MP6531A – 5V - 60V, THREE-PHASE BLDC MOTOR PRE-DRIVER

MP6531A Rev. 1.02

www.MonolithicPower.com

16

6/20/2017

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PCB Layout Guidelines

Efficient

PCB

layout

is

critical

for

the

performance of the MOSFET gate drivers. In

particular, the connection between the HS

source and LS drain must be as direct as

possible to avoid a negative undershoot on the

phase node due to parasitic inductances. The

pre-driver is designed to accommodate a

negative undershoot, but if it is excessive,

unpredictable operation or damage to the IC

can result. For best results, refer to Figure 7

(which shows the similar MP6532 IC) and follow

the guidelines below.

1. Use surface-mounted N-channel MOSFETs,

which allow for a very short connection

between the HS-FET and LS-FET.

2. Use wide copper areas for all of the high-

current paths.

3. Connect

the

low-side

sense

resistor

(composed of three resistors in parallel

(R25, R26, and R27)) to the input supply

ground and LS-FET source terminals with

wide copper areas.

4. Place the charge pump and supply bypass

capacitors very close to the IC.

5. Connect

the

grounded

side

of

these

capacitors to a ground plane connected to

the device ground pin and exposed pad.

6. Keep the high-current ground path between

the input supply, input bulk capacitor (C19),

and MOSFETs away from this area.

Figure 7: Recommended Layout