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RICOH RP108J SERIES Low Input Voltage 3A LDO Regulator User Guide

Summary

The RP108J Series is a high-performance, low-dropout voltage regulator ideal for powering modern, low-voltage LSI in portable and battery-operated electronics. Featuring 3A output capability and advanced protection circuits—including thermal shutdown, constant slope soft-start, and fold-back protection—it ensures robust power delivery even under demanding conditions. This manual provides comprehensive details on features, operational limits, adjustable configurations, and proper integration for designers building high-density devices such as portable cameras and home appliances.

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RP108J SERIES

Low Input Voltage 3A LDO Regulator

NO.EA-203-111018

OUTLINE The RP108J Series are CMOS-based voltage regulator ICs featuring 3A output with low ON-resistance. Each IC of this series consists of a voltage reference unit, an error amplifier, resistor-net for voltage setting, a fold-back protection circuit, and a thermal shutdown circuit. This series features both low supply current and high output current, and the dropout voltage is much smaller than bi-polar's. The minimum input voltage is as low as 1.6V and the output voltage can be set from 0.8V, therefore it can be connected with the DC/DC converter as the latter power supply for high density LSI that is operated by low output voltage. The output voltage of RP108J081x is externally adjustable by using external divide resistors. The CE pin of the RP108J Series can switch the regulator to standby mode. In addition to a fold-back protection circuit, which is already built in the conventional regulators, this series contain a thermal shutdown circuit, a constant slope circuit as a soft-start function and a reverse current protection circuit. Ceramic capacitors can be used.

FEATURES • Output Current Min. 3A • Supply Current Typ. 350μA • Standby Current Typ. 2μA • Input Voltage Range 1.6V to 5.25V • Output Voltage Range.................................................. 0.8V to 4.2V (0.1V steps) (For other voltages, please refer to MARK INFORMATIONS.) • Output Voltage Accuracy.............................................. ±1.0% (±15m V accuracy, When VOUT ≤ 1.5V) • Output Voltage Temperature-drift Coefficient ........... Typ. ±100ppm/°C • Ripple Rejection........................................................... Typ. 65d B (f =1k Hz, VOUT=2.8V) • Dropout Voltage Typ. 0.51V (VOUT=2.8V) • Line Regulation Typ. 0.1%/V • Package TO-252-5-P2 • Built-in Fold-back Protection Circuit............................. Typ. 220m A • Built-in Thermal Shutdown Circuit................................ Stops at 165°C • Built-in Constant Slope Circuit • Built-in Reverse Current Protection Circuit • Ceramic capacitors are recommended to be used with this IC ····· 10μF or more

APPLICATIONS • Power source for battery-powered equipments. • Power source for portable communication equipments such as cameras and VCRs. • Power source for electrical home appliances.

Page Summary Contents For RICOH RP108J SERIES Low Input Voltage 3A LDO Regulator User Guide

Page 1 RP108J SERIES Low Input Voltage 3A LDO Regulator NO.EA-203-111018 OUTLINE The RP108J Series are CMOS-based voltage regulator ICs featuring 3A output with low ON-resistance. Each IC of this series cons...
Page 2 RP108J BLOCK DIAGRAMS RP108Jxx1B RP108Jxx1D VDD VOUT VDD VOUT VFB VFB Vref Vref Current Limit Current Limit Thermal Shutdown Thermal Shutdown CE GND CE GND Reverse Detecter Reverse Detecter SELECTION ...
Page 3 RP108J PIN CONFIGURATIONS TO-252-5-P2 PIN DESCRIPTIONS TO-252-5-P2 Pin No. Symbol Description 1 CE Chip Enable Pin ("H" Active) 2 VDD Input Pin 3 GND Ground Pin 4 VOUT Output Pin 5 VFB Feedb...
Page 4 RP108J ELECTRICAL CHARACTERISTICS VIN=Set VOUT +1.0V, IOUT=1m A, CIN=COUT=10μF, unless otherwise noted. The specification in is checked and guaranteed by design engineering at −40°C ≤Topt ≤ 85°C, unle...
Page 5 RP108J • Dropout Voltage by Output Voltage Topt=25°C Dropout Voltage VDIF (V) Output Voltage VOUT (V) Condition Typ. Max. 0.8V ≤ VOUT < 0.9V 0.910 1.110 0.9V ≤ VOUT < 1.0V 0.865 1.000 1.0V ≤ VOU...
Page 6 RP108J TYPICAL APPLICATIONS VDD VOUT VOUT RP108J series C1 VFB C2 CE GND Typical Application (External Components) C1,C2: Ceramic Capacitors 10μF Kyocera CMX7R106M06AB When using the RP108J Series, pl...
Page 7 RP108J Technical Notes on External Adjustable Output Voltage Type VDD VOUT VOUT RP108J081x C1 VFB C2 CE GND Typical application for adjustable output voltage type (External Components) C1,C2: Ceramic ...
Page 8 RP108J Adjustable Output Voltage Type Settings • Output Voltage Setting Method RP108J081x can be adjusted the output voltage by using the external divider resistors. If the VFB voltage fixed into the ...
Page 9 RP108J REVERSE CURRENT PROTECTION CIRCUIT The RP108J Series include a Reverse Current Protection Circuit, which stops the reverse current from VOUT pin to VDD pin or to GND pin when VOUT becomes highe...
Page 10 RP108J CONSTANT SLOPE CIRCUIT RP108J Series has a Constant Slope Circuit as a function which prevents the overshoot of the output voltage. The constant slope is a kind of soft-start circuit which allo...
Page 11 RP108J TEST CIRCUITS VDD VOUT RP108J Series C1 VFB VC2 VOUT IOUT CE GND C1=Ceramic 10µF C2=Ceramic 10µF Basic Test Circuit VDD VOUT VOUT RP108J Series C1 VFB C2A ISS CE GND C1=Ceramic 10µF C2=Ceramic ...
Page 12 RP108J TEST CIRCUITS for Adjustable Output Voltage Type (RP108J081x) Please refer to "Technical Notes on Adjustable Output Voltage Type" when using R1 and R2 as output capacitors. VDD VOUT R...
Page 13 RP108J Su pp ly ur re nt (μ A) ut pu t V ol ta ge (V ut pu t V ol ta ge (V TYPICAL CHARACTERISTICS 1)Output Voltage vs. Input Voltage(C1=Ceramic10μF, C2=Ceramic10μF, Topt=25°C) RP108x081x RP108x151x 0...
Page 14 ho rt ur re nt im it (m Su pp ly ur re nt (μ A) RP108J RP108x281x RP108x421x Input Voltage VIN (V) Input Voltage VIN (V) 3)Short Current Limit vs. Temperature/ Current Limit vs. Temperature ur re nt i...
Page 15 RP108J ro po ut ol ta ge IF (m V) Su pp ly ur re nt (μ A) ro po ut ol ta ge IF (m V) 4)Supply Current vs. Temperature(C1=Ceramic10μF, C2=Ceramic10μF,IOUT=0mA) RP108x081x RP108x151x Temperature Topt (°...
Page 16 ip pl ej ec tio (d B) ip pl ej ec tio (d B) RP108J ip pl ej ec tio (d B) 7)Ripple Rejection vs. Input Voltage(C1=C2=10μF, Ripple=0.2Vp-p, IOUT=100m A Topt=25°C) RP108x081x RP108x251x 0.1k Hz 0.1k Hz 1...
Page 17 ut pu t V ol ta ge (V ut pu t V ol ta ge (V ut pu t V ol ta ge (V RP108J 9)Input Transient Response(C1=none, C2=10μF, IOUT=30m A, tr=tf=5μs, Topt=25°C) RP108x081x RP108x421x Input Voltage Input Voltag...
Page 18 ut pu t V ol ta ge (V ut pu t V ol ta ge (V ut pu t V ol ta ge (V RP108J 11)Turn on Speed with CE pin(C1=Ceramic10μF, C2=Ceramic10μF, Topt=25°C) RP108x081x RP108x151x VIN=1.8V VIN=2.5V 1.0 Iout=1m A 1...
Page 19 ut pu t V ol ta ge (V In pu t V ol ta ge (V ) / RP108J ut pu t V ol ta ge (V RP108x281x RP108x421x VIN=3.8V VIN=5.2V Iout=1m A Iout=1m A 2.0 Iout=100m A 3.0 Iout=100m A Iout=300m A Iout=300m A Su pp l...
Page 20 RP108J ESR vs. Output Current When using these ICs, consider the following points: The relations between IOUT (Output Current) and ESR of an output capacitor are shown below. The conditions when the w...
Page 21 1. The products and the product specifications described in this document are subject to change or discontinuation of production without notice for reasons such as improvement. Therefore, before decid...

Manual Details

Brand Ricoh
Pages 21
File Size 531.65 KB
Published June 04, 2026
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Frequently Asked Questions

What is the minimum input voltage range?

The input voltage range can be as low as 1.6V up to 5.25V.

How do I adjust or set the fixed output voltage?

For external adjustment, use external divide resistors; for a fixed output, connect the VOUT pin to the VFB pin.

What protective features does this regulator include?

It includes built-in fold-back protection (Typ. 220mA), thermal shutdown circuits, constant slope function, and reverse current protection.

Are specific components recommended for use with this IC?

Yes, using ceramic capacitors of 10μF or more is recommended.