Rainbow Electronics MAX5355 - Manual (Page 13)

The MAX5354’s total harmonic distortion plus noise
(THD+N) is typically less than -77dB (full-scale code),
and the MAX5355’s THD+N is typically less than -72dB
(full-scale code), given a 1Vp-p signal swing and input
frequencies up to 25kHz. The typical -3dB frequency is
650kHz for both devices, as shown in the
Typical
Operating Characteristics graphs.
Digitally Programmable Current Source
The circuit of Figure 12 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) x (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.
MAX5354/MAX5355
10-Bit Voltage-Output DACs
in 8-Pin µMAX
______________________________________________________________________________________ 13
NOTE: ( ) are for sub-bits.
MAX5354
MAX5355
DAC
REF
OUT
FB
GND
+5V/3.3V
V DD
Figure 8. Unipolar Output Circuit
Table 3. Bipolar Code Table
MAX5354
MAX5355
DAC
REF
OUT
10k
10k
GND
+5V/+3.3V
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

 

=