MV5087
1
DS3125-2.0 June 1993
MV5087
DTMF GENERATOR
The MV5087 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 either a standard 2-of-8 or a
single contact (form A) keyboard. 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
astaircase approximation of a sinewave with low total distortion.
Frequency and amplitude stability over operating voltage
and temperature range are maintained within industry
specifications.
TONE OUT
SINGLE TONE INHIBIT
ROW 1
ROW 2
ROW 3
ROW 4
MUTE
COLUMN 4
+V
DD
XMITR
COLUMN 1
COLUMN 2
COLUMN3
V
SS
OSC IN
OSC OUT
DP16
MP16
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Figure 1: Pin connections - top view
FEATURES
s Pin-for-Pin Replacement for MK5087
s Low Standby Power
s Minimum External Parts Count
s 3.5V to 10V Operatlon
s 2-of-8 Keyboard or Calculator-Type Single Contact (Form
A) Keyboard Input
s On-Chip Regulation of Output Tone
s Mute and Transmitter Drivers On-Chip
s High Accuracy Tones Provided by 3.58MHz Crystal
Oscillator
s Pin-Selectable Inhibit of Single Tone Generation
APPLICATIONS
DTMF Signalling for
s Telephone Sets
s Mobile Radio
s Remote Control
s Point-of-Sale and Banking Terminals
s Process Control
+
-
V
REF
V
DD
V
DD
TONE OUT
XMITR
MUTE OUT
D/A
CONVERTER
D/A
CONVERTER
SINE
WAVE
COUNTER
SINE
WAVE
COUNTER
TRANSMIT/MUTE
LOGIC
V
SS
R
C
R
C
R
C
R
C
12
3
4
COLUMN INPUTS
V
SS
OSC
IN
OSC
OUT
KEYBOARD LOGIC
4
COLUMN
COUNTER
ROW
COUNTER
V
DD
KEYBOARD LOGIC
12
3
4
ROW INPUTS
R
R
R
R
R
R
R
R
V
DD
V
DD
SINGLE TONE
INHIBIT
MV5087
Figure 2: Functional block diagram
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