BL34118 View Datasheet(PDF) - Shanghai Belling Co., Ltd.
Part Name
Description
MFG CO.
'BL34118' PDF : 11 Pages View PDF
PIN DESCRPTION
BL34118
Pin Name
Description
1
FO
Filter output. Output impedance is less than 50 ohms.
2
FI
Filter input. Input impedance is greater than 1.0 Mohm.
3
CD
Chip Disable. A logic low (<0.8V) sets normal operation. A logic high (>2.0V) disables the IC to
conserve power. Input impedance is nominally 90 kΩ.
4
VCC A supply voltage of +2.8 to +6.5 volts is required, at ≈ 5.0 mA. As Vcc falls from 3.5 to 2.8 volts, an
AGC circuit reduces the receive attenuator gain by ≈ 25 db (when in the receive mode).
5
HTO+ Output of the second hybrid amplifier. The gain is internally set at –1.0 to provide a differential
output, in conjunction with HTO-, to the hybrid transformer.
6
HTO- Output of the first hybrid amplifier. The gain of the amp is set by external resistors.
7
HTI
Input and summing node for the first hybrid amplifier. DC level is ≈ VB.
8
TXO Output of the transmit attenuator. DC level is approximately VB.
9
TXI
Input to the transmit attenuator. Max. signal level is 350 mVrms. Input impedance is ≈ 10 kΩ.
10
MCO Output of the microphone amplifier. The gain of the amplifier is set by external resistors.
11
MCI
Input and summing node of the microphone amplifier. DC level is ≈ VB.
12
MUT Mute input. A logic low (<0.8V) sets normal operation. A logic high (>2.0V) mutes the microphone
amplifier without affecting the rest of the circuit. Input impedance is nominally 90 kΩ.
13
VLC Volume control input. When VLC = VB, the receive attenuator is at maximum gain when in the
receive mode. When VLC = 0.3VB, the receive gain is down 35 dB. Does not affect the transmit
mode.
14
CT
An RC at this pin sets the response time for the circuit to switch modes.
15
VB
An output voltage ≈ Vcc/2. This voltage is a system as ground, and biases the volume control. A
filter cap is required.
16
CPT An RC at this pin sets the time constant for the transmit background monitor.
17
TLI2 Input to the transmit level detector on the mike/speaker side.
18
TLO2 Output of the transmit level detector on the mike/speaker side, and input to the transmit
background monitor.
19
RLO2 Output of the receive level detector on the mike/speaker side.
20
RLI2 Input to the receive level detector on the mike/speaker side.
21
RXI
Input to the receive attenuator and dial tone detector. Max input level is 350 mVrms. Input
impedance is ≈ 10 kΩ.
22
RXO Output of the receive attenuator. DC level is approximately VB.
23
TLI1 Input to the transmit level detector on the line side.
24
TLO1 Output of the transmit level detector on the line side.
25
RLO1 Output of the receive level detector on the line side, and input to the receive background monitor.
26
RLI1 Input to the receive level detector on the line side.
27
CPR An RC at this pin sets the time constant for the receive background monitor.
28
GND Ground pin for the entire IC.
http://www.belling.com.cn
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Total 11 Pages
8/15/2006
Wrote by 2006
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