8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

Generating accurate, stable, programmable dc voltages is a key requirement in most precision end equipment.

The DAC82002 serves a wide range of end equipment, such as battery testers, communications equipment,

factory automation and control, test and measurement. The DAC82002 tiny package, high resolution, fast

settling, and simple interface makes this device an excellent choice for applications such as offset and gain

control, arbitrary waveform generation (AWG), closed-loop control, and bipolar analog outputs. A wide variety of

operational amplifiers can be used as output buffers for the DAC82002, allowing the user to choose components

that best fit their design.

8.2 Typical Applications

8.2.1 Arbitrary Waveform Generator

Arbitrary waveform generation (AWG) circuits are common in test and measurement equipment. These circuits

are used to generate ac waveforms for test applications. The key performance parameters in test and

measurement circuits are total harmonic distortion and noise (THD+N), signal-to-noise ratio (SNR), and the

update rate. Figure 8-1 shows a basic example of an AWG circuit using the DAC82002.

DAC82002

VDD

VREF

47 pF

100 nF

+

–

OPA2328

+

–

VOUTA

VOUTB

+5 V

+5 V

Figure 8-1. Arbitrary Waveform Generator

8.2.1.1 Design Requirements

• DAC output range: 0 V to 2.5 V

• THD+N at 1 kHz: < –91 dB

• Update rate: 200 kHz

8.2.1.2 Detailed Design Procedure

Figure 8-1 shows a simplified circuit diagram of an arbitrary waveform generator. The DAC82002 specifies a

THD+N of –91 dB at 1 kHz. The OPA2328 provides a great balance between fast settling, bandwidth, and

voltage and current noise. The buffer must have a negative voltage supply rail or an output offset to make

sure the DAC output is not clipped. Attach two decoupling capacitors as close as possible to the VREF pin.

Use 100 nF for the first capacitor to provide very good noise performance for the system. Use 47 pF for the

second capacitor to allow for a good dynamic response performance that improves any code-to-code glitch.

The REF5025 is a low-noise, very low-drift, precise voltage reference that generates a 2.5-V reference for this

application.

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DAC82002

SBASAK1A – AUGUST 2022 – REVISED DECEMBER 2022

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