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ML9266
Step-up DC/DC converter
General Description
The ML9266 is a small, 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 ML9266 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 17A low quiescent current together with high efficiency maintains long battery lifetime. The ML9266 is available in small package SOT-26 and SOT89-5
Features
90% Efficiency High Supply Capability to Deliver 3.3V 100mA with 1 Alkaline cell 17A Quiescent (switch-off) Supply Current 450KHz Fixed Switching Frequency Zero Shutdown Mode Supply Current Providing Flexibility for Using Internal and External Power Switches 1.0V Low Start-up Input Voltage Small SOT-26 & SOT89-5 Package
Ordering Information
Item ML9266MRG ML9266PRG Package SOT-26 SOT-89-5 Shipping 3000pcs/Reel&Tape 1000pcs/Reel&Tape
Applications Package Information
LCD Panel DSC MP3 Wireless Equipment Portable Instrument PDA
Typical Application Circuit
L1 Vin + C3 100uF C2 1uF VDD CE EXT ML9266 GND LX FB R2 980k/1M 3.3~10uH 1N5819 D1
SOT89-5 Pin Configurations
SOT-26 1 2 3 4 5 6
SOT-23-6
R1 1.6M/3M +
Vout 3.3V/5V
C1 100uF
SOT-89-5 Pin NamePin Function 1 CE Chip enable EXT Output 5 GND Ground 4 LX Switching 2 VDD Input 3 FB Feedback input 1.25V
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Rev. C, Sep 2005
IPCore
Function Block Diagram
ML9266
Marking Information
Symbol Descripation Step-up DC-DC Converter 9 ML9266 1 Control Code
Test Circuit
I(V ) Vin
n A i
L1 10uH + C3 100uF R3 100 C2 1uF LX ML9266 FB GND
D1 1N5819 Vout 3.3V/5V + C4 R1 C1 1.6M/3M 102uF 100uF C5 106uF
I(V ) DD CE EXT
A
VDD
R2 980K/1M
SOT-26
SOT-89-5
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Rev. C, Sep 2005
IPCore
Absolute Maximum Ratings (Ta=25
Paramenter Supply Voltage LX Pin Switch Voltage Other I/O Pin Voltages Lx Pin Switch Current EXT Pin Driver Current Package Thermal Resistance Operating Junction Temperature Storage Temperature Range Symbol Ratings Vin - 0.3V 7V - 0.3 (VDD + 0.8V) VLX - 0.3V (VDD + 0.3V) Vss 2.5 ILX 200 IEXT Pd 145 45 Tj 125 - 65 ~ +150 Tstg Unit V V V A mA /W /W
ML9266
SOT-26 SOT-89-5
Electrical Characteristics (Vin =1.5V, VDD=3.3V, I=0, Ta = 25, unless otherwise specified)
Parameter Start-UP Voltage Operating VDD Range No Load Current I (VIN) Switch-off Current I (VDD) Shutdown Current I (VIN) 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 CE Pin Trip Level Temperature Stability for Vout Thermal Shutdown Thermal Shutdown Hysterises Symbol VST VDD INO LOAD ISWITCH OFF IOFF VREF FS DMAX ILIMIT Test Conditions IL = 1mA VDD pin voltage VIN = 1.5V, VOUT = 3.3V VIN = 6V CE Pin = 0V, VIN = 4.5V Close Loop, VDD = 3.3V VDD = 3.3V VDD = 3.3V VDD = 3.3V VDD = 3.3V VDD = 3.3V VDD = 3.3V VIN = 1.5 ~ 2.5V, IL = 1mA VIN = 2.5V, IL = 1 ~ 100mA VDD = 3.3V TS TSD TSD Min -2 ---1.225 --------0.4 ---Typ 0.98 -75 17 0.01 1.25 450 95 0.3 2 5 5 10 0.25 0.8 50 165 10 Max 1.05 6.5 --1 1.275 --------1.2 ---Units V V A A A V KHz % A
VLINE VLOAD
mV/V mV/mA V ppm/
* Note: The CE pin shall be tied to VDD pin and inhibit to act the ON/OFF state whenever the VDD pin voltage may reach to 5.5V or above.
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Rev. C, Sep 2005
IPCore
Applications
High Current Application
L1 3.3--10uH + C5 100uF C2 1uF VDD CE ML9266 GND EXT LX FB R2 980k/1M Vout 3.3V/5V
ML9266
Application Note
Output Voltage Setting Referring to application circuits, the output voltage of the switching regulator (VOUT) can be set VOUT1 = (1 + R1 R2 ) x 1.25V A
Vin
D1 1N5819
R1 1.6M/3M Q1 NMOS + C1 100uF
Feedback Loop Design Referring to application circuits, The selection of R1and R2 based on the trade-off between quiescent current consumption and interference immunity is stated below: Follow Equation A Higher R reduces the quiescent current (Path current =1.25V/R2), however resistors beyond 5M are not recommended. Lower R gives better noise immunity, and is less sensitive to interference, layout parasitics, FB node leakage, and improper probing to FB pins.
High Voltage Application
Vin=3.1V 5V Vout=12V Vin=2.8 5V Vout= V 9 V + C4 100uF
L1
D1 1N5819
C1=100uF C2=1uF C3=0.1uF R1=860K/620K R2=100K RM=0.22 CVDD=1uF 12V / 9V 300mA R1 + C1
4.7uH RVDD 100 CVDD
VDD CE
EXT
Q1 NMOS C3 RM R2
ML9266 LX
FB GND C2
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 M , and 10nF~0.1F for feedback resistors of tens to hundreds K . 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 R1and R2 are feedback needed. Such "high impedance loops" are sensitive to any interference, which require careful layout and avoid any interference, e.g. probing to FB pin.
Multi-Output Applications
R1=620K R2=100 C6=0.1uF D1 Vin 3.3V/5V R3 100 C1 1uF L1 3.3--10uH C2 10uF Q1 NMOS C7 1uF VDD CE ML9266 GND EXT LX FB R2 C6 R1 C5 10uF 1N5819 Vout2 +18V 10mA C8 1uF C3 10uF Vout1 +9V 100mA
C4 10uF
Vout3 -9V 10mA
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Rev. C, Sep 2005
IPCore
Package Dimensions
SOT-89-5 Units: mm Min Max 1.400 1.600 0.360 0.520 2.400 2.600 0.406 0.533 -4.250 0.800 -4.400 4.600 -1.700 1.400 1.600 0.380 0.430
ML9266
Symbol A b B b1 C C1 D D1 e H
SOT-26 Symbol A A1 B b C D e H L Units: mm Min Max 0.889 1.295 -0.152 1.397 1.803 0.356 0.559 2.591 2.997 2.692 3.099 0.838 1.041 0.102 0.254 0.356 0.610
DISCLAIMER: The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any
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Rev. C, Sep 2005

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