RN5RY251C-TL Ver la hoja de datos (PDF) - RICOH Co.,Ltd.

Número de pieza

componentes Descripción

Fabricante

RN5RY251C-TL

VFM STEP-UP DC/DC CONVERTER CONTROLLER

RICOH Co.,Ltd. 

RN5RY× × 1

TYPICAL APPLICATIONS

L1

VIN

+

C1

Cb

Rb

Q1

D1

RN5RY××1

VOUT

EXT

CE

GND

VOUT

+

C2

+

C3

Components : Inductor (L1)

Diode (D1)

Capacitor (C1)

Capacitor (C2)

Capacitor (C3)

Transistor (Q1)

Base Resistor (Rb)

Base Capacitor (Cb)

: CD105

: D1FS4A (Schottky Type)

: 33µF (Tantalum Type)

: 47µF (Tantalum Type)

: 47µF (Tantalum Type)

: 2SD1628G

: 220Ω

: 2200pF

APPLICATION HINTS

• A spike-shaped voltage higher than output voltage may be applied to the driver transistor. Therefore, care should be

paid regarding its absolute maximum ratings (VDS, VCF). We recommend to use a transistor having absolute maxi-

mum ratings of at least twice the set output voltage.

• We also recommend the use of an output capacitor with an allowable voltage which is at least 1.5 times the set out-

put voltage. This is because there may be the case where a spike-shaped voltage higher than the set output voltage

is generated.

Use capacitor with good high frequency characteristics such as tantalum capacitor.

• Choose such an inductor that a sufficiently small d.c. resistance and large allowable current, and hardly reaches

magnetic saturation.

• Use a diode of a Schottky type with high switching speed, and also take care of the rated current.

• Set external components as close as possible to the IC and minimize the current between the components and the

IC. In particular, make minimum connection with the output capacitor.

• Make sufficient grounding. A large current flows through GND Pin by switching. When the impedance of the GND

connection is high, the potential within the IC is varied by the switching current. This may result in unstable opera-

tion of the IC.

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