Datasheet

TLV5626
2.7-V TO 5.5-V LOW-POWER DUAL 8-BIT DIGITAL-TO-ANALOG
CONVERTER WITH INTERNAL REFERENCE AND POWER DOWN
SLAS236A –JUNE 1999 – REVISED JUNE 2000
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
examples of operation: (continued)
Set DAC A value, set DAC B value, update both simultaneously, select slow mode, select internal reference
at 1.024 V:
1. Set reference voltage to 1.024 V (CONTROL register):
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1
2. Write data for DAC B to BUFFER:
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
0 0 0 1 New DAC B value 0 0 0 0
X = Don’t care
3. Write new DAC A value and update DAC A and B simultaneously:
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
1 0 0 0 New DAC A value 0 0 0 0
X = Don’t care
Both outputs are updated on the rising clock edge after D0 from the DAC A data word is sampled.
Set power-down mode:
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
X X 1 X X X X X X X X X X X X X
X = Don’t care
linearity, offset, and gain error using single ended 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 then 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 14.
DAC Code
Output
Voltage
0 V
Negative
Offset
Figure 14. Effect of Negative Offset (single supply)