Azoteq IQ Switch ProxSense Series User Manual

AZD084 User Guide for Isolated
digital communications buffer
A technical guide for using the isolated
communications buffer device (AZP344C02)
1 Introduction
The in-line isolated buffer device was made for isolated I
wire streaming between an Azoteq USB device (such as the DS100 or CT210) and
Azoteq products.
The purpose of the device is to provide the designer with extensive visual feedback
whilst having a minimal impact on the sensor environment (no common signal
ground between test device and PC).
Azoteq
USB
DS100 / CT210
Figure 1-1 Isolated Communications PCB block diagram
The isolated streaming PCB plugs directly into the USB device. A standard Azoteq
20-pin male header is provided at the isolated side for connection to the test
system.
It is important to note that the isolated streaming PCB does add larger GND to the
test system. This effect is minimized in the layout. In addition capacitive coupling to
the PC GND is made mostly through the isolation ICs. This amounts to a total of
about 3pF as shown in Figure 1-2.
Copyright © Azoteq (Pty) Ltd 2013.
All Rights Reserved.
ProxSense
GUI
(PC)
Vdd
SDA (pin7)
Azoteq
SCL (pin9)
USB device
RDY (pin10)
RDY (pin8)
PC side Isolated Streaming PCB
®
IQ Switch
®
Series
Isolation
Solid
State
Relay
(<100mA)
SDA_ISO
SCL_ISO
Bi-directional
2 RDY1_ISO
I C isolators
RDY2_ISO
Revision 1.14
2
C communications and 1-
Isolated 3V3
Power Regulator
Supply (optional)
Direct
Supply
>100mA
(optional)
DUT
System to be tested
January 2014