TLC5617, TLC5617A

PROGRAMMABLE DUAL 10-BIT DIGITAL-TO-ANALOG CONVERTERS

SLAS151B – JULY 1997 – REVISED MARCH 2000

17

POST OFFICE BOX 655303

APPLICATION INFORMATION

general serial interface (continued)

SCLK

DIN

CS

TLC5617

SK

SO

I/O

Microwire

Port

Figure 23. Microwire Connection

SCLK

DIN

CS

TLC5617

SCK

MOSI

I/O

SPI/QSPI

Port

CPOL = 1, CPHA = 0

Figure 24. SPI/QSPI Connection

linearity, offset, and gain error using single-end supplies

When an amplifier is operated from a single supply, the voltage offset can still be either positive or negative. With

a positive offset, the output voltage changes on the first code change. With a negative offset, the output voltage

may not change with the first code depending on the magnitude of the offset voltage.

The output amplifier attempts to drive the output to a negative voltage. However, because the most negative

supply rail is ground, the output cannot drive below ground and clamps the output at 0 V.

The output voltage remains at zero until the input code value produces a sufficient positive output voltage to

overcome the negative offset voltage, resulting in the transfer function shown in Figure 25.

DAC Code

Output

Voltage

0 V

Negative

Offset

Figure 25. Effect of Negative Offset (Single Supply)

This offset error, not the linearity error, produces this breakpoint. The transfer function would have followed the

dotted line if the output buffer could drive below the ground rail.