Am7922
Subscriber Line Interface Circuit
The Am7922 Subscriber Line Interface Circuit implements the basic telephone line interface functions, and enables
the design of low cost, high performance, POTS line interface cards.
DISTINCTIVE CHARACTERISTICS
s
Control states: Active, Reverse Polarity, Tip
Open, Ringing, Standby, and Open Circuit
s
Low standby power (35 mW)
s
–19 V to –58 V battery operation
s
On-hook transmission
s
Two-wire impedance set by single external
impedance
s
Available in PLCC and SOIC
s
Programmable constant-current feed
s
Programmable loop-detect threshold
s
Ground-key detector
s
Programmable ring-trip detect threshold
s
No –5 V supply required
s
Current Gain = 500
s
On-chip Thermal Management (TMG) feature
s
Three on-chip relay drivers and relay snubbers,
1 ringing and 2 general purpose
s
Tip Open state for ground-start lines
BLOCK DIAGRAM
TMG
Relay
Driver
Relay
Driver
A(TIP)
Ring Relay
Driver
RYOUT2
RYOUT1
RINGOUT
D1
D2
HPA
Input Decoder
and Control
HPB
Two-Wire
Interface
C1
C2
C3
E1
DET
B(RING)
Signal
Transmission
Off-Hook
Detector
Power-Feed
Controller
VTX
RSN
RD
RDC
CAS
Ring-Trip
Detector
DA
DB
VBAT
BGND
VCC
VBREF
AGND/DGND
Publication#
22462
Rev:
A
Amendment: /0
Issue Date:
October 1999
ORDERING INFORMATION
Standard Products
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed
by a combination of the elements below.
Am7922
–1
J
C
TEMPERATURE RANGE
C = Commercial (0°C to +70°C)*
PACKAGE TYPE
J = 32-pin Plastic Leaded Chip Carrier (PL 032)
S = 28-pin Small Outline Integrated Circuit (SOW 028)
PERFORMANCE GRADE
–1 52 dB Longitudinal Balance, Polarity Reversal
–2 63 dB Longitudinal Balance, Polarity Reversal
–3 52 dB Longitudinal Balance, No Polarity Reversal
–4 63 dB Longitudinal Balance, No Polarity Reversal
DEVICE NUMBER/DESCRIPTION
Am7922
Subscriber Line Interface Circuit
Valid Combinations
–1
–2
Am7922
–3
–4
SC
JC
Valid Combinations
Valid Combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability
of specific valid combinations, to check on newly
released combinations, and to obtain additional
data on AMD’s standard military grade products.
Note:
* Functionality of the device from 0°C to +70°C is guaranteed by production testing. Performance from –40°C to +85°C is
guaranteed by characterization and periodic sampling of production units.
2
Am7922 Data Sheet
CONNECTION DIAGRAMS
Top View
28-Pin SOIC
BGND
VCC
RINGOUT
RYOUT1
RYOUT2
TMG
VBAT
D2
D1
E1
DET
C3
C2
C1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
B(RING)
A(TIP)
DB
DA
RD
HPB
HPA
VTX
VBREF
RSN
AGND/DGND
RDC
NC
CAS
32-Pin PLCC
RYOUT1
RINGOUT
B(RING)
BGND
A(TIP)
31
VCC
4
RYOUT2
NC
TMG
VBAT
D2
D1
NC
E1
DET
5
6
7
8
9
10
11
12
13
14
3
2
1
32
DB
30
29
28
27
26
25
24
23
22
21
DA
RD
HPB
HPA
NC
VTX
VBREF
RSN
AGND
RDC
15
16
C1
17 18
CAS
NC
19 20
NC
C3
Notes:
1. Pin 1 is marked for orientation.
2. NC = No Connect
C2
SLIC Products
3
PIN DESCRIPTIONS
Pin Name
AGND/DGND
A(TIP)
BGND
B(RING)
C3–C1
CAS
Type
Gnd
Output
Gnd
Output
Input
Capacitor
Analog and digital ground.
Output of A(TIP) power amplifier.
Battery (power) ground.
Output of B(RING) power amplifier.
Decoder. SLIC control pins. C3 is MSB and C1 is LSB.
Anti-saturation capacitor. Pin for capacitor to filter reference voltage when operating in
anti-saturation region.
Relay driver control. D1 and D2 control the relay drivers RYOUT1 and RYOUT2. Logic
Low on D1 activates the RYOUT1 relay driver. Logic Low on D2 activates the RYOUT2
relay driver.
Ring-trip negative. Negative input to ring-trip comparator.
Ring-trip positive. Positive input to ring-trip comparator.
Switchhook detector. A logic Low indicates that selected condition is detected. The
detect condition is selected by the logic inputs (C3–C1). The output is open-collector
with a built-in 15 kΩ pull-up resistor.
E1 = 1 selects the switchhook detector. E1 = 0 selects the ground-key detector.
Note:
In the Tip Open state, the ground-key detector is active irrespective of E1.
High-pass filter capacitor. A(TIP) side of high-pass filter capacitor.
High-pass filter capacitor. B(RING) side of high-pass filter capacitor.
No connect. This pin is not internally connected.
Detect resistor. Detector threshold set and filter pin.
DC feed resistor. Connection point for the DC feed current programming network. The
other end of the network connects to the receiver summing node (RSN).
Ring relay driver. Open-collector driver with emitter internally connected to BGND.
Receive summing node. The metallic current (both AC and DC) between A(TIP) and
B(RING) is equal to 500 times the current into this pin. The networks which program
receive gain, two-wire impedance, and feed resistance all connect to this node.
Relay/switch driver. Open-collector driver with emitter internally connected to BGND.
Relay/switch driver. Open-collector driver with emitter internally connected to BGND.
Thermal management. External resistor connects between this pin and VBAT to offload
power from SLIC.
Battery supply and connection to substrate.
This is an AMD reserved pin and must always be connected to the VBAT pin.
+5 V power supply.
Transmit audio. This output is a 0.50 gain version of the A(TIP) and B(RING) metallic
voltage. VTX also sources the two-wire input impedance programming network.
Description
D2–D1
DA
DB
DET
Input
Input
Input
Output
E1
HPA
HPB
NC
RD
RDC
RINGOUT
RSN
RYOUT1
RYOUT2
TMG
VBAT
VBREF
VCC
VTX
Input
Capacitor
Capacitor
—
Resistor
Resistor
Output
Input
Output
Output
Thermal
Battery
—
Power
Output
4
Am7922 Data Sheet
ABSOLUTE MAXIMUM RATINGS
Storage temperature ......................... –55°C to +150°C
V
CC
with respect to AGND/DGND ..... –0.4 V to +7.0 V
V
BAT
with respect to AGND/DGND:
Continuous..................................... +0.4 V to –70 V
10 ms ............................................. +0.4 V to –75 V
BGND with respect to AGND/DGND........ +3 V to –3 V
A(TIP) or B(RING) to BGND:
Continuous ......................................... V
BAT
to +1 V
10 ms (f = 0.1 Hz) ............................. –70 V to +5 V
1 µs (f = 0.1 Hz) ................................ –80 V to +8 V
250 ns (f = 0.1 Hz) .......................... –90 V to +12 V
Current from A(TIP) or B(RING).....................±150 mA
RINGOUT/RYOUT1,2 current............................50 mA
RINGOUT/RYOUT1,2 voltage .............. BGND to +7 V
RINGOUT/RYOUT1,2 transient .......... BGND to +10 V
DA and DB inputs
Voltage on ring-trip inputs ..................... V
BAT
to 0 V
Current into ring-trip inputs .........................±10 mA
C3–C1, D2–D1, and E1
Input voltage .........................–0.4 V to V
CC
+ 0.4 V
Maximum power dissipation, continuous,
T
A
= 70°C, No heat sink (See note)
In 32-pin PLCC package................................1.7 W
In 28-pin SOIC package ................................1.4 W
Thermal Data:
................................................................ θ
JA
In 32-pin PLCC package....................... 43°C/W typ
In 28-pin SOIC package ....................... 60°C/W typ
ESD immunity/pin (HBM) ..................................1500 V
Note:
Thermal limiting circuitry on-chip will shut down the cir-
cuit at a junction temperature of about 165°C. The device
should never see this temperature and operation above 145°C
junction temperature may degrade device reliability.
Stresses above those listed under Absolute Maximum
Ratings may cause permanent device failure. Functionality
at or above these limits is not implied. Exposure to
absolute maximum ratings for extended periods may affect
device reliability.
OPERATING RANGES
Commercial (C) Devices
Ambient temperature .............................0°C to +70°C*
V
CC
.....................................................4.75 V to 5.25 V
V
BAT
......................................................–19 V to –58 V
AGND/DGND .......................................................... 0 V
BGND with respect to
AGND/DGND ....................... –100 mV to +100 mV
Load resistance on VTX to ground .............. 20 k
Ω
min
The operating ranges define those limits between which the
functionality of the device is guaranteed.
* Functionality of the device from 0°C to +70°C is guaranteed
by production testing. Performance from –40°C to +85°C is
guaranteed by characterization and periodic sampling of
production units.
SLIC Products
5
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