®
RT9266
Tiny Package, High Efficiency, Step-up DC/DC Converter
General Description
Features
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.
z
1.0V Low Start-up Input Voltage
z
High Supply Capability to Deliver 3.3V 100mA with
1 Alkaline Cell
17μ
μA 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
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.
Ordering Information
RT9266
z
z
z
z
z
z
z
Applications
z
z
z
z
z
z
z
Package Type
E : SOT-23-6
X5 : SOT-89-5
PDA
DSC
LCD Panel
RF-Tags
MP3
Portable Instrument
Wireless Equipment
Pin Configurations
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Richtek products are :
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`
GND
LX
5
4
FB VDD LX
Note :
`
(TOP VIEW)
6
5
4
2
3
2
3
EN
VDD
FB
EN EXT GND
Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
1
SOT-23-6
SOT-89-5
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS9266-16
June 2013
is a registered trademark of Richtek Technology Corporation.
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1
RT9266
Typical Application Circuit
L1
+
VIN
D1
3.3 to 10 µH
C3
100µF
1N5819
VOUT
3.3V/5V
C2
1µF
R1
1.6M/3M
VDD
RT9266
LX
EXT
GND
FB
+
EN
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
VIN
L1
D1
+
4.7µH
C4
100µF
1N5819
RVDD
100
CVDD
1µF
VDD
EN
Q1
N MOS
EXT
LX
GND
FB
12V/9V
300mA
R1
C3
0.1µF 860k/620k
RM
0.22
R2
100k
C2
1µF
+
RT9266
C1
100uF
Figure 2. RT9266 High Voltage Applications
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is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
L1
D1
VOUT
3.3V/5V
+
VIN
3.3 to 10 µH
C3
100µF
1N5819
C2
1µF
VDD
EN
LX
RT9266 EXT
R1
1.6M/3M
+
GND
Q1
N MOS
FB
C1
100µF
R2
980k/1M
Figure 3. RT9266 for Higher Current Applications
L1
VIN
3.3V/5V
R3
100
C2
1µF
4.7µH
C8
1µF
C3
10µF
C1
1µF
Q1
EN
VDD
LX
RT9266
FB
GND
N MOS
C4
10µF
C6
C7
1µF 0.1µF
VOUT2
+18V
10mA
VOUT1
+9V
10mA
R1
620k
EXT
R2
100k
C5
10µF
VOUT3
-9V
10mA
Figure 4. RT9266 for Multi-Output Applications
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June 2013
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3
RT9266
Test Circuit
I (VIN)
L1
D1
10µH
+
A
VIN
C3
100µF
1N5819
VOUT
3.3V/5V
R1
1.6M/3M
VDD
EN
RT9266
LX
EXT
GND
FB
+
C2
1µF
A I (VDD)
C4
102
C1
100µF
C5
106
R2
980k/1M
Functional Pin Description
Pin No.
Pin Name
Pin Function
SOT-23-6
SOT-89-5
1
1
EN
Chip Enable (Active High).
2
--
EXT
Output Pin for Driving External N-MOSFET.
3
5
GND
Ground.
4
4
LX
Pin for Switching.
5
2
VDD
Input Positive Power Pin of RT9266.
6
3
FB
Feedback Input Pin.
Internal Reference Voltage for the Error Amplifier is 1.25V.
Function Block Diagram
EXT
RT9266
VDD
LX
-
FB
Loop Control Circuit
+
1.25V
Q1
N MOS
R1
VDD
R2
Shut Down
EN
Q2
N MOS
Over Temp.
Detector
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GND
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
Absolute Maximum Ratings
z
z
z
z
z
z
z
z
−0.3V to 7V
−0.3V to 7V
−0.3V to (VDD + 0.3V)
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, θJC ------------------------------------------------------------------------------------------------------SOT-89-5, θJC ------------------------------------------------------------------------------------------------------Operating Junction Temperature -------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------
2.5A
200mA
145°C/W
45°C/W
125°C
−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
z
z
(1)
−40°C to 125°C
−40°C to 85°C
Junction Temperature Range -------------------------------------------------------------------------------------Ambient Temperature Range --------------------------------------------------------------------------------------
Electrical Characteristics
(VIN = 1.5V, VDD set to 3.3V, Load Current = 0, TA = 25° C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Start-UP Voltage
VST
IL = 1mA
--
0.98
1.05
V
Operating VDD Range
VDD
VDD pin voltage
2
--
6
V
Shutdown Current I (VIN)
IOFF
EN Pin = 0V, VIN = 4.5V
--
0.01
1
μA
Switch-off Current I (VDD)
ISWITCH OFF VIN = 6V
--
17
25
μA
Continuous Switching Current
ISWITCH
0.4
0.55
0.7
mA
--
μA
VIN = EN = 3.3V, VFB = GND
(2)
No Load Current I (VIN)
INO LOAD
VIN = 1.5V, VOUT = 3.3V
--
Feedback Reference Voltage
VREF
Close Loop, VDD = 3.3V
1.225
1.25
1.275
V
Switching Frequency
FS
VDD = 3.3V
425
500
575
kHz
Maximum Duty
DMAX
VDD = 3.3V
85
95
--
%
VDD = 3.3V
--
0.3
1.1
Ω
LX ON Resistance
Current Limit Setting
75
(3)
VDD = 3.3V
1.6
2
EXT ON Resistance to VDD
VDD = 3.3V
--
5
8.5
Ω
EXT ON Resistance to GND
VDD = 3.3V
--
5
8.5
Ω
ILIMIT
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June 2013
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A
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5
RT9266
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
10
mV/V
--
mV/mA
Line Regulation
ΔVLINE
VIN = 3.5 ~ 6V, IL = 1mA
--
1.5
Load Regulation
ΔVLOAD
VIN = 2.5V, IL = 1 ~ 100mA
--
0.25
EN Pin Trip Level
VDD = 3.3V
(4)
0.4
0.8
1.2
V
Temperature Stability for VOUT
TS
--
50
--
ppm/°C
Thermal Shutdown Hysteresis
ΔTSD
--
10
--
°C
Note :
(1). The device is not guaranteed to function outside its operating conditions.
(2). No Load Current is highly dependent on practical system design and component selection that cannot be covered by
production testing. Typical No Load Current is verified by typical application circuit with recommended components. No
Load Current performance is guaranteed by Switch Off Current and Continuous Switching Current.
(3). Current Limit is guaranteed by design at TA = 25°C.
(4). Load Regulation is not tested at production due to practical instrument limitation. Load Regulation performance is
dominantly dependent on DC loop gain and LX ON Resistance that are guaranteed by “ Line Regulation” and “ LX ON
Resistance” tests in production.
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is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
Typical Operating Characteristics
(Refer to Test Circuit)
Efficiency vs. Output Current
Efficiency vs. Output Current
95
95
VOUT = 5V, TA = 25°C
VOUT = 3.3V, TA = 25°C
90
VIN = 4.5V
VIN = 4.0V
VIN = 3.5V
VIN = 3.0V
VIN = 2.5V
VIN = 2.0V
85
80
Efficiency (%)
Efficiency (%)
90
75
VIN = 3.0V
85
VIN = 2.5V
80
VIN = 2.0V
75
VIN = 1.5V
VIN = 1.5V
VIN = 1.0V
70
70
000
001
010
100
0.1
1000
1
1000
21
VIN = 3V, VOUT = 5V
VOUT = 5V @ no load
20
Input Current ( μ A)
200
Input Current ( μ A)
100
Input Current I(VDD) vs. Input Voltage
Input Current I(VDD) vs. Output Current
250
150
100
50
19
18
17
16
0
15
0.01
0.1
1
10
100
1000
2.5
3.0
3.5
Output Current (mA)
4.0
4.5
5.0
Input Voltage (V)
Supply Current I(VIN) vs. Input Voltage
Supply Current I(VIN) vs. Input Voltage
180
90
VOUT = 5V @ no load
VOUT = 3.3V @ no load
80
150
Supply Current ( μA)
Supply Current ( μA) 1
10
Output Current (mA)
Output Current (mA)
120
90
60
70
60
50
40
30
30
0
1.5
2.0
2.5
3.0
3.5
4.0
Input Voltage (V)
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
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June 2013
4.5
1.5
2
2.5
3
3.5
Input Voltage (V)
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RT9266
Switching
SwichtingFrequency
Frequencyvs.
vs. VDD
VDD Pin
PinVoltage
Voltage
Start Up Voltage vs. Output Current
1.6
VOUT = 3.3V
VIN = 2.4V to 2.8V
1.4
VIN = 3V to 5.6V
500
Start Up Voltage (V)
Switching
Rate
Frequency
(KHz).
Switching
Frequency
(kHz)
600
400
300
VIN = 1.2V to 2.2V
1.2
1.0
0.8
0.6
0.4
200
0.2
(In C.R. mode)
100
0.0
0
1
2
3
4
5
6
0
30
60
90
120
150
180
VDD Pin Voltage (V)
Output Current (mA)
LX & Output Ripple
LX & Output Ripple
VIN = 1V, VOUT = 3.3V @ 10mA
VIN = 1V, VOUT = 3.3V @ 100mA
Output Ripple
Output Ripple
LX
LX
210
Time (1µs/Div)
Time (1µs/Div)
LX & Output Ripple
LX & Output Ripple
LX
Time (1µs/Div)
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VIN = 2V, VOUT = 3.3V @ 10mA
Output Ripple
Output Ripple
LX
VIN = 2V, VOUT = 3.3V @ 200mA
Time (1µs/Div)
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
LX & Output Ripple
LX & Output Ripple
VIN = 3V, VOUT = 3.3V @ 10mA
Output Ripple
Output Ripple
LX
LX
VIN = 3V, VOUT = 3.3V @ 200mA
Time (1µs/Div)
Time (1µs/Div)
LX & Output Ripple
LX & Output Ripple
LX
VIN = 2V, VOUT = 5V @ 20mA
Output Ripple
Output Ripple
LX
VIN = 2V, VOUT = 5V @ 200mA
Time (1µs/Div)
Time (1µs/Div)
LX & Output Ripple
LX & Output Ripple
LX
Time (1µs/Div)
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS9266-16
VIN = 3V, VOUT = 5V @ 20mA
Output Ripple
Output Ripple
LX
VIN = 3V, VOUT = 5V @ 200mA
June 2013
Time (1µs/Div)
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9
RT9266
LX & Output Ripple
LX & Output Ripple
LX
VIN = 4.5V, VOUT = 5V @ 20mA
Output Ripple
Output Ripple
LX
VIN = 4.5V, VOUT = 5V @ 200mA
Time (1µs/Div)
Time (1µs/Div)
Transient Response
VIN = 3V, VOUT = 3.3V
IOUT = 10mA
IOUT = 10mA
200mA
Output Transient Voltage
VIN = 2V, VOUT = 3.3V
Output Transient Voltage
200mA
Time (50µs/Div)
Time (50µs/Div)
Transient Response
Transient Response
VIN = 3V, VOUT = 5V
VIN = 4.5V, VOUT = 5V
IOUT = 10mA
IOUT = 10mA
200mA
Time (50µs/Div)
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Output Transient Voltage
Output Transient Voltage
Transient Response
200mA
Time (50µs/Div)
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
Output Voltage vs. Temperature
Output Voltage vs. Temperature
5
3.34
VIN = 3V, VOUT = 5V, IOUT = 100mA
VIN = 1.8V, VOUT = 3.3V, IOUT = 100mA
4.98
Output Voltage(V)
Output Voltage(V)
3.32
3.3
3.28
3.26
3.24
3.22
4.94
4.92
4.9
4.88
4.86
4.84
3.2
-40
-10
20
50
80
110
Temperature (°C)
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DS9266-16
4.96
June 2013
140
-40
-10
20
50
80
110
140
Temperature (°C)
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11
RT9266
Application Information
Output Voltage Setting
Layout Guide
Referring to Typical Application Circuits, the output voltage
of the switching regulator (VOUT) can be set with Equation
(1).
VOUT = ( 1+
R1
R2
) × 1.25V
(1)
Feedback Loop Design
Referring to Typical Application Circuits. The selection of
R1 and R2 based on the trade-off between quiescent
current consumption and interference immunity is stated
below:
z
Follow Equation (1)
z
Higher R reduces the quiescent current (Path current =
1.25V/R2), however resistors beyond 5MΩ are not
recommended.
z
Lower R gives better noise immunity, and is less sensitive
to interference, layout parasitics, FB node leakage, and
improper probing to FB pins.
z
z
z
A full GND plane without gap break.
VDD to GND noise bypass − Short and wide connection
for the 1μF MLCC capacitor between Pin5 and Pin3.
VIN to GND noise bypass − Add a capacitor close to L1
inductor, when VIN is not an idea voltage source.
z
Minimized FB node copper area and keep far away from
noise sources.
z
Minimized parasitic capacitance connecting to LX and
EXT nodes, which may cause additional switching loss.
Board Layout Example (2-Layer Board)
(Refer to Typical Application Circuits Figure 2 for the board)
VOUT
Prober Parasitics
R1
FB Pin
_
Q
+
z
R2
- Top Layer -
A proper value of feed forward capacitor parallel with R1
can improve the noise immunity of the feedback loops,
especially in an improper layout. An empirical suggestion
is around 0~33pF for feedback resistors of MΩ, and
10nF~0.1μF for feedback resistors of tens to hundreds
kΩ.
For applications without standby or suspend modes, lower
values of R1 and R2 are preferred. For applications
concerning the current consumption in standby or suspend
modes, the higher values of R1 and R2 are needed. Such
“ high impedance feedback loops” are sensitive to any
interference, which require careful layout and avoid any
interference, e.g. probing to FB pin.
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- Bottom Layer -
is a registered trademark of Richtek Technology Corporation.
DS9266-16
June 2013
RT9266
Outline Dimension
H
D
L
C
B
b
A
A1
e
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
0.889
1.295
0.031
0.051
A1
0.000
0.152
0.000
0.006
B
1.397
1.803
0.055
0.071
b
0.250
0.560
0.010
0.022
C
2.591
2.997
0.102
0.118
D
2.692
3.099
0.106
0.122
e
0.838
1.041
0.033
0.041
H
0.080
0.254
0.003
0.010
L
0.300
0.610
0.012
0.024
SOT-23-6 Surface Mount Package
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is a registered trademark of Richtek Technology Corporation.
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RT9266
D
D1
b1
A
C
B
C1
e
e
H
A
b
b1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
1.397
1.600
0.055
0.063
b
0.356
0.508
0.014
0.020
B
2.388
2.591
0.094
0.102
b1
0.406
0.533
0.016
0.021
C
3.937
4.242
0.155
0.167
C1
0.787
1.194
0.031
0.047
D
4.394
4.597
0.173
0.181
D1
1.397
1.702
0.055
0.067
e
1.397
1.600
0.055
0.063
H
0.356
0.432
0.014
0.017
5-Lead SOT-89 Surface Mount Package
Richtek Technology Corporation
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
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DS9266-16
June 2013