MP5003 – 3.3V, 1A-3A PROGRAMMABLE CURRENT LIMIT SWITCH WITH AUTO ENABLE

MP5003 Rev. 0.921

www.MonolithicPower.com

12

2/29/2012

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At time T4 the part has cooled down below the

thermal hysteresis level. The enable pin goes

high and the part turns on again. But the short is

still present, causing the die temperature to

increase. At time T5 the power device turns off

and the Enable/Fault pin is driven to the low

level, again. The temperature begins to fall.

The cycle between times T3, T4 and T5 could

repeat indefinitely, but at time T6 the short is

removed. At time T7 the die temperature is below

the thermal hysteresis level and the part turns on

once again. This time there is no short, so the

output starts in normal operation and the die

temperature cools down to the normal operating

range.

PCB LAYOUT

PCB layout is very important to achieve stable

operation. Please follow these guidelines and

take below figure for reference.

Place Rlimit close to Ilimit pin, Cdv/dt close to

dv/dt pin and input cap close to VIN (Exposed

Pad). Keep the N/C pin float. Put vias in thermal

pad and ensure enough copper area near VIN

and

VOUT

to

achieve

better

thermal

performance.

Top Layer

Bottom Layer

Figure 4—PCB Layout