U4082B-MFLG3G Atmel, U4082B-MFLG3G Datasheet - Page 27

• Manufacturer Part Number: U4082B-MFLG3G
• Description: IC VOICE-SWITCH SPKR CIRC 28SOIC
• Manufacturer: Atmel

Specifications of U4082B-MFLG3G

• Function: Voice-Switched Speakerphone
• Number Of Circuits: 1
• Voltage - Supply: 3.5 V ~ 6.5 V
• Current - Supply: 5.5mA
• Power (watts): 520W
• Operating Temperature: -20°C ~ 60°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Includes: Background Noise Monitor, Chip Disable, Dial Tone Detection, MUTE
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

9. Application Information
9.1
9.2
4743D–CORD–03/06
Dial Tone Detector
Background Noise Monitors
Equation 13 is independent of the volume control setting. Conversely, the acoustic coupling of a
designed system helps determine the minimum slope of that line. Using the component values
of
ever, that an acoustic coupling loss of 40 dB is desirable.
Using the component values of
of 0 dB. Experience has shown, however, that a minimum of 6.0 dB loss is preferable.
The above equations can be used to determine the resistor values for the level detector inputs.
Equation 6 can be used to determine the R
the R
resistor and coupling capacitor at each level detector input. The magnitude of each RC's imped-
ance should be kept within the range of 2.0 k to 15 k in the voice band (due to the typical
signal levels present) to obtain the best performance from the level detectors. The specific R
and C at each location will determine the frequency response of that level detector.
The threshold for the dial tone detector is internally set at 15 mV (10 mVrms) below V
ure 3-3 on page
The resistor value is calculated from:
where V
resistor from V
where V is the amount of the threshold increase.
For testing or circuit analysis purposes, the transmit or receive attenuators can be set to the “on”
position by disabling the background noise monitors and applying a signal so as to activate the
level detectors. Grounding the CPR pin will disable the receive background noise monitor,
thereby indicating the “presence of speech” to the attenuator control block. Grounding CPT does
the same for the transmit path.
Additionally, the receive background noise monitor is automatically disabled by the dial tone
detector whenever the receive signal exceeds the detector's threshold.
G
R
R
• The M
ST
Figure 1-2 on page 2
=
=
can be found using the following equation:
=
10 k
10 k
1
-R
----------------------------------- -
2
B
2
T
is the voltage at pin 15, and V is the amount of threshold reduction. By connecting a
ratio. In
------- - 1
V
------------------- - 1
V
R
line helps define the maximum side tone coupling (G
V
S
B
R
2
–
4
–
V
S
V
G
to RI, the threshold can be increased. The resistor value is calculated from:
B
7). That threshold can be reduced by connecting a resistor from RI to ground.
FO
–
Figure 8-3 on page
in equation 13 yields a G
(14)
Figure 1-2 on page 2
23, R
1
1
-R
-R
3
4
ratio, and equation 10 can be used to determine
each represent the combined impedance of the
AC(MAX)
in equation 14 yields a maximum side tone
of –37 dB. Experience has shown, how-
ST
) allowed in the system. G
U4082B
B
(see
ST
Fig-
27