R1800K Series
144 nA IQ Low Quiescent Current Buck DC/DC Converter for Energy Harvester
No. EA-414-181213
1
R1800K is a power-storing buck DC/DC converter for a photovoltaic and vibration energy harvester. A low
operating quiescent current allows a harvester to be used under a low-illumination environment, and it is
suitable for an equipment with low power supplied from a harvester.
● Providing a low operating quiescent current (IQ 144 nA) and a high efficiency (approximately 90%@10 µA).
● A Control function that enables a maximum power optimizes a power supply from an energy harvester.
Input Voltage Range: 2.0 V to 5.5 V
Output Voltage Range: 2.0 V to 4.5 V
Output Voltage Accuracy: ±3.0%
Operating Quiescent Current:
Typ.144 nA (Ta = 25°C, at no load)
Starting Power: 720 nW
Reverse Current Protection (VIN ≥ 2.0 V)
Accuracy of Maximum Power Voltage: 200 mV
Efficiency vs. Output Current V
SET = 3.3 V
Energy harvesting module of a photovoltaic
and vibration energy harvester
L = 22 µH, CIN = 10 µF, COUT = 47 µF
Product Name Package Quantity per Reel
R1800KxxxA-TR DFN(PLP)2730-12 5,000 pcs
xxx: Select the ideal combination of the set output
voltage (VSET) and the set maximum power
voltage (VMPSET) from the code number
starting from 002.
0
20
40
60
80
100
0.1 1 10 100 1000 10000
Efficiency (%)
Output Current (uA)
Vin= 4 V
Vin= 4.5 V
Vin= 5 V
OVERVIEW
KEY BENEFITS
KEY SPECIFICATIONS
SELECTION GUIDE
TYPICAL CHARACTERISTICS
PACKAGE
APPLICATIONS
DFN(PLP)2730-12
2.7 mm x 3.0 mm x 0.6 mm
TYPICAL APPLICATION
R1800
K
No. EA-414-181213
2
SELECTION GUIDE
The set output voltage and set maximum power voltage are user-selectable options.
Selection Guide
Product Name Package Quantity per Reel Pb Free Halogen Free
R1800KxxxA-TR DFN(PLP)2730-12 5,000 pcs Yes Yes
xxx: Select the ideal combination of the set output voltage (VSET) and
the set maximum power voltage (VMPSET) from the code number starting from 002.
Output voltage: 2.0 V to 4.5 V in 0.1 V step
Maximum power voltage: 2.0 V to 5.3 V in 0.1 V step
BLOCK DIAGRAM
R1800K Block Diagram
R1800K
No. EA-414-181213
3
PIN DESCRIPTION
Top View
Bottom View
1
DFN(PLP)2730-12 Pin Configuration
DFN(PLP)2730-12 Pin Description
Pin No. Symbol Description
1 AGND AGND Pin
2 TEST1 Pin for Testing (Must not be connected)
3 TEST2 Pin for Testing (Must not be connected)
4 VM Pin for Testing (Must not be connected)
5 NC No Connection (Must not be connected)
6 NC No Connection (Must not be connected)
7 VFB Feedback Pin
8 PGND PGND Pin
9, 10 LX DC/DC Switching Pin
11, 12 VIN Pin for Connecting Photovoltaic Element

(1) The tab on the bottom of the package enhances thermal performance and is electrically connected to GND (substrate
level). It is recommended that the tab be connected to the ground plane on the board, or otherwise be left floating.
1 2 3 4 5 6
7 8 9 10 11 12
6 5 4 3 2 1
12 11 10 9 8 7
(1)
R1800
K
No. EA-414-181213
4
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings (GND = 0 V)
Symbol Parameter Rating Unit
VIN VIN Pin Voltage −0.3 to 6.5 V
VLX LX Pin Voltage −0.3 to VIN + 0.3 V
VVFB VFB Pin Voltage −0.3 to 6.5 V
PD Power Dissipation (1)
[ DFN(PLP)2730-12, JEDEC STD. 51-7 Test Land Pattern ] 1850 mW
Tj Junction Temperature Range −40 to 85 C
Tstg Storage Temperature Range −55 to 125 C
ABSOLUTE MAXIMUM RATINGS
Electronic and mechanical stress momentarily exceeded absolute maximum ratings may cause the permanent
damages and may degrade the life time and safety for both device and system using the device in the field.
The functional operation at or over these absolute maximum ratings are not assured.
RECOMMENDED OPERATING CONDITIONS
Recommended Operating Conditions
Symbol Parameter Rating Unit
VIN Input Voltage 2.0 to 5.5 V
Ta Operating Temperature Range −40 to 85 °C
RECOMMENDED OPERATING CONDITIONS
All of electronic equipment should be designed that the mounted semiconductor devices operate within the
recommended operating conditions. The semiconductor devices cannot operate normally over the recommended
operating conditions, even if when they are used over such conditions by momentary electronic noise or surge. And
the semiconductor devices may receive serious damage when they continue to operate over the recommended
operating conditions.
(1) Refer to POWER DISSIPATION for detailed information.
R1800K
No. EA-414-181213
5
ELECTRICAL CHARACTERISTICS
The specifications surrounded by are guaranteed by design engineering at −40°C ≤ Ta ≤ 85°C.
R1800K Electrical Characteristics (Ta = 25°C)
Symbol Parameter Condition Min. Typ. Max. Unit
VOUT Output Voltage VIN ≥ VSET + 0.5 V, at no load x 0.97 x 1.03 V
IQ Operating Quiescent
Current
VIN = 5.0 V,
VSET = 3.0 V, device not switching 144 300 nA
PST Minimum Starting Power Ta = 25°C, VIN = 4 V, VSET = 3.3 V,
when constant current is applied 720 nW
VMP Accuracy of Maximum
Power Voltage 200 mV
IREV Reverse Current
VIN ≥ 2.0 V, VFB = 4.5 V
(When VIN drops from 2.5 V or more)
Charging current to CIN and COUT are
not included(1)
10 100 nA
All test items listed under Electrical Characteristics are done under the pulse load condition (Tj ≈ Ta = 25°C).
Test circuit is operated with “Open Loop Control” (GND = 0 V), unless otherwise specified.
(1) Reverse current protection operates at VIN ≥ 2 V. It does not function with the voltage under 2 V. Set as VMPSET > VSET
+ 0.5 V. Due to having a hysteresis in the reverse current protection, a state may be detected as a reverse current even
if VIN = VOUT.
R1800
K
No. EA-414-181213
6
The specifications surrounded by are guaranteed by design engineering at −40°C ≤ Ta ≤ 85°C.
Product-specific Electrical Characteristics
Product Name VOUT [V] VMP [V]
Min. Typ. Max. Typ. Max.
R1800K002A 1.940 2.0 2.060 2.5 2.7
R1800K003A 1.940 2.0 2.060 3.8 4.0
R1800K004A 1.940 2.0 2.060 4.0 4.2
R1800K005A 1.940 2.0 2.060 4.5 4.7
R1800K006A 1.940 2.0 2.060 5.0 5.2
R1800K008A 3.201 3.3 3.399 3.8 4.0
R1800K009A 3.201 3.3 3.399 4.0 4.2
R1800K010A 3.201 3.3 3.399 4.5 4.7
R1800K011A 3.201 3.3 3.399 5.0 5.2
R1800K014A 4.365 4.5 4.635 5.0 5.2
R1800K016A 3.783 3.9 4.017 4.4 4.6
R1800K019A 2.910 3.0 3.090 4.4 4.6
R1800K020A 2.910 3.0 3.090 4.2 4.4
R1800K021A 2.619 2.7 2.781 3.9 4.1
R1800K022A 2.619 2.7 2.781 4.4 4.6
R1800K023A 2.619 2.7 2.781 5.0 5.2
R1800K
No. EA-414-181213
7
THEORY OF OPERATION
MAXIMUM POWER CONTROL
R1800K transfers power to a secondary side at the maximum power voltage (VMP), which is the operating point
of the maximum amount of power generation of a solar cell. After R1800K receives power from the solar cell,
the input voltage increases and when it reaches the VMP, a switching starts and the R1800K transfers power
to the secondary side. When a power transfer amount exceeds the supplied power from the solar cell, the input
voltage decreases by the switching. At a certain point, the switching stops and a state changes to a charging
mode. When the input voltage reaches the VMP again, the R1800K transfers power to the secondary side. By
repeating this operation enables transferring power to the secondary side while maintaining the operating point
of the maximum amount of power generation of the solar cell.
R1800
K
No. EA-414-181213
8
REVERSE CURRENT DETECTION
V (V)
R1800K has a reverse current protection to maintain an electric charge of the output side when the light is cut
off. When the light is cut off after a normal operation and a power supply from the solar cell is discontinued,
the charge of supply current of a circuit connected respectively to the input and output sides is drawn. When
the input voltage drops below the output voltage, the reverse current protection operates (at the backflow) and
prevents the charge drawn from the output side. As shown in the figure above, this protection operates at 2 V
or higher. When the input voltage drops below 2 V, the charge of the output side flows back to the input side.
The drawn charge increases for a moment, but the R1800K returns to the reverse current protection state. The
average amount of charge drawn from the output side is extremely minute.
R1800K
No. EA-414-181213
9
APPLICATION INFORMATION
Typical Application Circuit
VIN
VM
LX
VFB
L
R1800K
TEST1
COUT
TEST2
Load
PGND
CIN
AGND
vibration
energy
harvester
R1800K Typical Application Circuit
Recommended External Components
Symbol Descriptions Parts Name
CIN Ceramic Capacitor 10 µF or higher C1608X5R1E106M080AC
COUT Ceramic Capacitor 47 µF or higher C3216X6S1A476M160AC
Large-capacity Electrical Storage Device (1)
L Inductor 22 µH VLS201612CX-220M-1
(1) Large-capacity electrical storage device including EDLC, LiC, LiB, and all-solid Li.
Examples: LiB, UMAC040130A003TA01, UMAL361421A024TA01
R1800
K
No. EA-414-181213
10
TECHNICAL NOTES
The performance of a power source circuit using this device is highly dependent on a peripheral circuit. A
peripheral component or the device mounted on PCB should not exceed a rated voltage, a rated current or a
rated power. When designing a peripheral circuit, please be fully aware of the following points.
External components must be connected as close as possible to the IC and make wiring as short as
possible. Especially, the capacitor connected in between VIN pin and GND pin must be wiring the shortest.
If their impedance is high, internal voltage of the IC may shift by the switching current, and the operating
may be unstable. Make the power supply and GND lines sufficient.
As for wirings of the power, the ground, the inductor, the LX and the VFB pins, due consideration must be
given to large current occurred by switching.
Using a ceramic capacitor with a lower equivalent series resistance (ESR) is recommended; a capacitor
of 10µF or higher for CIN between VIN and GND pins, a capacitor of 47µF or higher for COUT. Using a mass-
storage device for COUT also is recommended. Please choose capacitors depending on the bias
characteristics, VIN and VOUT. (Refer to Recommended External Components )
Please choose inductors which have low direct-current resistance, enough allowable current and low
magnetic saturation. Current-limited circuit may operate with LX peak current before reaching expected
load current in case of low allowable current and extremely low inductance value under load condition.
Note that the current-limited circuit is self-heating and radiation environment sensitive.
R1800K
No. EA-414-181213
11
PCB Layout
R1800KxxxA-TR (PKG:DFN(PLP)2730-12)
Top Layer Bottom Layer
R1800
K
No. EA-414-181213
12
TYPICAL CHARACTERISTICS
Note: Typical Characteristics are intended to be used as reference data; they are not guaranteed.
1) Efficiency vs. Output Current VSET = 3.3 V 2) Quiescent Current vs. Temperature
3) Output Voltage vs. Output Current
Until IOUT = VOUT drops to 90%
0
20
40
60
80
100
0.1 1 10 100 1000 10000
Efficiency (%)
Output Current (uA)
Vin= 4 V
Vin= 4.5 V
Vin= 5 V 0
20
40
60
80
100
120
140
160
180
200
-50-25 0 255075100
Quiescent Current IQ(nA)
Temperature Ta (°C)
3
3.05
3.1
3.15
3.2
3.25
3.3
3.35
0 500 1000 1500 2000
Output Voltage (V)
Output Current (uA)
Vin= 4 V
Vin= 4.5 V
Vin= 5 V
3.2
3.22
3.24
3.26
3.28
3.3
3.32
3.34
3.36
3.38
3.4
0 200 400 600 800 1000
Output Voltage (V)
Output Current (uA)
Vin= 4 V
Vin= 4.5 V
Vin= 5 V
POWER DISSIPATION DFN(PLP)2730-12
Ver. A
i
The power dissipation of the package is dependent on PCB material, layout, and environmental conditions.
The following measurement conditions are based on JEDEC STD. 51-7.
Measurement Conditions
Item
Measurement Conditions
Environment Mounting on Board (Wind Velocity = 0 m/s)
Board Material Glass Cloth Epoxy Plastic (Four-Layer Board)
Board Dimensions 76.2 mm × 114.3 mm × 0.8 m m
Copper Ratio Outer Layer (First Layer): Less than 95% of 50 mm Square
Inner Layers (Second and Third Layers): Approx. 100% of 50 mm Square
Outer Layer (Fourth Layer): Approx. 100% of 50 mm Square
Through-holes φ 0.3 mm × 23 pcs
Measurement Result (Ta = 25°C, Tjmax = 8 5°C)
Item Measurement Result
Power Dissip ati on 1850 mW
Thermal Resistance (θja) θja = 32°C/W
Thermal Characterization Parameter (ψjt) ψjt = 8°C/W
θja: Junction-to-Ambient Thermal Resistance
ψjt: Junction-to-Top Thermal Characterization Parameter
Power Dissipation vs. Ambient Temperature
Measurement Board Pattern
0
500
1000
1500
2000
2500
020 40 60 80
Power Dissipation (mW)
Ambient Temperature (°C)
85
1850
PACKAGE DIMENSIONS DFN
PLP
2730-12
Ver. A
i
DFN(PLP)2730-12 Package Dimensions (Unit: mm)
*
∗The tab on the bottom of the package shown by blue circle is a substrate potential (GND). It is recommended that this
tab be connected to the ground plane on the board but it is possible to leave the tab floating.
2.700.05
3.000.05
A B
INDEX
0.575±0.025
S 0.05 S
7
0.250.05
0.250.05
0.250.05
0.50
0.05 M AB
1.700.05
12
6 1
0.5
0.05
2.700.05
C 0.05
Bottom View
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.
Halogen Free
https://www.e-devices.ricoh.co.jp/en/
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