Texas Instruments ISO3086T Small EVM ISO3086TEVM-436 ISO3086TEVM-436 Datenbogen
Produktcode
ISO3086TEVM-436
T
T
U1
U2
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Overview
Figure 7. Five-Node Multipoint Circuit
Notice that the bus configuration shown in
can be redrawn as shown in
. Additional
EVMs can be obtained and connected to the bus, but the termination resistors on those EVMs need to be
removed so that the bus is terminated only at each end.
removed so that the bus is terminated only at each end.
Figure 8. Two-Node Multipoint Circuit
1.4
Operation Over Extended Common-Mode Voltage Range
One of the features of the three ISO devices is their operation over an extremely wide common-mode
voltage range or –7 Vdc to +12 Vdc. This can be evaluated using two EVMs, each powered from a
separate independent power supply. This extended common-mode range is important because
communications between equipment located hundreds of meters apart usually means a voltage offset
exists between the grounds of each node. The EVMs can be configured with three power supplies with
isolated outputs in such a way as to input a fixed offset between the grounds (see
voltage range or –7 Vdc to +12 Vdc. This can be evaluated using two EVMs, each powered from a
separate independent power supply. This extended common-mode range is important because
communications between equipment located hundreds of meters apart usually means a voltage offset
exists between the grounds of each node. The EVMs can be configured with three power supplies with
isolated outputs in such a way as to input a fixed offset between the grounds (see
). This induces
a ground potential difference voltage (VGPD) between EVM#1 and EVM#2. To demonstrate this
capability, the following steps are presented.
capability, the following steps are presented.
1. Adjust PS1 and PS2 to the supply voltage (+5 V) and current limit to 200 mA.
2. Set PS3 to 0 V.
3. Induce a ground offset by varying the output of PS3.
2. Set PS3 to 0 V.
3. Induce a ground offset by varying the output of PS3.
WARNING
PS3 output must not exceed +12 V to -7 V to remain within the
device ratings.
device ratings.
7
SLLU122A – April 2010 – Revised July 2010
ISO1176T/35T/3086T Evaluation Module
Copyright © 2010, Texas Instruments Incorporated