Description
ISAR740 - USB Isolator with ADuM3165/ADuM3166 and Ultra-Low-Noise DC-DC Converter muRata NXE2.
ISAR740 is an USB isolator for interconnection of sensitive USB devices, such as USB DACs or Weather Stations.
It will isolate the power from the USB host and the connected device and provides a cleaner 5V DC USB voltage to the USB device.
The isolator will create a new ground for the USB device so that it doesn't have to share ground with your computer and other devices
you might have connected in the same premise. USB devices with their own power supply can still be connected.
The effective isolation of the USB device from the host most often ensures not only a measurable, but also a hearable improvement when using it together with an USB DAC.
Without isolation, the digital signal processing in the computer otherwise impacts stability of ground signals quite dramatically.
As soon as an audio amplifier with its own ground and its own power supply is connected for analog audio amplification,
current flows for potential compensation between computer and amplifier on common ground signals.
This current will then most often be heard as noise, high frequency whistling, humming, howling or chirping.
Some applications on the computer, which sometimes generate pretty intense noise are scolling in the internet browser or playing videos -
and its related CPU- and GPU-intense signal processing.
When connecting a Weather Station with its own grounding or relatively long USB cable outdoors, sometimes connection between Weather Station and computer suffers.
A new ground - to be more precise, an isolation of computer-ground and device ground - adds clarity and cares for a strict separation of different ground signals.
Therefore, ISAR740 is the prerequisite for a high quality sound experience and reliable data connection.
Unfortunately, all DC-DC converters, not only those for USB isolation, quite often generate a new little problem with their ripple and noise on the new USB ground by themselves.
While most USB isolators are based on simple DC-DC converters, ISAR740 on the other hand utilizes a high-end converter muRata NXE2. This fact improves sound quality significantly.
NXE2 by muRata specifies its output ripple & noise with 55mVp-p. ISAR740 in addition utilizes a L-C circuit which lowers noise at normal load to 5mVp-p.
Analog Devices ADuM3165/ADuM3166 is a USB 2.0 port isolator, utilizing
AD iCoupler® technology to dynamically support
all USB 2.0 data rates: low (1.5 Mbps), full (12 Mbps), or high
(480 Mbps), as required. The devices support host isolation with
automatic speed negotiation as well as peripheral isolation.
High speed data is retimed for jitter reduction. The ADuM3165/ADuM3166 supports the clock or
crystal input on the upstream side to best suit the system design.
The low power standby mode for downstream (Side 2) supports
applications with limited available power, such as battery-operated
peripherals. The upstream (Side 1) standby current meets USB 2.0
requirements for suspended operation.
Unlike ISAR520 or ISAR540, ISAR740 supports three USB protocols: USB HIGH SPEED with 480Mbps,
USB FULL SPEED with 12 Mbps and USB LOW SPEED.
The current protocol is automatically detected by the isolator.
Thus, all common DAC sampling rates with 384kHz 192kHz 96kHz 48KHz and 44.1kHz are supported.
ISAR740 is the all-rounder among the USB isolators.
