s-8337aaca-t8t1g Seiko Instruments Inc., s-8337aaca-t8t1g Datasheet - Page 18

• Manufacturer Part Number: s-8337aaca-t8t1g
• Description: Step-up, 1.2 Mhz High-frequency, Pwm Control Switching Regulator Controller
• Manufacturer: Seiko Instruments Inc.

18
STEP-UP, 1.2 MHz HIGH-FREQUENCY, PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8337/8338 Series
4. 2 Enhancement MOS FET type
Use an Nch power MOS FET. For high efficiency, using a MOS FET with a low ON resistance
(R
generally share a trade-off relationship. The ON resistance is efficient in a range in which the
output current is relatively great during low-frequency switching, and the input capacitance is
efficient in a range in which the output current is middling during high-frequency switching. Select
a MOS FET whose ON resistance and input capacitance are optimal depending on the usage
conditions.
The input voltage (V
a gate withstanding voltage that is equal to the maximum usage value of the input voltage or
higher and a drain withstanding voltage that is equal to the amount of the output voltage (V
and diode voltage (V
If a MOS FET with a threshold that is near the UVLO detection voltage is used, a large current
may flow, stopping the output voltage from rising and possibly generating heat in the worst case.
Select a MOS FET with a threshold that is sufficiently lower than the UVLO detection voltage
value.
ON
) and small input capacitance (C
IN
D
) is supplied for the gate voltage of the MOS FET, so select a MOS FET with
) or higher.
Seiko Instruments Inc.
ISS
) is ideal, however, ON resistance and input capacitance
Rev.3.1
OUT
_00
)