AD9961BCPZRL Analog Devices Inc, AD9961BCPZRL Datasheet - Page 54
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AD9961BCPZRL
Manufacturer Part Number
AD9961BCPZRL
Description
Dual 16B, 200 MSPS D-A Converter
Manufacturer
Analog Devices Inc
Datasheet
1.AD9961BCPZRL.pdf
(60 pages)
Specifications of AD9961BCPZRL
Features
*
Package / Case
72-VFQFN, CSP Exposed Pad
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
AD9961/AD9963
The curves in Figure 89 represent four of the possible DAC
transfer functions with the full-scale voltage of 3.0 V and spans
of 0.5 V, 1.0 V, 1.5 V, and 2.0 V. The curves in Figure 90
represent four of the possible DAC transfer functions with the
full-scale voltage of 1.5 V and spans of 0.5 V, 1.0 V, 1.5 V, and
2.0 V. Note that the 2.0 V span results in clamping at the lower
end of the scale at 0 V where the equation resultsin negative
output voltages.
12-Bit Auxiliary DACs
The two 12-bit DACs have similar transfer functions and are
output on the DAC12A and DAC12B pins. The two DACs can
be independently enabled and configured. Figure 91 shows a
simplified schematic of the 12-bit auxiliary DAC.
Figure 89. AUXDAC10 Voltage Output vs. Digital Code, V
Figure 90. AUXDAC10 Voltage Output vs. Digital Code, V
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
0
128
128
256
256
(R
(R
384
384
TOP
TOP
= 3.2 kΩ)
= 8.0 kΩ)
CODE
CODE
512
512
640
640
768
768
RNG00
RNG01
RNG10
RNG11
RNG00
RNG01
RNG10
RNG11
896
896
TOP
TOP
= 3.0 V
= 1.5 V
1024
1024
Rev. 0 | Page 54 of 60
Note that VREF can be derived from a 1.0 V bandgap reference
or be ratiometric with the AUX33V supply. An additional gain
stage follows the DAC that sets the final full-scale output
voltage . The following equation describes the no load output
voltage:
where V
Table 29. 12-Bit Auxiliary DAC Full-Scale Voltage Selection
AUXDAC_REF
0
0
1
1
1
The curves in Figure 92 show the two transfer functions when
using the internal 1.0 V bandgap reference.
x = A or B.
2.3Ω
AUX33V
R
V
OUT
3.5
3.0
2.5
2.0
1.5
1.0
0.5
Figure 91. Simplified Schematic of the 12-Bit Auxiliary DAC
FS
0
0
is set with the combination of bits shown in Table 29.
Figure 92. AUXDAC12 Voltage Output vs. Digital Code
REFIO
=
DACCODE
V
128
FS
×
AUXDACREF
256
DACCODE
1
0
DAC10x_RNG
0
1
0
1
1024
VREF
384
CODE
512
0 TO VREF
1
V
V
FS
FS
R
640
DAC12TOP: 0 = R
= 3.3V
= 1.8V
R
768
V
AUX33V
0.54 × AUX33V
3.3 V
1.8 V
TOP
FS
1 = R
896
TOP
TOP
= 0.8R
= 2.3R
DAC12
1024