Maxim公司的MAX40056是具有輸入共模擬抑制范圍-0.1V到+65V的雙向電流放大器（CSA），非常適合電感負載如馬達和螺線管，其PWM是用來控制驅動電壓和電流，從500V/μs PWM邊沿，具有快速的2μs PWM 邊沿恢復（1%），共模抑制比（CMRR）典型為60dB （50V， ±500V/μs輸入）和140dB DC.工作電壓+2.7V到 +5.5V，工作溫度-40℃ 到 +125℃，主要用在PWM H橋馬達電流檢測，螺線管電流檢測，電感負載電流檢測，電池堆棧監視器和汽車電子。本文介紹了MAX40056主要優勢和特性，框圖，應用電路，以及評估板MAX40056 EVK主要特性，電路圖，材料清單和PCB設計圖。

The MAX40056 is a bidirectional current-sense amplifierwith an input common-mode range that extends from-0.1V to +65V together with protection against negative inductive kickback voltages to -5V. This CSA is well-suitedfor phase current monitoring of inductive loads， such asmotors and solenoids， where pulse width modulation isused to control the drive voltage and current. TheMAX40056 uses an improved technique to help reject common-mode input PWM edges with slew rates up toand beyond ±500V/μs. Common mode rejection ratio（CMRR） is typically 60dB （50V， ±500V/μs input） and140dB DC， typical.

The MAX40056 has an internal +1.5V reference for usewith a nominal +3.3V power supply. The reference can alsobe used to drive an adjoining differential ADC. The referenceis used to offset the output to indicate the directionof the input sensed current. The REF pin can source currentinto external loads and helps to avoid the performance compromises resulting from routing reference voltagesacross noisy PCBs. Alternatively， for higher supplyvoltages and higher full-scale output swings， the internalreference can be overridden by a higher voltage， externalreference.

The internal or external reference can be used to definethe trip threshold for the integrated overcurrent comparator.This can provide immediate indication of an overcurrentfault condition.

The MAX40056 operates over the full -40°C to +125°Ctemperature range and runs from a supply voltage of+2.7V to +5.5V. It is offered in a 2.02mm x 1.4mm 8-pinwafer-level package （WLP） and 8-pin μMAX packages.

MAX40056主要優勢和特性：

● Fast， 2μs PWM Edge recovery （1%） from500V/μs PWM Edges

● 60dB AC CMRR Rejection at 50V， ±500V/μs PWMEdges

● 140dB DC CMRR Rejection

● -0.1V to +65V Input Voltage Range

● -5V to +70V Protective Immunity

● 300kHz， -3dB Bandwidth

● Multiple Gain Options; 10V/V， 20V/V， 50V/V

● Internal， 1% Reference for Bidirectional Offset

● 5μV （Typ） Input Offset Voltage

● Rail-to-Rail Output

● 2.02mm x 1.4mm WLP-8 and 8-pin μMAX

● -40℃ to +125℃ Temperature Range

MAX40056應用：

● PWM H-Bridge Motor In-line/In-phase/Winding Current Sensing

● Solenoid Current Sensing

● Current Monitoring of Inductive Loads

● Battery Stack Monitors

● Automotive

圖1.MAX40056簡化框圖

圖2.MAX40056應用電路：馬達控制在線電流檢測

圖3.MAX40056應用電路：三相伺服馬達的電流檢測

評估板MAX40056 EVK

The MAX40056 evaluation kit （EV kit） is a fully assembled electrical demonstration kit that provides a proven design to evaluate the MAX40056F/MAX40056T/MAX40056U high-precision， high-voltage， bidirectional current sense amplifier for PWM applications， such as servo motor con-trol and solenoid drive. The MAX40056F/MAX40056T/ MAX40056U are ideal for 48V， or less BLDC， induction motor applications （such as robotics）， pick-and-place machines， 3D prints， or other servo motor control systems.

This EV kit demonstrates the MAX40056FAUA+ in an 8-pin μMAX package， with Gain = 50V/V. For other available pin-compatible options （MAX40056TAUA+， Gain = 20V/V， MAX40056HAUA+， Gain = 10V/V）， contact the factory.

評估板MAX40056 EVK主要特性：

Precision Real-Time Current-Monitoring with Fault Detection

Internal Available1.5V Reference

-0.3V to +65V Input Common Mode Range

-40℃ to +125℃° Temperature Range

Evaluates 8-μMAX MAX40056FAUA+ Device

Proven PCB Layout

Fully Assembled and Tested

圖4.評估板MAX40056 EVK外形圖

圖5.評估板MAX40056 EVK電路圖

評估板MAX40056 EVK材料清單：

圖6.評估板MAX40056 EVK PCB設計圖：頂層裝配圖

圖7.評估板MAX40056 EVK PCB設計圖：左：頂層絲印;右：底層

圖8.評估板MAX40056 EVK PCB設計圖：左：頂層布局;右：底層絲印