AD9963 Analog Devices, AD9963 Datasheet - Page 54

• Manufacturer Part Number: AD9963
• Description: 10-/12-Bit, Low Power, Broadband MxFE
• Manufacturer: Analog Devices

Specifications of AD9963

• Resolution (bits): 12bit
• Throughput Rate: 100MSPS
• # Chan: 2
• Supply V: Multi(+1.8Anlg, +1.8Dig),Multi(+1.8Anlg, +3.3Dig) ,Single(+1.8),Single(+3.3)
• Sample Rate: 100MSPS
• Adc Bits X #adcs-speed: 12x2-100 MHz
• Dac Bits X #dacs-clkspeed: 12x2-170 MHz
• Pkg Type: CSP
• Primary Application: Broadband Wireless

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