and RINGX, the AC metallic voltage, is  
reproduced as an unbalanced GND referenced signal at VTX with a gain of 0.5 (or 0.25, see pin PTG).  
The two-wire impedance programming network connects between VTX and RSN.  
SLIC Operating States  
State  
C3  
C2  
C1  
SLIC operating state  
Active detector  
0
1
2
3
4
5
6
7
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Open circuit  
Ringing state  
Active state  
Active state  
Tip open state  
Active state  
-
Ring trip detector (active low)  
Loop detector (active low)  
Line voltage measurement (note 9)  
Loop detector (active low)  
Ground key detector (active high)  
Loop detector (active low)  
Ground key detector (active high)  
Active reverse  
Active reverse  
Table 1. SLIC operating states.  
9
PBL 386 50/2  
Four-Wire to Two-Wire Gain  
From (1), (2) and (3) with EL = 0:  
VTR  
TIPX  
G42  
=
=
TIP  
I
+
L
VRX  
R
R
P
F
F
Z
ZT  
ZL  
L
Z
+
TR  
VTX  
V
ZT  
αRSN  
TR  
ZRX  
RHP  
G
+
2-4S  
+ G24S (ZL + 2RF + 2RP)  
-
+
E
-
L
V
TX  
R
R
P
-
I
L
RING  
-
RINGX  
Z
T
For applications where  
ZT/(αRSN·G2-4S) + 2RF + 2RP is chosen to  
be equal to ZL the expression for G4-2  
simplifies to:  
Z
RX  
ZT  
1
RSN  
+
V
G42 = −  
ZRX 2G24S  
RX  
I /αRSN  
L
-
Four-Wire to Four-Wire Gain  
From (1), (2) and (3) with EL = 0:  
VTX  
PBL 386 50/2  
G44  
=
=
Figure 9. Simplified ac transmission circuit.  
VRX  
ZT  
G24S (ZL + 2RF + 2RP)  
+ G24S (ZL + 2RF + 2RP )  
Functional Description  
and Applications  
Information  
ZT  
αRSN  
ZRX  
ZT determines the SLIC TIPX to  
RINGX impedance at voice  
frequencies.  
ZRX controls four- to two-wire gain.  
VRX is the analog ground referenced  
receive signal.  
Hybrid Function  
The hybrid function can easily be  
Transmission  
implemented utilizing the uncommitted  
amplifier in conventional CODEC/filter  
combinations. Please, refer to figure 10.  
Via impedance ZB a current proportional  
to VRX is injected into the summing node  
of the combination CODEC/filter ampli-  
fier. As can be seen from the expression  
for the four-wire to four-wire gain a  
voltage proportional to VRX is returned to  
VTX. This voltage is converted by RTX to a  
current flowing into the same summing  
node. These currents can be made to  
αRSN is the receive summing node current  
to metallic loop current gain = 200.  
General  
A simplified ac model of the transmis-  
sion circuits is shown in figure 9. Circuit  
analysis yields:  
Note that the SLICs two-wire to four-  
wire gain, G2-4S, is user programmable  
between two fix values. Refer to the  
VTX  
VTR  
=
+ IL (2RF + 2RP )  
(1)  
(2)  
datasheets for values on G2-4S.  
G24S  
VTX VRX  
Two-Wire Impedance  
IL  
+
=
To calculate ZTR, the impedance  
presented to the two-wire line by the  
SLIC including the fuse and protection  
resistors RF and RP, let VRX = 0.  
From (1) and (2):  
ZT  
ZRX  
αRSN  
cancel by letting:  
VTX VRX  
VTR = EL - IL · ZL  
where:  
(3)  
+
= 0(EL = 0)  
RTX  
ZB  
The four-wire to four-wire gain, G4-4  
includes the required phase shift and  
thus the balance network ZB can be  
calculated from:  
,
ZT  
VTX is a ground referenced version of  
the ac metallic voltage between the  
TIPX and RINGX terminals.  
ZTR  
=
+ 2RF + 2RP  
αRSN G24S  
Thus with ZTR, αRSN, G2-4S, RP and RF  
known:  
G2-4S is the programmable SLIC two-wire  
V
RX  
to four-wire gain (transmit  
direction). See note below.  
VTR is the ac metallic voltage between  
tip and ring.  
EL is the line open circuit ac metallic  
voltage.  
Z
= −R  
=
B
TX  
V
TX  
ZT = αRSN G24S (ZTR 2RF 2RP )  
Z
T
+ G  
(Z + 2R + 2R )  
L F P  
24S  
Z
α
RX  
RSN  
G
Two-Wire to Four-Wire Gain  
R
TX  
Z
(Z + 2R + 2R )  
L F P  
T
24S  
From (1) and (2) with VRX = 0:  
IL  
is the ac metallic current.  
VTX  
VTR  
ZT / αRSN  
G24  
=
=
When choosing RTX, make sure the  
output load of the VTX terminal is >20k.  
RF is a fuse resistor.  
RP is part of the SLIC protection  
ZL is the line impedance.  
ZT  
αRSN G24S  
+ 2RF + 2RP  
10  
PBL 386 50/2  
If calculation of the ZB formula above  
yields a balance network containing an  
inductor, an alternate method is recom-  
mended. Contact Ericsson Microelectron-  
ics for assistance.  
R
FB  
R
The PBL 386 50/2 SLIC may also be  
used together with programmable  
CODEC/filters. The programmable  
CODEC/filter allows for system controller  
adjustment of hybrid balance to accom-  
modate different line impedances without  
change of hardware. In addition, the  
transmit and receive gain may be  
adjusted. Please, refer to the program-  
mable CODEC/filter data sheets for  
design information.  
TX  
VTX  
V
T
PBL  
386 50/2  
Z
Z
Combination  
CODEC/Filter  
V
T
B
Z
RX  
RX  
RSN  
Figure 10. Hybrid function.  
Longitudinal Impedance  
A feed back loop counteracts longitudi-  
nal voltages at the two-wire port by  
injecting longitudinal currents in opposing  
phase.  
AC - DC Separation Capacitor, CHP  
ance) forms the total two wire output  
impedance of the SLIC. The choise of  
these programmable components have  
an influence on the power supply  
The high pass filter capacitor con-  
nected between terminals HP and TIPX  
provides the separation of the ac signal  
from the dc part. CHP positions the low  
end frequency response break point of  
the ac loop in the SLIC. Refer to table 1  
for recommended values of CHP.  
Example: A CHP value of 150 nF will  
position the low end frequency response  
3dB break point of the ac loop at 1.8 Hz  
(f3dB) according to f3dB = 1/(2·π·RHP·CHP)  
where RHP = 600 k.  
Thus longitudinal disturbances will  
appear as longitudinal currents and the  
TIPX and RINGX terminals will experi-  
ence very small longitudinal voltage  
excursions, leaving metallic voltages well  
within the SLIC common mode range.  
The SLIC longitudinal impedance per  
wire, ZLoT and ZLoR, appears as typically  
20to longitudinal disturbances. It  
should be noted that longitudinal currents  
may exceed the dc loop current without  
disturbing the vf transmission.  
rejection ratio (PSRR) from VBAT to the  
two wire side at sub-audio frequencies.  
At these frequencies capacitor CLP also  
influences the transversal to longitudinal  
balance in the SLIC. Table 1 suggests  
suitable values on CLP for different  
feeding characteristics. Typical values of  
the transversal to longitudinal balance  
(T-L bal.) at 200Hz is given in table 1 for  
the chosen values on CLP.  
High-Pass Transmit Filter  
The capacitor CTX in figure 12 con-  
nected between the VTX output and the  
CODEC/filter forms, together with RTX  
and/or the input impedance of a pro-  
grammable CODEC/filter, a high-pass  
RC filter. It is recommended to position  
the 3 dB break point of this filter between  
30 and 80 Hz to get a faster response for  
the dc steps that may occur at DTMF  
signalling.  
RFeed  
RSG  
CLP  
T-L bal. CHP  
@200Hz  
Capacitors CTC and CRC  
The capacitors designated CTC and CRC  
in figure 12, connected between TIPX  
and ground as well as between RINGX  
and ground, can be used for RFI filtering.  
The recommended value for CTC and  
CRC is 2200 pF. Higher capacitance  
values may be used, but care must be  
taken to prevent degradation of either  
longitudinal balance or return loss. CTC  
and CRC contribute to a metallic imped-  
ance of 1/(π·f·CTC) = 1/(π·f·CRC), a TIPX to  
ground impedance of 1/(2·π·f·CTC) and a  
RINGX to ground impedance of  
[]  
2·50  
2·200 60.4  
2·400 147  
2·800 301  
[k]  
0
[nF] [dB]  
[nF]  
47  
150  
100  
47  
-46  
-46  
-43  
-36  
150  
150  
150  
22  
Table 1. RSG , CLP and CHP values for  
different feeding characteristics.  
Capacitor CLP  
The capacitor CLP, which connects  
between the terminals CLP and VBAT,  
positions together with the resistive loop  
feed resistor RSG (see section Battery  
Feed), the high end frequency break  
point of the low pass filter in the dc loop  
in the SLIC. CLP together with RSG, CHP  
and ZT (see section Two-Wire Imped-  
1/(2·π·f·CRC).  
11  
PBL 386 50/2  
The current limit (reference C in figure  
13) is adjusted by connecting a resistor,  
RLC, between terminal PLC and ground  
according to the equation:  
receive output via the resistor RRX, is dc  
biased with +1.25V. This makes it  
possible to compensate for currents  
floating due to dc voltage differences  
between RSN and the CODEC output  
without using any capacitors. This is  
done by connecting a resistor RR be-  
tween the RSN terminal and ground.  
With current directions defined as in  
figure 14, current summation gives:  
Battery Feed  
The PBL 386 50/2 SLIC emulate  
resistive loop feed, programmable  
between 2·50and 2·900 , with  
adjustable current limitation. In the  
current limited region the loop current  
has a slight slope corresponding to  
2·30 k, see figure 13 reference B.  
The open loop voltage measured  
between the TIPX and RINGX terminals  
is tracking the battery voltage VBat. The  
signalling headroom, or overhead voltage  
1000  
LProg + 4  
RLC  
=
I
where RLC is in kfor ILProg in mA.  
A second, lower battery voltage may be  
connected to the device at terminal  
VBAT2 to reduce short loop power  
dissipation. The SLIC automatically  
switches between the two battery supply  
voltages without need for external  
control. The silent battery switching  
occurs when the line voltage passes the  
value |VB2| - 40·IL - (VOHVirt -1.3),  
if IL > 6 mA.  
For correct functionality it is important  
to connect the terminal VBAT2 to the  
second power supply via the diode DVB2  
in figure 12.  
An optional diode DBB connected  
between terminal VB and the VB2 power  
supply, see figure 12, will make sure that  
the SLIC continues to work on the  
second battery even if the first battery  
voltage disappears.  
IRSN = IRT + IRRX + IRR  
=
1,25 1,25 VCODEC  
1,25  
RR  
VTRO, is programmable with a resistor ROV  
+
+
RT  
RRX  
connected between terminal POV on the  
SLIC and ground. Please refer to section  
“Programmable overhead voltage(POV)”.  
The battery voltage overhead, VOH  
depends on the programmed signal  
overhead voltage VTRO. VOH defines the  
TIP to RING voltage at open loop  
conditions according to VTR(at IL = 0 mA)  
where VCODEC is the reference voltage of  
the CODEC at the receive output.  
From this equation the resistor RR can be  
calculated as  
,
1,25  
RR  
=
= |VBat| - VOH  
.
1,25 VCODEC  
1,25  
RT  
IRSN  
Refer to table 2 for typical values on  
VOH and VOHVirt. The overhead voltage is  
changed when the line current is ap-  
proaching open loop conditions. To  
ensure maximum open loop voltage,  
even with a leaking telephone line, this  
occurs at a line current of approximately  
6 mA. When the overhead voltage has  
changed, the line voltage is kept nearly  
constant with a steep slope correspond-  
ing to 2·25 (reference G in figure 13).  
The virtual battery overhead, VOHVirt, is  
defined as the difference between the  
battery voltage and the crossing point of  
all possible resistive feeding slopes, see  
figure 13 reference J. The virtual battery  
overhead is a theoretical constant  
RRX  
For values on IRSN, see table 3.  
The resistor RR has no influence on the  
ac transmission.  
If a second battery voltage is not used,  
VBAT2 is connected to VBAT on the  
SLIC and CVB2, DBB and DVB2 are removed.  
SLIC  
IRSN [µA]  
PBL 386 50/2  
-155  
Metering applications  
For designs with metering applications  
please contact Ericsson Microelectronics  
for assistance.  
Table 3. The SLIC internal bias current  
with the direction of the current defined  
as positive when floating into the terminal  
RSN.  
CODEC Receive Interface  
Programmable overhead voltage(POV)  
The PBL 386 50/2 SLIC have got a  
completely new receive interface at the  
four wire side which makes it possible to  
reduce the number of capacitors in the  
applications and to fit both single and  
dual battery feed CODECs. The RSN  
terminal, connecting to the CODEC  
needed to be able to calculate the  
feeding characteristics.  
With the POV function the overhead  
voltage can be increased.  
If the POV pin is left open the overhead  
voltage is internally set to 3.2 VPeak in off-  
SLIC  
VOH(typ)  
[V]  
VOHVirt(typ)  
[V]  
PBL 386 50/2 3.0 +VTRO 4.9 +VTRO  
12  
11  
10  
9
Table 2. Battery overhead.  
8
off-hook  
on-hook  
7
6
5
4
3
2
The resistive loop feed (reference D in  
figure 13) is programmed by connecting  
a resistor, RSG, between terminals PSG  
and VBAT according to the equation:  
1
0
RSG + 2·104  
RFeed  
=
+ 2RF  
0
10  
20  
30  
40  
50  
60  
200  
R
ov  
(K)  
where RFeed is in for RSG and RF in .  
Figure 11. Programmable overhead voltage (POV). RL = 600 or .  
12  
PBL 386 50/2  
hook and 1.3 VPeak on-hook. If a resistor  
ROV is connected between the POV pin  
and AGND, the overhead voltage can be  
set to higher values, typical values can  
be seen in figure 11. The ROV and  
corresponding VTRO (signal headroom)  
are typical values for THD <1% and the  
signal frequency 1000Hz.  
Observe that the 4-wire output terminal  
VTX can not handle more than 3.2 VPeak. So  
if the gain 2-wire to 4-wire is -6.02dB,  
6.4 VPeak is maximum also for the 2-wire  
side. Signal levels between 6.4 and  
12.8 VPeak on the 2-wire side can be han-  
dled with the PTG shorted so that the gain  
G2-4S become -12.04dB. Please note that  
the 2-wire impedance, RR and the 4-wire to  
4-wire gain has to be recalculated if the  
PTG is shorted.  
Please note that the maximum signal  
current at the 2-wire side can not be  
greater than 29 mA.  
Analog Temperature Guard  
The widely varying environmental  
conditions in which SLICs operate may  
lead to the chip temperature limitations  
being exceeded. The PBL 386 50/2 SLIC  
reduce the dc line current when the chip  
temperature reaches approximately  
145°C and increases it again automati-  
cally when the temperature drops.  
Accordingly transmission is not lost  
under high ambient temperature condi-  
tions.  
How to use POV:  
1. Decide what overhead voltage(VTRO) is  
needed. The POV function is only  
needediftheoverheadvoltageexceeds  
3.2 VPeak  
2. In figure 11 the corresponding ROV for  
the decided VTRO can be found.  
3. If the overhead voltage exceeds  
6.4 VPeak , the G2-4S gain has to be  
changed to -12.04dB by connecting  
the PTG pin to AGND. Please note  
that the two-wire impedance, RR and  
the 4-wire to 4-wire gain has to be  
recalculated.  
The detector output, DET, is forced to a  
logic low level when the temperature  
guard is active.  
RFB  
PBL 386 50/2  
CTX  
RTX  
KR  
-
PTG  
VTX  
-
0
+
+
RT  
RRLY  
HP  
AGND  
RSN  
NC  
RB  
+12 V /+5V  
RRX  
0
CGG  
DHP  
CHP  
NC  
CODEC/  
Filter  
RF2  
RR  
RP2  
RING  
TIP  
RINGX  
BGND  
TIPX  
VBAT  
VBAT2  
PSG  
NC  
REF  
PLC  
POV  
PLD  
VCC  
NC  
RREF  
RLC  
ROV  
RLD  
CRC  
CTC  
VB  
OVP  
RF1  
RP1  
PBL 386 50/2  
DVB2  
VB2  
VB  
VCC  
VCC  
DBB  
RSG  
CVB2  
DVB  
CVCC  
DET  
C1  
CLP  
ERG  
CVB  
R1  
LP  
RRT  
DT  
C2  
R2  
DR  
C3  
C1  
C2  
SYSTEM CONTROL  
INTERFACE  
R3  
R4  
SLIC No. 2 etc.  
RESISTORS: (Values according to IEC E96 series)  
CAPACITORS: (Values according to IEC E96 series)  
OVP:  
RSG  
RLD  
ROV  
RLC  
RREF  
RR  
= 0 Ω  
1% 1/10 W  
1% 1/10 W  
CVB  
CVB2  
CVCC  
CTC  
CRC  
CHP  
CLP  
CTX  
CGG  
C1  
= 100 nF  
= 150 nF  
= 100 nF  
= 2.2 nF  
= 2.2 nF  
= 47 nF  
100 V 10%  
100 V 10%  
10 V 10%  
100 V 10%  
100 V 10%  
100 V 10%  
100 V 10%  
10 V 10%  
100 V 10%  
63 V 10%  
63 V 10%  
Secondary protection ( e.g. Power  
Innovations TISPPBL2). The ground  
terminals of the secondary protection should  
be connected to the common ground on the  
Printed Board Assembly with a track as  
short and wide as possible, preferable a  
groundplane.  
= 49.9 kΩ  
= User programmable  
= 32.4 kΩ  
= 49.9 kΩ  
= 11.5 kΩ  
= 52.3 kΩ  
= 32.4 kΩ  
= 57.6 kΩ  
= 52.3 kΩ  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
RT  
= 150 nF  
= 68 nF  
NOTES:  
RTX  
RB  
1. RP1 and RP2 may be omitted if DVB is in  
place.  
= 220 nF  
= 330 nF  
= 330 nF  
RRX  
RFB  
R1  
2. It is required to connect DHP between  
terminal HP and ground if CHP >47nF.  
Depending on CODEC / filter  
C2  
= 604 kΩ  
= 604 kΩ  
= 249 kΩ  
= 280 kΩ  
= 330 Ω  
10 Ω  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
1% 1/10 W  
5% 2 W  
DIODES:  
DVB  
R2  
= 1N4448  
= 1N4448  
= 1N4448  
R3  
DVB2  
R4  
DBB  
RRT  
RP1, RP2  
RF1, RF2  
DHP  
= 1N4448 (Note 2)  
1% 1/10 W (Note 1)  
= Line resistor, 40 1% match  
Figure 12. Single-channel subscriber line interface with PBL 386 50/2 and combination CODEC/filter.  
13  
PBL 386 50/2  
DC characteristics  
A
A
B
C
B
C
D
D
E
G
F
F
H
J
VTR [V]  
|VBat| - VOHVirt - RFeed · (ILProg + 4·10-3)  
E:  
F:  
G:  
H:  
J:  
IL 6 mA  
Apparent battery VBat(@ IL = 0) =|VBat| - VOHVirt - (RFeed · 4·10-3)  
feedG = 2 · 25 Ω  
A:  
IL (@ VTR = 0V) = ILProg +  
60 · 103  
B:  
C:  
RfeedB = 2 · 30 kΩ  
R
103  
ILConst(typ) = ILProg  
=
- 4·10-3  
RLC  
VTROpen = |VBat| - VOH  
VTR = |VBat| - VOHVirt - RFeed · (ILProg + 4·10-3)  
Virtual battery VBatVirt (@ IL = 4 mA) = |VBat| - VOHVirt  
RSG + 2 · 104  
D:  
RFeed =  
200  
Figure 13. Battery feed characteristics (without the protection resistors on the line).  
Loop Monitoring Functions  
and is calculated according to  
Ring Trip Detector  
500  
Ring trip detection is accomplished by  
connecting an external network to a  
comparator in the SLIC with inputs DT  
and DR. The ringing source can be  
balanced or unbalanced superimposed  
on VB or GND. The unbalanced ringing  
source may be applied to either the ring  
lead or the tip lead with return via the  
other wire. A ring relay driven by the  
SLIC ring relay driver connects the  
ringing source to tip and ring.  
The ring trip function is based on a  
polarity change at the comparator input  
when the line goes off-hook. In the on-  
hook state no dc current flows through  
the loop and the voltage at comparator  
input DT is more positive than the  
voltage at input DR. When the line goes  
off-hook, while the ring relay is ener-  
The loop current, ground key and ring  
trip detectors report their status through a  
common output, DET. The detector to be  
connected to DET is selected via the  
three bit wide control interface C1, C2  
and C3. Please refer to section Control  
Inputs for a description of the control  
interface.  
RLD  
=
ILTh  
The current detector is internally filtered  
and is not influenced by the ac signal at  
the two wire side.  
Ground Key Detector  
The ground key detector is indicating  
when the ground key is pressed (active)  
by putting the output pin DET to a logical  
high level when selected. The ground  
key detector circuit senses the difference  
in TIPX and RINGX currents. When the  
current at the RINGX side exceeds the  
current at the TIPX side with the thresh-  
old value the detector is triggered. For  
threshold current values, please refer to  
the datasheet.  
Loop Current Detector  
The loop current detector is indicating  
that the telephone is off hook and that  
current is flowing in the loop by putting  
the output DET to a logical low level  
when selected. The loop current thresh-  
old value, ILTh, at which the loop current  
detector changes state is programmable  
by selecting the value of resistor RLD. RLD  
connects between pin PLD and ground  
14  
PBL 386 50/2  
gized, dc current flows and the compara-  
tor input voltage reverses polarity.  
Figure 12 gives an example of a ring  
trip detection network. This network is  
applicable, when the ring voltage is  
superimposed on VB and is injected on  
the ring lead of the two-wire port. The dc  
voltage across sense resistor RRT is  
monitored by the ring trip comparator  
input DT and DR via the network R1, R2,  
R3, R4, C1 and C2. With the line on-hook  
(no dc current) DT is more positive than  
DR and the DET output will report logic  
level high, i.e. the detector is not tripped.  
When the line goes off-hook, while  
ringing, a dc current will flow through the  
loop including sense resistor RRT and will  
cause input DT to become more negative  
than input DR. This changes output DET  
to logic level low, i.e. tripped detector  
condition. The system controller (or line  
card processor) responds by de-energiz-  
ing the ring relay, i.e. ring trip.  
VTX  
PBL386 50/2  
CODEC  
DC-GND  
RT  
I
IRT  
IRSN  
IRRX  
RRX  
_
RSN  
+
IRR  
+1.25 V  
UREFcodec  
RR  
Figure 14. CODEC receive interface.  
and the programmed dc characteristic,  
with the longitudinal current compensa-  
tion (see section Longitudinal Imped-  
ance) not active, to the line on the  
RINGX pin.  
Ringing State  
The ring relay driver and the ring trip  
detector are activated and the ring trip  
detector is indicating off hook with a logic  
low level at the detector output.  
Complete filtering of the 20 Hz ac  
component at terminal DT and DR is not  
necessary. A toggling DET output can be  
examined by a software routine to  
determine the duty cycle. When the DET  
output is at logic level low for more than  
half the time, off-hook condition is  
The loop current detector is active.  
The SLIC is in the active normal state.  
Active Polarity Reversal State  
Active States  
TIPX and RINGX polarity is reversed  
from the Active State: RINGX is the  
terminal closest to ground and sources  
loop current while TIPX is the more  
negative terminal and sinks current. Vf  
signal transmission is normal. The loop  
current or the ground key detector is  
activated. The loop current detector is  
indicating off hook with a logic low level  
and the ground key detector is indicating  
active ground key with a logic high level  
present at the detector output.  
TIPX is the terminal closest to ground  
and sources loop current while RINGX is  
the more negative terminal and sinks  
loop current. Vf signal transmission is  
normal. The loop current or the ground  
key detector is activated. The loop  
current detector is indicating off hook  
with a logic low level and the ground key  
detector is indicating active ground key  
with a logic high level present at the  
detector output.  
In PBL 386 50/2 a line voltage meas-  
urement feature is available in the active  
state, which may be used for line length  
estimations or for line test purposes. The  
line voltage is presented on the detector  
output as a pulse at logic high level with  
a pulsewidth of 5.5 µs/V. To start the line  
voltage measurement this mode has to  
be entered from the Active State with the  
loop or ground key detector active. The  
pulse presented at the DET output  
proportional to the line voltage starts  
when entering the line voltage measuring  
mode.  
indicated.  
Relay driver  
The PBL 386 50/2 SLIC incorporates a  
ring relay driver designed as open  
collector (npn) with a current sinking  
capability of 50mA. The drive transistor  
emitter is connected to BGND. The relay  
driver has an internal zener diode clamp  
for inductive kickback voltages. Care  
must be taken when using the relay  
driver together with relays that have high  
impedance.  
Overvoltage Protection  
The PBL 386 50/2 SLIC must be  
protected against overvoltages on the  
telephone line caused by lightning, ac  
power contact and induction. Refer to  
Maximum Ratings, TIPX and RINGX  
terminals, for maximum allowable  
continuous and transient currents that  
may be applied to the SLIC.  
Control Inputs  
The PBL 386 50/2 SLIC have three  
digital control inputs, C1, C2 and C3.  
A decoder in the SLIC interprets the  
control input condition and sets up the  
commanded operating state.  
C1 to C3 are internal pull-up inputs.  
Open Circuit State  
Secondary Protection  
In the Open Circuit State the TIPX and  
RINGX line drive amplifiers as well as  
other circuit blocks are powered down.  
This causes the SLIC to present a high  
impedance to the line. Power dissipation  
is at a minimum and no detectors are  
active.  
The circuit shown in figure 12 utilizes  
series resistors together with a  
programmable overvoltage protector  
(e.g. PowerInnovations TISPPBL2),  
serving as a secondary protection.  
Tip Open State  
Tip Open State is used for ground start  
signalling.  
In this state the SLICs present a high  
impedance to the line on the TIPX pin  
15  
PBL 386 50/2  
needed to carry enough charge to supply  
a high enough current to quickly turn on  
the thyristor in the protector. CGG shall be  
placed close to the overvoltage  
protection device. Without the capacitor  
even the low inductance in the track to  
the VBat supply will limit the current and  
delay the activation of the thyristor  
clamp.  
The fuse resistors RF serve the dual  
purposes of being non- destructive  
energy dissipators, when transients are  
clamped and of being fuses, when the  
line is exposed to a power cross.  
If a PTC is choosen for RF, note that it  
is important to always use PTC´s in  
series with resistors not sensitive to  
temperature, as the PTC will act as a  
capacitance for fast transients and  
therefore will not protect the SLIC.  
The TISPPBL2 is a dual forward-  
conducting buffered p-gate overvoltage  
protector. The protector gate references  
the protection (clamping) voltage to  
negative supply voltage (i e the battery  
voltage, VB ). As the protection voltage  
will track the negative supply voltage the  
overvoltage stress on the SLIC is  
minimized.  
Power-up Sequence  
No special power-up sequence is  
necessary except that ground has to be  
present before all power supply voltages.  
Printed Circuit Board Layout  
Care in PCB layout is essential for  
proper function. The components  
connecting to the RSN input should be  
placed in close proximity to that pin, so  
that no interference is injected into the  
RSN pin. Ground plane surrounding the  
RSN pin is advisable.  
Analog ground (AGND) should be  
connected to battery ground (BGND) on  
the PCB in one point.  
Positive overvoltages are clamped to  
ground by a diode. Negative  
overvoltages are initially clamped close  
to the SLIC negative supply rail voltage  
and the protector will crowbar into a low  
voltage on-state condition, by firing an  
internal thyristor.  
A gate decoupling capacitor, CGG, is  
The capacitors for the battery should  
be connected with short wide leads of the  
same length.  
Ordering Information  
Package  
Temp. Range  
Part No.  
24 pin SSOP Tape & Reel 0° - +70° C PBL 386 50/2SHT  
24 pin SOIC Tube 0° - +70° C PBL 386 50/2SOS  
24 pin SOIC Tape & Reel 0° - +70° C PBL 386 50/2SOT  
28 pin PLCC Tube 0° - +70° C PBL 386 50/2QNS  
28 pin PLCC Tape & Reel 0° - +70° C PBL 386 50/2QNT  
Information given in this data sheet is believed to be  
accurate and reliable. However no responsibility is  
assumed for the consequences of its use nor for any  
infringement of patents or other rights of third parties  
which may result from its use. No license is granted  
by implication or otherwise under any patent or  
patent rights of Ericsson Microelectronics. These  
products are sold only according to Ericsson  
Microelectronics' general conditions of sale, unless  
otherwise confirmed in writing.  
Specifications subject to change without  
notice.  
1522-PBL 386 50/2 Uen Rev. A  
© Ericsson Microelectronics AB 1999  
This product is an original Ericsson  
product protected by US, European and  
other patents.  
Ericsson Microelectronics AB  
SE-164 81 Kista-Stockholm, Sweden  
Telephone: +46 8 757 50 00  
16  

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