A8904SLB View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
'A8904SLB' PDF : 19 Pages View PDF
8904
3-PHASE BRUSHLESS DC
MOTOR CONTROLLER/DRIVER
as opposed to the ESR that dominates the overall impedance of
the input filter, Cfilter. Therefore, it is possible to reduce con-
ducted electromagnetic emissions further, by simply increasing
the value of Cfilter. In extremely sensitive systems, it may be
necessary to introduce a differential mode inductor in series with
the load supply line.
Layout considerations. The TSSOP part (A8904SLP)
has three separate ground connections, analog, digital, and
power that must be connected together externally. A ground
plane should be used to provide heat sinking for the power
switches and the reduction of potential noise pick-up through
inductive loops and radiated emissions. The ground plane
should cover the area beneath the A8904 and extend beyond the
outline to form a plane around all the external components. The
exposed thermal pad of the TSSOP part should be connected
to the ground plane.
Filter components, especially Cfilter, timing, and delay
capacitors should be positioned as close as possible to the device
terminals. It is also imperative that the traces to the serial port
and oscillator are as short and as wide as possible to reduce stray
inductance and prevent potential data corruption. In addition,
these traces should be positioned well away from any noisy
signals.
Typical application
(A8904SLB)
www.allegromicro.com
15
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