XJIsolator

Overview
Benefits
Features

XJIsolator provides galvanic isolation between a Unit Under Test (UUT) and an XJLink2 JTAG controller. Its small form factor means an XJIsolator board can be easily mounted inside a test fixture.

Key Benefits

Provides high levels of galvanic isolation

Compatible with other accessories from XJTAG

Simple ‘Plug & Play’ installation

Features

Isolation for voltages up to 443 Vrms
Supports TCK clock frequencies, up to 50 MHz
Very low unidirectional propagation delay, typically 8 ns
Single power supply required, referenced to UUT ground
Flexible power supply voltage: 5 V to 15 V
Variable I/O voltages from 1.8 V to 3.3 V (set by JTAG controller or UUT)
5 V I/O voltage option available
Offers 8 isolated signal channels configured as 6 downlink and 2 uplink
Requires no configuration in XJTAG software · Compatible with XJExtender and XJXDP

Galvanic isolation

Galvanic isolation overcomes the challenge of connecting a test system to a UUT in situations where (either intentionally or unintentionally) they do not have a common ground. XJIsolator provides galvanic isolation for the Test Access Port (TAP) signals that are used when testing a UUT with JTAG.

Plug & Play

XJIsolator easily integrates into a test set-up via its two 20-way IDC connectors, using standard ribbon cables. It supports all of the TAP signals required for JTAG testing, passing them to and from the UUT.

XJTAG’s JTAG controllers have an advanced auto-skew algorithm which automatically compensates for the small additional delay introduced by adding the XJIsolator to a test set-up, making it simple to use and ‘invisible’ to XJTAG’s software.

Integrated power supply

The UUT side of XJIsolator runs at logic levels of 1.8 V to 3.3 V, set by reference voltage on the JTAG controller or optionally on the UUT. To isolate the UUT signals from the JTAG controller an external power supply (not supplied) is required, supplying 5-15 V DC.

Extending test capability

XJIsolator has been designed to work with XJTAG’s existing hardware accessories, and complements the XJExtender and XJXDP boards. Combining XJIsolator with these boards can address signal integrity issues and/or high drive strength requirements as well as galvanic isolation.