ALLEGRO ACS772CB Evaluation Board User Guide

: June 13, 2024
: ALLEGRO

Table of Contents

DESCRIPTION
FEATURES
EVALUATION BOARD CONTENTS
USING THE EVALUATION BOARD
SCHEMATIC
LAYOUT
Thermal Rise vs. Primary Current
BILL OF MATERIALS
RELATED LINKS AND APPLICATION SUPPORT
Revision History
Documents / Resources

ASEK772ECB-200B-T
ACS772CB Evaluation Board User Guide

DESCRIPTION

Evaluation boards offer a method for quickly evaluating Allegro current sensors in a lab environment without needing a custom circuit board.
This document describes the use of the ACS772CB Evaluation Board.
This evaluation board (TED-0003440) is intended for use with the ACS772CB custom 3-pin SOIC current sensor IC.

FEATURES

8-layer PCB with 4 oz. copper weight on all layers
Flexible instrument connection:
Standard Keystone test points, banana jack connectors are provided
NOTE : If using the evaluation board with high currents, remove the banana jacks and use screws and lugs for connection.

EVALUATION BOARD CONTENTS

Printed circuit board with populated components.
Recommended bill of materials (BOM) for all compatible current sensor are listed in the “Bill of Materials” section below.

USING THE EVALUATION BOARD

Evaluation Board Components

U1 is an CB package footprint. The ACS772 should be populated here. See yellow highlight on Figure 4.
U1 pins (3 to 5; see top view of EVB) allow the option to connect:
□ C4: Load capacitor on VIOUT, can be used to decrease the bandwidth of the sensor in order to optimize noise performance.
□ C1/C2/C3: Bypass capacitor from VCC or VIN to GND.
□ JP1: Connects the output of U2 to VCC.
□ See blue highlight on Figure 4 for above connection locations.
Test points allowing easy access to sensor pins.
□ See Test Point locations (VOUT, GND, and VCC) highlighted in orange.
□ See TPGND allowing easy connection to GND highlighted in orange.
Standard banana jack connectors IP+ and IP- (primary current mounting position) highlighted in gray. Positive current flow direction is left to right.
RB1, RB2, RB3, and RB4: Rubber bumper mounting positions located in top and bottom left and right hand corners. Highlighted in gray.

Evaluation Board Procedure
CONNECTING TO THE EVALUATION BOARD
The best way to connect measurement instruments to the evaluation board is to use the provided Keystone test points and banana jack connectors for the applied current.

SCHEMATIC

LAYOUT

ALLEGRO ACS772CB Evaluation Board - LAYOUT

Gerber files for the ASEK772 evaluation board are available for download from the Allegro website. See the technical documents section of the ACS772 device webpage.

Thermal Rise vs. Primary Current

Self-heating due to the flow of current 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 as current moves through the system.
The thermal response is highly dependent on PCB layout, copper thickness, cooling techniques, and the profile of the injected current.
The current profile includes peak current, current on-time, and duty cycle.
While the data presented in this section was collected with direct current (DC), these numbers may be used to approximate thermal response for both AC signals and current pulses.
The plot in Figure 7 shows the measured rise in steady-state die temperature of the ACS772 versus continuous current at an ambient temperature, TA, of 25°C. The thermal offset curves may be directly applied to other values of TA. Conversely, Figure 8 shows the maximum continuous current at a given TA. Surges beyond the maximum current listed in Figure 8 are allowed given the maximum junction temperature, TJ(MAX) (165℃), is not exceeded.

ALLEGRO ACS772CB Evaluation Board - Heating The thermal capacity of the ACS772 should be verified by the nd user in the application’s specific conditions. The maximum junction temperature, TJ(MAX) (165℃), should not be exceeded.
Further information on this application testing is available in the DC and Transient Current Capability application note on the Allegro website.

BILL OF MATERIALS

Table 1: Evaluation Board Bill of Materials

Item| Qty| S| Manufacturer| P/N| Description| Designator
---|---|---|---|---|---|---
1| 1| 9| Allegro| ACS772| IC, through-hole, current sensor| U1
2| 1| 6| AVX| 06035C104K4T2A| Capacitor, 0603, mono, X7R, 50 V, 100 nF| C1
3| 2| | | | Do not install| C2, J2
4| 2| 6| Panduit| LAMA6-14-QY| Connector, through-hole, mechanical lug, 14 g to 6 g, 0.25 inch stud // comes in package of 25| J3, J4
5| 3| 6| Keystone| 5005| Test point, thro, compact, for 62 mil PCB, red| GND, VCC, VOUT
6| 1| 6| | | Jumper, through, used as scope gnd, bend from 18 g wire, install 0.25 inches above PCB| TPGND
7| 2| 6| | | Nut, metal, 1/4″ 20 tpi // package of 100| nut1, nut2
8| 2| 6| | | screw, metal, zinc-plated, panhead, phillips, 1/4″ x 5/8″ 20 tpi // package of 50| screw1, screw2
9| 4| 6| Keystone| 1450C| Standoff, metal, hex-threaded, female-female, 4-40 x 0.5inch| standoff1, standoff2, standoff3, standoff4
10| 4| 6| | | Screw, metal, zinc-plated, button, slotted, 4-40 x 0.25 inch| screw1, screw2, screw3, screw4
11| 4| 10| McMaster-Carr| 98017A655| Washer, flat, 1/4 inch, stainless // sold in package of 250 // use two per lug location| w1, w2, w3, w4
12| 1| 10| | | PCB, as from TED-0003440-R1 gerber files| PCB

Table 2: Related Documentation and Application Support

Documentation	Summary	Location
Allegro Current Sensors Webpage	Product datasheet defining common electrical
characteristics and performance characteristics

https://www.allegromicro.com/en/products/sense/current-sensor-ics
Allegro Current Sensor Package Documentation| Schematic files, step files, package images| https://www.allegromicro.com/en/designsupport/packaging
An Effective Method for Characterizing
System Bandwidth in Complex Current Sensor Applications| Application note describing methods used by Allegro to measure and quantify system bandwidth| https://allegromicro.com/en/insights-andinnovations/technical-documents/hall- effectsensor-ic-publications/an-effective-method-forcharacterizing-system- bandwidth-an296169
DC and Transient Current Capability/Fuse Characteristics of Surface Mount Current Sensor ICs| DC and Transient Current Capability/Fuse Characteristics of Surface Mount Current Sensor ICs| https://www.allegromicro.com/en /Insights-andInnovations/Technical-Documents/Hall-EffectSensor-IC-Publications /DC-and-TransientCurrent-Capability-Fuse-Characteristics.aspx
High-Current Measurement with Allegro Current Sensor IC and Ferromagnetic Core: Impact of Eddy Currents| Application note focusing on the effects of alternating current on current measurement| https://allegromicro.com/en /insights-and-innovations/technical-documents/hall- effect-
sensor-ic-publications/an296162_a1367_current-sensor-eddy-current- core
Secrets of Measuring Currents Above 50 Amps| Application note regarding current measurement greater than 50 A| https://allegromicro.com/en/insights- andinnovations/technical-documents/hall-effectsensor-ic-publications/an296141 -secrets-ofmeasuring-currents-above-50-amps
Allegro Hall-Effect Sensor ICs| Application note describing Hall-effect principles| https://allegromicro.com/en/insights-andinnovations/technical- documents/hall-effectsensor-ic-publications/allegro-hall-effect-sensorics
Hall-Effect Current Sensing in Electric and Hybrid Vehicles| Application note providing a greater understanding of hybrid electric vehicles and the contribution of Hall-effect sensing technology| https://allegromicro.com/en /insights-andinnovations/technical-documents/hall-effectsensor-ic-publications /hall-effect-currentsensing-in-electric-and-hybrid-vehicles
Hall-Effect Current Sensing in Hybrid Electric Vehicle (HEV) Applications| Application note providing a greater understanding of hybrid electric vehicles and the contribution of Hall-effect sensing technology| https://allegromicro.com/en/insightsand-innovations/technical-documents/hall- effect-sensor-ic-publications/hall-effectcurrent-sensing-in-hybrid-electric- vehicle-hevapplications
Achieving Closed-Loop Accuracy in Open-Loop Current Sensors| Application note regarding current sensor IC solutions that achieve near closed-loop accuracy using open-loop topology| https://allegromicro.com/en/insights-andinnovations /technical-documents/hall-effectsensor-ic-publications/achieving-closed- loopaccuracy-in-open-loop-current-sensors
Allegro Current Sensor ICs Can Take the Heat! Unique Packaging Options for Every Thermal Budget| Application note regarding current sensors and package selection based on thermal capabilities| https://allegromicro.com/-/media/files/application-notes/an296190-current- sensorthermals.pdf
Explanation Of Error Specifications For
Allegro Linear Hall-Effect-Based Current Sensor lcs And Techniques For Calculating Total System Error| Application note describing error sources and their effect on the current sensor output| https://allegromicro.com/-/media/files/application- notes/an296181-acs72981-errorcalculation.pdf

Revision History

Number	Date	Description
–	21-Jun-23	Initial release

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.

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com