MAX5158 Maxim, MAX5158 Datasheet - Page 14

• Manufacturer Part Number: MAX5158
• Description: Low-Power / Dual / 10-Bit / Voltage-Output DACs with Serial Interface
• Manufacturer: Maxim

produce a range of 0V to 2.5V with a 1.25V reference.
Table 2 lists the unipolar output codes. An offset to the
output can be achieved by connecting a voltage to
OS_, as shown in Figure 10. By applying V
the output values will range between 1V and (1V +
V
The MAX5158/MAX5159 can be configured for a bipo-
lar output, as shown in Figure 11. The output voltage is
given by the equation (OS_ = AGND):
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.
Low-Power, Dual, 10-Bit Voltage-Output DACs
with Serial Interface
Note: ( ) are for the sub bits.
14
Table 3. Bipolar Code Table
Figure 11. Bipolar Output Circuit
REF
1 1 1 1 1 1
1 0 0 0 0 0
1 0 0 0 0 0
0 1 1 1 1 1
0 0 0 0 0 0
0 0 0 0 0 0
REF_
MSB
DAC _
______________________________________________________________________________________
x 2).
DAC CONTENTS
MAX5158
MAX5159
V
OUT
1 1 1 1 ( 0 0 0 )
0 0 0 1 ( 0 0 0 )
0 0 0 0 ( 0 0 0 )
1 1 1 1 ( 0 0 0 )
0 0 0 1 ( 0 0 0 )
0 0 0 0 ( 0 0 0 )
+5V/+3V
DGND
V
DD
= V
LSB
REF
R
R
AGND
[((2 x NB) / 1024) - 1]
OUT_
OS_
-V
10k
10k
ANALOG OUTPUT
REF
10k
+V
+V
-V
-V
Bipolar Output
REF
REF
REF
REF
512
512
0V
512
512
512
511
512
511
V+
V-
10k
1
1
OS
- V
_ = -1V,
REF
V
OUT
In applications where the reference has an AC signal
component, the MAX5158/MAX5159 have multiplying
capabilities within the reference input voltage range
specifications. Figure 12 shows a technique for apply-
ing a sinusoidal input to REF_, where the AC signal is
offset before being applied to the reference input.
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. The typical -3dB frequency is 300kHz
for both devices, as shown in the Typical Operating
Characteristics.
Figure 13. Digital Calibration
Figure 12. AC Reference Input Circuit
REFERENCE
500mVp-p
+5V/
+3V
P
INPUT
AC
DIN
26k
REF_
AGND
DAC _
10k
MAX5158
MAX5159
Harmonic Distortion and Noise
+5V/+3V
+5V/+3V
V
DD
AGND
DAC_
Using an AC Reference
REF
MAX495
DGND
R
R
MAX5158
MAX5159
OUT_
OS_
V
DD
DGND
V+
R
R
PHOTODIODE
PULLDOWN
R
V+
V-
OS_
OUT_
V
OUT