S39421 datasheet(17/28 Pages) SUMMIT

Part #	S39421

Description	Hot Swap Voltage Controller

PDF	28 Pages

Scroll/Zoom	100%

Manufacturer	SUMMIT [Summit Microelectronics, Inc.]

Direct Link	http://www.summitmicro.com

Logo

17 / 28 page

S39421

2024 9.0 8/8/00

56k

Ω

47nF

GND

56k

Ω

VGATE5

VGATE3

to 5V MOSFET

to 3V MOSFET

2024 ILL25.0

Card Power-Down

The S39421 provides a turn-on slew-rate of 250V/s and a

fast turn-off performed by internally shorting the VGATE3

and VGATE5 outputs to ground. If the card circuitry or

host power supply cannot accept a fast shutdown then a

CR time constant may be added as shown below. The

resistors in series with the 47nF(X7R) capacitors increase

the discharge time of the MOSFET gates. The values

shown provide a shutdown slew of ~5V/ms. Decreasing

the resistor values increases the shutdown slew-rate, and

vice-versa. The capacitor values may also be increased

but this will decrease the 250V/s turn-on slew-rate.

FIGURE 20. POWER-DOWN RAMP RATE CONTROL

S39421 Datasheet(PDF) 17 Page - Summit Microelectronics, Inc.