UBA2050 Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Fabricante

UBA2050

One-chip telephone ICs with speech, dialler and ringer functions

Philips Electronics 

Philips Semiconductors

One-chip telephone ICs with speech,

dialler and ringer functions

Product specification

UBA2050(A); UBA2051(A;C)

TONE DIALLER (PINS MDY/TONE AND LED)

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 (tp).

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)”].

Valid keys are the digits [0] to [9], [∗/T], [#], [R], [LNR/P]

and [P → T].

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 VDD < VPOR.

The DTMF standard frequencies are implemented as

shown in Table 4.

handbook, full pagewidth

KEYS .....[3] ......[3] ..............[LNR/P].......................[4].............. [R]....................... [2]

internal

MUTE

DP/FL

tt tp

tp

tap

MDY/TONE

(1)

LED

tt tp tfl

tifp

tfho

high impedance

tmho

tp

MGU141

tt = burst time.

tp = pause time.

tap = access pause time.

tfl = flash time.

tifp = interflash pause time.

tmho = mute holdover time.

tfho = flash holdover time.

Note: the maximum tone burst and pause times are equal to the real key press/release time.

(1) pin LED only available inUBA205xA.

Fig.22 Timing diagram in tone dialling mode.

2000 May 19

21

Share Link: