TLC5617_05 Datasheet, PDF (17/21 Pages) Texas Instruments – PROGRAMMABLE DUAL 10-BIT DIGITAL-TO-ANALOG CONVERTERS

TLC5617, TLC5617A
PROGRAMMABLE DUAL 10-BIT DIGITAL-TO-ANALOG CONVERTERS
APPLICATION INFORMATION
SLAS151B – JULY 1997 – REVISED MARCH 2000
general serial interface (continued)
SCLK
DIN
TLC5617
CS
SK
SO Microwire
Port
I/O
Figure 23. Microwire Connection
SCLK
DIN
TLC5617
CS
SCK
MOSI _SPI/QSPI
Port
I/O
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.
Output
Voltage
0V
Negative
Offset
DAC Code
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.
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