EVAL-AD5063EB datasheet(16/20 Pages) AD

16 / 20 page

AD5063

Rev. C | Page 16 of

APPLICATIONS

Table 7. Recommended Precision References for the AD5063

Part No.

Initial

Accuracy

(mV max)

Temperature Drift

(ppm/°C max)

CHOOSING A REFERENCE FOR THE AD5063

To achieve optimum performance of the AD5063, thought

should be given to the choice of a precision voltage reference.

The AD5063 has one reference input, VREF. The voltage on the

reference input is used to supply the positive input to the DAC;

therefore, any error in the reference is reflected in the DAC.

0.1 Hz to 10 Hz

Noise (μV p-p typ)

ADR435

±2

3 (R-8)

ADR425

±2

3 (R-8)

3.4

ADR02

±3

3 (R-8)

ADR02

±3

3 (SC-70)

There are four possible sources of error when choosing a voltage

reference for high accuracy applications: initial accuracy, ppm

drift, long-term drift, and output voltage noise. Initial accuracy

on the output voltage of the DAC leads to a full-scale error in the

DAC. To minimize these errors, a reference with high initial

accuracy is preferred. Also, choosing a reference with an output

trim adjustment, such as the ADR423, allows a system designer to

trim out system errors by setting a reference voltage to a voltage

other than the nominal. The trim adjustment can also be used at

any point within the operating temperature range to trim out error.

ADR395

±5

9 (TSOT-23)

BIPOLAR OPERATION USING THE AD5063

The AD5063 has been designed for single-supply operation, but

a bipolar output range is also possible by using the circuit shown

in Figure 37. This circuit yields an output voltage range of ±4.096 V.

Rail-to-rail operation at the amplifier output is achievable using

AD8675/AD8031/AD8032 or an OP196.

The output voltage for any input code can be calculated as

Because the supply current required by the AD5063 is extremely

low, the parts are ideal for low supply applications. The ADR395

voltage reference is recommended; it requires less than 100 μA of

quiescent current and can, therefore, drive multiple DACs in one

system, if required. It also provides very good noise performance

at 8 μV p-p in the 0.1 Hz to 10 Hz range.

⎥

⎦

⎤

⎢

⎣

⎡

⎟

⎠

⎞

⎜

⎝

⎛

−

⎟

⎠

⎞

⎜

⎝

⎛

⎟

⎠

⎞

⎜

⎝

⎛

536

where D represents the input code in decimal (0 to 65,536).

With VREF = 5 V, R1 = R2 = 30 kΩ

AD5063

3-WIRE

SERIAL

INTERFACE

SYNC

SCLK

DIN

VOUT = 0V TO 5V

ADR395

65536

−

⎟

⎠

⎞

⎜

⎝

⎛ ×

This is an output voltage range of ±5 V, with 0x0000 corresponding

to a −5 V output and 0xFFFF corresponding to a +5 V output.

AD5063

DACGND

VVREF

OUT

SCLK

DIN

SYNC

+5V

+4.096V

EXTERNAL

OP AMP

BIPOLAR

OUTPUT

µF

SERIAL

INTERFACE

0.1

µF

0.1

µF

INV

RINV

+5V

–5V

RFB

AGND

Figure 36. ADR395 as a Reference to AD5063

Long-term drift is a measure of how much the reference drifts

over time. A reference with a tight long-term drift specification

ensures that the overall solution remains relatively stable during

its entire lifetime. The temperature coefficient of a reference’s

output voltage affects INL, DNL, and TUE. A reference with a

tight temperature coefficient specification should be chosen to

reduce the temperature dependence of the DAC output voltage

on ambient conditions.

Figure 37. Bipolar Operation

In high accuracy applications, which have a relatively low

tolerance for noise, reference output voltage noise needs to be

considered. It is important to choose a reference with as low an

output noise voltage as practical for the system noise resolution

required. Precision voltage references, such as the ADR435,

produce low output noise in the 0.1 Hz to 10 Hz region. Exam-

ples of some recommended precision references for use as the

supply to the AD5063 are shown in Table 7.

EVAL-AD5063EB Datasheet(PDF) 16 Page - Analog Devices

EVAL-AD5063EB Datasheet(HTML) 16 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

Datasheet Download

Link URL