Datasheet

TLC7225C, TLC7225I
QUADRUPLE 8-BIT DIGITAL-TO-ANALOG CONVERTERS
SLAS109B – OCTOBER 1996 – REVISED FEBRUARY 2001
12
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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.
_
+
DAC A
_
+
DAC B
_
+
DAC C
_
+
DAC D
5
REFA
2
1
24
23
OUTA
OUTB
OUTC
OUTD
REFB
REFC
REFD
V
SS
AGND DGND
4
21
20
Figure 8. Unipolar Output Circuit
LSBMSB
DAC LATCH CONTENTS
ANALOG OUTPUT
V
ref
255
256
1111 1111
V
ref
129
256
1000 0001
1000 0000
V
ref
128
256
V
ref
2
0111 1111
V
ref
127
256
0000 0001
V
ref
1
256
0000 0000 0 V
NOTE 3 : 1 LSB
V
ref
2
–8
V
ref
1
256
Table 3. Unipolar Code