F1912 Datasheet

R35DS0055EU0100 Rev.1.00

Nov 10, 2022

Page 11

3.3

Parallel Control Mode

For the F1912 the user has the option of running in one of two parallel modes. Direct Parallel Mode or Latched

Parallel Mode.

3.3.1.

Direct Parallel Mode

Direct Parallel Mode is selected when VMODE (pin 13) is less than VIL and LE (pin 5) is greater than VIH. In this

mode the device will immediately react to any voltage changes to the parallel control pins [pins 1, 15, 16, 17, 19,

20]. Use direct parallel mode for the fastest settling time.

3.3.2.

Latched Parallel Mode

Latched Parallel Mode is selected when VMODE is less than VIL and LE (pin 5) is toggled from less than VIL to

greater than VIH. To utilize Latched Parallel Mode:

■

Set LE < VIL

■

Adjust pins [pins 1, 15, 16, 17, 19, 20] to the desired attenuation setting. (Note the device will not react to

these pins while LE < VIL.)

■

Pull LE > VIH. The device will then transition to the attenuation settings reflected by pins D5 – D0.

Latched Parallel Mode implies a default state for when the device is first powered up with VMODE < VIL and LE

< VIL. In this case the default setting is MAXIMUM Attenuation.

Table 5 - Truth Table for the Parallel Control Word

D5

D4

D3

D2

D1

D0

Attenuation (dB)

0

0

0

0

0

0

0

0

0

0

0

0

1

0.5

0

0

0

0

1

0

1

0

0

0

1

0

0

2

0

0

1

0

0

0

4

0

1

0

0

0

0

8

1

0

0

0

0

0

16

1

1

1

1

1

1

31.5