Rainbow Electronics MAX5304 - Manual (Page 10)

MAX5304
10-Bit Voltage-Output DAC
in 8-Pin µMAX
10 ______________________________________________________________________________________
The MAX5304’s total harmonic distortion plus noise
(THD+N) is typically less than -77dB (full-scale code),
given a 1Vp-p signal swing and input frequencies up to
25kHz. The typical -3dB frequency is 650kHz, as
shown in the Typical Operating Characteristics graphs.
Digitally Programmable Current Source
Figure 12’s circuit places an NPN transistor (2N3904 or
similar) within the op amp feedback loop to implement
a digitally programmable, unidirectional current source.
The output current is calculated with the following
equation:
I OUT = (V REF / R)(NB / 1024)
where NB is the numeric value of the DAC’s binary
input code, and R is the sense resistor shown in Figure
12.
Note: ( ) are for sub-bits.
MAX5304
DAC
REF
OUT
FB
GND
+5V
V DD
Figure 8. Unipolar Output Circuit
Table 3. Bipolar Output Codes
MAX5304
DAC
REF
OUT
10k
10k
GND
+5V
V DD
FB
Figure 9. Unipolar Rail-to-Rail Output Circuit
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 ) 0V
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 )
0 0 0 0 0 0 0 0 0 1 ( 0 0 0 )
+V
511
512
REF

 

+V
1
512
REF

 

-V
1
512
REF

 

-V
511
512
REF

 

-V
512
512
- V
REF REF

 

=