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BL1062A1 Dataheets PDF



Part Number BL1062A1
Manufacturers SHANGHAI BELLING
Logo SHANGHAI BELLING
Description Low voltage transmission
Datasheet BL1062A1 DatasheetBL1062A1 Datasheet (PDF)

www.DataSheet4U.com BL1062A1 Low voltage transmission circuits with dialer interface 1. GENERAL DESCRIPTION The BL1062A1 is integrated circuits that perform all speech and line interface functions required in fully electronic telephone sets. It performs electronic switching between dialling and speech. The ICs operate at line voltage down to 1.6 V DC (with reduced performance) to facilitate the use of more telephone sets connected in parallel. BL1062A1 improves the EMC performance in-circuit th.

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www.DataSheet4U.com BL1062A1 Low voltage transmission circuits with dialer interface 1. GENERAL DESCRIPTION The BL1062A1 is integrated circuits that perform all speech and line interface functions required in fully electronic telephone sets. It performs electronic switching between dialling and speech. The ICs operate at line voltage down to 1.6 V DC (with reduced performance) to facilitate the use of more telephone sets connected in parallel. BL1062A1 improves the EMC performance in-circuit that can enhance the telephone sets’ EMC. 2. FEATURES Low DC line voltage; operates down to 1.6 V (excluding polarity guard) Voltage regulator with adjustable static resistance Provides a supply for external circuits Symmetrical high-impedance inputs (64 Κ Ω ) for dynamic, magnetic or piezoelectric microphones Asymmetrical high-impedance input (32 ΚΩ) for electret microphones DTMF signal input with confidence tone Mute input for pulse or DTMF dialling, active LOW (MUTE) Receiving amplifier for dynamic, magnetic or piezoelectric earpieces Large gain setting ranges on microphone and earpiece amplifiers Line loss compensation (line current dependent) for microphone and earpiece amplifiers Gain control curve adaptable to exchange supply DC line voltage adjustment facility Enhanced EMC performanc 3. BLOCK DIAGRAM Fig. 1 Block Diagram http://www.belling.com.cn -18/25/2006 Wrote by 2006 Total 7 Pages BL1062A1 4. Pin Configurations, Definitions SYMBOL PIN DESCRIPTION LN 1 positive line terminal GAS1 2 gain adjustment; transmitting amplifier GAS2 3 gain adjustment; transmitting amplifier QR 4 non-inverting output; receiving amplifier GAR 5 gain adjustment; receiving amplifier 6 Inverting microphone input MIΧ− MIC+ 7 non-inverting microphone input NC 8 NC VEE 9 Negative line terminal IR 10 Receiving amplifier input DTMF 11 dual-tone multi-frequency input MUTE 12 mute input (see note 1) VCC 13 positive supply decoupling REG 14 voltage regulator decoupling AGC 15 automatic gain control input SLPE 16 slope (DC resistance) adjustment 5. Function Description Power for the IC and its peripheral circuits is usually obtained from the telephone line. The Supplies VCC , LN, SLPE, REG supply voltage is derived from the line via a dropping resistor and regulated by the IC. The supply voltage VCC may also be used to supply external circuits e.g. dialling and control circuits. Decoupling of the supply voltage is performed by a capacitor between VCC and VEE . The internal voltage regulator is decoupled by a capacitor between REG and VEE . The DC current flowing into the set is determined by the exchange supply voltage Vexch, the feeding bridge resistance Rexch and the DC resistance of the telephone line Rline . At line currents below 9 mA the internal reference voltage is automatically adjusted to a lower value (typically 1.6 V at 1 mA). This means that more sets can be operated in parallel with DC line voltages (excluding the polarity guard) down to an absolute minimum voltage of 1.6 V. At line currents below 9 mA the circuit has limited sending and receiving levels. The internal reference voltage can be adjusted by means of an external resistor (RVA ). This resistor when connected between LN and REG will decrease the internal reference voltage and when connected between REG and SLPE will increase the internal reference voltage. Microphone inputs MIC+ and MIC− and gain pins GAS1 and GAS2 The circuit has symmetrical microphone inputs. Its input impedance is 64 kΩ (2 x 32 kΩ) and its voltage gain is typically 52 dB (when R7 = 68 kΩ, see Figures 2 and 3). Dynamic, magnetic, piezoelectric or electret (with built-in FET source followers) can be used. The gain of the microphone amplifier can be adjusted between 44 dB and 52 dB to suit the sensitivity of the transducer in use. The gain is proportional to the value of R7, which is connected between GAS1 and GAS2. http://www.belling.com.cn -2- 8/25/2006 Wrote by 2006 Total 7 Pages BL1062A1 Input MUTE When MUTE is LOW or open-circuit, the DTMF input is enabled and the microphone and receiving amplifier inputs are inhibited. The reverse is true when MUTE is HIGH. MUTE switching causes only negligible clicking on the line and earpiece output. If the number of parallel sets in use causes a drop in line current to below 6 mA the DTMF amplifier becomes active independent to the DC level applied to the MUTE input. Dual-tone multi-frequency input DTMF When the DTMF input is enabled dialling tones may be sent on to the line. The voltage gain from DTMF to LN is typically 25.5 dB (when R7 = 68 kΩ) and varies with R7 in the same way as the microphone gain. The signalling tones can be heard in the earpiece at a low level (confidence tone). Receiving amplifier IR, QR and GAR The receiving amplifier has one input (IR) and a non-inverting output (QR). The IR to QR gain is typically 31 dB (when R4 = 100 kΩ). It can be adjusted between 20 and 31 dB to match the sensitivity of the transducer in use. The gai.


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