SLLU367 july   2023 ISO1228

 

  1.   1
  2.   Description
  3.   Features
  4.   4
  5. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  6. 2Hardware
    1. 2.1 Pin Configuration of the ISO1228
    2. 2.2 EVM Board Block Diagram and Image
    3. 2.3 EVM Setup and Operation
      1. 2.3.1 EVM Jumper Settings
  7. 3Hardware Design Files
    1. 3.1 Schematics
    2. 3.2 PCB Layouts
    3. 3.3 Bill of Materials

1.4 Device Information

The evaluation module contains one ISO1228 and all other passive components required for operation. Various components included in the evaluation module directly control the operation and functionality of the ISO1228. If necessary, components can be removed, added, or replaced to modify the behavior of the ISO1228 accordingly for any given application.

The external resistor on the AVCC supply path, RILIM (R18) sets the current limit to be drawn from each digital input. This current limit must be common to all input channels. The RPAR resistors (R10, R11, R12, R13, R14, R15, R16, and R17), between each INx and LEDx pin, are chosen according to the selected RILIM value. The RTHR resistors (R1, R2, R3, R4, R5, R6, R7, and R8), located on each input pin, can be used to increase the voltage transition thresholds as well as attenuate any surge current seen on the input pins. RSURGE (R9) along with CSURGE (C1) and CFIL (C2) filter any surges or transients seen on the power supply.

For more information on selecting the RILIM, RPAR, RTHR, or RSURGE resistor values, see Table 2-1 or the ISO1228 data sheet. For Type 2 inputs, RTHR values can be same as Type 3 inputs.

Table 1-1 Sink Mode RTHR Admissible Values (Ω)
SINK MODE
RILIM = 0 Ω, RPAR = 16 kΩ, RSURGE = 1 kΩ, (IL = 2.5 mA) RILIM = 1 kΩ, RPAR = 10.7 kΩ, RSURGE = 1 kΩ, (IL = 3.5 mA)
Min Typical Max Min Typical Max
Type 1 180 1000 2400 Type 1 110 910 1900
Type 3 180 1000 1300 Type 3 110 910 950

The on-board LEDs demonstrate the functionality of the ISO1228's field side LED indication feature. When a digital input signal crosses the programmable input voltage threshold VIH, current being drawn from the digital inputs is diverted to the corresponding LED. This provides a visual indication of which channels are receiving valid digital input signals at any time. Additionally, by using the current from the digital input, no additional power is required from the device or system. When the digital input voltage falls below the programmable input voltage threshold VIL, the current bypasses the LEDs resulting in the indicators switching off.

For a full list of components included in the ISO1228 Evaluation Module, please see the Bill of Materials.