TS7514
PROGRAMMABLE V.23 MODEM WITH DTMF
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PROGRAMMABLE MODES :
- Modem 75bps transmit, 1200bps receive
- Modem 1200bps transmit, 75bps receive
- DTMF dialing
- Call status tone detection
- Auxiliary analog transmit input
- Analog test loopback
PROGRAMMABLE FUNCTIONS :
- Transmission level
- Hysteresis and detection level
- Filters (reception and transmission)
- Line monitoring and buzzer
- DTMF frequencies
FIXED COMPROMISE LINE EQUALIZER
AUTOMATIC BIAS ADJUSTMENT
INTEGRATED DUPLEXER
STANDARD LOW COST CRYSTAL (3.579MHz)
TAX TONE REJECTION
POWER-UP INITIALIZATION OF REGISTERS
OPERATES FROM
±
5V
CMOS
DIP24
(Plastic Package)
PLCC28
(Plastic Leaded Chip Carrier Package)
on a 4-wire line. Its programming concept makes it
the ideal component to design low-cost intelligent
modems, featuring auto dialing and auto answer-
ing. The TS7514 conforms to CCITT V.23 recom-
mendation. The chip incorporates DTMF dialing,
line monitoring, tone and dialing detection.
ORDER CODES
TS7514CP
TS7514CFN
0 to 70 C
0 to 70
o
C
o
DESCRIPTION
The TS7514 is an FSK modem which can be
programmed for asynchronous half-duplex voice-
band communications on a 2-wireline or full duplex
PIN CONNECTIONS
DIP24
MOD/DTMF
MC/BC
RTS
ENP
DGND
TxD
PRD
XTAL IN
XTAL OUT
DCD
RxD
ZCO
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
AXTL
DIP24
PLCC28
PLCC28
MOD/DTMF
MC/BC
ATXL
WLO
ATO
RTS
WLO
ATO
N/C
28
27
V+
ENP
5
6
7
8
9
10
11
12
13
14
15
16
17
18
25
24
23
22
21
20
19
V+
AGND
V-
RAO1
RAI1
RAI2
N/C
7514-01.EPS / 7514-02.EPS
AGND
V-
RAO1
RAI1
RAI2
RAO2
RFO
DGND
TxD
PRD
N/C
XTAL IN
XTAL OUT
N/C
ZCO
RDI
DCD
RFO
RxD
RDI
RAO2
26
4
3
2
1
November 1998
1/19
7514-01.TBL
Part Number
Temperature Range
Package
TS7514
PIN DESCRIPTION
Name
MOD/DMTF
Pin Number
DIP24
1
PLCC28
1
MODEM or DMTF Operating Mode Selection.
Also controls write operations to control registers (if MOD/DMTF = 0 and
MC/BC = 0).
Digital Control Input.
In MODEM mode, it sets transmission mode to main or back channel. It also
permits selection of dialing or control registers programming.
Request to Send.
When RTS = 0, the circuit sends an analog signal to the ATO output. The signal
depends on the operating mode selected.
When RTS = 1, the signal sent to ATO is suppressed after its first zero crossing.
When MOD/DMTF = 0 and MC/BC = 0, the RTS pin acts as a clock for serial
data loading into the input register.
Serial Register Write Select Input. When ENP = 0, the serial register input is
connected to TxD. When ENP = 1, the register input is connected to PRD.
Digital Ground = 0V. All digital signals are referenced to this pin.
Digital Input for Transmit or Control Data
Digital Input for Control Data. Selected through ENP
Crystal Oscillator Input. Can be tied to an external clock generator.
f
QUARTZ
= 3.579MHz.
Crystal Oscillator Output
Data Carrier Detect Output
Digital Receive Data Output
Zero Crossing Rx Digital Output (ringing detection)
Analog Output for the Receive Signal after Filtering or Analog Input for the
Amplifier-limiter.
Analog Receive Filter Output
A2 Amplifier Output
A2 Amplifier Inverting Input
A1 Amplifier Inverting Input
A1 Amplifier Output
Negative Supply Voltage : – 5V
±5%
Analog Ground = 0 V. Reference Pin for Analog Signals
Positive Supply Voltage : + 5V
±5%
Analog Transmit Output
Analog Output for Line Monitoring and Buzzer
Direct Analog Input Transmit Filter
7514-02.TBL
Description
MC/BC
2
3
RTS
3
4
ENP
DGND
TxD
PRD
XtaIIN
XtaIOUT
DCD
RxD
ZCO
RDI
RFO
RAO2
RAI2
RAI1
RAO1
V-
AGND
V+
ATO
WLO
ATxI
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
5
6
7
8
10
11
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
2/19
TS7514
FUNCTIONAL DESCRIPTION
The TS7514 circuit is an FSK modem for half-du-
plex, voice-band asynchronoustransmissions on a
2-wire line according to CCITT recommendation
V.23 or full duplex on 4 wire-line.
The circuit features DTMF dialing, call status tone
detection and line monitoring in both dialing and
automaticanswer modes. A signalling frequency is
available at the line monitoring output (buzzer).
Ring detection is possible by using the signal de-
tection function and bypassing the receive filter.
The receive signal at ZCO output can be filtered in
the associated microprocessor.
The TRANSMIT channel (Tx) includes :
- Two programmable frequency generators.
- One switched capacitor filter (SCF) with low-pass
or bandpass configuration and its associated
propagation delay corrector.
- One continuous time low-pass smoothing filter.
- One attenuator, programmable from 0 to + 13dB
by 1dB steps.
- One programmable analog input.
The RECEIVE channel (Rx) includes :
- Two operational amplifiers for duplexer imple-
mentation.
- One continuous time low-pass anti-aliasing filter.
- One programmable gain amplifier.
- One linear compromise equalizer.
- One switched capacitor band pass filter (can be
set to either main or back channel).
- One continuous time low pass smoothing filter.
- One limiting amplifier.
- One correlation demodulator.
- One programmable level signal detector.
Figure 2 :
Internal Control Register
RTS
The LINE MONITORING channel includes :
- One buzzer.
- One 3-channel multiplexer to select beetwen :
- Transmit channel monitoring.
- Receive channel monitoring.
- Buzzer.
- One programmable attenuator
Internal Control
Power-up Initialization
The TS7514includes power-up initializationof con-
trol registers. This system sets the ATO transmis-
sion output to an infinite attenuation position,
leaving time for the microprocessor to set up the
RPROG input on power up. Control registers are
also initialized when V+ is lower than 3V or V-
greater than -3V.
Registers
Writeaccess to the DTMF data registerand to other
control registers is achievedin serial mode through
TxD input or PRD input. Addressing of these 4 bit
registers is indirect. They are accessed through an
8 bit shift register addressedwhen MOD/DTMF = 0
and MC/BC = 0. Data sent to the TxD input is
strobed on the RTS signal trailing edge.
Serial data is sent to the TxD input, with Least
Significant Bit (LSB) first. The 4 Most Significant
Bits (MSB) contain the control register address
while the 4 LSB contain associated data.
Data transfer from the input register to the control
register (addressed by the MSB’s) is started by the
operating mode (MODEM or DTMF) selection
(MOD/DTMF = 1 or MC/BC = 1).
CLK
TxD or
PRD
8-BIT SHIFT REGISTER
(Input Register)
Datas
4-Bit Control
Register
RPROG
RDTMF
RATTE
RWLO
RPTF
RHDL
RPRX
RPROG
7514-04.EPS
Addresses
MOD/DTMF
MC/BC
RTS
TxD or PRD
D0
D1
D2
D3
D4
D5
D6
D7
Data
Time
Address
4/19
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