SGS Thomson Microelectronics ST952 Datasheet
.
HOOK SWITCH DRIVER
.
RING INDICATOR
.
LINE INTERFAC E
- DC TERMINATION (4V AT 20mA )
- 2W/4W HYBRID CONVERTER
- FLAT FREQUENCY RESPONSE DOWN TO
10Hz FOR 56Kps MODEM
.
INTERFACE WITH CAPACITIVE ISOLATION
BARRIER
.
CALLER ID INTERFA CE
.
DIGITAL PHONE LINE OR OVER LOOP
CURRENT LIMIT DETECT
.
PHONE LINE IN USE CHECK
APPLICA TIONS
.
MODEMS UP TO V.34, 33.6KBPS A ND 56K bps
.
PCMCIA CARDS
.
FAX MA CHINES
.
PERSONAL DIGITAL ASSISTANTS
.
ANSWERING MACHINES
.
HIGH FEATURE PHONES
.
WEBPHONES AND SET TOP BOXES
DESCRIPTION
ST952 is a line interface designed to implement
Modem application up to 56Kbps and Voice applications.
ST952 interfaces between telephone line and capacitive isolation barrier.
A complete D. A.A. is made with ST75951 which
interfaces between capacitive isolation barrier and
the DSP or HSP signals.
Tip
Digital
ST75951 ST952
Signals
It incorporates Krypton Isolation Inc. patented silicon DAA technology.
The ring burst signal is detected by ST952 and is sent
to ST75951 through the capacitive isolation barrier.
Using t he control signals given by ST7 5951, through
the cap ac itiv e isolation barrier, ST952 ac ti va tes t he
off-hook or the CLID external transistor sw it c h.
Ring
ST952
D.A.A. LINE INTERFACE
PRELIMINARY DATA
TQFP32
(Thin Plastic Quad Flat Pack)
ORDER CODE :
If CLID external transistor switch is enabled, a
limited amount of current, less than 1mA, is drawn
from the line.
In off-hook state, ST952 DC voltage, 4V at a 20mA
line current, allows to interface with most of public
networks in the world.
The return loss is externally adjustable t o real or
complex impedance.
In case of a wrong connection in a digital phone
line, ST952 detects the over current value and
sends to ST75951 an alert signal through the ca pacitive isolation barrier.
Before starting a line connection, ST952 is abled
to check if the line is used by an other terminal
connected on the same telephone line.
PIN CONNECTIONS
16
17TER1
SET
VDR
LINE
IDG
952-02.EPS
IDI
LINI
GAIN
18
19
20
21
22
23
24
25 26 27 28 29
(7 x 7 x 1.4mm)
TER2
VDREF
IREF
AIN
AOUT
LCOM
ST952TQF7
OHC
NC
NCNC
30 31 32
D1
NC
101112131415
COM
D2
IDC
9
8
7
6
5
4
3
2
1
LCOM
LIM1
LIM2
TOFF
D6
D5
RIN
D4
D3
952-01.EPS
December 1998
This is advance information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
1/12
ST952
PIN LIST
Pin Number Name Type Description
1 D3 Output Isolation Signal Output
2 D4 Output Isolation Signal Output
3 RIN Input Ring Signal Input
4 D5 Input Isolation Control Signal Input
5 D6 Input Isolation Control Signal Input
6 TOFF Supply Internal Reference Supply
7 LIM2 Input Loop Current Limiter Control
8 LIM1 Output Loop Current Limiter Control
9 IDC Output Caller ID Control Output
10 COM Output Off-hook & ID Commun Output
11 OHC Output Off-hook Control Output
12 N.C. - Not Connected
13 N.C. - Not Connected
14 IREF Input Current Reference Setting
15 VDREF Supply Internal Reference Pin
16 TER2 Output Current Regulator Control Feedback
17 TER1 Output Current Regulator Control Output
18 SET Input Current Regulator Filter
19 VDR Supply Line DC Voltage Regulator
20 LINE Output Line AC Signal Output
21 IDG Input Caller ID Voltage Reference Input
22 IDI Input Caller ID Signal Input
23 LINI Input Line AC Signal Input
24 GAIN Input Transmit Gain / Trans-Hybrid Loss Set
25 LCOM Ground Line Side Common Ground
26 AIN Input Analog Transmit Signal Input
27 AOUT Output Analog Transmit Signal Output
28 N.C. - Not Connected
29 N.C. - Not Connected
30 D1 Input Isolation Signal Input
31 D2 Input Isolation Signal Input
32 LCOM Ground Line Side Common Ground
Note :
Pins 12, 13, 28 and 29 must be left opened.
952-01.TBL
2/12
PIN DESCRIPTION
D1 - D2
These pins input the A C signal modulated at Fmod
coming from ST75951 through the capacitive isolation barrier.
ST952
RIN
During the ring burst, a 1MHz oscillator is pow ered
on this pin and a 6V
and D4 to indicate the ring presence.
/1MHz signal is sent on D3
PP
D3 - D4
These pins output the AC signal modulated at Fmod
in off-hook mode and at Fmod /2 in CLID mode to
ST7 59 51 through t he capacitiv e isolatio n barrier .
In ring mode, these pins out put the ring information,
a differential 6V
/1MHz signal.
PP
D5 - D6
These control pins input a 5V
/Fmod signal com-
PP
ing from ST75951 through the capacitive isolation
barrier.
These signals control the off-hook and CLID external transistor switches and are sent to the internal
transmit demodulator and receive modulator.
Off-hook mode is enabled with a 5V
/Fmod signal
PP
sent on D5 and D6 inputs with an opposite phase
(see Figure 1). With a dedicated application it is
possible to reduce the input level to 3V
CLID mode is enabled with a 5V
.
PP
/Fmod signal
PP
sent on D5 input only ( s ee Figure 2). With a dedicated application it is possible to reduce the input
level to 3V
PP
.
Figure 1
D5
D6
5V
Fmod
5V
Fmod
LINE
DC positive line connection and line AC signal output.
LCOM
Negative line connection.
LINI
Line AC signal input in off-hook mode.
AIN - AOUT
The transmit signal coming from AIN pin is injected
in AOUT pin to the 2W/4W internal converter stage.
The line echo is minimized if R3, connected between LINE and VDR pins is equal to 620Ω.
IREF
Internal reference current source setting, R4 must
be equal to 82kΩ.
VDR
Power supply for the transmit and receive paths in
Off-Hook mode.
VDREF
Internal resistor reference.
SET
Line gyrator AC/DC filter.
OHC
When D5 and D6 inputs a 5V
/Fmod signal in
PP
opposite phase, this pin puts ON the hook swit ch
external Q1/Q2 transistor stage.
IDC
When D5 input a 5V
/Fmod sign al, this pin puts
PP
ON the CLID external Q3/Q4 transistor stage.
R2 limits t he line current in CL ID mode at 1mA
max.
COM
Commun output for off-hook and CLID external
transistor stages
TER1 - TER2
These pins control the external Q5 transistor, in
which the main part of the line current goes
through to meet the line DC, V = f(I
952-03.EPS
), termination
L
requirements.
IDI
Line AC signal input in CLID mode.
IDG
Power supply for the r ec eive path in CLID mode.
LIM1 - LIM2
200mA over current detection for device protection.
TOFF
Internal Reference Supply.
Figure 2
GAIN
R1 connected on this pin fi xes the transm it gain.
The R1 recommanded value, on a 600Ω AC line
termination, is 82Ω.
D5
D6
5V
Fmod
3/12
952-04.EPS
ST952
BLOCK DIAGRAM
C8
Tip
2627
R8
Ring
C6
R7
R6
R2
IDG
21
CLID
Q4 Q5
Q2
R3
C3
VDR
191415
VOLTAGE
REFERENCE
C4
R4
DREF
REF
V
I
VOLTAGE
OFF-HOOK
REFERENCE
C5
TER1
TER2
R5
Q3
Q1
C1
R1
LINE
GAIN
20
24
Output
Amplifier
23
C2
LINI
IDI
22
C7
SET
R9
16 17 18
4/12
AOUT AIN
ST952
FILTER
LOW PASS
FILTER
HIGH PASS
30
31
D1
D2
Fmod
2W/4W
& HYBRID
CONVERTER
1
2
D3
D4
ST75951
RING
DETECT
3
RIN
Fmod
LIMITER
CURRENT
CLID & OFF-HOOK
SWITCH CONTROL
4
5
D5
D6
8
LIM1
7
LIM2
IDC
9
OHC
11
COM
10
TOFF
6
LCOM
25
LCOM
32
C9
952-05.EPS
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