uba2051t NXP Semiconductors, uba2051t Datasheet - Page 21

• Manufacturer Part Number: uba2051t
• Description: Uba2050 A ; Uba2051 A;c One-chip Telephone Ics With Speech, Dialler And Ringer Functions
• Manufacturer: NXP Semiconductors

Philips Semiconductors
T
The digits are transmitted as two simultaneously
generated tones: the Dual-Tone Multi-Frequency (DTMF)
system. These dual tones which are provided at the
MDY/TONE output are internally generated with two digital
sine wave synthesizers together with digital-to-analog
converters. Their amplitudes are precisely scaled
according to a band gap voltage reference. This ensures
tone output levels independent of the supply voltage and
temperature. The two sine waves are summed and then
filtered by an on-chip switched capacitor filter, followed by
an active RC low-pass filter. These guarantee that all
DTMF tones generated fulfil the CEPT CS203
recommendations with respect to amplitude, frequency
deviation, total harmonic distortion and suppression of
unwanted frequency components. Tone digits are
separated by a pause time (t
At dialling, the DTMF input of the transmission part is
enabled while the microphone and receive amplifier inputs
are disabled. The signal at the DTMF input is sent to the
receive output at a low level [see Section “DTMF
amplification (pin DTMF)”].
2000 May 19
handbook, full pagewidth
ONE DIALLER
One-chip telephone ICs with speech,
dialler and ringer functions
t
t
t
t
t
t
p
ap
fl
ifp
= burst time.
= pause time.
= flash time.
= interflash pause time.
= access pause time.
(
PINS
MDY/TONE
MDY/TONE
internal
MUTE
DP/FL
LED
KEYS
p
).
(1)
AND
.....[3] ...... [3] .............. [LNR/P] ....................... [4] .............. [R] ....................... [2]
LED)
Fig.22 Timing diagram in tone dialling mode.
t t
t p
t
t
Note: the maximum tone burst and pause times are equal to the real key press/release time.
(1) pin LED only available inUBA205xA.
mho
fho
= flash holdover time.
= mute holdover time.
t p
t ap
21
Valid keys are the digits [0] to [9], [ /T], [#], [R], [LNR/P]
and [P
The dialling mode, the flash time and the access pause
time depend on the resistor options: PTS, FTSA, FTSB
and APT (see Fig.25 and Table 7).
Figure 22 shows the timing diagram in tone dialling mode
when keys [3], [3], [LNR/P], [4], [R] and [2] are pressed.
In DTMF dialling mode, pin LED of the UBA205xA is set
LOW after the hook-switch changes to off-hook and
becomes HIGH as soon as a key is pressed and the first
DTMF code is sent. Pin LED is a push-pull output and is
LOW when V
The DTMF standard frequencies are implemented as
shown in Table 4.
t t
t p
high impedance
T].
t fho
t fl
UBA2050(A); UBA2051(A;C)
DD
< V
t ifp
POR
.
t mho
MGU141
t p
Product specification