Maxim公司的MAX22191是IEC 61131-2兼容的工業數字輸入（DI），能把24V數字工業輸入轉換成2.4mA電流，用來驅動光隔離器。電壓閾值和電流值和Type 1和Type 3輸入，采用額外外接電阻還和48V輸入兼容，工作溫度-40℃ - +125℃，主要用在過程自動化，工業自動化，馬達控制，單個隔離輸入以及電流源輸入。本文介紹了MAX22191主要優勢和特性，框圖和應用框圖，以及評估板MAX22191PMB# EVK主要特性，電路圖，材料清單和PCB設計圖。

The MAX22191 is an IEC 61131-2 compliant， industrial digital input （DI） device that translates a 24V digital industrial input to a 2.4mA （typ） current for driving optical isolators. Voltage thresholds and current levels in the MAX22191 are compliant with Type 1 and Type 3 inputs， while minimizing power dissipation. The MAX22191 is also compliant with 48V inputs， with the addition of external resistors.

Operating power is derived from the input signal， eliminating the need for an external field-side power supply. A 250ns （max） fast response time is ideal for high-speed inputs. Additionally， a CMOS-compatible test input is available for safety diagnostics.

The MAX22191 features robust functionality for harsh industrial systems and is capable of normal operation with input signals ranging from -60V to +60V. Integrated thermal shutdown further protects the device when VCC is present.

The MAX22191 is available in a small， 6-lead SOT23 package and operates over the -40℃ to +125℃ ambient temperature range.

MAX22191主要優勢和特性：

High Integration for Flexible Circuit Designs 250ns （max） Response Time

Parasitically Powered from the Field Input

Current Sourcing Input with Optical Isolators

Current Sinking Input with Optical Isolators

Current Sinking Input with Logic Devices

Test Pulse Input

Reduced Power and Heat Dissipation Current Limited Input

Robust Design Operates from -60V to +60V Input Voltage

-40℃ to +125℃ Ambient Operating Temperature

MAX22191應用：

Process Automation

Industrial Automation

Motor Controls

Individually Isolated Inputs

Current Sourcing Inputs

圖1.MAX22191簡化框圖

圖2.MAX22191典型工作電路圖

圖3.MAX22191工作電路圖（1）

圖4.MAX22191工作電路圖（2）

圖5.MAX22191工作電路圖（3）

評估板MAX22191PMB#

The MAX22191PMB# peripheral module provides the hardware to evaluate the MAX22191 parasitically powered digital input. Refer to the MAX22191 IC data sheet for detailed information regarding operation of the IC. The PMB features two circuits： one for isolated parasitically powered circuit （using an optoisolator） and one for a 24V input signal with the circuit powered from a low-voltage logic supply.

The module can be used in various ways. Maxim sells low-cost USB2PMB1#， USB2PMB2#， and USB2GPIO# adapter boards that use the Munich GUI software for communication through a USB cable. This is not included with this board. Alternatively， any microcontroller or FPGA with a 12-pin Pmod?-compatible connector can be used. Another option for the user is to wire-wrap a temporary connection from their system to the pins on connector X1. For these later two options the user needs to write their own control software.

The Pmod PCB dimension is just 42mm long x 20mm wide， with the width determined by the size of the X1 connector.

評估板MAX22191PMB#主要特性：

Easy Evaluation of the MAX22191

Isolated， Paristically Powered and Logic-Powered Circuits for Easy Evaluation

Proven PCB Layout

Works with USB2PMB2# or USB2GPIO# Adapter and Munich GUI Software

圖6.評估板MAX22191PM#外形圖

圖7.評估板MAX22191PM#和USB2PMB2#適配器連接圖

圖8.評估板MAX22191PM# EVK電路圖

評估板MAX22191PM# EVK材料清單：

圖9.評估板MAX22191PM# EVK PCB設計圖：左：頂層絲印;右：頂層布局

圖10.評估板MAX22191PM# EVK PCB設計圖：底層布局

詳情請見：

https://datasheets.maximintegrated.com/en/ds/MAX22191.pdf

和https://datasheets.maximintegrated.com/en/ds/MAX22191EVKIT.pdf

MAX22191.pdf