MV5089 Datasheet, PDF (4/7 Pages) Zarlink Semiconductor Inc – DTMF GENERATOR

MV5089
PIN FUNCTIONS
PIN
NAME
DESCRIPTION
1
V_DD
Positive Power Supply
2
TONE
This input has an internal pull-up resistor to V_DD. When connected to V_SS no
DISABLE
tones are generated by ant key depression allowing the keyboard to be used for
purposes other than DTMF signalling.
3,4,5,9
6
7,8
Column 1-4
V_SS
OSC In,
OSC Out
These CMOS inputs are held at V_SS by an internal pull-up resistor and are activated
by the application of V_SS.
Negative Power Supply (OV)
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 This input has a pull-up resistor to V_SS. When left unconnected or tied to V_SS,
Inhibit
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 V_DD. 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 V_DD, connection of V_SS to a
single column causes the generation of that Column tone.
Connection of V_SS to more than one Column will result in no
Column tones being generated. Connection of V_SS to Rows
only generates no tone - a Column must be connected to V_SS.
A single Row tone only may be generated by connecting 2
columns, and the desired row, to V_SS.
OUTPUT TONE LEVEL
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.
COL
V_SS
ROW
Figure 4: 2 of 8 DTMF keyboard
V_DD
COLUMN
V_SS
V_DD
ROW
V_SS
Figure 5: Electronic input
ROW
INPUT
V_DD
R_R
STATIC
PROTECTION
COLUMN
INPUT
STATIC
PROTECTION
R_C
V_DD
Row input
sensing circuit
Column input
sensing circuit
Figure 6: Row and Column inputs
3