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
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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
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
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Applications
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Ordering Information
RT9266
Package Type
E : SOT-23-6
X5 : SOT-89-5
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
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PDA
DSC
LCD Panel
RF-Tags
MP3
Portable Instrument
Wireless Equipment
Pin Configurations
(TOP VIEW)
GND
FB
VDD
5
2
LX
4
3
5
4
LX
Note :
RichTek Pb-free and Green 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.
}100%
matte tin (Sn) plating.
6
1
EN
1
2
3
EXT GND
EN
VDD
FB
SOT-23-6
SOT-89-5
Marking Information
For marking information, contact our sales representative
directly or through a RichTek distributor located in your
area, otherwise visit our website for detail.
Note
: There is no pin1 indicator on top mark for SOT-23-6
type, and pin 1 will be lower left pin when reading top mark
from left to right.
DS9266-12 May 2007
www.richtek.com
1
RT9266
Absolute Maximum Ratings
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Supply Voltage ---------------------------------------------------------------------------------------------------
−
0.3V to 7V
LX Pin Switch Voltage ------------------------------------------------------------------------------------------
−
0.3V to 7V
Other I/O Pin Voltages ------------------------------------------------------------------------------------------
−
0.3V to (V
DD
+ 0.3V)
LX Pin Switch Current ------------------------------------------------------------------------------------------- 2.5A
EXT Pin Driver Current ------------------------------------------------------------------------------------------ 200mA
Package Thermal Resistance
SOT-23-6,
θ
JC
----------------------------------------------------------------------------------------------------- 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
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
Line Regulation
Load Regulation
EN Pin Trip Level
Temperature Stability for Vout
Thermal Shutdown Hysterises
Symbol
V
ST
V
DD
I
OFF
I
L
= 1mA
Test Conditions
Min
--
2
--
--
0.4
--
1.225
425
85
--
1.6
--
--
--
--
0.4
--
--
Typ
0.98
--
0.01
17
0.55
75
*
Max
1.05
6
1
25
0.7
--
1.275
575
--
1.1
2.6
**
Units
V
V
µA
µA
mA
µA
V
kHz
%
Ω
A
Ω
Ω
mV/V
mV/mA
V
ppm/
°C
°C
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
∆V
LINE
∆V
LOAD
V
IN
= 3.5 ~ 6V, I
L
= 1mA
V
IN
= 2.5V, I
L
= 1 ~ 100mA
V
DD
= 3.3V
T
S
∆T
SD
1.25
500
95
0.3
2
5
5
1.5
0.25
***
8.5
8.5
10
--
1.2
--
--
0.8
50
10
DS9266-12 May 2007
www.richtek.com
5
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