AD1853: Two devices in parallel

Question Is it possible direct paralleling two AD1853 DA Converters for lower noise and distortion? Answer Since the AD1853 has current outputs, these can be tied together with no problem and the output will be the sum of the two channels. See datasheet page 16 figure 30 (mono application circuit). The noise/distortion results depend heavily on the rest of the circuit design. e.g. if the output op amps saturate because they are receiving 2x the current then the result on distortion is rather terrible! The noise in the two channels is uncorrelated so you should theoretically get an improvement in noise by a factor of sqrt 2 (from the DAC). This will not help much if the majority of the noise comes from the amplifiers.

AD1853: output impedance

Question Output impedance of AD1853 current output audio DAC The data sheet for AD1853 specify a couple of things for the analog outputs, but not the output impedance (it specifies output capacitance). Would it be possible to obtain that information? Answer Normally the output impedance of the AD1853 is so high that it can be neglected and the current output DAC simply looks like a current source. To reach the specified performance the AD1853 should drive an op-amp I to V converter, as shown in figure 29 and 30. By driving the virtual earth at the -ve terminal of the op-amp, the DAC is looking into a very low impedance because the voltage at the virtual earth hardly changes over the output current range of the DAC. For some other type of load e.g. a passive load referred to ground, the voltage at the DAC outputs changes with output current, which causes the specifications to be degraded, and therefore the I to V converter is the recommended load. Also, please ignore the section entiltled Output Drive, Buffering and Loading. this is a datasheet error and refers to a DAC with voltage output, not current output. If you are looking for a DAC with a voltage output, you might wish to consider the AD1852.

Question Where can I find the AD1853 EVB User Guide? Answer Please refer to the attached pdf. Please note that this evaluation board is no longer available and AD1853 is no longer recommended for new designs. Instead we recommend AD1955

English

Forums
Popular Forums
Product Forums
View All
Application Forums
Design Center Forums
Learn
Highlighted Webinar

Fast-Track Certification: Leveraging IC Safety App Notes for Functional Safety Designs
Stop guessing, start certifying. Learn how to use IC safety application notes to streamline your FMEDA and meet IEC 61508 and ISO 13849 standards with...
Places
Libraries
Community Hub
Challenge Yourself!
View All
What's Brewing
View All
Places
Resources
View All
ContentZone
Visit ContentZone
Search content by industry or technology.

Blogs

Technical Articles

Tutorials

Videos

Webinars

Your ADI content all in one place.
View ContentZone
The Latest Read

A Systematic Checklist for RF Transceiver Testing
RF transceiver bring-up is the initial process of powering, configuring, and verifying a transceiver on new hardware to ensure basic functionality and...

New Release

Signal Chain Designer: DC Error Simulation
This video covers the DC error calculation capabilities of Signal Chain Designer. DC error is unique in that often requires calibration and has so many...

Recent Technical Insights

Phase Sync in Digital Phased Arrays Through Direct RF SamplingPart 1: The Basics
This article presents a methodology to synchronize multiple modular circuit boards, equipped with high speed data converters, to build a concept of a scalable...

EngineerZone

Audio

Log In

User
Site
Search

OR

Ask a Question

Audio

Documents AD1853: FAQ

Q&A
FAQs/Docs
Members
Sub-Groups
Tags
Cancel

Products Mentioned

AD1853 Obsolete
The AD1853 is the first audio DAC to support the 192 kHz Sample Rate now included in the DVD-Audio specification. The AD1853 is fully compatible with sample...
AD1853 on Analog.com