®
RT9266
Tiny Package, High Efficiency, Step-up DC/DC Converter
General Description
The RT9266 is a compact, high efficiency, and low voltage
step-up DC/DC converter with an Adaptive Current Mode
PWM control loop, includes an error amplifier, ramp
generator, comparator, switch pass element and driver in
which providing a stable and high efficient operation over
a wide range of load currents. It operates in stable
waveforms without external compensation.
The low start-up input voltage below 1V makes RT9266
suitable for 1 to 4 battery cells applications of providing
up to 300mA output current. The 450kHz high switching
rate minimized the size of external components. Besides,
the 17μA low quiescent current together with high
efficiency maintains long battery lifetime.
The output voltage is set with two external resistors. Both
internal 2A switch and driver for driving external power
devices (NMOS or NPN) are provided.
Features
1.0V Low Start-up Input Voltage
High Supply Capability to Deliver 3.3V 100mA with
1 Alkaline Cell
17μA Quiescent (Switch-off) Supply Current
μ
Zero Shutdown Mode Supply Current
90% Efficiency
450kHz Fixed Switching Frequency
Providing Flexibility for Using Internal and External
Power Switches
Small
SOT-23-6
& SOT-89-5 Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
PDA
DSC
LCD Panel
RF-Tags
MP3
Portable Instrument
Wireless Equipment
Ordering Information
RT9266
Package Type
E : SOT-23-6
X5 : SOT-89-5
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Pin Configurations
(TOP VIEW)
GND
FB VDD LX
6
5
4
LX
5
4
2
3
1
2
3
EN EXT GND
EN
VDD
FB
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
SOT-23-6
SOT-89-5
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
www.richtek.com
1
RT9266
Typical Application Circuit
L1
V
IN
+
D1
1N5819
C2
1µF
V
OUT
3.3V/5V
R1
1.6M/3M
+
C3
100µF
3.3 to 10 µH
VDD
EN
EXT
RT9266
GND
LX
FB
C1
100µF
R2
980k/1M
Figure 1. RT9266 Typical Application for Portable Instruments
3.1V to 5V for 12V
2.8V to 5V for 9V
V
IN
+
L1
4.7µH
RVDD
100
CVDD
1µF
VDD
EXT
LX
FB
RM
0.22
Q1
N MOS
D1
1N5819
C4
100µF
EN
RT9266
GND
R1
C3
0.1µF 860k/620k
+
12V/9V
300mA
R2
100k
C2
1µF
C1
100uF
Figure 2. RT9266 High Voltage Applications
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9266-16
June 2013
RT9266
L1
V
IN
+
D1
1N5819
C3
100µF
3.3 to 10 µH
V
OUT
3.3V/5V
C2
1µF
VDD
EN
LX
Q1
N MOS
R1
1.6M/3M
+
RT9266
EXT
GND
FB
C1
100µF
R2
980k/1M
Figure 3. RT9266 for Higher Current Applications
L1
V
IN
3.3V/5V
C1
1µF
Q1
VDD
EN
RT9266
GND
LX
FB
EXT
R2
100k
C5
10µF
N MOS
C6
C7
1µF 0.1µF
R1
620k
C4
10µF
R3
100
C2
1µF
4.7µH
C8
1µF
C3
10µF
V
OUT2
+18V
10mA
V
OUT1
+9V
10mA
V
OUT3
-9V
10mA
Figure 4. RT9266 for Multi-Output Applications
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
www.richtek.com
3
RT9266
Test Circuit
I (V
IN
)
V
IN
L1
C3
100µF
10µH
+
D1
1N5819
V
OUT
3.3V/5V
+
A
A
I (V
DD
)
VDD
EN
EXT
RT9266
GND
LX
FB
C2
1µF
R1
1.6M/3M
C4
102
C1
100µF
C5
106
R2
980k/1M
Functional Pin Description
Pin No.
SOT-23-6
1
2
3
4
5
6
SOT-89-5
1
--
5
4
2
3
EN
EXT
GND
LX
VDD
FB
Pin Name
Pin Function
Chip Enable (Active High).
Output Pin for Driving External N-MOSFET.
Ground.
Pin for Switching.
Input Positive Power Pin of RT9266.
Feedback Input Pin.
Internal Reference Voltage for the Error Amplifier is 1.25V.
Function Block Diagram
EXT
VDD
RT9266
LX
FB
1.25V
VDD
R2
Shut Down
EN
Q2
N MOS
Over Temp.
Detector
-
+
Loop Control Circuit
Q1
N MOS
R1
GND
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9266-16
June 2013
RT9266
Absolute Maximum Ratings
Supply Voltage ------------------------------------------------------------------------------------------------------
LX Pin Switch Voltage ---------------------------------------------------------------------------------------------
Other I/O Pin Voltages --------------------------------------------------------------------------------------------
LX Pin Switch Current ---------------------------------------------------------------------------------------------
EXT Pin Driver Current ---------------------------------------------------------------------------------------------
Package Thermal Resistance
SOT-23-6,
θ
JC
-------------------------------------------------------------------------------------------------------
−
0.3V to 7V
−
0.3V to 7V
−
0.3V to (V
DD
+ 0.3V)
2.5A
200mA
145°C/W
SOT-89-5,
θ
JC
------------------------------------------------------------------------------------------------------- 45°C/W
Operating Junction Temperature -------------------------------------------------------------------------------- 125°C
Storage Temperature Range -------------------------------------------------------------------------------------
−
65°C to +150°C
NOTE:
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
Recommended Operating Conditions
(1)
Junction Temperature Range --------------------------------------------------------------------------------------
−
40°C to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------
−
40°C to 85°C
Electrical Characteristics
(V
IN
= 1.5V, VDD set to 3.3V, Load Current = 0, T
A
= 25° C, unless otherwise specified)
Parameter
Start-UP Voltage
Operating VDD Range
Shutdown Current I (V
IN
)
Switch-off Current I (VDD)
Continuous Switching Current
No Load Current I (V
IN
)
Feedback Reference Voltage
Switching Frequency
Maximum Duty
LX ON Resistance
Current Limit Setting
EXT ON Resistance to VDD
EXT ON Resistance to GND
Symbol
V
ST
V
DD
I
OFF
I
L
= 1mA
Test Conditions
Min
--
2
--
--
0.4
--
1.225
425
85
--
1.6
--
--
Typ
0.98
--
0.01
17
0.55
75
(2)
Max
1.05
6
1
25
0.7
--
1.275
575
--
1.1
2.6
(3)
Unit
V
V
μA
μA
mA
μA
V
kHz
%
Ω
A
Ω
Ω
V
DD
pin voltage
EN Pin = 0V, V
IN
= 4.5V
I
SWITCH OFF
V
IN
= 6V
I
SWITCH
I
NO LOAD
V
REF
F
S
D
MAX
V
IN
= EN = 3.3V, V
FB
= GND
V
IN
= 1.5V, V
OUT
= 3.3V
Close Loop, VDD = 3.3V
V
DD
= 3.3V
V
DD
= 3.3V
V
DD
= 3.3V
I
LIMIT
V
DD
= 3.3V
V
DD
= 3.3V
V
DD
= 3.3V
1.25
500
95
0.3
2
5
5
8.5
8.5
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
www.richtek.com
5
