MAX5104CEE MAXIM [Maxim Integrated Products], MAX5104CEE Datasheet - Page 11

• Manufacturer Part Number: MAX5104CEE
• Description: Low-Power, Dual, Voltage-Output, 12-Bit DAC with Serial Interface
• Manufacturer: MAXIM [Maxim Integrated Products]

where NB represents the numeric value of the DAC’s
binary input code. Table 3 shows digital codes and the
corresponding output voltage for Figure 11’s circuit.
In applications where the reference has an AC signal
component, the MAX5104 has multiplying capabilities
within the reference input voltage range specifications.
Figure 12 shows a technique for applying a sinusoidal
input to REF_, where the AC signal is offset before
being applied to the reference input.
Table 3. Bipolar Code Table
Note: ( ) are for the sub-bit.
Figure 11. Bipolar Output Circuit
MSB
1 1 1 1 1 1 1 1 1 1 1 1 ( 0 )
1 0 0 0 0 0 0 0 0 0 0 1 ( 0 )
1 0 0 0 0 0 0 0 0 0 0 0 ( 0 )
0 1 1 1 1 1 1 1 1 1 1 1 ( 0 )
0 0 0 0 0 0 0 0 0 0 0 1 ( 0 )
0 0 0 0 0 0 0 0 0 0 0 0 ( 0 )
REF_
DAC CONTENTS
DAC _
MAX5104
Low-Power, Dual, Voltage-Output, 12-Bit DAC
V
OUT
+5V/+3V
DGND
V
= V
DD
______________________________________________________________________________________
LSB
REF
R
R
AGND
[((2 · NB) / 4096) - 1]
Using an AC Reference
OUT_
OS_
-V
10k
ANALOG OUTPUT
10k
REF
10k
+V
+V
-V
+V
REF
REF
REF
2048
2048
REF
0V
2047
2048
2048
10k
V+
V-
2048
2047
4096
1
1
- V
REF
2
V
OUT
The total harmonic distortion plus noise (THD+N) is typ-
ically less than -78dB at full scale with a 1Vp-p input
swing at 5kHz.
Figure 13 shows the MAX5104 in a digital calibration
application. With a bright-light value applied to the pho-
todiode (on), the DAC is digitally ramped until it trips
the comparator. The microprocessor (µP) stores this
“high” calibration value. Repeat the process with a dim
light (off) to obtain the dark current calibration.
Figure 13. Digital Calibration
Figure 12. AC Reference Input Circuit
REFERENCE
500mVp-p
+5V/
+3V
INPUT
P
AC
DIN
with Serial Interface
26k
REF_
AGND
10k
DAC _
MAX5104
Harmonic Distortion and Noise
+5V/+3V
+5V/+3V
V
DD
AGND
DAC_
Digital Calibration and
REF
MAX495
DGND
Threshold Selection
R
R
MAX5104
OUT_
OS_
V
DD
DGND
V+
R
R
PHOTODIODE
PULLDOWN
R
V+
V-
OS_
OUT_
V
OUT
11