ALLEGRO ACSEVB-MA16-LA16 MA and LA Generic Evaluation Board User Guide

ALLEGRO ACSEVB-MA16-LA16 MA and LA Generic Evaluation Board

Product Specifications

• Product Name: ACSEVB-MA16-LA16
• Package: MA/LA Package Generic Evaluation Board
• Compatibility: Intended for use with any MA or LA package (16-pin SOICW Allegro current sensor)
• Features:
  • Standard Keystone test points, SMA/SMB connector, or 2-pin headers options
  • Transition temperature

Product Usage Instructions

Evaluation Board Contents

Note: The board does not come populated with an Allegro current sensor.

• U1: MA/LA package footprint (Pin 1 is on the bottom left side)
• Keystone 5005 test points
• Standard SMB/SMA connector
• 2-pin 100 mil header connector option
• Primary current cables mounting positions
• 2-pin 100 mil header connector for voltage drop measurement
• RB1, RB2, RB3, and RB4: rubber bumper mounting positions

DESCRIPTION

Generic evaluation boards offer a method for quickly evalu-ating Allegro current sensors in a lab environment without needing a custom circuit board. This document describes the use of the MA/LA current sensor evaluation board. This evaluation board (ACSEVB-MA16-LA16, TED-0004111) is intended for use with any MA or LA package (16-pin SOICW Allegro current sensor).

FEATURES

• Enhanced thermal performance:
  • 6-layer PCB with 2 oz copper weight on all layers
  • Nonconductive filled Via-In-Pad used
  • High-performance FR4 material with 180°C glass transition temperature
• Flexible instrument connection:
  • Standard Keystone test points, SMA/SMB connector or 2-pin headers options are provided
• Sensor-integrated current loop resistance can be measured directly on the evaluation board; voltage drop can be measured for the approximating power loss in the package.

Evaluation Board Procedure

• Bare printed circuit board without populated components
  NOTE: It is up to the user to assemble the board with the desired current sensor. This board does not come populated with an Allegro current sensor.

• Recommended bill of materials (BOM) for all compatible current sensors are listed in the Bill of Materials section.

USING THE EVALUATION BOARD

Evaluation Board Components

1. U1 is an MA/LA package footprint (Pin 1 is on bottom left side, see the small white dot)
2. U1 pins allow the option to connect:
3. RPU: Pull-up resistor to VCC
4. RPD: Pull-down resistor to GND
5. C: decoupling or load capacitor to GND
6. All passive components are 0603 package size
7. Keystone 5005 test points (e.g., Digikey #36-5005-ND)
8. Standard SMB/SMA connector (e.g., Digikey #1868-1429-ND)
9. 2-pin 100 mil header connector option (note: either SMB or header can be assembled)
10. Primary current cables mounting positions (positive current flow direction is left to right)
11. 2-pin 100 mil header connector for voltage drop measure-ment across the integrated current loop of the current sensor
12. RB1, RB2, RB3, and RB4: rubber bumper mounting posi-tions (e.g., Digikey #SJ61A6-ND)

Evaluation Board Procedure

CONNECTING TO THE EVALUATION BOARD

The best way to connect measurement instruments to the evaluation board is to use SMB/SMA or 2-pin headers connectors along with coaxial cables. This configuration will be most resilient to external coupling, and it is preferred way for measurement, e.g., high-speed dI/dt transients.
Keystone test points are a convenient way to connect any instrument, but is it recommended for DC setups only?

EVALUATION BOARD PERFORMANCE DATA

Thermal Rise vs. Primary Current

Self-heating due to the flow of current in the package IP conduc-tor should be considered during the design of any current sensing system. The sensor, printed circuit board (PCB), and contacts
to the PCB will generate heat and act as a heat sink as current moves through the system.
The thermal response is highly dependent on PCB layout, cop-per thickness, cooling techniques, and the profile of the injected current. The current profile includes peak current value, current on-time, and duty cycle.
Placing vias under the copper pads of the Allegro current sen-sor evaluation board minimize the current path resistance and improves heatsinking to the PCB, while vias outside of the pads limit the current path to the top of the PCB trace and have worse heatsinking under the part (see Figure 4 and Figure 5 below). The ACSEVB-MA16-LA16 does include vias in pad and is recom-mended to improve thermal performance.

The plot in Figure 6 shows the measured rise in steady-state die temperature of the MA package versus DC continuous current at an ambient temperature, TA, of 25 °C for two board designs: filled vias under copper pads and no vias under copper pads. The plot in Figure 7 shows the measured rise in steady- state die temperature of the LA package versus DC continuous current at an ambient temperature, TA, of 25 °C for two board designs: filled vias under copper pads and no vias under copper pads. Note: Using in-pad vias has better thermal performance that no in-pad vias, and this is the design the ACSEVB- MA16-LA16 uses.

The thermal capacity of the MA and LA package should be veri-fied by the end user in the application’s specific conditions. The
maximum junction temperature, TJ(max) (165℃), should not be exceeded. Measuring the temperature of the top of the package is a close approximation of the die temperature.

SCHEMATIC

LAYOUT

The MA/LA Current Sensor Evaluation board features test points that allow the current sensor integrated current loop resistance to be measured directly from the evaluation board. The voltage drop sensing is routed in the first internal layer (as to not reduce isolation spec of the package). As a consequence, the voltage drop will include the parasitic resistance of the vias between the top layer and the first interior layer.

BILL OF MATERIALS

Components listed are based on the typical application circuit given in the respective device datasheet.

RELATED LINKS AND APPLICATION SUPPORT

Revision History

Copyright 2023, 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.
Copies of this document are considered uncontrolled documents.

Frequently Asked Questions (FAQ)

Q: Can I use any Allegro current sensor with this evaluation board?

A: Yes, the evaluation board is compatible with any MA or LA package (16-pin SOICW) Allegro current sensor.

Q: How should I connect measurement instruments to the board?

A: It is recommended to use SMB/SMA or 2-pin headers connectors along with coaxial cables for resilience to external coupling. Keystone test points are suitable for DC setups only.

References

• Semiconductors - Products | Allegro MicroSystems

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