RICOH RP108J Technical data
RP108J Series
Low Voltage 3A LDO Regulator with Ext. V
The RP108J Series are CMOS-based LDO regulators featurin g 1A output with low on-resistance. The CMOS process provides both
large output current and low supply current. The drop out voltage is significantly lower than bipolar regulators. The RP108J handles
low voltage with an input voltage from 1.6V and an output voltage from 0.8V. Accordi ngly, the device supports highly integrated, low
voltage-driven LSI as a rear stage of the DC/DC converter. PR108J081x can set adjustable output voltage with an external resistor.
The CE pin can switch the regulator into standby mode. In addition to a fold-back protection circuit built into conventional LDO
regulators, RP108J has a thermal shutdown circuit, a reverse current protection circui t and a constant slope circuit. The constant
slope circuit is a soft start function to prevent inrush current and mis operation of devices. Ceramic capacitors can be used.
FEATURES
• Supply Current (ISS) ························ Typ. 350μA (IOUT=0mA, VIN=5.25V)
• Standby Current (Istandby) ·················Typ. 2μA
• Dropout Voltage (VDIF) ···················· Typ. 0.51V (IOUT=3A, VOUT=2.8V)
• Ripple Rejection (RR)····················· Typ. 65dB (f=1kHz)
• Input Voltage Range1 (VIN) ············· 1.6V to 5.25V
• Output Voltage Range (VOUT)··········0.8V to 4.2V (internally fixed)
0.8V with external resistors
• Output Voltage Accuracy ················± 1%
• Temp.coeff.of Output Voltage ········· Typ. ± 100ppm/°C
(The above shows specification at Topt=25°C. Design assurance value at -40°C ≤ To p t ≤ 85°C is also available. For details, please refer to the datasheet.)
BLOCK DIAGRAMS
RP108Jxx1B RP108Jxx1D
(Without Auto-Discharge function) (With Auto-Discharge function)
DD
V
V
OUT
V
FB
• Load Regulation ·····························Typ. 0.1%/V
• Line Regulation·······························Typ. 3mV (IOUT=3A)
• Fold-back Protection Circuit ···········Current limit Typ. 220mA
• Reverse current protection Circuit
• Constant Slope Circuit
• Thermal Shutdown Circuit ··············Stops at 165°C
• Auto-Discharge function ················· D Version
• Package··········································TO-252-5-P2
• Ceramic capacitors can be used. ··· 10μF or more
DD
V
OUT
Adjustable
V
OUT
V
FB
Vref
Current Limit
Thermal Shutdown
CE
Reverse Detecter
GND
CE
Vref
Current Limit
Thermal Shutdown
Reverse Detecter
SELECTION GUIDES TYPICAL APPLICATION
Halogen Free
.xx. : Specify the output voltage within the range of
Package
TO-252-5-P2 5,000 pcs
Q'ty per Reel
Part No.
0.8V (.08.) to 4.2V (.42.) in 0.1V steps.
: Select from (.B.) without auto-discharge function or
.∗
(.D.) with auto-discharge function
RP108J.xx.1.∗ -T1-FE
Internally fixed output voltage
RP108Jxx1x
IN
The VOUT pin should be connected
C
IN
V
CE GND
to the V
DD
RP108J
V
OUT
V
FB
FB pin
C
OUT
OUT
Output voltage should be set 4.2V
(For details, please refer to the datasheet.)
PACKAGES TYPICAL CHARACTERISTIC
TO-252-5-P2
1 2 3 4 5
1 CE 4 VOUT
2 VDD
∗) The tab is substrate level. (GND)
The V
OUT pin should be connected to the VFB pin when the output voltage is fixed inside the IC.
APPLICATIONS
3 GND
5 VFB
• Power source for hand-held communication equipment, cameras, and VCRs
• Power source for home appliances
RP108J251x Dropout V olt age vs. Output Current
700
600
500
(mV)
DIF
400
300
200
Dropout Volt age V
100
0
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
85
℃
25
℃
-40
℃
Output Current I
OUT
• Power source for battery-powered equipment
GND
Ext. adjustable output voltage
RP108J081x
V
DD
RP108J
CIN
CE GND
OUT = 0.8×((R1+R2) / R2
V
(A)
V
OUT
R1
V
FB
R2
OUTIN
C
OUT
No.EK-203-111003 CMOS LDO Regulator
RP108J Series CMOS LDO Regulator
Low Voltage 3A LDO Regulator with Ext. VOUT Adjustable
Technical Information on Ricoh LDO Regulators
Low supply current and high performance
by CMOS process
RP108J is high output current of 3A. It has been low supply current (Typ.350mA) because it is CMOS manufacturing process.
It has become the supply current of less than one tenth compared to other bipolar high current regulators.
The low dropout voltage is 0.51V and is significantly lower than bipolar regulators.
Good Load Regulation
RP108J is less affected by the output current load because it separates the output voltage pin and the feedback voltage pin.
So, RP108J is very good load regulation, the load regulation is TYP.3mV (I
Reverse Current Protection Circuit
The Reverse Current Protection Circuit stops the reverse current if the reverse detector detects that the VOUT pin voltage has
become higher than the V
In the RP108J series the reverse current (I
DD pin voltage.
REV) is restricted to Max 10μA. (When VOUT ≥ 0.5V and 0V ≤ VIN ≤ 5.25V)
Constant Slope Circuit
Some products have 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 allows the output voltage to start up gradually. The capacitor to create the
start-up slope is built-in the IC that doesn't require any external components. The start-up time and start-up slope angle are fixed
inside the IC.
If the capacitance of the external output capacitor becomes more than the certain capacitance, the output current limit circuit
minimizes the incoming current of the output capacitor at the start-up. As a result, the start-up time becomes longer and the start-up
slope angle becomes more gentle.
The constant slope circuit is an especially effective function for large current product like 3A output, because driver's ability is high,
and it allows a large current to flow at the start-up.
OUT=3A)
Inrush current limit circuit of conventional products Constant Slope Circuit
(Imaginary graph)
CE Input Voltage
Time (μs)
CE入力電
出力電圧
Inrush Current
突入電流
CE Input Voltage
Time (μs)
CE入力電圧
出力電圧
Output Voltage Output Voltage
突入電流
Inrush Current
The currently available information as of October 2011 is provided in this New Product News.
EK-203-111003
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