RP402x Series
High Efficiency Small Packaged Step-up DC/DC Converter
No. EA-317-200604
OUTLINE
The RP402x is a high efficiency step-up DC/DC converter with synchronous rectifier. The device can start up
with low voltage of typically 0.7 V which is ideal for the applications powered by either one-cell or two-cell
alkaline, nickel-metal-hydride (NiMH) or one-cell Lithium-ion (Li+) batteries.
Internally, the RP402x consists of an oscillator, a reference voltage unit with soft start, a chip enable circuit, an
error amplifier, phase compensation circuits, a slope circuit, a PWM control circuit, a start-up circuit, a
PWM/VFM mode control circuit, internal switches and protection circuits.
The RP402x is employing synchronous rectification for improving the efficiency or rectification by replacing
diodes with built-in switching transistors. Using synchronous rectification not only increases circuit performance
but also allows a design to reduce parts count.
The RP402x is available in either internally fixed output voltage type or adjustable output voltage type. The
RP402xxxxx is the internally fixed output voltage type. The RP402x00xx is the adjustable output voltage type,
which allows output voltages that range from 1.8 V to 5.5 V via an external divider resistor.
The RP402x provides the forced PWM control and the PWM/VFM auto switching control. Either one of these
can be selected by inputting a signal to the MODE pin. The forced PWM control switches at fixed frequency
rate in low output current in order to reduce noise. Likewise, the PWM/VFM auto switching control automatically
switches from PWM mode to VFM mode in low output current in order to achieve high efficiency. The RP402N
is available in the PWM/VFM auto switching control. However, the RP402N is also available in the forced PWM
control as a custom-designed IC
(1)
.
The RP402x has a soft-start time of typically 0.5 ms.
The RP402x features the complete output disconnect shutdown option and the input-to-output bypass
shutdown option. The RP402xxxxA/ B/ E/ F incorporates the complete output disconnect shutdown option,
which allows the output to be disconnected from the input. The RP402xxxxC/ D/ G/ H incorporates the input-
to-output bypass shutdown option, which allows the output to be connected to the input.
The RP402x is protected against damage by a short-current protection, an over-voltage lockout, an over
voltage protection, an anti-ringing switch and a latch-type protection. An anti-ringing switch prevents the
occurrence of noise when an inductor current reaches a discontinuous mode. The RP402x provides optional
Latch function with current limit detection which can turn off the power in case the limit values are detected for
a fixed time and current limit circuit controls peak inductor currents in every clock. The latch-type protection
can be released by switching the CE pin from high to low while the power is turned on.
The RP402x is offered in a compact 5-pin SOT23-5 package or a 8-pin DFN(PLP)2020-8 package.
(1)
As for the custom-designed IC, please contact our sales representatives.
1
RP402x
No. EA-317-200604
FEATURES
Low Voltage Start-up ·································· Typ. 0.7 V
Input Voltage Range ··································· Fixed Output Voltage Type: 0.6 V to 4.8 V
Adjustable Output Voltage Type: 0.6 V to 4.6 V
High Efficiency ·········································· 94% (100 mA/ 5.0 V, V
IN
= 3.6 V, 25°C)
90% (1 mA/ 5.0 V, V
IN
= 3.6 V, 25°C)
Output Current ·········································· 800 mA: V
IN
= 3.6 V, V
OUT
= 5.0 V
L
X
Driver ON Resistance ····························· NMOS/ PMOS: 0.20
Ω (V
OUT
= 5.0 V, 25°C)
PWM Oscillator Frequency ·························· 1.2 MHz (Normal PWM), 1.0 MHz (Forced PWM)
Output Voltage Range································· Fixed Output Voltage Type: 1.8 V to 5.5 V, 0.1 V step
Adjustable Output Voltage Type: 1.8 V to 5.5 V (recommended)
OVLO Detector Threshold ··························· Typ. 5.1 V
OVP Detector Threshold······························ Typ. 6.0 V
L
X
Peak Current Limit ································· Typ. 1.5 A
Latch Protection Delay Time ························· Typ. 3.3 ms (RP402Kxx1x, RP402Nxx1x)
Typ. 4.1 ms (RP402Kxx2x)
Soft-start Time ·········································· Typ. 0.5 ms
EMI Suppression (Built-in Anti-ringing Switch) (RP402Kxx1x, RP402Nxx1x)
Voltage Regulation at V
IN
> V
OUT
Zero Input Complete Shutdown at V
IN
= 0 V
Input-to-Output Bypass Shutdown Option at CE = L (RP402xxxxC/ D/ G/ H)
Ceramic Capacitor Capable
Package ·················································· DFN(PLP)2020-8, SOT23-5
APPLICATIONS
MP3 Players, PDA
Digital Still Cameras
LCD Bias Supplies
Portable Blood Pressure Meter
Wireless Handset
GPS
USB-OTG
HDMI
2
RP402x
No. EA-317-200604
SELECTION GUIDE
The package type, the set output voltage, the PWM control type, the shutdown option, the MODE pin option,
and the latch function are user-selectable options.
Selection Guide
Product Name
RP402Kxx#$-TR
RP402Nxx#$-TR-FE
Package
DFN(PLP)2020-8
SOT-23-5
Quantity per Reel
5,000 pcs
3,000 pcs
Pb Free
Yes
Yes
Halogen Free
Yes
Yes
xx: Specify the set output voltage (V
SET
).
00: Adjustable Output Voltage Type (1.8 V to 5.5 V, recommended voltage range)
xx: Fixed Output Voltage Type (1.8 V to 5.5 V, adjustable in 0.1 V step)
Please note:
SOT-23-5 package is only available with fixed output voltage type.
#: Specify the PWM control type.
1: Normal PWM operation
2: Forced PWM operation
$: Specify the combination of the shutdown option, the MODE pin option and the latch function.
Version
A
B
C
D
E
F
G
H
Shutdown Options at CE = L
Complete Output Disconnect
Complete Output Disconnect
Input-to-Output Bypass
Input-to-Output Bypass
Complete Output Disconnect
Complete Output Disconnect
Input-to-Output Bypass
Input-to-Output Bypass
MODE Pin
Yes
Yes
Yes
Yes
No
No
No
No
Latch Function
Yes
No
Yes
No
Yes
No
Yes
No
Please refer to
Selection Guide Table
on the next page for detailed information.
3
RP402x
No. EA-317-200604
Selection Guide Table
Package
Output
Voltage
Type
#$
Shutdown
Option
at CE = L
MODE Pin Function
MODE
Pin
Power Controlling Method
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Forced PWM Control
Note: “H” recommended
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Forced PWM Control
Note: “H” recommended
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Forced PWM Control
Note: “H” recommended
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Forced PWM Control
Note: “H” recommended
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
“H”: Normal PWM Control,
“L”: PWM/VFM Auto Switching
Control
PWM/VFM Auto Switching Control
PWM/VFM Auto Switching Control
No
1G Input-to-
Output
1H Bypass
PWM/VFM Auto Switching Control
PWM/VFM Auto Switching Control
PWM
Latch
Controlling
Function
Method
Normal
PWM
Forced
PWM
Normal
PWM
Forced
PWM
Normal
PWM
Normal
PWM
Normal
PWM
Forced
PWM
Normal
PWM
Forced
PWM
Normal
PWM
Normal
PWM
Normal
PWM
Normal
PWM
Normal
PWM
Normal
PWM
Yes
Yes
1A
2A Complete
Output
Disconnect
1B
Fixed Output
Voltage Type
2B
1C
Yes
No
1D
DFN(PLP)2020-8
1A
Input-to-
Output
Bypass
Yes
No
Yes
Adjustable
Output
Voltage
Type
2A Complete
Output
Disconnect
1B
2B
1C
No
1D
Input-to-
Output
Bypass
No
Yes
No
Yes
No
SOT-23-5
Fixed Output
Voltage Type
1E Complete
Output
1F Disconnect
4
RP402x
No. EA-317-200604
BLOCK DIAGRAMS
*1
*2
This Bypass Switch is included in the RP402KxxxC / D only.
This Latch Timer is included in the RP402KxxxA / C only.
BYPASS
SW
*1
OVER VOLTAGE
PROTECTION
V
IN
Lx
REVERSE
DETECTOR
V
OUT
MODE
VFM
CONTROLLER
OSCILLATOR
POWER
CONTROLLER
VREF
+
-
PWM
CONTROLLER
STARTUP
CIRCUIT
BACKGATE
CONTROLLER
SOFT
START
SWITCHING
CONTROLLER
SHORT
PROTECTION
RAMP
COMPENSATION
CE
CHIP
ENABLE
LATCH
TIMER
*2
CURRENT
PROTECTION
＋
CURRENT
FEEDBACK
GND
RP402Kxxxx Block Diagram
*1
*2
This Bypass Switch is included in the RP402KxxxC / D only.
This Latch Timer is included in the RP402KxxxA / C only.
BYPASS
SW
*1
OVER VOLTAGE
PROTECTION
V
IN
Lx
REVERSE
DETECTOR
V
OUT
MODE
VFM
CONTROLLER
OSCILLATOR
POWER
CONTROLLER
VREF
+
-
PWM
CONTROLLER
STARTUP
CIRCUIT
BACKGATE
CONTROLLER
SOFT
START
SWITCHING
CONTROLLER
SHORT
PROTECTION
RAMP
COMPENSATION
CE
CHIP
ENABLE
LATCH
TIMER
*2
CURRENT
PROTECTION
V
FB
＋
CURRENT
FEEDBACK
GND
RP402K00xx Block Diagram
5
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