NT95089 Datasheet, PDF (1/11 Pages) List of Unclassifed Manufacturers – Tone Dialer

NT95089
Features
T Wide operating voltage range: 2.5V - 10V
T Optimum use with a constant operating supply voltage
(typically 3.5V )
T Tone amplitude stability of ±1.5dB within the
suggested operating temperature range
T Device power may be derived directly from telephone
lines or from small batteries
T Low total harmonic distortion
General Description
The NT95089 DTMF generator is specifically designed
for applications requiring a fixed supply operating voltage
and a high stability tone output, making it ideal for
electronic telephone applications. The NT95089
interfaces directly to a standard push-button telephone
keyboard (common terminal connected to VSS) and
operates directly from telephone lines. All necessary
dual-tone frequencies are derived from the widely-used
TV crystal standard, providing high accuracy and
Pin Configuration
Tone Dialer
T TV crystal standard (3.58MHz) is used to derive all
frequencies, providing high accuracy and stability
T Specifically designed for electronic telephone
applications
T Interfaces directly with a standard push-button
telephone keyboard with common terminal
T Dual tone/single tone capability
stability. The required sinusoidal waveform for individual
tones is digitally synthesized on the chip, resulting in a
waveform with low total harmonic distortion. A voltage
reference which is stable over the operating temperature
range is generated on the chip; this reference is used to
regulate the dual tone frequency levels to ensure that
they meet recommended telephone industry
specifications.
Keyboard Assignments
1
2
3A
R1
4
5
6B
R2
7
8
9C
R3
*
0
#D
R4
C1 C2 C3 C4
1