TLC5617, TLC5617A

PROGRAMMABLE DUAL 10-BIT DIGITAL-TO-ANALOG CONVERTERS

SLAS151B – JULY 1997 – REVISED MARCH 2000

14

POST OFFICE BOX 655303

APPLICATION INFORMATION

latch B and double-buffer 1 write (D15 = low, D12 = low)

The SIR data are written to both latch B and the double buffer. Latch A is unaffected.

Serial

Interface

Register

D12 = Low

Latch A

Latch B

Double

Buffer

Latch

To DAC A

To DAC B

D15 = Low

Figure 20. Latch B and Double-Buffer Write

double-buffer-only write (D15 = low, D12 = high)

The SIR data are written to the double buffer only. Latch A and B contents are unaffected.

Serial

Interface

Register

D12 = High

Latch A

Latch B

Double

Buffer

To DAC A

To DAC B

D15 = Low

Figure 21. Double-Buffer-Only Write

purpose and use of the buffer

Normally only one DAC output can change after a write. The double buffer allows both DAC outputs to change

after a single write. This is achieved by the two following steps.

1.

A double-buffer-only write is executed to store the new DAC B data without changing the DAC A and B

outputs.

2.

Following the previous step a write to latch A is executed. This writes the SIR data to latch A and also writes

the double-buffer contents to latch B. Thus both DACs receive their new data at the same time and so both

DAC outputs begin to change at the same time.

Unless a double-buffer-only write is issued, the latch B and double-buffer contents are identical. Thus, following

a write to latch A or B with another write to latch A does not change the latch B contents.