IR3831MPBF datasheet(14/31 Pages) IRF

Part #	IR3831MPBF

Description	HIGHLY EFFICIENT INTEGRATED SYNCHRONOUS BUCK REGULATOR FOR DDR APPLICATIONS

PDF	31 Pages

Scroll/Zoom	100%

Manufacturer	IRF [International Rectifier]

Direct Link	http://www.irf.com

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14 / 31 page

11/05/10

IR3831MPbF

Thermal Shutdown

Temperature sensing is provided inside IR3831.

The trip threshold is typically set to 140oC. When

trip threshold is exceeded, thermal shutdown

turns off both MOSFETs and discharges the soft

start capacitor.

Automatic restart is initiated when the sensed

temperature drops within the operating range.

There is a 20oC hysteresis in the thermal

shutdown threshold.

Power Good Output

The IC continually monitors the output voltage via

Feedback (Fb pin). The feedback voltage is

compared to a fixed voltage. As soon as the Fb

voltage reaches 0.515 V, the Power Good signal

flags. This pin is open drain and it needs to be

externally pulled high. High state indicates that

output is in regulation. Fig 8. shows the timing

diagram for the PGood function.

Fig.8a IR3831 Non-Tracking Operation

TIMING DIAGRAM OF PGOOD FUNCTION

Fig.8b IR3831 Tracking Operation

IR3831MPBF Datasheet(PDF) 14 Page - International Rectifier