TDK 75T2089

75T2089/2090/2091
DTMF Transceivers
April 2000
DESCRIPTION
FEATURES
TDK Semiconductor’s 75T2089/2090/2091 are
complete
Dual-Tone
Multifrequency
(DTMF)
Transceivers that can both generate and detect all
16 DTMF tone-pairs.
These ICs integrate the
performance-proven 75T202 DTMF receiver with a
DTMF generator circuit.
•
•
•
•
•
The DTMF receiver electrical characteristics are
identical
to
the
standard
75T202
device
characteristics.
The DTMF generator provides
performance similar to the Mostek MK5380, but with
an improved (tighter) output amplitude range
specification and with the addition of independent
latch and reset controls.
•
•
•
•
An additional feature of the 75T2090/2091 is
"imprecise" call progress detector. The detector
detects the presence of signals in the 305-640 Hz
band.
•
•
(continued)
•
BLOCK DIAGRAM
RS
X
1
XOUT
XIN
DTMF Generator and Receiver on one-chip
Call progress detection (2090/2091 only)
Early detect output (2091 only)
DTMF Receiver exhibits excellent speech
immunity
Analog input range from -32 to -2 dBm
(ref 600Ω )
Three-state outputs (4-bit hexadecimal) from
DTMF Receiver
AC coupled, internally biased analog input
Latched DTMF Generator inputs
DTMF output typ. -8 dBm (Low Band) and
-5.5 dBm (High Band)
Easy interface for microprocessor dialing
Uses inexpensive 3.579545 MHz crystal for
reference
Low-power 5 volt CMOS
XEN ATB
Vp
INTERNAL
CLOCK
8
BANDSPLIT
FILTERS
LIN
(2090/2091 only)
ENERGY
DETECTOR
DET
(2090/2091 only)
Vp
D7
D
Q
D6
D
Q
D5
D
Q
D4
D
CK
DTMF
GENERATOR
Q
Vp
LATCH
CK
Vp
Vp
RESET
DTMF
OUT
Q
D CLR
BANDPASS
FILTERS
BANDPASS
FILTERS
697
BS1
770
DIN
AMPLITUDE
DETECTORS
ED
(2091 only)
TIMING
CIRCUITRY
852
941
DV
STROBE
1209
BS2
DV
F.F.
DV
1336
D3
1477
D2
OUTPUT
DECODER
AND
REGISTER
1633
D1
D0
POWER REGULATOR
Vp
Vn
VOLTAGE
REF
DE
75T2089/2090/2091
DTMF Transceivers
DESCRIPTION (continued)
The IC is designed to accept sinusoidal input
waveforms but will operate satisfactorily with any
input that has the correct fundamental frequency
with harmonics greater than -20 dB below the
fundamental.
The 75T2091 also incorporates an early detect
function which is useful in multi-channel radio
scanning
applications.
The
only
external
components necessary for the 75T2089/2090/2091
are a 3.58 MHz “colorburst” crystal with a parallel 1
MΩ resistor. This provides the time base for digital
functions and switched-capacitor filters in the device.
No external filtering is required.
CRYSTAL OSCILLATOR
The IC contains an onboard inverter with sufficient
gain to provide oscillation when connected to a lowcost television “colorburst” crystal. The crystal is
placed between XIN and XOUT in parallel with a
1Mz resistor, while XEN is tied high. Since the
switched-capacitor-filter time base is derived from
the crystal oscillator, the frequency accuracy of all
portions of the IC depends on the time base
tolerance. The DTMF Receiver frequency response
and timing is specified for a time base accuracy of at
least =0.005%. ATB is a clock output with the
frequency of 1/8 of crystal. Other devices may use
the same frequency reference by tying their ATB
pins to the ATB of a crystal connected device. XIN
and XEN of the auxiliary devices must then be tied
high and low respectively, XOUT is left floating.
XOUT is designed to drive a resonant circuit only
and is not intended to drive additional devices. Ten
devices may run off a single crystal-connected
transceiver as shown in Figure 2.
CIRCUIT OPERATION
RECEIVER
The DTMF Receiver in the 75T2089/2090/2091 detects
the presence of a valid tone pair (indicating a single
dialed digit) on a telephone line or other transmission
medium. The analog input is pre-processed by 60 Hz
reject and band-splitting filters, then hard-limited to
provide Automatic Gain Control. Eight bandpass filters
detect the individual tones. The digital post-processor
times the tone durations and provides the correctly
coded digital outputs. The outputs will drive standard
CMOS circuitry, and are three-state enabled to facilitate
bus-oriented architectures.
DIN
This pin accepts the analog input. It is internally
biased so that the input signal may be AC coupled.
The input may be DC coupled as long as it does not
exceed the positive supply. Proper input coupling is
illustrated in Figure 1.
VP
Vp
Vp
0.01 µF
8
10 pF
DIN
(On Chip)
8
DIN
ATB
VIN>VP
(On Chip)
VIN<VP
XIN
75T20XX
XEN
XIN Connected to VP
10 pF
>100 k Ω
GND
XOUT
>100 k Ω
ATB
75T20XX
XEN
GND
Up to 10 Devices
FIGURE 1: Input Coupling
FIGURE 2: Crystal Connections
2
75T2089/2090/2091
DTMF Transceivers
RECEIVER OUTPUTS AND THE DE PIN
ED OUTPUT (75T2091 only)
Outputs D0, D1, D2, D3 are CMOS push-pull when
enabled (DE low) and open-circuited (high
impedance) when disabled (DE high). These digital
outputs
provide
the
hexadecimal
code
corresponding to the detected digit. Figure 3 shows
that code.
The ED output goes high as soon as the 75T2091
begins to detect a DTMF tone pair and falls when the
75T2091 begins to detect a pause. The D1, D2, D4,
and D8 outputs are guaranteed to be valid when DV
is high, but are not necessarily valid when ED is high.
GENERATOR
The digital outputs become valid and DV signals a
detection after a valid tone pair has been sensed.
The outputs and DV are cleared when a valid pause
has been timed.
The DTMF generator responds to a hexadecimal
code input with a valid tone pair. Pins D4-D7 are the
data inputs for the generator. A high to low transition
on LATCH causes the hexadecimal code to be
latched internally and generation of the appropriate
DTMF tone pair to begin. The DTMF output is
disabled by a high on RESET and will not resume
until new data is latched in.
Hexadecimal Code
Digit In
Out
D7
D3
D6
D2
D5
D1
D4
D0
1
0
0
0
1
DIGITAL INPUTS
2
0
0
1
0
3
0
0
1
1
4
0
1
0
0
5
0
1
0
1
6
0
1
1
0
7
0
1
1
1
The D4, D5, D6, D7, LATCH, RESET inputs to the
DTMF generator may be interfaced to open-collector
TTL with a pull-up resistor or standard CMOS. These
inputs follow the same hexadecimal code format as the
DTMF receiver output. Figure 4 shows the code for
each digit. The dialing matrix and detection frequency
table below list the frequencies of the digits.
8
1
0
0
0
9
1
0
0
1
0
1
0
1
0
*
1
0
1
1
#
1
1
0
0
A
1
1
0
1
B
1
1
1
0
C
1
1
1
1
D
0
0
0
0
Col 0
Col 1
Col 2
Col 3
Row 0
1
2
3
A
Row 1
4
5
6
B
Row 2
7
8
9
C
Row 3
*
0
#
D
NOTE: Column 3 is for special applications
and is not normally used in telephone dialing.
FIGURE 3
FIGURE 4: DTMF Dialing Matrix
DETECTION FREQUENCY
Low Group f0
Row
Row
Row
Row
3
0
1
2
3
=
=
=
=
697Hz
770Hz
852Hz
941Hz
High Group f0
Column
Column
Column
Column
0
1
2
3
=
=
=
=
1209Hz
1336Hz
1477Hz
1633Hz
75T2089/2090/2091
DTMF Transceivers
DTMF OUT
LIN INPUT (75T2090/2091)
The output amplitude characteristics listed in the
specifications are given for a supply voltage of 5.0V.
However, the output level is directly proportional to
the supply, so variations in it will affect the DTMF
output. A recommended line interface for this output
is shown in Figure 5.
This analog input accepts the call progress signal
and should be used in the same manner as the
receiver input DIN.
1:1
DTMF
OUT
CALL PROGRESS DETECTION
(75T2090/2091)
The 75T2090/2091 have a Call Progress Detector
that consists of a bandpass filter and an energy
detector for turning the on/off cadences into a
microprocessor compatible signal.
TIP
RING
100Ω
DET OUTPUT (75T2090/2091)
FIGURE 5: DTMF Output
The output is TTL compatible and will be of a
frequency corresponding to the various candences
of Call Progress signals such as: on 0.5 sec/off 0.5
sec for a busy tone, on 0.25 sec/off 0.25 sec for a
reorder tone and on 0.8-1.2 sec/off 2.7-3.3 sec for
an audible ring tone.
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Operating above absolute maximum ratings may damage the device.
PARAMETER
RATING
DC Supply Voltage (Vp - Vn)
+7V
Voltage at any Pin (Vn = 0)
-0.3 to Vp + 0.3V
DIN Voltage
Vp + 0.5 to Vp - 10V
Current through any Protection Device
=20mA
Operating Temperature Range
-40 to + 85°C
Storage Temperature
-65 to 150°C
RECOMMENDED OPERATING CONDITIONS
PARAMETER
CONDITIONS
MIN
MAX
UNIT
5.5
V
10
mVp-p
-40
+85
°C
-0.01
+0.01
%
Crystal Shunt Resistor
0.8
1.2
MΩ
DTMF OUT Load Resistance
100
Supply Voltage
4.5
Power Supply Noise (wide band)
Ambient Temperature
Crystal Frequency
NOM
(F Nominal = 3.579545MHz)
4
Ω
75T2089/2090/2091
DTMF Transceivers
DIGITAL AND DC REQUIREMENTS
The following electrical specifications apply to the digital input and output signals over the recommended
operating range unless otherwise noted. The specifications do not apply to the following pins: LIN, DIN, XIN,
XOUT, and DTMF OUT. Positive current is defined as entering the circuit. Vn = 0 unless otherwise stated.
PARAMETER
CONDITIONS
MIN
Supply Current*
NOM
MAX
UNIT
15
30
mA
225
mW
Power Dissipation
Input Voltage High
0.7Vp
V
Input Voltage Low
0.3Vp
V
Input Current High
10
µA
Input Current Low
Output Voltage High
Ioh = -0.2mA
Output Voltage Low
IoI = +0.4mA
-10
µA
Vp-0.5
V
Vn+0.5
V
* with DTMF output disabled
DTMF RECEIVER: Electrical Characteristics
PARAMETER
CONDITIONS
Frequency Detect Bandwidth
Amplitude for Detection
Each Tone
Twist Tolerance
MIN
NOM
MAX
UNIT
=(1.5+2Hz)
=2.3
=3.5
%Fo
-32
-2
dBm/tone
-10
+10
dB
0.8
Vrms
0
dB*
60Hz Tolerance
Dial Tone Tolerance
Precise Dial Tone
Speech Immunity
MITEL Tape #CM7290
Noise Tolerance
MITEL Tape #CM7290
Input Impedance
2
hits
-12
100
dB*
kΩ
* Referenced to lowest amplitude tone
DTMF RECEIVER: Timing Characteristics
PARAMETER
TON
Tone Time for Detect
TON
Tone Time for No Detect
TOFF
Pause Time for Redetection
TOFF
Pause Time for Bridging
TD1
Detect Time
TR1
Release Time
CONDITIONS
MIN
NOM
MAX
40
ms
20
40
5
UNIT
ms
ms
20
ms
25
46
ms
35
50
ms
75T2089/2090/2091
DTMF Transceivers
DTMF RECEIVER: Timing Characteristics (Continued)
PARAMETER
TSU1
Data Set Up Time
THD1
Data Hold Time
TED
ED Detect Time
BER
ED Release Time
CONDITIONS
MIN
NOM
MAX
UNIT
µs
7
4.2
5.0
ms
75T2091 only
7
22
ms
75T2091 only
2
18
ms
Output Enable Time
200
ns
Output Disable Time
200
ns
-1.0
+1.0
%Fo
Low Band
-9.2
-7.2
dBm
High Band
-6.6
-4.6
dBm
-20
dB
2.5
µs
DTMF GENERATOR: Electrical Characteristics
Frequency Accuracy
Output Amplitude
Output Distortion
R1 = 100Ω to Vn, Vp - Vn = 5.0V
DC to 50 kHz
DTMF GENERATOR: Timing Characteristics
TSTART
Start-Up Time
TSU2
Data Set-Up Time
100
ns
THD2
Data Hold Time
50
ns
TRP
RESET Pulse Width
100
ns
TPW
LATCH Pulse Width
100
ns
CALL PROGRESS DETECTOR: Electrical Characteristics (75T2090/2091 only)
Amplitude for Detection
305 Hz-640 Hz
Amplitude for No Detection
Detect Output
-40
0
dBm
305 Hz-640 Hz
-50
dBm
f>2200 Hz, <160 Hz
-25
dBm
Logic 0
0.5
V
Logic 1
"LIN" Input
Max. Voltage
Input Impedance
500 Hz
4.5
VDD-10
100
6
V
VDD
V
kΩ
75T2089/2090/2091
DTMF Transceivers
CALL PROGRESS DETECTOR: Electrical Characteristics (Continued)
PARAMETER
CONDITIONS
MIN
NOM
MAX
UNIT
ms
10
ms
TON
Signal Time for Detect
TON
Signal Time for No Detect
TOFF
Interval Time for Detect
TOFF
Interval Time for No Detect
20
ms
TD2
Detect Time
40
ms
TR2
Release Time
40
ms
TON
40
ms
40
TOFF
tone burst 1
TON
tone burst 2
TOFF
DIN
TD1
tone burst 1
TR1
tone burst 2
DIN
TD1
TR1
DV
TSU1
THD1
DV
TSU1
THD1
D0, D1, D2, D3
TED
ED
TER
D0, D1, D2, D3
*
*75T2091 only
FIGURE 6: DTMF Decoder
FIGURE 7: Call Progress Detector
(75T2090/2091 only)
THD2
D4, D5, D6, D7
TSU2
TPW
LATCH
TPW
(SEE NOTE)
RESET
TSTART
TRP
DTMF OUT
NOTE: THE INDICATED TIME MAY BE AS SMALL AS 0 SEC., MEANING THAT THE
LATCH AND RESET LINES MAY BE TIED TOGETHER.
FIGURE 8: DTMF Generator
7
75T2089/2090/2091
DTMF Transceivers
MECHANICAL SPECIFICATIONS
22-Pin DIP
28-Pin PLCC
8
75T2089/2090/2091
DTMF Transceivers
PACKAGE PIN DESIGNATIONS
CAUTION: Use handling procedures necessary for
a static sensitive component.
D2
2
21
D7
D1
3
20
D0
4
19
DE
5
18
2
1
28 27 26
D6
3
D7
4
DE
5
25
D5
D6
VP
6
24
D4
D5
ED
7
23
LATCH
D4
N/C
8
22
N/C
N/C
9
21
N/C
20
RST
19
DET
VP
6
17
LATCH
XEN
7
16
RST
XEN
10
DIN
8
15
DET*
N/C
11
13
DTMFOUT
ATB
11
12
VN
LIN
10
VN
XIN
DTMFOUT
LIN*
ATB
14
XIN
9
XOUT
12 13 14 15 16 17 18
DIN
XOUT
DV
DV
D3
22
D2
1
D1
D3
D0
(Top View)
* 75T2090 only
75T2089/2090
22-Pin DIP
75T2091
28-Pin PLCC
ORDERING INFORMATION
PART DESCRIPTION
ORDER NUMBER
PACKAGING MARK
75t2089
22-Pin Plastic DIP
75T2089-IP
75T2089-IP
22-Pin DIP
75T2090-IP
75T2090-IP
28-Pin PLCC
75T2091-IH
75T2091-IH
75T2090
75T2091
No responsibility is assumed by TDK Semiconductor Corporation for use of this product nor for any infringements of patents and trademarks
or other rights of third parties resulting from its use. No license is granted under any patents, patent rights or trademarks of TDK
Semiconductor Corporation and the company reserves the right to make changes in specifications at any time without notice. Accordingly, the
reader is cautioned to verify that the data sheet is current before placing orders.
TDK Semiconductor Corporation, 2642 Michelle Drive, Tustin, CA 92780-7019, (714) 508-8800, FAX: (714) 508-8877
1991 - 2000 TDK Semiconductor Corporation
04/24/00- rev. E
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