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 17µA low quiescent current together with high effic-
iency 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
◆
17µA 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
P1 / 5
Rev. C, Sep 2005
IPCore
■
Function Block Diagram
ML9266
■
Marking Information
①
②
③④
Symbol Descripation
Step-up DC-DC Converter
9
ML9266
1
Control Code
■
Test Circuit
I(V )
Vin
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
A
n
I(V )
DD
CE
EXT
A
VDD
R2
980K/1M
SOT-26
SOT-89-5
P2 / 5
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
½
7V
- 0.3
½
(VDD + 0.8V)
V
LX
- 0.3V
½
(VDD + 0.3V)
Vss
2.5
I
LX
200
I
EXT
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 (V
IN
)
Switch-off Current I (VDD)
Shutdown 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
CE Pin Trip Level
Temperature Stability for Vout
Thermal Shutdown
Thermal Shutdown Hysterises
Symbol
V
ST
V
DD
I
NO LOAD
I
SWITCH OFF
I
OFF
V
REF
F
S
D
MAX
I
LIMIT
Test Conditions
I
L
= 1mA
VDD pin voltage
V
IN
= 1.5V, V
OUT
= 3.3V
V
IN
= 6V
CE Pin = 0V, V
IN
= 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
V
IN
= 1.5 ~ 2.5V, I
L
= 1mA
V
IN
= 2.5V, I
L
= 1 ~ 100mA
VDD = 3.3V
T
S
T
SD
△T
SD
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
µA
µA
µA
V
KHz
%
A
△V
LINE
△V
LOAD
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.
P3 / 5
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 (V
OUT
) can be set
V
OUT1
= (1 +
R1
R2
) × 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
½
Vin=2.8
½
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~0.1µF 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
P4 / 5
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
P5 / 5
Rev. C, Sep 2005
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