MX8682

IXYS

Application Example

This application example illustrates one method of incorporating the MX8682 into a power circuit board

design. The double-sided 8oz copper traces carry 10A (5A on the top trace and 5A on the bottom trace)

around the center section of the planar E-core. The MX8682 is mounted on a small single layer flex

circuit that effectively adds a third layer. The flex also fans out the fine pitch DFN package to a pitch

compatible with the power board. The magnetic circuit consists of two ferrite E14 planar cores. The

center post of one of the cores is gapped to accommodate the MX8682 package thickness plus the flex

circuit thickness. For the 10A full scale application a gap of 47 to 52 mils is appropriate (1.2 to 1.32 mm).

The gain trim range of the MX8682 can accommodate even larger gaps if required.

Flex circuit

MX8682

(2) E14 planar cores

Cross Section (drawing not to scale)

PCB top layer: (scale 1X)

PCB bottom layer: (top view, 1X)

Flex circuit: (component side, 1X)

This following example illustrates the MX8682 mounted directly on a 1oz PCB with a copper strap

positioned around the Hall element to carry the current being measured.

MX8682

Copper stamping, thickness as required

Design alternatives:

The use of an E-I core pair results in a lower profile than E-E however a thinner board must be used. A

thinner sensor can be obtained by FCOF (flip chip on flex) packaging of the MX8682 bumped die. The

maximum mounting height of the DFN package is 1.1 mm whereas the chip height is about 0.4 mm.

MX8682

7

03/03/08

Drawing No. 0868209

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