TP5088 DTMF Generator for Binary Data
October 1991
TP5088 DTMF Generator for Binary Data
General Description
This CMOS device provides low cost tone-dialing capability
in microprocessor-controlled telephone applications 4-bit
binary data is decoded directly without the need for conver-
sion to simulated keyboard inputs required by standard
DTMF generators With the TONE ENABLE input low the
oscillator is inhibited and the device is in a low power idle
mode On the low-to-high transition of TONE ENABLE data
is latched into the device and the selected tone pair from
the standard DTMF frequencies is generated An open-drain
N-channel transistor provides a MUTE output during tone
generation
Features
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Direct microprocessor interface
Binary data inputs with latches
Generates 16 standard tone pairs
On-chip 3 579545 MHz crystal-controlled oscillator
Better than 0 64% frequency accuracy
High group pre-emphasis
Low harmonic distortion
MUTE output interfaces to speech network
Low power idle mode
3 5V鈥?V operation
Block Diagram
TL H 5004 鈥?1
Crystal Specification Parallel Resonant 3 579545 MHz R
S
s
150X L
e
100 mH C
0
e
5 pF C
1
e
0 02 pF
C
1995 National Semiconductor Corporation
TL H 5004
RRD-B30M115 Printed in U S A
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