Data Sheet
April 2000
L8560 Low-Power SLIC with Ringing
Features
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Description
The L8560 full-feature, low-power subscriber line
interface circuit (SLIC) is optimized for low power
consumption while providing an extensive set of fea-
tures. This part is ideal for ISDN terminal adapter
applications and short-loop, power-sensitive applica-
tions such as pair gain and cable telephony. This part
is also designed for PBX, DLC, or CO applications.
The SLIC includes an auxiliary battery input and a
battery switch. In short-loop applications, SLICs can
be used in high battery to present a high on-hook
voltage, and then switched to low battery to reduce
off-hook power.
To help minimize the required auxiliary battery volt-
age, the dc feed resistance and overhead voltage are
set at 55
Ω
and 6.7 V, respectively. This allows an
undistorted on-hook transmission of a 3.14 dBm sig-
nal into a 900
Ω
loop impedance.
The device offers the reverse battery function. Using
the reverse battery, the device can provide a bal-
anced power ring signal to tip and ring. In this
mode of operation, the battery switch is used to
apply a high-voltage battery during ringing and a
lower-voltage battery during the talk and idle states.
Also included in the L8560 is a dc current-limit
switch, which increases the dc current limit during
power ringing. In addition, dc overhead voltage is
reduced during the ring state. With the battery and
current-limit switches, and overhead reduction, the
L8560 can provide sufficient power to ring a true
North American 5 REN load of 1386
Ω
+ 40
µF.
The device offers ring trip and loop closure supervi-
sion with 0.3 V and 2 mA hysteresis, respectively. It
also includes the ground start state and ring ground
detection. A summing node for meter pulse injection
to 2.2 Vrms is also included. The 44-pin PLCC ver-
sion also has a spare uncommitted op amp, which
may be used for ac gain setting or meter pulse filter-
ing.
Full-feature set for central office applications
Also ideal for ISDN terminal adapters, pair gain,
and cable telephony applications
Auxiliary input for second battery, and internal
switch to enable its use to save power in short tele-
phone loops
5 V only operation or optional ±5 V operation for
reduced power consumption
Low active power (85 mW typical) and scan power
(61 mW typical) with 5 V only operation
Low active power (68 mW typical with auxiliary bat-
tery) and scan power (45 mW typical) with ±5 V
operation
Quiet tip/ring polarity reversal
Per-line ringing available for short loops
Reduced overhead and increased current limit dur-
ing ring mode for lower-battery operation or
increased ring loop length
Supports meter pulse injection
Distortion-free full duplex from 0 mA dc loop cur-
rent on-hook transmission
Convenient operating states:
— Forward powerup
— Polarity reversal powerup
— Forward sleep
— Ground start
— Disconnect
Adjustable supervision functions:
— Off-hook detector with longitudinal rejection
— Ground key detector with longitudinal rejection
— Ring trip detector
Independent, adjustable dc and ac parameters:
— dc feed resistance (44-pin PLCC version)
— Loop current limit
— Termination impedance
Thermal protection
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L8560 Low-Power SLIC with Ringing
Data Sheet
April 2000
Table of Contents
Contents
Page
Contents
Page
Features .................................................................... 1
Description ................................................................. 1
Pin Information ........................................................... 6
Functional Description ................................................ 9
Absolute Maximum Ratings ..................................... 10
Recommended Operating Conditions ...................... 11
Electrical Characteristics .......................................... 11
Ring Trip Requirements ......................................... 16
Test Configurations .................................................. 17
Applications ............................................................. 19
Characteristic Curves............................................. 19
dc Applications ...................................................... 21
Battery Feed...................................................... 21
Overhead Voltage ............................................ 22
Adjusting Overhead Voltage ............................. 23
Adjusting dc Feed Resistance........................... 23
Adjusting Overhead Voltage and dc Feed
Resistance Simultaneously.............................. 24
Loop Range....................................................... 24
Off-Hook Detection ........................................... 24
Ring Ground Detection...................................... 25
Longitudinal Balance.............................................. 25
Power Derating ..................................................... 25
Battery Switch ....................................................... 26
V
CC
/V
EE
Supplies ................................................... 27
Power Ringing ....................................................... 27
Ringing SLIC Balanced Ring Signal
Generation ....................................................... 27
POTS for ISDN Terminal Adapters ................... 27
Power Ringing Load .......................................... 28
Crest Factor....................................................... 28
Current-Limit Switch .......................................... 29
Ring Trip............................................................ 29
Reference Designs for ISDN TA Applications ... 31
Design Considerations .......................................... 33
Unbalanced Bused Ring Signal Application ...... 33
Ring Trip Detection............................................ 33
ac Design .............................................................. 37
First-Generation Codecs ................................... 37
Second-Generation Codecs .............................. 37
Third-Generation Codecs .................................. 37
Design Examples ................................................... 39
Example 1, Real Termination ............................ 39
Example 2, Complex Termination ..................... 39
Example 3, Complex Termination Without
Spare Op Amp ................................................. 39
Complex Termination Impedance Design
Example Using L8560 Without Spare
Op Amp ............................................................ 40
ac Interface Using First-Generation Codec ....... 40
Transmit Gain.................................................... 41
Receive Gain..................................................... 42
Hybrid Balance .................................................. 42
Blocking Capacitors........................................... 43
Outline Diagrams...................................................... 44
32-Pin PLCC ......................................................... 44
44-Pin PLCC ......................................................... 45
Ordering Information................................................. 46
2
Lucent Technologies Inc.
Data Sheet
April 2000
L8560 Low-Power SLIC with Ringing
Table of Contents
(continued)
Figures
Page
Figure 32. Thevenin Equivalent Ring Trip Circuit
for Balanced Ringing SLIC..................... 29
Figure 33. POTS Interface with Balanced Ringing
Using L8560 SLIC and T8503 Codec .... 31
Figure 34. Ring Trip Equivalent Circuit and
Equivalent Application ........................... 33
Figure 35. Basic Loop Start Application Circuit
Using T7504 Codec and Bused
Ringing................................................... 34
Figure 36. Ground Start Application Circuit .............. 35
Figure 37. ac Equivalent Circuit Not Including
Spare Op Amp ....................................... 38
Figure 38. ac Equivalent Circuit Including Spare
Op Amp.................................................. 38
Figure 39. Interface Circuit Using First-Generation
Codec (Blocking Capacitors Not
Shown) ................................................... 41
Figure 40. ac Interface Using First-Generation
Codec (Including Blocking Capacitors)
for Complex Termination Impedance ..... 43
Figure 1. Functional Diagram ..................................... 5
Figure 2. 32-Pin Diagram (PLCC Chip) ...................... 6
Figure 3. 44-Pin Diagram (PLCC Chip) ...................... 6
Figure 4. Ring Trip Circuits....................................... 16
Figure 5. Basic Test Circuit ...................................... 17
Figure 6. Metallic PSRR ........................................... 17
Figure 7. Longitudinal PSRR .................................... 17
Figure 8. Longitudinal Balance ................................. 18
Figure 9. RFI Rejection............................................. 18
Figure 10. Longitudinal Impedance .......................... 18
Figure 11. ac Gains .................................................. 18
Figure 12. L8560 Receive Gain and Hybrid
Balance vs. Frequency .......................... 19
Figure 13. L8560 Transmit Gain and Return Loss
vs. Frequency ........................................ 19
Figure 14. L8560 Typical V
CC
Power Supply
Rejection ................................................ 19
Figure 15. L8560 Typical V
BAT
Power Supply
Rejection ................................................ 19
Figure 16. Loop Closure Program Resistor
Selection ................................................ 20
Figure 17. Ring Ground Detection Programming ..... 20
Figure 18. Loop Current vs. Loop Voltage................ 20
Figure 19. Loop Current vs. Loop Resistance .......... 20
Figure 20. L8560 Typical SLIC Power Dissipation
vs. Loop Resistance............................... 21
Figure 21. Power Derating........................................ 21
Figure 22. Loop Current vs. Loop Voltage................ 21
Figure 23. SLIC 2-Wire Output Stage....................... 23
Figure 24. Equivalent Circuit for Adjusting the
Overhead Voltage .................................. 23
Figure 25. Equivalent Circuit for Adjusting the
dc Feed Resistance ............................... 23
Figure 26. Adjusting Both Overhead Voltage and
dc Feed Resistance ............................... 24
Figure 27. Off-Hook Detection Circuit....................... 24
Figure 28. POTS Controlled from an ISDN
Terminal Adapter ................................... 28
Figure 29. Ringing Waveform Crest Factor = 1.6 ..... 28
Figure 30. Ringing Waveform Crest Factor = 1.2 ..... 28
Figure 31. Equivalent Ring Trip Circuit for
Balanced Ringing SLIC ......................... 29
Tables
Page
Table 1. L8560 Product Family Feature Summary ..... 4
Table 2. Pin Descriptions............................................ 7
Table 3. Input State Coding........................................ 9
Table 4. Supervision Coding ...................................... 9
Table 5. Power Supply ............................................. 12
Table 6. 2-Wire Port ................................................. 13
Table 7. Analog Pin Characteristics ......................... 14
Table 8. Uncommitted Op Amp
Characteristics (44-Pin PLCC Only).......... 14
Table 9. ac Feed Characteristics .............................. 15
Table 10. Logic Inputs and Outputs.......................... 16
Table 11. Parts List for Balanced Ringing Using
T8503 Codec .......................................... 32
Table 12. Parts List for Loop Start with Bused
Ringing and Ground Start Applications .. 35
Table 13. 600
Ω
Design Parameters ........................ 37
Lucent Technologies Inc.
3
L8560 Low-Power SLIC with Ringing
Data Sheet
April 2000
The L8560DAU and L8560EP are available in the
32-pin and 44-pin PLCC packages and have feature
sets identical to the L8560AAU and L8560AP, respec-
tively, with the following modifications. These parts are
graded as high longitudinal balance (63 dB), and have
an additional logic state (scan with low battery) which
allows for low on-hook power dissipation.
The L8560FAU and L8560GP are available in the
32-pin and 44-pin PLCC packages and have feature
sets identical to the L8560AAU and L8560AP, respec-
tively, with the following modifications. These parts are
graded for lower longitudinal balance (50 dB), and
have an additional logic state (scan with battery) which
allows for low on-hook power dissipation.
Table 1 below summarizes the features in the L8560
product family.
Description
(continued)
The L8560 product family is graded by different fea-
tures, specifications, and package options. The
L8560Axx is the basic full-feature SLIC that operates
with 5 V and a battery supply, and is available in the
32-pin PLCC (AAU) package and the 44-pin PLCC
package (AP). This part is graded as the 54 dB longitu-
dinal balance part. Additional features (spare op amp
and overhead voltage programming) are available in
the 44-pin PLCC package.
The L8560CAU is available only in the 32-pin PLCC
package and has a feature set similar to the AAU ver-
sion, except the CAU version requires +5 V, –5 V, and
battery power supplies. With this option, power con-
sumption is greatly reduced.
Table 1. L8560 Product Family Feature Summary
Feature
32-Pin PLCC
44-Pin PLCC
5 V Operation
±5 V Operation (reduced power consumption)
Operational V
BAT1
(V)
Battery Switch
Balanced Ring Mode
Adjustable Overhead
Spare Op Amp
Reverse Battery
Scan Mode
Scan Mode with Low Battery
Longitudinal Balance (dB)*
On-hook Transmission
Ground Start
Loop Start
Ring Trip Detector
Programmable Current Limit
Thermal Protection
L8560
AAU
X
NA
X
NA
–70
X
X
NA
NA
X
X
NA
54
X
X
X
X
X
X
AP
NA
X
X
NA
–70
X
X
X
X
X
X
NA
54
X
X
X
X
X
X
CAU
X
NA
NA
X
–70
X
X
NA
NA
X
X
NA
54
X
X
X
X
X
X
DAU
X
NA
X
NA
–70
X
X
NA
NA
X
X
X
63
X
X
X
X
X
X
EP
NA
X
X
NA
–70
X
X
X
X
X
X
X
63
X
X
X
X
X
X
FAU
X
NA
X
NA
–70
X
X
NA
NA
X
X
X
50
X
X
X
X
X
X
GP
NA
X
X
NA
–70
X
X
X
X
X
X
X
50
X
X
X
X
X
X
* More information is provided in the Applications section of this document.
4
Lucent Technologies Inc.
Data Sheet
April 2000
L8560 Low-Power SLIC with Ringing
Description
(continued)
V
EE
(OPTIONAL
ON L8560C)
SEE ENLARGED DETAIL
BGND
V
BAT2
V
BAT1
V
BAT1
V
BAT2
BS1
BS2
V
CC
AGND
FB1
FB2
CF1
CF2
TG
DCOUT
VITR
SN
XMT
44-PIN
PLCC
ONLY
2
19.2
RCVN
RCVP
B0
B1
B2
BR
NSTAT
RGDET
BATTERY
SWITCH
V
BAT1
INTERNAL SWITCH
DECISION
V
REG
BATTERY SWITCH
POWER CONDITIONING
& REFERENCE
RECTIFIER
ENLARGED DETAIL
–
AX
+
V
TX
0.1
µF
C
EXTERNAL
–
+
T
XI
PT
A=4
SPARE
OP AMP
–
PR
A = –4
1
+
44-PIN
PLCC
ONLY
dc RESISTANCE
ADJUST
BATTERY FEED
STATE CONTROL
DCR
I
PROG
CURRENT-LIMIT
ADJUST
LOOP CLOSURE DETECTOR
LCTH
+
–
RTSP
RTSN
ICM
RING TRIP DETECTOR
RING GROUND
DETECTOR
+
–
12-2569.c (F)
Figure 1. Functional Diagram
Lucent Technologies Inc.
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