Applications information, Table 2. unipolar code table, Unipolar output – Rainbow Electronics MAX5355 User Manual
Page 12: Bipolar output, Using an ac reference
Figure 7 shows a method of connecting several
MAX5354/MAX5355s. In this configuration, the clock
and the data bus are common to all devices, and sepa-
rate chip-select lines are used for each IC.
__________Applications Information
Unipolar Output
For a unipolar output, the output voltage and the refer-
ence input have the same polarity. Figure 8 shows the
MAX5354/MAX5355 unipolar output circuit, which is
also the typical operating circuit. Table 2 lists the unipo-
lar output codes.
Figure 9 illustrates a rail-to-rail output configuration.
This circuit shows the MAX5354 with the output amplifi-
er configured for a closed-loop gain of +2, to provide a
0V to 5V full-scale range when a 2.5V reference is
used. When the MAX5355 is used with a 1.25V refer-
ence, this circuit provides a 0V to 2.5V full-scale range.
Bipolar Output
The MAX5354/MAX5355 output can be configured for
bipolar operation using Figure 10’s circuit, according to
the following equation:
V
OUT
= V
REF
[(2NB / 1024) - 1]
where NB is the numeric value of the DAC’s binary
input code. Table 3 shows digital codes (offset binary)
and corresponding output voltage for Figure 10’s circuit.
Using an AC Reference
In applications where the reference has AC-signal com-
ponents, the MAX5354/MAX5355 have multiplying
capability within the reference input range specifica-
tions. Figure 11 shows a technique for applying a sine-
wave signal to the reference input where the AC signal
is offset before being applied to REF. The reference
voltage must never be more negative than GND.
MAX5354/MAX5355
10-Bit Voltage-Output DACs
in 8-Pin µMAX
12
______________________________________________________________________________________
TO OTHER
SERIAL DEVICES
MAX5354
MAX5355
DIN
SCLK
CS
MAX5354
MAX5355
DIN
SCLK
CS
MAX5354
MAX5355
DIN
SCLK
CS
DIN
SCLK
CS1
CS2
CS3
Figure 7. Multiple MAX5354/MAX5355s Sharing Common DIN and SCLK Lines
Table 2. Unipolar Code Table
NOTE: ( ) are for sub-bits.
ANALOG OUTPUT
1 1 1 1 1 1 1 1 1 1
( 0 0 0 )
1 0 0 0 0 0 0 0 0 1
( 0 0 0 )
DAC CONTENTS
MSB
LSB
1 0 0 0 0 0 0 0 0 0
( 0 0 0 )
0 1 1 1 1 1 1 1 1 1
( 0 0 0 )
0 0 0 0 0 0 0 0 0 0
( 0 0 0 )
0V
0 0 0 0 0 0 0 0 0 1
( 0 0 0 )
+V
1023
1024
REF
+V
513
1024
REF
+V
512
1024
V
2
REF
REF
=
+
+V
511
1024
REF
+V
1
1024
REF