三合微科股份有限公司
SM7153
SAMHOP Microelectronics Corp. ELECTRONIC VOLUME
CONTROLLER
FUNCTION DESCRIPTION
(1) Setting Of Attenuation
After power on, attenuation is automatically set at -40dB.
POWER SUPPLY
U/D
OSC
-30dB
-32dB
-34dB
-36dB
-38dB
-40dB
Figure 1
When the UP key is pressed after power ON, the U/D terminal is placed in the up state at
' H ' level, and the oscillator is actuated.
When the DOWN key is pressed, t
DOWN key is pressed, and the oscillator is actuated in the down state and therefore,
attenuation is decreased. Oscillation frequency is decided by Cx and Rx.
fosc≒
1
0.7 Cx * Rx
(Hz) (Rs≧3Rx)
VDD
RS
UP
CX
OSC
osc
RX
U/D
DWOM
+
RX=33 KΩ
- 2.2uF CX=4.7µF
RS=100 KΩ
VSS
Figure 2
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