TLC7225 Datasheet, PDF (12/22 Pages) Texas Instruments – QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS

TLC7225C, TLC7225I
QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS109B – OCTOBER 1996 – REVISED FEBRUARY 2001
APPLICATION INFORMATION
unipolar output operation
The unipolar output operation is the basic mode of operation for each channel of the TLC7225, with the output
voltages having the same positive polarity as V_ref. The TLC7225 can be operated with a single supply
(V_SS = AGND) or with positive or negative supplies. The voltage at V_ref must never be negative with respect
to DGND to prevent parasitic transistor turnon. Connections for the unipolar output operation are shown in
Figure 8. The transfer values are shown in Table 3.
_
REFA ⁵
DAC A
+
2
OUTA
_
4
REFB
DAC B
+
1 _OUTB
_
REFC ²¹
DAC C
+
24
OUTC
20
REFD
_
DAC D
+
23 _OUTD
VSS AGND DGND
Figure 8. Unipolar Output Circuit
Table 3. Unipolar Code
DAC LATCH CONTENTS
MSB LSB
1111 1111
1000 0001
1000 0000
0111 1111
0000 0001
ANALOG OUTPUT
ǒ Ǔ ) Vref
255
256
ǒ Ǔ ) Vref
129
256
ǒ Ǔ ) + ) Vref
128
256
Vref
2
ǒ Ǔ ) Vref
127
256
ǒ Ǔ ) Vref
1
256
+ ǒ Ǔ + ǒ Ǔ ^{0000 0000}
NOTE 3 : 1 LSB
Vref 2^{– 8}
0V
Vref
1
256
12
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