cxa1746q Sony Electronics, cxa1746q Datasheet - Page 17

• Manufacturer Part Number: cxa1746q
• Description: Electronic Volume
• Manufacturer: Sony Electronics

(4) Zero-cross detector and Timer
(5) VCT pin
(6) Power-off Mute
A built-in zero-cross detection circuit is used to detect the zero-cross points of the input signal. When data
arrived at the IC, they are executed at the next zero-cross point or when there is no input signal. This is to
minimize 'click' noise during the transition of levels.
The timer circuit is added to ensure that the data is executed even when a zero-cross point is not detected
after a pre-determined period of time from the falling edge of the CE pulse.
The internal circuit of VCT pin has the following structure.
Insert a buffer when using it as a reference voltage for an external circuit.
This function mutes the output pins FNTO1, FNTO2, REO1 and REO2, when the V
turning off the bias of the output stage of the fader circuit. By so doing, the 'pop' noise caused by the drop
in these pins potential from V
CC
/2 during power-off can be avoided.
VCT
CE
17
Time constant=(0.5/10µ) C [sec]
CXA1746Q
V
15
CC
C
10µA
TIMER
GND
V
—17—
CC
100k
100k
0.5V
CXA1746Q
CC
goes below 5V, by
CXA1746Q