
Global		RICOH Co.,Ltd. Electronic Devices Company	\| Site Map \|

Products & Solutions > Industrial Products > Electronic Devices > Power Management Ics
> DC/DC Converters > Step-down with VR and Reset > RP902x Series


	Products
		Power Management ICs
		Real-time clock ICs
		PC Interface
		Communication LSI / Image Processing LSI
		Manufacturing Service
		Product List

	Search ricoh.com/LSI/

RP902x Series

Compound power supply IC with VD

Outline

RP902 Series are CMOS-based compound power supply IC with Voltage Detector (VD), Voltage Detector (VD), PWM/VFM Auto-switching Step-down DC/DC Converter with synchronous rectifier (DD1), PWM Step-down DC/DC Converter control type with synchronous rectifier (DD2) and PWM Step-up DC/DC Converter control type (DD3).

PWM/VFM Auto-switching Step-down DC/DC Converter control type with synchronous rectifier (DD1) has the adoption of the synchronous rectification method that the switching element is built- in. A highly effective step-up DC/DC converter can be composed only of the coil and the capacitor as external parts. The PWM/VFM auto-switching control method is for achieving highly effective at VFM mode.

PWM Step-down DC/DC Converter with synchronous rectifier (DD2) has the adoption of the synchronous rectification method that the switching element is built- in. A highly effective step-up DC/DC converter can be composed only of the coil and the capacitor as external parts.

PWM Step-up DC/DC Converter (DD3) has the asynchronous rectification method by NMOS switching element built-in. The step-up DC/DC converter can be composed only of the diode, the coli, the capacitors and resistances as external parts.

When a large output current is necessary, to control by the additional external NMOS is possible. When the output voltage is necessary to cut when it is off, to control additional external PMOS is possible.

As the protection circuits, the current limit circuits of DD1 and DD2 for limiting peak current of Lx at each clock cycle, and DD3 has the ratio limitation time function. This IC has also the built-in reset type protection function.

When the limited condition is continue in certain time, the reset-start function is operated. The built-in low voltage detection circuit (UVLO) is operating for stopping the output to prevent the malfunction when a low voltage is detected.

As the soft-start circuits, the time of DD1, DD2 and DD3 is fixed. And DD1 and DD2 have the start-up order control function by the trimming.

DD1 and DD2 have the built-in feed-back resistance. The setting output voltage is fixed. It can set by the trimming in 0.1V step. DD3 has the feed-back resistance in externally. The setting output voltage can set between 5.0V and 11V.

Controlling the external pin, it is possible to changing the output voltage dramatically from 72.7% to 100%.
(The output voltage range is between 11V and 8.0V (72.7%) when the default output voltage is set to 11V by the external feed-back)
To using the trimming options, it is also possible to changing the output voltage dramatically from 57.8% to 100%.
(The output voltage range is between 9V and 5.2V (57.8%) when the default output voltage is set to 9V by the external feed-back)
The Voltage Detector is monitoring the input voltage; the output is Nch open drain output. Power-on reset delay time is also included and it is possible to selected 50ms or 100ms by the trimming.

To Top

Features

Input Voltage Range

4.5V~5.5V

Package

QFN0404-20

External components

CIN＝0.1µF, 10µF
COUT＝10µF，L=4.7µH（DD1）
COUT＝10µF，L=4.7µH（DD2）
COUT＝10µF＊３，L=4.7µH（DD3）

PWM/VFM Auto-switching Step-down DC/DC Converter with synchronous rectifier (DD1)

Output voltage range

The output voltage in the range of 1.2V to 2.5V can be set by trim.

Output Voltage accuracy

±2.0%

Oscillation Frequency

Typ. 1.35MHz

Internal drive ON resistance

Typ. Pch 0.5Ω, Nch 0.25Ω

Soft-start function

Typ. 1ms is fixed.
(The turning-on order with DD2 can be set by the trim.)

Lx peak limit current function

Typ. 1.3A

Output current

Max.800mA

Reset type protection function

Typ. 1ms

PWM Step-down DC/DC Converter with synchronous rectifier (DD2)

Output voltage range

The output voltage in the range of 1.2V to 3.3V can be set by trim.

Output Voltage accuracy

±2.0%

Oscillation Frequency

Typ. 1.35MHz

Internal drive ON resistance

Typ. Pch 0.5Ω, Nch 0.5Ω

Soft-start function

Typ. 1ms is fixed.
(The turning-on order with DD1 can be set by the trim.)

Lx peak limit current function

Typ. 1.0A

Output current

Max. 500mA

Reset type protection function

Typ. 1ms

PWM Step-up DC/DC Converter (DD3)

Output voltage range

The output voltage in the range of 5.0V to 11V can be set by the external resistances.

Output Voltage accuracy

±2.0%

Oscillation Frequency

Typ. 1.35MHz

Internal drive ON resistance

Typ. Nch-0.4Ω

Soft-start function

Typ. 10ms is fixed.

Ratio limitation time function

Typ.75%

Output current

Max.300mA(When internal FET is used )

Reset type protection function

Typ. 1.5ms

Voltage Detector Threshold voltage range

The voltage detector threshold voltage in the range of 3.0V to 5.0V can be set by trim.

Delay time for Release

Typ.50ms or 100ms can be set by trim.

To Top

Applications

	Power source for digital home appliance such as DVD player.(both blue and red type LD)
	Power source for DVD-ROM/R/RW(both blue and red type LD) of note PC and desktop PC.