*RP503Z (WLCSP-6-P2) is the discontinued product. As of June in 2016.
RP503x SERIES
600mA∗ Step-down DC/DC Converter with Synchronous Rectifier
NO.EA-235-140530
OUTLINE
∗
The RP503x Series are low supply current CMOS-based 600mA step-down DC/DC Converters with
synchronous rectifier. Each of these ICs consists of an oscillator, a switching control circuit, a reference voltage
unit, an error amplifier, a soft-start circuit, UVLO circuit, a latch protection circuit, switching transistors, and so on.
A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only an inductor
and capacitors.
In terms of the output voltage, since the feedback resistances are built-in, the voltage is fixed internally. 0.1V
step output can be set by laser-trim and 1.5% or 18mV tolerance depending on the output voltage is guaranteed.
RP503x is PWM/VFM auto switching control in which mode automatically switches from PWM mode to
high-efficiency VFM mode in low output current. The efficiency in low output current (VFM mode) improved
compared with existing products.
As protection circuits, the current limit circuit which limits peak current of Lx at each clock cycle, and the latch
type protection circuit which works if the term of the over-current condition keeps on a certain time exist. The
latch-type protection circuit works to latch an internal driver with keeping it disable. To release the condition of
the protection, after disabling this IC with a chip enable circuit, enable it again, or restart this IC with power-on or
make the supply voltage at UVLO detector threshold level or lower than UVLO.
Since packages are WLCSP-6-P2, DFN1616-6, SOT-23-5, high density mounting on boards is possible.
∗)This is an approximate value, because output current depends on conditions and external parts.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Supply Current ......................................................Typ. 20μA (at VFM mode, at no load)
Standby Current ....................................................Max. 5μA
Input Voltage Range .............................................2.5V to 5.5V (Absolute maximum rating; 6.5V)
Output Voltage Range...........................................0.8V to 2.5V (0.1V step)
Output Voltage Accuracy.......................................±1.5% (VOUT≥1.2V), ±18mV (VOUT0).
In the case of PWM control system, the output voltage is maintained by controlling the on-time period (ton), with
the oscillator frequency (fosc) being maintained constant.
The maximum value (ILmax) and the minimum value (ILmin) of the current flowing through the inductor are the
same as those when Pch Tr. turns on and off.
The difference between ILmax and ILmin, which is represented by ΔI:
∆I = ILmax − ILmin = VOUT × topen / L = (VIN − VOUT) × ton / L ..........................................Equation 1
wherein,
T = 1 / fosc = ton + toff
duty (%) = ton / T × 100 = ton × fosc × 100
topen ≤ toff
In Equation 1, VOUT × topen / L and (VIN − VOUT) × ton / L respectively show the change of the current at "ON", and
the change of the current at "OFF".
12
*RP503Z (WLCSP-6-P2) is the discontinued product. As of June in 2016.
RP503x
Discontinuous mode and Continuous mode
When the output current (IOUT) is relatively small, topen < toff as illustrated in the above diagram. In this case,
the energy is charged in the inductor during the time period of ton and is discharged in its entirely during the time
period of toff, therefore ILmin becomes to zero (ILmin=0). When IOUT is gradually increased, eventually, topen
becomes to toff (topen=toff), and when IOUT is further increased, ILmin becomes larger than zero (ILmin>0). The
former mode is referred to as the discontinuous mode and the latter mode is referred to as continuous mode.
Discontinuous mode
Continuous mode
ILmax
IL
IL
ILmax
ILmin
ILmin
topen
t
ton
toff
T=1/fosc
Iconst
t
ton
toff
T=1/fosc
In the continuous mode, when Equation 1 is solved for ton and assumed that the solution is tonc,
tonc = T × VOUT / VIN ....................................................................................................... Equation 2
T
When ton1mA
0
0.90
0.85
0.80
Output Voltage
0.75
0.70
0
20
40
60
Time t (µs)
80
100
0
200
RP503x08xA
400
600
Time t (µs)
800
1000
RP503x08xA
600
Output Current 200mA-->500mA
200
0
0.85
0.80
Output Voltage
0.75
0.70
Output Current 500mA-->200mA
400
200
0
0.90
0.85
Output Voltage
0.80
0.75
0.70
0.65
0
26
Output Current IOUT (mA)
Output Voltage V OUT (V)
400
Output Voltage V OUT (V)
600
20
40
60
Time t (µs)
80
100
0
20
40
60
Time t (µs)
80
100
Output Current O
I UT (mA)
Output Voltage V OUT (V)
200
Output Current 1mA-->300mA
Output Current O
I UT (mA)
400
Output Voltage V OUT (V)
400
*RP503Z (WLCSP-6-P2) is the discontinued product. As of June in 2016.
RP503x
RP503x12xA
RP503x12xA
400
0
1.25
1.20
Output Voltage
1.15
1.10
0
1.30
1.25
1.20
Output Voltage
1.15
1.10
20
40
60
80
100
0
200
Time t (µs)
RP503x12xA
400
600
Time t (µs)
800
RP503x12xA
600
600
200
0
1.25
1.20
Output Voltage
1.10
Output Voltage V OUT (V)
Output Current IOUT (mA)
1.05
Output Current 500mA-->200mA
400
200
1.30
0
1.25
1.20
Output Voltage
1.15
1.10
1.05
0
20
40
60
80
100
0
20
Time t (µs)
RP503x18xA
40
60
Time t (µs)
80
RP503x18xA
400
200
0
1.85
1.80
Output Voltage
1.70
Output Current O
I UT (mA)
Output Current 1mA-->300mA
Output Voltage V OUT (V)
400
1.75
100
Output Current 300mA-->1mA
200
0
1.90
1.85
1.80
Output Voltage
1.75
1.70
Output Current IOUT (mA)
Output Voltage V OUT (V)
400
Output Current 200mA-->500mA
1.15
1000
Output Current O
I UT (mA)
0
Output Voltage V OUT (V)
200
Output Current 300mA-->1mA
Output Current IOUT (mA)
Output Current 1mA-->300mA
Output Voltage V OUT (V)
200
Output Current O
I UT (mA)
Output Voltage V OUT (V)
400
1.65
1.65
0
20
40
60
Time t (µs)
80
100
0
200
400
600
Time t (µs)
800
1000
27
*RP503Z (WLCSP-6-P2) is the discontinued product. As of June in 2016.
RP503x
RP503x18xA
RP503x18xA
600
0
1.85
1.80
Output Voltage
1.75
1.70
400
Output Current 500mA-->200mA
200
1.90
0
1.85
1.80
Output Voltage
1.75
1.70
1.65
1.65
20
40
60
Time t (µs)
80
0
100
20
40
60
Time t (µs)
RP503x25xA
80
100
RP503x25xA
0
2.55
2.50
Output Voltage
2.45
2.40
2.35
400
Output Voltage V OUT (V)
200
Output Current 1mA-->300mA
Output Current IOUT (mA)
200
Output Current 300mA-->1mA
0
2.65
2.60
2.55
2.50
Output Voltage
2.45
2.40
0
20
40
60
Time t (µs)
80
100
0
200
RP503x25xA
400
600
Time t (µs)
800
1000
RP503x25xA
600
600
0
2.55
2.50
Output Voltage
2.45
2.40
2.35
Output Voltage V OUT (V)
200
Output Current IOUT (mA)
Output Voltage V OUT (V)
400
Output Current 200mA-->500mA
Output Current 500mA-->200mA
400
200
2.65
0
2.60
2.55
2.50
Output Voltage
2.45
2.40
0
20
40
60
Time t (µs)
80
100
0
20
40
60
Time t (µs)
80
100
Output Current IOUT (mA)
Output Voltage V OUT (V)
400
Output Current IOUT (mA)
0
28
Output Current IOUT (mA)
200
Output Voltage V OUT (V)
400
Output Current 200mA-->500mA
Output Current IOUT (mA)
Output Voltage V OUT (V)
600
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 deciding to use the products, please
refer to Ricoh sales representatives for the latest information thereon.
2. The materials in this document 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 document 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, telecommunication 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 to 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 document.
8. The X-ray exposure can influence functions and characteristics of the products. Confirm the product functions and
characteristics in the evaluation stage.
9. WLCSP products should be used in light shielded environments. The light exposure can influence functions and
characteristics of the products under operation or storage.
10. There can be variation in the marking when different AOI (Automated Optical Inspection) equipment is used. In the
case of recognizing the marking characteristic with AOI, please contact Ricoh sales or our distributor before attempting
to use AOI.
11. Please contact Ricoh sales representatives should you have any questions or comments concerning the products or
the technical information.
Halogen Free
Ricoh is committed to reducing the environmental loading materials in electrical devices
with a view to contributing to the protection of human health and the environment.
Ricoh has been providing RoHS compliant products since April 1, 2006 and Halogen-free products since
April 1, 2012.
https://www.e-devices.ricoh.co.jp/en/
Sales & Support Offices
Ricoh Electronic Devices Co., Ltd.
Shin-Yokohama Office (International Sales)
2-3, Shin-Yokohama 3-chome, Kohoku-ku, Yokohama-shi, Kanagawa, 222-8530, Japan
Phone: +81-50-3814-7687 Fax: +81-45-474-0074
Ricoh Americas Holdings, Inc.
675 Campbell Technology Parkway, Suite 200 Campbell, CA 95008, U.S.A.
Phone: +1-408-610-3105
Ricoh Europe (Netherlands) B.V.
Semiconductor Support Centre
Prof. W.H. Keesomlaan 1, 1183 DJ Amstelveen, The Netherlands
Phone: +31-20-5474-309
Ricoh International B.V. - German Branch
Semiconductor Sales and Support Centre
Oberrather Strasse 6, 40472 Düsseldorf, Germany
Phone: +49-211-6546-0
Ricoh Electronic Devices Korea Co., Ltd.
3F, Haesung Bldg, 504, Teheran-ro, Gangnam-gu, Seoul, 135-725, Korea
Phone: +82-2-2135-5700 Fax: +82-2-2051-5713
Ricoh Electronic Devices Shanghai Co., Ltd.
Room 403, No.2 Building, No.690 Bibo Road, Pu Dong New District, Shanghai 201203,
People's Republic of China
Phone: +86-21-5027-3200 Fax: +86-21-5027-3299
Ricoh Electronic Devices Shanghai Co., Ltd.
Shenzhen Branch
1205, Block D(Jinlong Building), Kingkey 100, Hongbao Road, Luohu District,
Shenzhen, China
Phone: +86-755-8348-7600 Ext 225
Ricoh Electronic Devices Co., Ltd.
Taipei office
Room 109, 10F-1, No.51, Hengyang Rd., Taipei City, Taiwan (R.O.C.)
Phone: +886-2-2313-1621/1622 Fax: +886-2-2313-1623