AD-DPGIOZ datasheet(54/61 Pages) AD

54 / 61 page

AD9961/AD9963

Data Sheet

Rev. A | Page 54 of 60

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.

0.5

1.0

1.5

2.0

CODE

2.5

3.0

3.5

128

256

384

512

640

768

896

1024

RNG00

RNG01

RNG10

RNG11

Figure 89. AUXDAC10 Voltage Output vs. Digital Code, VTOP = 3.0 V

(RTOP = 3.2 kΩ)

0.25

0.50

0.75

CODE

1.25

1.75

1.00

1.50

2.00

128

256

384

512

640

768

896

1024

RNG00

RNG01

RNG10

RNG11

Figure 90. AUXDAC10 Voltage Output vs. Digital Code, VTOP = 1.5 V

(RTOP = 8.0 kΩ)

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.

AUX33V

AUXDACREF

2.3

Ω

RTOP

VREF

DAC12

DAC12TOP: 0 = RTOP = 0.8R

1 = RTOP = 2.3R

0 TO VREF

REFIO

DACCODE

Figure 91. Simplified Schematic of the 12-Bit Auxiliary DAC

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:

























1024

DACCODE

OUT

where VFSis set with the combination of bits shown in Table 29.

Table 29. 12-Bit Auxiliary DAC Full-Scale Voltage Selection

AUXDAC_REF

DAC10x_RNG1

AUX33V

0.54 × AUX33V

3.3 V

1.8 V

1 x = A or B.

The curves in Figure 92 show the two transfer functions when

using the internal 1.0 V bandgap reference.

0.5

1.0

1.5

2.0

2.5

3.0

3.5

128

256

384

512

640

768

896

1024

CODE

VFS = 3.3V

VFS = 1.8V

Figure 92. AUXDAC12 Voltage Output vs. Digital Code

AD-DPGIOZ датащи(PDF) 54 Page - Analog Devices

AD-DPGIOZ датащи(HTML) 54 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

датащи скачать

ссылки URL