SNC688

4-Channel Speech Controller

5.10 8-bit PWM

A PWM (pulse width modulation) circuit is built-in SNC688. PWM can convert input

digital data into pulse trains with suitable different pulse width. The maximum

resolution of PWM is 8 bits. Two huge output stage circuits are included in SNC688.

Both of them are capable of driving speaker directly. Besides, 15 level PWM output

current is provided for volume adjust function.

#

VOL[3..0]

Output Current

(VDD=3V, Vo=1.5V)

0

0000

120mA

1

0001

105mA

2

0010

90mA

3

0011

75mA

4

0100

60mA

5

0101

52.5mA

6

0110

45mA

7

0111

37.5mA

8

1000

30mA

9

1001

22.5mA

A

1010

15mA

B

1011

10.25mA

C

1100

7.5mA

D

1101

3.75mA

E

1110

3.75mA

F

1111

0mA

15 levels PWM output current control

BUO1/VO

BUO2

PWM output

Ver: 1.3

June 8, 2005

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