THIS DOCUMENT IS FOR MAINTENANCE
PURPOSES ONLY AND IS NOT
RECOMMENDED FOR NEW DESIGNS
MV5089
DS3126-2.0 June 1993
MV5089
DTMF GENERATOR
The MV5089 is fabricated using ISO-CMOS high density
technology and offers low power and wide voltage operation.
An inexpensive 3.58MHz TV crystal completes the reference
oscillator. From this frequency are derived 8 different
sinusoidal frequencies which, when appropriately mixed,
provide Dual-Tone Multi-Frequency (DTMF) tones.
Inputs are compatible with a standard 2-of-8 active-low
keyboard and the keyboard entries determine the correct
division of the reference frequency by the row and column
counters.
D-to-A conversion, using R-2R ladder networks, results in
a staircase approximation of a sinewave with low total distortion.
Frequency and amplitude stability over operating voltage
and temperature range are maintained within industry
specifications.
VDD
1
16
TONE OUT
TONE DISABLE
2
15
SINGLE TONE INHIBIT
COLUMN 1
3
14
ROW 1
COLUMN 2
4
13
ROW 2
COLUMN 3
5
12
ROW 3
VSS
6
11
ROW 4
OSC IN
7
10
ANY KEY DOWN
OSC OUT
8
9
COLUMN 4
DP16
MP16
Figure 1: Pin connections - top view
FEATURES
■
■
■
■
■
■
Pin-for-Pin Replacement for MK5089
Low Standby Power
Minimum External Parts Count
2.75V to 10V Operatlon
2-of-8 Keyboard Input
High Accuracy Tones Provided by 3.58MHz Crystal
Oscillator
■ Pin-Selectable Inhibit of Single Tone Generation
APPLICATIONS
DTMF Signalling for
■ Telephone Sets
■ Mobile Radio
■ Remote Control
■ Point-of-Sale and Banking Terminals
■ Process Control
ROW INPUTS
{
1
2
3
SINGLE TONE
INHIBIT
4
RR
RR
VDD
VSS
RR
RR
VDD
KEYBOARD LOGIC
ROW
COUNTER
÷4
OSC
OUT
SINE
WAVE
COUNTER
D/A
CONVERTER
VDD
1/
V
2 DD
OSC
IN
COLUMN
COUNTER
SINE
WAVE
COUNTER
+
-
TONE OUT
VDD
D/A
CONVERTER
KEYBOARD LOGIC
TONE
DISABLE
VDD
RC
RC
VSS
RC
KEYBOARD LOGIC
VSS
ANY KEY
DOWN
RC
2
3
4
{
1
COLUMN INPUTS
Figure 2: Functional block diagram
1
MV5089
OUTPUT FREQUENCY
Standard
DTMF
(Hz)
Table 1 shows the output frequency deviation from the
standard DTMF frequencies when a 3.58MHz crystal is used
as the reference.
The row and column output waveforms are digitally
synthesised using R-2R D-to-A converters (see Fig.3),
resulting in staircase approximations to a sinewave. An opamp
mixes these tones to produce a dual-tone waveform. Single
tone distortion is typically better than 7% and all distortion
components of the mixed dual-tone should be 30dB relative to
the strongest fundamental (column tone).
697
770
852
941
1209
1336
1477
1633
f1
f2
f3
f4
f5
f6
f7
f8
Row
Column
Tone Output
Frequency Using
3.5795545 MHz
Crystal
701.3
771.4
857.2
935.1
1215.9
1331.7
1471.9
1645.0
% Deviation
from Standard
+0.62
+0.19
+0.61
-0.63
+0.57
-0.32
-0.35
+0.73
Table 1: Output frequency deviation
VOUT
a)
t
VOUT
b)
t
Figure 3: Typical sinewave output (a) Row tones (b) Column tones
DISTORTION MEASUREMENTS
THD for the single tone is defined by:
100 (
2 + V2 + ---- V2 ) %
V22f + V3f
nf
4f
V fundamental
Where V2f --- Vnf are the Fourier components of the waveform.
THD for the dual tone is defined by:
100 (
2 + V2 + V2 + V2 --- V2 + V2 )
V22R+ V3R
nR
V2
2C
ROW
where
2
3C
nc
IMD
+ V2
COL
VROW is the row fundamental amplitude
VCOL is the column fundamental amplitude
V2R—VnR are the Fourier component amplitudes of the row frequencies
V2C—VnC are the Fourier component amplitudes of the column frequencies
VIMD is the sum of all intermodulation components.
Low
Group
High
Group
MV5089
PIN FUNCTIONS
PIN
NAME
DESCRIPTION
1
VDD
Positive Power Supply
2
TONE
DISABLE
This input has an internal pull-up resistor to VDD. When connected to VSS no
tones are generated by ant key depression allowing the keyboard to be used for
purposes other than DTMF signalling.
3,4,5,9
Column 1-4
These CMOS inputs are held at VSS by an internal pull-up resistor and are activated
by the application of VSS.
6
VSS
Negative Power Supply (OV)
7,8
OSC In,
OSC Out
On-chip inverter completes the oscillator when a 3,579545 MHz crystal is
connected to these pins. OSC In is the inverter input and OSC Out is the output.
10
Any Key Down This is an NMOS transistor output which switches to VSS while any key is
depressed. Otherwise this output is high impedance. Switching is independent of
Tone Disable and Single Tone Inhibit.
11,12,13,14
Row 1-4
As Column 1-4 inputs.
15
Single Tone
Inhibit
This input has a pull-up resistor to VSS. When left unconnected or tied to VSS,
dual tones may be generated, but keyboard input combinations resulting
in single tone generation are inhibited. When VDD is applied single or
dual tones may be generated.
16
Tone Out
Emitter output of a bipolar NPN transistor whose collector is tied to VDD. Input to
this transistor is from an op-amp which mixes the row and column tones.
ROW AND COLUMN INPUTS
These inputs are compatible with the standard 2-of-8
keyboard or with an electronic input. Figures 4 and 5 show
these input configurations and Fig.6 shows the internal chip
structure of these inputs.
When operating with a keyboard, dual tones are generated
when any single button is pushed.
With Single Tone Inhibit at VDD, connection of VSS to a
single column causes the generation of that Column tone.
Connection of VSS to more than one Column will result in no
Column tones being generated. Connection of VSS to Rows
only generates no tone - a Column must be connected to VSS.
A single Row tone only may be generated by connecting 2
columns, and the desired row, to VSS.
COLUMN
VDD
VSS
VDD
ROW
VSS
Figure 5: Electronic input
VDD
OUTPUT TONE LEVEL
RR
The output tone level of the MV5089 is proportional to the
applied DC supply voltage.
A regulated supply will normally be used which may be
designed to provide stability over the temperature range.
ROW
INPUT
STATIC
PROTECTION
COLUMN
INPUT
STATIC
PROTECTION
Row input
sensing circuit
Column input
sensing circuit
RC
COL
VDD
VSS
ROW
Figure 4: 2 of 8 DTMF keyboard
Figure 6: Row and Column inputs
3
MV5089
ABSOLUTE MAXIMUM RATINGS
VDD - VSS
Voltage on any pin
Current on any pin
Operating temperature
Storage temperature
Min.
Max.
-0.3V
VSS - 0.3V
10.5V
VDD + 0 3V
10 mA
+85°C
+150°C
-40°C
-65°C
Min.
Power dissipation
Derate 16 mW/°C above 75°C
(All leads soldered to PCB)
Max.
850 mW
DC ELECTRICAL CHARACTERISTICS
Test conditions (unless othenwise stated):
Tamb = +25°C, VDD = 3V to 10V
OUTPUTS
INPUTS
SUPPLY
Characteristics
Operating Supply Voltage
Symbol
Min.
VDD
2.75
Standby Supply Current
IDDS
Operating Supply Current
SINGLE TONE Input High Voltage
INHIBIT
Input Low Voltage
TONE DISABLE Input Resistance
ROW 1-4
Input High Voltage
COLUMN 1-4
Input Low Voltage
IDD
VIH
VIL
RIN
VIH
VIL
ANY KEY
DOWN
IOL
IOZ
Sink Current
Leakage Current
Typ.
0.2
0.5
1.0
5.0
0.7VDD
0
Max.
Units
10
100
200
2.0
10.0
VDD
0.3VDD
V
uA
uA
mA
mA
V
V
KΩ
V
V
mA
mA
uA
60
0.7VDD
0
0.5
1.0
VDD
0.3VDD
1
Ref. to VSS
VDD = 3V
VDD = 10V
VDD = 3V
VDD = 10V
No Key Depressed
All outputs Unloaded
One Key Depressed
All outputs Unloaded
VDD = 3V, VOL = 0.5V
VDD = 10V, VOL = 0.5V
VDD = 3V,
AC ELECTRICAL CHARACTERISTICS
Test conditions (unless othenwise stated):
Tamb = +25°C, VDD = 3V to 10V
Characteristics
TONE OUT
OUTPUT LEVEL,
ROW
PRE EMPHASIS, High Band
OUTPUT DISTORTION (Dual Tone)
Tone Output Rise Time
4
Symbol
Min.
Typ.
Max.
Units
VOUT
-10
-8
-7
dBm
2.4
2.7
3.0
-20
dB
dB
5
ms
tr
3
VDD = 3V. Single Tone. RL = 100kΩ
Total out-of-band power relative to
sum of row and column
fundamental power
Time for waveform to reach 90%
of magnitude of either frequency
from initial key stroke
MV5089
VDD
COL 1
3
1
SINGLE TONE INHIBIT
15
7
COL 2 4
COL 3
5
COL 4
9
1
2
3
A
4
5
6
B
7
8
9
C
*
0
#
D
VSS
ROW 1
ROW 2
3.58 MHz XTAL
8
TONE DISABLE
MV5089 2
16
14
TONE OUTPUT
RL
13
ROW 3 12
ROW 4
VSS
11
6
10
VSS
ANY
KEY
DOWN
Figure 7: Connection diagram
5