SLLU375 September   2024 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
  8. 4Additional Information
    1. 4.1 Trademarks

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 full-bridge rectifier (D10, D11, D12, D13) connected to AVCC and AVSS allow for the supply to be plugged in either direction, enabling the EVM to be evaluated in sink or source mode.

The external resistor on the AVCC supply path, RILIM (R18) sets the current limit to the digital inputs. The current limit set by RILIM applies to all input channels. The RPAR resistors (R10, R11, R12, R13, R14, R15, R16, and R17), between each INx and LEDx pins, 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 set the voltage transition thresholds. These resistors also serve as current limiting resistors for any voltage transients occurring at input terminals. RSURGE (R9) along with CSURGE (C1) filter any surges or transients seen on the power supply.

For recommendations on selecting the RILIM, RPAR, RTHR, or RSURGE resistor values for each operational mode, see Table 1-1, Table 1-2, Table 1-3, or the ISO1228 Eight-Channel Isolated Digital Input Receiver data sheet. Two channels of ISO1228 can be connected to create one Type 2 input. Set RILIM = 1kΩ to support 3.5mA current on each channel, and connect each Type 2 digital input to two ISO1228 input terminals. Each two channel pair consumes a total current of 7mA and meet the current requirements of a Type 2 digital input. ISO1228 allows for evaluation of four Type 2 digital inputs using this method.

Table 1-1 Sink Mode RTHR Admissible Values (Ω)
SINK MODE
RILIM = 0Ω, RPAR = 13kΩ, RSURGE = 1kΩ, (IL = 2.5mA)RILIM = 1kΩ, RPAR = 10.7kΩ, RSURGE = 1kΩ, (IL = 3.5mA)
MinTypicalMaxMinTypicalMax
Type 118010002400Type 11109101740
Type 318010001300Type 3110910930
Table 1-2 Source Mode RTHR Admissible Values (Ω)
SOURCE MODE
RILIM = 0Ω, RPAR = 13kΩ, RSURGE = 1kΩ, (IL = 2.5mA)RILIM = 1kΩ, RPAR = 10.7kΩ, RSURGE = 1kΩ, (IL = 3.5mA)
MinTypicalMaxMinTypicalMax
Type 118010002400Type 1200020002000
Type 318010001300Type 3Not Supported
Table 1-3 Sink/Source Mode RTHR Admissible Values (Ω)
SINK/SOURCE MODE
RILIM = 1kΩ, RPAR = 13kΩ, RSURGE = 1kΩ, (IL = 3.5mA)
MinTypicalMax
Type 118010002400
Type 318010001300

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. The corresponding LED 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 through LEDs is bypassed, resulting in the indicators switching off.

For a full list of components included in the ISO1228 evaluation module, see Section 3.3.