Data Sheet
September 2001
L9215A/G
Short-Loop Sine Wave Ringing SLIC
Introduction
The Agere Systems Inc. L9215 is a subscriber line
interface circuit that is optimized for short-loop,
power-sensitive applications. This device provides
the complete set of line interface functionality (includ-
ing power ringing) needed to interface to a subscriber
loop. This device has the capability to operate with a
V
CC
supply of 3.3 V or 5 V and is designed to mini-
mize external components required at all device
interfaces.
Applications
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Voice over Internet Protocol (VoIP)
Cable Modems
Terminal Adapters (TA)
Wireless Local Loop (WLL)
Telcordia Technologies
™
GR-909 Access
Network Termination (NT)
Key Systems
Features
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Onboard ringing generation
Three ringing input options:
— Sine wave
— PWM
— Logic level square wave
Flexible V
CC
options:
— 5 V or 3.3 V V
CC
— No –5 V required
Battery switch to minimize off-hook power
11 operating states:
— Scan mode for minimal power dissipation
— Forward and reverse battery active
— On-hook transmission states
— Meter pulse states
— Ring mode
— Disconnect mode
Ultralow on-hook power:
— 27 mW scan mode
— 42 mW active mode
Two SLIC gain options to minimal external compo-
nents in codec interface
Loop start, ring trip, and ground key detectors
Software- or hardware-controllable current-limit
and overhead voltage
Meter pulse compatible
32-pin PLCC package
48-pin MLCC package
Description
This device is optimized to provide battery feed, ring-
ing, and supervision on short-loop plain old tele-
phone service (POTS) loops.
This device provides power ring to the subscriber
loop through amplification of a low-voltage input. It
provides forward and reverse battery feed states, on-
hook transmission, a low-power scan state, meter
pulse states, and a forward disconnect state.
The device requires a V
CC
and battery to operate.
V
CC
may be either a 5 V or a 3.3 V supply. The ring-
ing signal is derived from the high-voltage battery. A
battery switch is included to allow for use of a lower-
voltage battery in the off-hook mode, thus minimizing
short-loop off-hook power.
Loop closure, ring trip, and ground key detectors are
available. The loop closure detector has a fixed
threshold with hysteresis. The ring trip detector
requires a single-pole filter, thus minimizing external
components required.
This device supports meter pulse applications. Meter
pulse is injected into a dedicated meter pulse input.
Injection of meter pulse onto tip and ring is controlled
by the device’s logic input pin.
Both the dc current limit and overhead voltage are
programmable. Programming may be done by exter-
nal resistors or an applied voltage source. If the volt-
age source is programmable, the current limit and
overhead may be set via software control.
The device is offered with two gain options. This
allows for an optimized codec interface, with minimal
external components regardless of whether a first-
generation or a programmable third-generation
codec is used.
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L9215A/G
Short-Loop Sine Wave Ringing SLIC
Data Sheet
September 2001
Table of Contents
Contents
Page
Contents
Page
Introduction..................................................................1
Features ....................................................................1
Applications...............................................................1
Description ................................................................1
Features ......................................................................4
Description...................................................................4
Architecture Diagram...................................................7
Pin Information ............................................................8
Operating States........................................................11
State Definitions ........................................................12
Forward Active ........................................................12
Reverse Active........................................................12
Forward Active with PPM ........................................12
Reverse Active with PPM........................................12
Scan........................................................................12
On-Hook Transmission—Forward Battery ..............12
On-Hook Transmission with PPM—Forward
Battery ....................................................................13
On-Hook Transmission—Reverse Battery ..............13
On-Hook Transmission with PPM—Reverse
Battery ....................................................................13
Disconnect ..............................................................13
Ring.........................................................................13
Thermal Shutdown..................................................13
Absolute Maximum Ratings.......................................14
Electrical Characteristics ...........................................15
Test Configurations ...................................................22
Applications ...............................................................24
Power Control .........................................................24
dc Loop Current Limit..............................................24
Overhead Voltage ...................................................25
Active Mode .........................................................25
On-Hook Transmission Mode...............................26
Scan Mode ...........................................................26
Ring Mode............................................................26
Loop Range ........................................................... 26
Battery Reversal Rate ............................................ 26
Supervision............................................................... 27
Loop Closure.......................................................... 27
Ring Trip ................................................................ 27
Tip or Ring Ground Detector .................................. 27
Power Ring ............................................................ 27
Sine Wave Input Signal and Sine Wave Power
Ring Signal Output............................................ 28
PWM Input Signal and Sine Wave Power
Ring Signal Output............................................ 30
5 V V
CC
Operation ............................................... 31
3.3 V V
CC
Operation ............................................ 32
Square Wave Input Signal and Trapezoidal
Power Ring Signal Output ................................ 32
Periodic Pulse Metering (PPM) ................................ 34
ac Applications ......................................................... 34
ac Parameters........................................................ 34
Codec Types .......................................................... 34
First-Generation Codecs ..................................... 34
Third-Generation Codecs .................................... 34
ac Interface Network .............................................. 34
Design Examples ................................................... 35
First-Generation Codec ac Interface
Network—Resistive Termination ...................... 35
Example 1, Real Termination .............................. 36
First-Generation Codec ac Interface
Network—Complex Termination ....................... 39
Complex Termination Impedance Design
Example............................................................ 39
ac Interface Using First-Generation Codec ......... 39
Set Z
TG
—Gain Shaping....................................... 39
Transmit Gain...................................................... 40
Receive Gain....................................................... 41
Hybrid Balance .................................................... 41
Blocking Capacitors............................................. 42
Third-Generation Codec ac Interface
Network—Complex Termination ....................... 45
Outline Diagrams...................................................... 47
32-Pin PLCC .......................................................... 47
48-Pin MLCC.......................................................... 48
48-Pin MLCC, JEDEC MO-220 VKKD-2................ 49
Ordering Information................................................. 50
2
Agere Systems Inc.
Data Sheet
September 2001
L9215A/G
Short-Loop Sine Wave Ringing SLIC
Table of Contents
(continued)
Figures
Page
Tables
Page
Figure 1. Architecture Diagram ...................................7
Figure 2. 32-Pin PLCC Diagram .................................8
Figure 3. 48-Pin MLCC Diagram .................................8
Figure 4. Basic Test Circuit ......................................22
Figure 5. Metallic PSRR ...........................................23
Figure 6. Longitudinal PSRR ....................................23
Figure 7. Longitudinal Balance .................................23
Figure 8. ac Gains ....................................................23
Figure 9. Ringing Waveform Crest Factor = 1.6 .......27
Figure 10. Ringing Waveform Crest Factor = 1.2 .....27
Figure 11. Ring Mode Typical Operation ...................28
Figure 12. RING
IN
Operation ....................................29
Figure 13. L9215/16 Ringing Input Circuit Selection
Table for Square Wave and PWM
Inputs........................................................30
Figure 14. Modulation Waveforms ............................31
Figure 15. 5 V PWM Signal Amplitude ......................31
Figure 16. Ringing Output on RING, with
Vcc = 5 V..................................................31
Figure 17. 3.3 V PWM Signal Amplitude ...................32
Figure 18. Ringing Output on RING, with
Vcc = 3.1 V...............................................32
Figure 19. Square Wave Input Signal and Trapezoidal
Power Ring Signal Output ........................32
Figure 20. Crest Factor vs. Battery Voltage...............33
Figure 21. Crest Factor vs. R (kΩ) ............................33
Figure 22. ac Equivalent Circuit ................................36
Figure 23. Agere T7504 First-Generation Codec
Resistive Termination; Nonmeter Pulse
Application................................................37
Figure 24. Interface Circuit Using First-Generation
Codec (Blocking Capacitors
Not Shown) ..............................................40
Figure 25. ac Interface Using First-Generation
Codec (Including Blocking Capacitors)
for Complex Termination Impedance ......42
Figure 26. Agere T7504 First-Generation Codec
Complex Termination; Meter Pulse
Application................................................43
Figure 27. Third-Generation Codec ac Interface
Network; Complex Termination ...............45
Table 1. Pin Descriptions ........................................... 9
Table 2. Control States ............................................ 11
Table 3. Supervision Coding .................................... 11
Table 4. Recommended Operating
Characteristics ........................................... 14
Table 5. Thermal Characteristics.............................. 14
Table 6. Environmental Characteristics .................... 15
Table 7. 5 V Supply Currents ................................... 15
Table 8. 5 V Powering .............................................. 15
Table 9. 3.3 V Supply Currents................................. 16
Table 10. 3.3 V Powering ......................................... 16
Table 11. 2-Wire Port .............................................. 17
Table 12. Analog Pin Characteristics ...................... 18
Table 13. ac Feed Characteristics ........................... 19
Table 14. Logic Inputs and Outputs (V
CC
= 5 V) ...... 20
Table 15. Logic Inputs and Outputs (V
CC
= 3.3 V) ... 20
Table 16. Ringing Specifications ............................. 21
Table 17. Ring Trip .................................................. 21
Table 18. PPM ......................................................... 21
Table 19. Typical Active Mode On- to Off-Hook
Tip/Ring Current-Limit Transient
Response ................................................ 25
Table 20. FB1 and FB2 Values vs. Typical
Ramp Time .............................................. 26
Table 21. Onset of Power Ringing Clipping
V
CC
= 5 V, Cinput = 0.47
µF
.................... 29
Table 22. Onset of Power Ringing Clipping
V
CC
= 3.1 V, Cinput = 0.47
µF
................. 29
Table 23. Signal and Component Selection Chart ... 30
Table 24. Parts List L9215; Agere T7504
First-Generation Codec Resistive Termina-
tion; Nonmeter Pulse Application ............ 38
Table 25. Parts List L9215; Agere T7504
First-Generation Codec Complex Termina-
tion; Meter Pulse Application ................... 44
Table 26. Parts List L9215; Agere T8536
Third-Generation Codec Meter Pulse
Application ac and dc Parameters;
Fully Programmable ................................ 46
Agere Systems Inc.
3
L9215A/G
Short-Loop Sine Wave Ringing SLIC
Data Sheet
September 2001
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Features
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Adjustable current limit:
— 10 mA to 70 mA programming range
Overhead voltage:
— Clamped typically <51 V differentially
— Clamped maximum <56.5 V single-ended
— Adjustable in active mode
Thermal shutdown protection with hysteresis
Longitudinal balance:
— ETSI/ITU-T balance
—
Telcordia Technologies
GR-909 balance
Meter pulse compatible:
— Dedicated meter pulse signal input
— On-hook transmission of PPM
ac interface:
— Two SLIC gain options to minimize external com-
ponents required for interface to first- or third-gen-
eration codecs
— Sufficient dynamic range for direct coupling to
codec output
32-pin PLCC package/48-pin MLCC package
90 V CBIC-S technology
Onboard balanced ringing generation:
— No ring relay
— No bulk ring generator required
— 15 Hz to 70 Hz ring frequency supported
— Sine wave input-sine wave output
— PWM input-sine wave output
— Square wave input-trapezoidal output
Power supplies requirements:
— V
CC
talk battery and ringing battery required
— No –5 V supply required
— No high-voltage positive supply required
Flexible Vcc options:
— 5 V or 3.3 V V
CC
operation
— 5 V or 3.3 V V
CC
interchangeable and transparent
to users
Logic-controlled battery switch:
— Minimize off-hook power dissipation
Minimal external components required
11 operating states:
— Forward active, V
BAT2
applied
— Polarity reversal active, V
BAT2
applied
— On-hook transmission, V
BAT1
applied
— On-hook transmission polarity reversal, V
BAT1
applied
— PPM active forward active, V
BAT2
applied
— PPM active polarity reversal active, V
BAT2
applied
— PPM active on-hook transmission, V
BAT1
applied
— PPM active on-hook transmission polarity rever-
sal, V
BAT1
applied
— Scan
— Forward disconnect
— Ring mode
Unlatched parallel data control interface
Ultralow SLIC power:
— Scan 38 mW (V
CC
= 5 V)
— Forward/reverse active 57 mW (V
CC
= 5 V)
— Scan 27 mW (V
CC
= 3.3 V)
— Forward/reverse active 42 mW (V
CC
= 3.3 V)
Supervision:
— Loop start, fixed threshold with hysteresis
— Ring trip, single-pole ring trip filtering, fixed thresh-
old as a function of battery voltage
— Common-mode current for ground key applica-
tions, user-adjustable threshold
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Description
The L9215 is designed to provide battery feed, ringing,
and supervision functions on short plain old telephone
service (POTS) loops. This device is designed for
ultralow power in all operating states.
The L9215 offers 11 operating states. The device
assumes use of a lower-voltage talk battery, a higher-
voltage ringing battery, and a V
CC
supply.
The L9215 requires only a positive V
CC
supply. No
–5 V supply is needed. The L9215 can operate with a
V
CC
of either 5 V or 3.3 V, allowing for greater user flex-
ibility. The choice of V
CC
voltage is transparent to the
user; the device will function with either supply voltage
connected.
Two batteries are used:
1. A high-voltage ring battery (V
BAT1
).
V
BAT1
is a maximum –75 V. V
BAT1
is used for power
ring signal amplification and for scan and on-hook
transmission modes. This supply is current limited
to approximately the maximum power ringing cur-
rent, typically 50 mA.
2. A lower-voltage talk battery (V
BAT2
).
V
BAT2
is used for active mode powering.
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Agere Systems Inc.
Data Sheet
September 2001
L9215A/G
Short-Loop Sine Wave Ringing SLIC
This feature eliminates the need for a separate external
ring relay, associated external circuitry, and a bulk ring-
ing generator. See the Applications section of this data
sheet for more information.
PPM is injected at the PPM
IN
pin (ac coupled). This is a
high-impedance input that controls the PPM differential
voltage on tip and ring. The PPM signal may be
present at this pin at all times; however, PPM will only
be transmitted to tip and ring during a PPM active
mode. There are forward and reverse active, and for-
ward and reverse on-hook transmission modes with
PPM active.
No PPM shaping is done by the device. It is assumed
that a shaped PPM input is presented to PPM
IN
.
The maximum allowed PPM current at the 200
Ω
ac
meter pulse load to avoid saturation of the device’s
internal AAC amplifier is 3 mArms. This signal level
is sufficient to provide a minimum 200 mVrms to the
200
Ω
PPM load under maximum specified dc loop
conditions. Above 3 mArms PPM current, external
meter pulse rejection may be required. See the Appli-
cations section of this data sheet for more information if
on-hook transmission of PPM is required. Sufficient
overhead to accommodate on-hook transmission must
be programmed by the user at the OVH input.
Both the ring trip and loop closure supervision func-
tions are included. The loop closure has a fixed typical
10.5 mA on- to off-hook threshold in the active mode
and a fixed 11.5 mA on- to off-hook threshold from the
scan mode. In either case, there is a 2 mA hysteresis.
The ring trip detector requires only a single-pole filter at
the input, minimizing external components. The ring
trip threshold at a given battery voltage is fixed. Typical
ring trip threshold is 42.5 mA for a –75 V V
BAT1.
Description
(continued)
Forward and reverse battery active modes are used for
off-hook conditions. Since this device is designed for
short-loop applications, the lower-voltage V
BAT2
is
applied during the forward and reverse active states.
Battery reversal is quiet, without breaking the ac path.
Rate of battery reversal may be ramped to control
switching time.
The magnitude of the overhead voltage in the forward
and reverse active modes has a typical default value of
6.0 V, allowing for an undistorted signal of 3.14 dBm
into 900
Ω.
This overhead can be increased to accom-
modate higher signal levels and/or PPM. The ring trip
detector is turned off during active modes to conserve
power.
Because on-hook transmission is not allowed in the
scan mode, an on-hook transmission mode is defined.
This mode is functionally similar to the active mode,
except the tip ring voltage is derived from the higher
V
BAT1
rather than V
BAT2
.
In the on-hook transmission modes with a primary bat-
tery whose magnitude is greater than a nominal
51 V, the magnitude of the tip-to-ground and ring-to-
ground voltage is clamped at less than 56.5 V.
To minimize on-hook power, a low-power scan mode is
available. In this mode, all functions except off-hook
supervision are turned off to conserve power. On-hook
transmission is not allowed in the scan mode.
In the scan mode with a primary battery whose magni-
tude is greater than a nominal 51 V, the magnitude of
the tip-to-ground and ring-to-ground voltage is clamped
at less than 56.5 V.
A forward disconnect mode is provided, where all cir-
cuits are turned off and power is denied to the loop.
The device offers a ring mode, in which a power ring
signal is provided to the tip/ring pair. During the ring
mode, a user-supplied, low-voltage ring signal (ac cou-
pled) is input to the device’s RING
IN
input. This signal is
amplified to produce the power ring signal. This signal
may be a sine wave or filtered square wave to produce
a sine wave on trapezoidal output. Ring trip detector
and common-mode current detector are active during
the ring mode.
Agere Systems Inc.
5
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