CT430-20AC Evaluation Board User Guide

Description

The CT430 is a high bandwidth and ultralow-noise integrated contact current sensor that uses Allegro patented XtremeSense™ tunnel magnetoresistance (TMR) technology. It enables high-accuracy current measurements for industrial, consumer, and automotive applications. The device supports multiple current ranges, with the integrated current-carrying conductor (CCC) handling up to 70 A of current. It generates a current measurement as a linear analog output voltage. The device achieves a total output error of less than ±1% full-scale (FS) over the full temperature range. It features a ~300 ns output response time, ~6 mA current consumption, and immunity to common-mode fields. The CT430 is optimized for high dV/dt applications, minimizing capacitive coupling to VOUT, making it suitable for switching applications. The CT430 is offered in an industry-standard 16-lead small-outline integrated circuit (SOIC) wide package that is green and RoHS-compliant.

Figure 1: CT430-20AC Evaluation Board

This image shows the physical layout of the evaluation board. Key connectors are labeled: 'Current Out', 'Current In', 'Vout', 'Filter', 'Gnd', and 'Vdd'. The Allegro CT430 sensor IC is visible, along with other surface-mount components and connectors.

Features

• Integrated contact current sensing for ±20 A
• Optimized for high dV/dt applications
• Integrated current-carrying conductor
• Response time: ~300 ns
• Total error output ≤ ±1% FS, -40°C to 125°C
• Immunity to common-mode fields: -54 dB
• Linear analog output voltage
• Supply voltage: 4.75 V to 5.5 V

Evaluation Board Contents

• CT430-20AC evaluation board

Configurations and Specifications

Table 1: CT430-20AC Evaluation Board Configurations

Table 2: General Specifications

Using the Evaluation Board

Introduction

This section provides an overview of the connections and configuration options of the CT430-20AC evaluation board. The proper configuration is shown in Figure 2 and is detailed in the sections that follow. The CT430 datasheet contains detailed information about the use and functionality of each pin and detailed specifications about the sensor, and it should be consulted for more detailed information than is contained in this user guide.

Figure 2: CT430-20AC Evaluation Board

This image provides another view of the evaluation board, similar to Figure 1, emphasizing the screw connectors for current input/output and the Vout SMA connector.

Power Input

The two large connectors (with screws) are used to connect and drive the external current to be measured. Due to the PCB trace thermal limitation of the CT430 evaluation board, do not exceed 20 A_PK.

Board Configuration

A fully assembled evaluation board is illustrated in Figure 1 and Figure 2. The current to be measured is connected to the screw connectors located on the right side of the PCB. These connectors are galvanically isolated from the rest of the PCB. The CT430 can be biased by applying a 3.3 V bias voltage between the VDD and GND pins on the PCB. Its output can be measured either from the VOUT SMA connector or the VOUT header pin on the PCB. In addition, if C2 is populated with a 100 pF capacitor, the FILTER SMA connector provides a filtered output of the CT430 with a 3 dB cutoff frequency of approximately 100 kHz; otherwise, the 3 dB cutoff frequency is 1 MHz. See Figure 3.

Figure 3: CT430-20AC Evaluation Board

This graph illustrates the relationship between the filter capacitor (C_FILTER) value in picofarads (pF) on the x-axis and the bandwidth in kilohertz (kHz) on the y-axis. It shows that increasing the filter capacitor decreases the bandwidth, with a 3 dB cutoff frequency of approximately 100 kHz when C2 is populated with a 100 pF capacitor, and 1 MHz otherwise.

Schematic

The schematic of the CT430-20AC evaluation board is shown in Figure 4.

Figure 4: CT430-20AC Evaluation Board Schematic

This diagram shows the electrical schematic of the evaluation board. It details the connections to the CT430 sensor IC (U1), including pins for VDD, GND, FILTER, OUT, and FLAG. It also shows associated passive components like resistors (R1-R4) and capacitors (C1, C2), along with various connectors (JP1, JP2, JPN, JPP) and test points.

Layout

The top and bottom layers of the CT430-20AC evaluation board are shown in Figure 5 and Figure 6, respectively.

Figure 5: Top Layer

This diagram displays the top layer of the printed circuit board (PCB) layout. It shows the placement of components such as the CT430 sensor (U1), resistors (R1-R7), capacitors (C1, C2), connectors (J1, J2, VOUT, FLT, P1-P7), and the trace routing.

Figure 6: Bottom Layer

This diagram displays the bottom layer of the printed circuit board (PCB) layout, showing ground planes and trace routing.

Bill of Materials

Related Links

CT430 product page: https://www.allegromicro.com/en/products/sense/current-sensor-ics/zero-to-fifty-amp-integrated-conductor-sensor-ics/CT430

For samples or applications support, visit https://www.allegromicro.com/en/about-allegro/contact-us/technical-assistance and navigate to the appropriate region.

Revision History

Copyright 2024, Allegro MicroSystems.

Allegro MicroSystems reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current.

Allegro's products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro's product can reasonably be expected to cause bodily harm.

The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use.

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