RP400x Series
Current Mode PWM/VFM Step-up DC/DC Converter
The RP400x Series are CMOS-based automatic switch PWM- or VFM-controlled step-up DC/DC converters. RP400x includes a soft
start circuit. By simply using an inductor, a capacitor, a diode, and (resistors) as external components, a high-efficiency step-up
DC/DC converter can be easily configured. Due to current mode PWM control, the RP400x provides a fast response and high
efficiency. Ceramic output capacitors can be used. The output voltage can be selected from the internally fixed or the externally
adjustment. The RP400x has an anti-ringing switch that prevents inductor current from ringing in PWM discontinuous mode. RP400x
switches automatically to VFM control in low output current, keeping high efficiency. In addition to SOT-23-5 package, a 1.8mm
×
2.0mm square DFN(PLP)1820-6 package is also available.
FEATURES
•
Supply Current (I
DD1
)·······················Typ. 300μA (RP400x301, V
IN
=V
OUT
=SET V
OUT
×
0.95)
•
Supply Current (I
DD2
)·······················Typ. 160μA (V
IN
=5V, In non-switching)
•
Standby Current (I
standby
)··················Max. 3μA (In standby, only A Version)
•
Input Voltage Range (V
IN
) ···············0.9V to 5.5V
•
Start-up Voltage (V
start
) ····················Max. 0.9V
•
Output Voltage Range (V
OUT
)··········1.8V to 5.0 V (internally fixed) (xx1)
Externally adjustable (Feedback voltage of 0.6V)
(001)
•
Output Voltage Accuracy················
±
2%
•
Oscillator Frequency (f
osc
) ·············· 700kHz
•
Oscillator Maximum Duty Cycle (Maxduty) ·· Typ. 88%
•
Soft Start Time (t
start
)······················· Typ. 0.7ms
•
Anti-ringing Switch ························· Internal EMI Suppression
•
Packages ······································· DFN(PLP)1820-6,
SOT-23-5
BLOCK DIAGRAMS
RP400xxx1x
(Internally fixed output voltage type)
L
X
Startup
Circuit
Control
Logic
Startup
Circuit
Control
Logic
RP400K001x
(Externally adjustable output voltage type)
L
X
V
IN
Buffer
V
IN
Buffer
PWM
Control
Current
Sense
PWM
Control
Current
Sense
V
OUT
ErrorAmp
ErrorAmp
CE
Chip
Enable
fosc
OSC
V
OUT
CE
Chip
Enable
fosc
OSC
V
FB
VFM Control
Vref
VFM Control
Vref
only A Version
GND
only A Version
GND
SELECTION GUIDES
Quantity per
Part No.
Reel
DFN(PLP)1820-6 5,000 pcs RP400K
.xx.1.
∗
-TR
SOT-23-5
3,000 pcs RP400N
.xx.1.
∗
-TR-F
Package
.xx.
: Specify the output voltage within the range
1.8V (.18.) to 5.0V (.50.) in 0.1V steps.
For the externally adjustable output voltage type, (.00.).
.∗
: Select from (.A.) With CE pin or (.B.) Without CE pin.
TYPICAL APPLICATIONS
RP400xxx1A
(Internally fixed output Voltage type)
L10μH
SD
V
IN
V
IN
C
IN
10μF
"H"active
RP400x
OUT
CE
V
OUT
C
OUT
10μF
"H"active
CE
GND
V
FB
R1
RP400x001A
(Externally adjustable output voltage type)
L10μH
SD
V
IN
V
IN
C
IN
10μF
L
X
RP400x001A
V
OUT
C
OUT
10μF
V
OUT
1.8V to 5.0V
R2
L
X
GND
PACKAGES
DFN(PLP)1820-6
Top View
6
5
4
TYPICAL CHARACTERISTIC
SOT-23-5
5
4
RP400x001A Efficiency vs. Output Current
100
90
SET V
OUT
=3.0V
Bottom View
4
5
6
∗
1
2
3
3
2
1
1
2
3
4
5
6
xx1A
V
IN
CE
GND
L
X
NC
V
OUT
001A
V
IN
CE
GND
L
X
V
FB
V
OUT
xx1B
V
IN
NC
GND
L
X
NC
V
OUT
001B
V
IN
NC
GND
L
X
V
FB
V
OUT
1
2
3
4
5
xx1A
CE
GND
V
IN
V
OUT
L
X
xx1B
NC
GND
V
IN
V
OUT
L
X
Efficiency
η
(%)
1
2
3
80
70
60
50
40
V
IN
=2.5V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=0.8V
0
200
400
600
Output Current I
OUT
(mA)
800
∗
)
The tab is substrate level (GND).
APPLICATIONS
•
MP3 players and PDA
•
Digital cameras
No.EK-193-091101
•
LCD bias power supply
•
Personal medical equipment
•
Wireless Handset
•
GPS
Step-up DC/DC Converter
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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.
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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.
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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
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