APPLICATION MANUAL
LOW RIPPLE VOLTAGE REGULATOR
WITH EXTERNAL TRANSISTOR
RN5RF SERIES
NO. EA-043-9803
ELECTRONIC DEVICES DIVISION
NOTICE
1. The products and the product specifications described in this application manual are subject to change or
discontinuation of production without notice for reasons such as improvement. Therefore, before deciding to
use the products, please refer to Ricoh sales representatives for the latest information thereon.
2. This application manual may not be copied or otherwise reproduced in whole or in part without prior written
consent of Ricoh.
3. Please be sure to take any necessary formalities under relevant laws or regulations before exporting or
otherwise taking out of your country the products or the technical information described herein.
4. The technical information described in this application manual shows typical characteristics of and example
application circuits for the products. The release of such information is not to be construed as a warranty of or a
grant of license under Ricoh's or any third party's intellectual property rights or any other rights.
5. The products listed in this document are intended and designed for use as general electronic components in
standard applications (office equipment, computer equipment, measuring instruments, consumer electronic
products, amusement equipment etc.). Those customers intending to use a product in an application requiring
extreme quality and reliability, for example, in a highly specific application where the failure or misoperation of
the product could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system, traffic
control system, automotive and transportation equipment, combustion equipment, safety devices, life support
system etc.) should first contact us.
6. We are making our continuous effort to improve the quality and reliability of our products, but semiconductor
products are likely to fail with certain probability. In order prevent any injury to persons or damages to property
resulting from such failure, customers should be careful enough to incorporate safety measures in their design,
such as redundancy feature, fire-containment feature and fail-safe feature. We do not assume any liability or
responsibility for any loss or damage arising from misuse or inappropriate use of the products.
7. Anti-radiation design is not implemented in the products described in this application manual.
8. Please contact Ricoh sales representatives should you have any questions or comments concerning the
products or the technical information.
June 1995
RN5RF SERIES
APPLICATION MANUAL
CONTENTS
OUTLINE
......................................................................................................1
FEATURES
...................................................................................................1
APPLICATIONS
.............................................................................................1
BLOCK DIAGRAMS
.......................................................................................2
SELECTION GUIDE
.......................................................................................2
PIN CONFIGURATION
...................................................................................3
PIN DESCRIPTION
........................................................................................3
ABSOLUTE MAXIMUM RATINGS
...................................................................3
ELECTRICAL CHARACTERISTICS
................................................................4
OPERATION
..................................................................................................6
TEST CIRCUITS
............................................................................................7
TYPICAL CHARACTERISTICS
.......................................................................8
1) Output Voltage vs. Input Voltage........................................................................8
2) Output Voltage vs. Output Current .....................................................................8
3) Dropout Voltage vs. Output Current....................................................................8
4) Output Voltage vs. Temperature ........................................................................9
5) Supply Current vs. Input Voltage .......................................................................9
6) Supply Current vs. Temperature........................................................................9
7) Ripple Rejection vs. Frequency .......................................................................10
8) Line Transient Response...............................................................................10
9) Load Transient Response..............................................................................10
TYPICAL APPLICATION
..............................................................................11
PACKAGE DIMENSION
................................................................................11
TAPING SPECIFICATION
.............................................................................12
1
LOW RIPPLE VOLTAGE REGULATOR
WITH EXTERNAL TRANSISTOR
RN5RF SERIES
OUTLINE
The RN5RF Series are voltage regulator ICs which control external driver transistors with high ripple rejection, high accu-
racy output voltage, low supply current by CMOS process. Each of these voltage regulator ICs consists of a voltage refer-
ence unit, an error amplifier, output voltage setting resistor, short circuit current limiting circuit and chip enable circuit.
These ICs are suitable for constructing regulators with ultra low dropout voltage and an output current in the range of sev-
eral tens of mA and several hundreds mA. In addition to low supply current by CMOS process, chip enable function can
be used to conserve battery life during standby.
Furthermore, a supreme ripple rejection and a transient response are suited for portable communicatior such as cell
phones, PDAs, walky talkies. SOT23-5 (Mini Mold) package is available.
FEATURES
• Ultra Low Supply Current .....................TYP. 30µA
• Standby Mode ........................................TYP. 0.1µA
• High Accuracy Output Voltage ............±2.0%
• High Ripple Rejection............................TYP. 60dB/f=1kHz
• Low Dropout Voltage.............................TYP. 0.1V/IOUT=100mA, dependent on External Tr.
• Low Temperature Drift .........................TYP. ±100ppm/˚C
• High Line Regulation.............................TYP. 0.05%/V
• Output Voltage .......................................Stepwise setting with a step of 0.1V in the range of 2.0V to 6.0V
• Current Limit for external Tr................TYP. 8mA, Limit a base current
APPLICATIONS
• Power source for battery-powered equipment
• Telecommunications, Cameras, VCRs
• Power source for domestic appliances
RN5RF
2
BLOCK DIAGRAM
SELECTION GUIDE
The output voltage, the chip enable active type, the packing type and the taping type for the ICs can be selected at the user's
request.
The selection can be made by designating the part number as shown below:
RN5RF ××××–××← Part Number
↑ ↑↑ ↑
a b c d
2
51
VOUT
GND
VDD
CE
Vref
3
Current Limit
+
–
RN5RF××ARN5RF××B
4EXT
2
51
VOUT
GND
VDD
CE
Vref
3
Current Limit
+
–
4EXT
}
}
Code Contents
aSetting Output Voltage (VOUT) :
Stepwise setting with a step of 0.1V in the range of 2.0V to 6.0V is possible.
Designation of Chip enable Active Type
b A : “L” active type
B : “H” active type
Designation of Packing type
c A : Taping
C : Antistatic bag only for samples
dDesignation of Taping type
Ex. TR, TL (refer to Taping Specifications, TR type is prescribed as a standard.)
3
RN5RF
PIN CONFIGURATION
1 2 3
5 4
(mark side)
CE/CE EXT
GND VDD VOUT
• SOT-23-5
PIN DESCRIPTION
Pin No. Symbol Pin Description
1 GND Ground Pin
2 VDD Input Pin
3 VOUT Output Pin
4 EXT External Transistor Drive Pin (CMOS Output)
5 CE or CE Chip Enable Pin
ABSOLUTE MAXIMUM RATINGS
Symbol Item Rating Unit
VIN Input Voltage 12 V
VCE Input Voltage for CE/CE Pin –0.3 to VIN +0.3 V
VEXT EXT Output Voltage 12 V
IEXT EXT Output Current 50 mA
PDPower Dissipation 150 mW
Topt Operating Temperature Range –40 to +85 ˚C
Tstg Storage Temperature Range –55 to +125 ˚C
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under
any conditions. Moreover, such values for any two items must not be reached simultaneously. Operation
above these absolute maximum ratings may cause degradation or permanent damage to the device. These
are stress ratings only and do not necessarily imply functional operation below these limits.
RN5RF
4
ELECTRICAL CHARACTERISTICS
Symbol Item Conditions MIN. TYP. MAX. Unit
VOUT Output Voltage VIN–VOUT=1.0V VOUT VOUT V
IOUT=50mA ×0.98 ×1.02
IOUT Output Current VIN–VOUT=1.0V 1*1A
IEXT EXT Current VIN=4.0V, VEXT=2.0V 5 8 15 mA
∆VOUT Load Regulation VIN–VOUT=1.0V –60 60 mV
∆IOUT 1mA≤IOUT≤100mA
VDIF Dropout Voltage IOUT=100mA 0.1 0.2 V
Iss Supply Current VIN–VOUT=1.0V 30 50 µA
IOUT=0mA
Istandby Standby Current VIN=10.0V 0.01 0.1 1.0 µA
IEXTleak EXT Leakage Current 0.5 µA
∆VOUT Line Regulation IOUT=50mA 0 0.05 0.30 %/V
∆VIN VOUT+0.5V≤VIN≤10V
RRRipple Rejection f=1kHz, sinusoidal 0.5Vp-p 60 dB
VIN–VOUT=1.0V
VIN Input Voltage 10 V
VEXT EXT Output Voltage 10 V
∆VOUT Output Voltage IOUT=10mA ±100 ppm/˚C
∆Topt Temperature Coefficient –40˚C≤Topt≤85˚C
RPU Pull up resistance for CE pin 4 MΩ
VCEH CE Input Voltage “H” 1.5 VIN V
VCEL CE Input Voltage “L” 0 0.25 V
Topt=25˚C
*1) The output current depends on the performance of external PNP transistor. Use External PNP transistor of a low saturation type, with an hFE between
100 and 300.
*) With respect to Test Circuit, refer to Typical Application.
5
RN5RF
Symbol Item Conditions MIN. TYP. MAX. Unit
VOUT Output Voltage VIN–VOUT=1.0V VOUT VOUT V
IOUT=50mA ×0.98 ×1.02
IOUT Output Current VIN–VOUT=1.0V 1*1A
IEXT EXT Current VIN=4.0V, VEXT=2.0V 5 8 15 mA
∆VOUT Load Regulation VIN–VOUT=1.0V –60 60 mV
∆IOUT 1mA≤IOUT≤100mA
VDIF Dropout Voltage IOUT=100mA 0.1 0.2 V
Iss Supply Current VIN–VOUT=1.0V 30 50 µA
IOUT=0mA
Istandby Standby Current VIN=10.0V 0.01 0.1 1.0 µA
IEXTleak EXT Leakage Current 0.5 µA
∆VOUT Line Regulation IOUT=50mA 0 0.05 0.30 %/V
∆VIN VOUT+0.5V≤VIN≤10V
RRRipple Rejection f=1kHz, sinusoidal 0.5Vp-p 60 dB
VIN–VOUT=1.0V
VIN Input Voltage 10 V
VEXT EXT Output Voltage 10 V
∆VOUT Output Voltage IOUT=10mA ±100 ppm/˚C
∆Topt Temperature Coefficient –40˚C≤Topt≤85˚C
RPD Pull down resistance for CE pin 4 MΩ
VCEH CE Input Voltage “H” 1.5 VIN V
VCEL CE Input Voltage “L” 0 0.25 V
Topt=25˚C
*1) The output current depends on the performance of external PNP transistor. Use External PNP transistor of a low saturation type, with an hFE between
100 and 300.
*) With respect to Test Circuit, refer to Typical Application.
RN5RF
6
OPERATION
In these ICs, Output Voltage VOUT is detected by Feed-back Resistors, RAand RBand the detected Output Voltage is com-
pared with a reference voltage by Error Amplifier so that the base current of External PNP Transistor can be adjusted and
Output Voltage VOUT is able to be regulated.
The base current of an external Tr. is monitored and controlled by an internal Base Current Limit circuit to keep current
within a proper range. Furthermore, the other current limit circuit prevents a problem which is that a base current increas-
es sharply when input Voltage VIN becomes lower than Set Output Voltage.
2
51
VOUT
GND
VDD
CE Vref
3
Current Limit
+
–
4EXT
IN RN5RF××A
PNP Tr
Ra
Rb CL
OUT
GND
Notes on selecting external components
(1) On external PNP transistor
Be careful of output current, input voltage and power dissipation of External PNP Transistor.
It is said that External PNP Transistor with a low VCE (sat) and an hFE between 100 and 300 is suitable.
(2) On phase compensation
In these ICs, phase compensation is made for securing stable operation on the output stage even if the
load current is varied. For this purpose, be sure to use a capacitor CL(tantalum type) with a capacitance
of 10µF of more. There may be the case the loop oscillation takes place when a tantalum capacitor CLwith
a large ESR is used, so select the CLcarefully including the frequency characteristics.
7
RN5RF
TEST CIRCUITS
PNP
EXT
VOUT OUT
10µF
GND
CE
10µF
VDD
IN
RN5RF××A
5
1
3
4
2IOUT
Basic Test Circuit
PNP
EXT
VOUT OUT
10µF
GND
CE
10µF
VDD
IN
RN5RF××A
5
1
3
4
2
ISS
Test Circuit for Supply Current
PNP
EXT
VOUT OUT
10µF
GND
CE
VDD
IN
RN5RF××A
5
1
3
4
2
P.G
IOUT
Test Circuit for Ripple Rejection and Line Transient Response
PNP
EXT
VOUT OUT
10µF
GND
CE
10µF
VDD
IN
RN5RF××A
5
1
3
4
2
Test Circuit for Load Transient Response
RN5RF
8
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Input Voltage (Topt=25˚C)
RN5RF30A
3.20
2.60
2.40
2.20
3.00
2.80
2.00
Input Voltage VIN(V)
Output Voltage VOUT(V)
2345678910
IOUT=0mA
IOUT=100mA
IOUT=500mA
RN5RF50A
5.20
4.60
4.40
4.20
5.00
4.80
4.00
Input Voltage VIN(V)
Output Voltage VOUT(V)
4 5 6 7 8 9 10
IOUT=0mA
IOUT=100mA
IOUT=500mA
3) Dropout Voltage vs. Output Current
RN5RF30A
0.50
0.20
0.40
0.30
0.10
0.00
Output Current IOUT(mA)
Dropout Voltage VDIF(V)
0 300100 200 400 500
Topt=–40˚C
Topt= 25˚C
Topt= 85˚C
RN5RF50A
0.50
0.20
0.40
0.30
0.10
0.00
Output Current IOUT(mA)
Dropout Voltage VDIF(V)
0 300100 200 400 500
Topt=–40˚C
Topt= 25˚C
Topt= 85˚C
2) Output Voltage vs. Output Current (Topt=25˚C)
RN5RF30A
3.10
2.95
2.90
2.85
3.05
3.00
2.80
Output Current IOUT(mA)
Output Voltage VOUT(V)
0 100 200 300 400 500
VIN=4V
RN5RF50A
5.10
4.95
4.90
4.85
5.05
5.00
4.80
Output Current IOUT(mA)
Output Voltage VOUT(V)
0 100 200 300 400 500
VIN=6V
9
RN5RF
4) Output Voltage vs. Temperature
RN5RF30A
3.10
3.00
3.05
2.95
2.90
Temperature Topt(˚C)
Output Voltage VOUT(V)
VIN=4V, IOUT=10mA
–40 10–15 35 60 85
RN5RF50A
5.10
5.00
5.05
4.95
4.90
Temperature Topt(˚C)
Output Voltage VOUT(V)
VIN=6V, IOUT=10mA
–40 10–15 35 60 85
6) Supply Current vs. Temperature
RN5RF30A
50
30
40
20
10
0
Temperature Topt(˚C)
Supply Current ISS(µA)
VIN=4V, IOUT=0mA
–40 10–15 35 60 85
RN5RF50A
50
30
40
20
10
0
Temperature Topt(˚C)
Supply Current ISS(µA)
–40 10–15 35 60 85
VIN=6V, IOUT=0mA
5) Supply Current vs. Input Voltage (Topt=25˚C)
RN5RF30A
100
60
50
80
70
90
40
30
20
10
0
Input Voltage VIN(V)
Supply Current ISS(µA)
0 42 6 8 10
IOUT=0mA
RN5RF50A
100
60
50
80
70
90
40
30
20
10
0
Input Voltage VIN(V)
Supply Current ISS(µA)
0 42 6 8 10
IOUT=0mA
RN5RF
10
7) Ripple Rejection vs. Frequency (Topt=25˚C)
RN5RF30A
80
70
50
60
40
20
30
10
0
Frequency f (kHz)
Ripple Rejection RR (dB)
0.01 0.1 1 10 100
V
IN
=4Vdc+0.5Vp-p, I
OUT
=100mA, C
L
=10µF
RN5RF50A
80
70
50
60
40
20
30
10
0
Frequency f (kHz)
Ripple Rejection RR (dB)
0.01 0.1 1 10 100
V
IN
=6Vdc+0.5Vp-p, I
OUT
=100mA, C
L
=10µF
9) Load Transient Response (Topt=25˚C)
RN5RF30A
200
100
0
–100
–200
–300
–400
3.3
3.2
3.1
3
2.9
2.8
2.7
Time t (µs)
Output Current IOUT(mA)
Output Voltage VOUT(V)
–100 0 100 200 300 400
VIN=4V, CL=10µF
Output Current
Output Voltage
RN5RF50A
200
100
0
–100
–200
–300
–400
Time t (µs)
Output Current IOUT(mA)
–100 0 100 200 300 400
VIN=6V, CL=10µF 5.3
5.2
5.1
5
4.9
4.8
4.7
Output Current VOUT(V)
Output Current
Output Voltage
8) Line Transient Response (Topt=25˚C)
RN5RF30A
6
5
4
3
2
1
0
Time t (µs)
Input Voltage VIN(V)
–50 0–25 25 50 75 100 125 150
IOUT=300mA, CL=10µF 3.3
3.2
3.1
3
2.9
2.8
2.7
Output Voltage VOUT(V)
Input Voltage
Output Voltage
RN5RF50A
8
7
6
5
4
3
2
Time t (µs)
Input Voltage VIN(V)
–50 0–25 25 50 75 100 125 150
IOUT=300mA, CL=10µF 5.3
5.2
5.1
5
4.9
4.8
4.7
Ourput Voltage VOUT(V)
Input Voltage
Output Voltage
11
RN5RF
TYPICAL APPLICATION
PNP Tr
EXT
OUT
Cap.
+
GND
CE
VDDIN RN5RF××AVOUT
Cap.
+
Parts Transistor : 2SB766A
Capacitor : 10µF (tantalum type)
PACKAGE DIMENSION (Unit : mm)
· SOT-23-5
2.9±0.2
0.8±0.1
0.4±0.1
1.9±0.2
(0.95) (0.95)
5 4
1 2 3
+0.2
–0.1
1.6
+0.2
–0.1
1.1
+0.1
–0.05
0.15
2.8±0.3
0 to 0.1
0.2 MIN.
RN5RF
12
RN5RF
12
TAPING SPECIFICATION (Unit : mm)
· SOT-23-5
T R T L
User Direction of Feed.
2.0MAX.
0.3±0.1 4.0±0.1
2.0±0.05
4.0±0.1
3.3
3.2
8.0±0.3
1.75±0.1
3.5±0.05
1.5+0.1
–0
ø
APPLICATION HINTS
Using these ICs, be sure to take care of the following points:
1) Minimize the impedance of VDD and GND wiring. A large current flows through these wiring. When the
wiring impedance is high, the operation of the ICs tends to be unstable and is vulnerable to noise.
2) Provide a capacitor with a capacitance of about 10µF (tantalum type) between VDD pin and GND pin with a
minimum wiring length.
3) Rush current flows into the capacitor connected to the output of Regulators at the start of the operation of
the Regulators. As these ICs are used with external PNP Transistor, the current drive performance of this
Regulator is excellent. Therefore, when Regulator stars to operate, for example, under the conditions that
hFE of External PNP Transistor is 100 and the base current of the limiter is 8mA, a rush current becomes
800mA.
4) In these ICs, phase compensation is made for securing stable operation on the output stage even if the
load current is varied. For this purpose, be sure to use a capacitor CL(tantalum type) with a capacitance
of 10µF of more. There may be the case the loop oscillation takes place when a tantalum capacitor CLwith
a large ESR is used, so select the CLcarefully including the frequency characteristics.
5) Set external parts as close as possible to the IC and minimize the connection between the parts and the IC.
RICOH COMPANY, LTD.
ELECTRONIC DEVICES DIVISION
HEADQUARTERS
13-1, Himemuro-cho, Ikeda City, Osaka 563-8501, JAPAN
Phone 81-727-53-1111 Fax 81-727-53-6011
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3-2-3, Shin-Yokohama, Kohoku-ku, Yokohama City, Kanagawa 222-8530,
JAPAN
Phone 81-45-477-1697 Fax 81-45-477-1694 • 1695
http://www.ricoh.co.jp/LSI/english/
RICOH CORPORATION
ELECTRONIC DEVICES DIVISION
SAN JOSE OFFICE
3001 Orchard Parkway, San Jose, CA 95134-2088, U.S.A.
Phone 1-408-432-8800 Fax 1-408-432-8375
