®
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.
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DS9266-16
June 2013
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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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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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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.
DS9266-16
June 2013
4.5
1.5
2
2.5
3
3.5
Input Voltage (V) is a registered trademark of Richtek Technology Corporation.
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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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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)
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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)
Copyright © 2013 Richtek Technology Corporation. All rights reserved.
DS9266-16
4.96
June 2013
140
-40
-10
20
50
80
110
140
Temperature (°C)
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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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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
