ACS780 datasheet(22/24 Pages) ALLEGRO

22 / 24 page

High-Precision Linear Hall-Effect-Based

Current Sensor IC With 200 µΩ Current Conductor

ACS780xLR

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Figure 4: ACS780 Current Trace Approach – the desired

range of the angle θ is from 0° to 85°

ENCROACHMENT UNDER THE IC

In the LR package, the encroachment of the current-carrying

trace under the device actually changes the path of the current

flowing through the IP bus. This can cause a change in the cou-

pling factor of the IP bus to the IC and can significantly reduce

deviceperformance.UsingANSYSMaxwellElectromagnetic

Suites, the current density and magnetic field generated from the

currentflowweresimulated.InFigure5,thereareresultsfrom

two different simulations. The first is the case where the current

trace leading up to the IP bus terminates at the desired point. The

second case is where the current trace encroaches far up the IP

bus. The red arrows in both simulations represent the areas of

high current density. In the simulation with no excess overlap, the

red areas, and hence the current density, are very different from

the simulation with the excess overlap. It was also observed that

the field on H1 was larger when there was no excess overlap.

This can be observed by the darker shade of blue.

Figure 5: Simulations of ACS780 Leadframe with Differ-

ent Overlap of the Current Trace and the IP Bus

ACS780 Datasheet(PDF) 22 Page - Allegro MicroSystems