Motore di ricerca datesheet componenti elettronici |
|
TP5700AM Scheda tecnica(PDF) 4 Page - National Semiconductor (TI) |
|
|
TP5700AM Scheda tecnica(HTML) 4 Page - National Semiconductor (TI) |
4 / 8 page Functional Description (Continued) vides automatic gain compensation to reduce the gain as loop length decreases The AGC range can be adjusted by means of RAGC to limit the maximum loss on a short loop from 0 to 6 dB RECEIVE AMPLIFIER This buffer amplifier provides the necessary gain or loss for the receive signal RCV IN should be AC coupled to SIDE- TONE (pin 4) Automatic gain control is built into the amplifi- er to reduce the gain as loop length decreases The AGC range is adjusted in common with the transmit AGC range with a range of adjustment for maximum loss from 0 to 6 dB Push-pull complementary outputs provide balanced direct drive to a dynamic transducer which may have an imped- ance as low as 100X The effective receive gain can be reduced by adding a resistor in series with the transducer The receive gain is automatically reduced by 20 dB when the MUTE input is pulled high SIDETONE CIRCUIT The level of Sidetone cancellation may be adjusted by con- necting an external balance impedance to SIDETONE (pin 4) and coupling this point to Va For good sidetone cancel- lation the balance impedance should be approximately 10 times the subscriber line input impedance Some typical component values to match a precise 600X termination for test purposes are shown in Figure 2 Use the component values shown in the Applications Section for better results over a wide range of telephone line impedances DTMF AMPLIFIER An additional transmit amplifier is included to enable the open-emitter output of a conventional DTMF generator to be connected to the line via the transmit output stage This path includes the transmit AGC section When the MUTE input is pulled high the DTMF input is enabled and the MIC input disabled When MUTE IN is open-circuit or pulled to Vb the DTMF input is switched off and the MIC input is enabled VOLTAGE REGULATOR OUTPUTS A precision band-gap voltage reference controls a regulator to provide bias for internal circuits Two auxiliary outputs are also available VREG1 is provided specifically for powering a low voltage pulse dialer or DTMF generator In order to pro- tect this output in low voltage situations where the instanta- neous voltage across the Speech Circuit may swing below the VREG1 output voltage an internal switch controls the maximum available output current In speech mode MUTE IN is low VREG1 output will track approximately the Tip- Ring voltage and the available output current is limited to 200 mA This is adequate to power a DTMF generator in standby mode When MUTE IN is pulled high to switch the Speech Circuit to the DTMF dialing mode VREG1 is switched to a 3V regulated output and up to 2 mA may be drawn from it to power the active DTMF generator A 12V regulated output is also provided at VREG2 to power a low voltage 2-wire electret microphone such as the Primo EM80-PMI2 TLH5201 – 4 See Figure 3 Note ZBAL circuit shown is for test purposes with a resistive line termination See Applications Information for suggested component values for normal reactive line applications FIGURE 2 TP5700A Telephone Speech Circuits 4 |
Codice articolo simile - TP5700AM |
|
Descrizione simile - TP5700AM |
|
|
Link URL |
Privacy Policy |
ALLDATASHEETIT.COM |
Lei ha avuto il aiuto da alldatasheet? [ DONATE ] |
Di alldatasheet | Richest di pubblicita | contatti | Privacy Policy | scambio Link | Ricerca produttore All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |