MST9220B
Milestone Semiconductor Inc.
1.2MHz, 2A Output Current, Boost Converter
General Description
Features
The MST9220B is a high efficiency current-mode boost
converter with a fixed operation frequency. The MST9220B has
been integrated a very low Rds -on NMOSFET to reduce power
loss and achieve high efficiency. The maximum efficiency is up
to 93%. The output Voltage can be programmed by feedback
resistances, and the maximum output voltage is 10V. MST9220B
can output 2A current when VIN is higher than 3.3V and output is
5V. 1.2 MH z operation frequency minimizes L and C value, and
internal compensation network reduces external component
counts. SOT23-6 package provides the best solution for PCB.
layout area.
·Wide Input Range: 2.5-6V Input,·
·MST9220B Up To 2A Output Current
·1.2MHz Switching Frequency
·Low RDS(ON): 70
mΩ
·Up to 93% Efficiency
. Over Voltage Protection
·Under-Voltage Lockout Protection
·Over-Temperature Protection
·Internal Soft Start
·1uA Shutdown Current
·Accurate Reference: 0.6V VREF
·Compact package: SOT23-6
Pin Configuration
Applications
SW
GND
FB
1
TOP VIEW
6
NC
VIN
EN
2
5
3
4
SOT23-6
Pin Descriptions
Pin Name
1
2
3
Symbol
SW
GND
FB
Pin Function
Power switch output. Connect the inductor and the
blocking Schottky diode to SW.
GND
Feedback
Enable pin. A high input at EN enables the device
and a low input disables the devices. When not
used, connect EN to the input source for
automatic startup.
Input supply pin. Must be locally bypassed.
No Internal Connection
4
5
6
EN
VIN
NC
Page1-8
Rev. 1.3 Nov.14, 2013
A fabless company serves market with technology innovation
MST9220B
Milestone Semiconductor Inc.
1.2MHz, 2A Output Current, Boost Converter
Block Diagram
VIN
SW
UVLO
OTP
Internal
Compensation
Internal
Soft Start
Logic
Control
+
PWM
-
Currnet Sense
Slope
Compensation
EN
EN
Logic
+ -
Vref2
Vref
EA
Driver
-
+
GND
FB
MST9220B
Absolute Maximum Ratings
SYMBOL
V
IN
V
SW
V
IO
P
TR1
T
stg
T
solder
NAME
Input Voltage
Voltage at SW Pin
All Other I/O Pins
Thermal Resistance(SOT23-6)
Θ
JA
Storage Temperature
Package Lead Soldering Temperature
VALUE
-0.3½6.5
-0.5½12
GND-0.3 to VDD+0.3
220
-55 to 150
260℃, 10s
2
UNIT
V
V
V
℃/W
℃
kV
ESD Susceptibility
HBM(Human Body Mode)
Note1: Exceeding these ratings may damage the device.
Recommended Operating Conditions(Note 2)
SYMBOL
V
IN
V
SW
T
OTP
NAME
VIN Supply Voltage
Output Voltage
Operating Temperature
VALUE
2.5 to +6
V
IN
to 10
-40 to +85
UNIT
V
V
℃
Note2: The device is not guaranteed to function outside of its operating rating.
Page2-8
Rev. 1.3 Nov.14, 2013
A fabless company serves market with technology innovation
MST9220B
Milestone Semiconductor Inc.
1.2MHz, 2A Output Current, Boost Converter
Electrical Characteristics
(VIN = 3.3V, VOUT=5V, IOUT=100mA, TA = 25° unless otherwise specified)
C
SYMBOL
ITEMS
V
IN
Input Voltage
Feedback
V
FB
Feedback Voltage
I
bias
FB Pin Input Bias Current
UVLO
UVLO
Under Voltage Lock Out
Operating Current
I
of f
I
sby
F
sw
D
max
Chip Enable
V
EN_H
V
EN_L
V
HY S
I
EN
OTP
OTP
Operating Current（Shutdown）
No Switching
Switching Frequency
Maximum Duty Cycle
EN Minimum High Level
EN Maximum Low Level
EN Hysteresis
EN Input Bias Current
Vin=3V VFB=0.7V
V
FB
=0V
1.5
0.4
90
1
160
20
SW On Resistance (Note 3)
MST9220B
V
sw
＝5V
V
OUT
Soft Start
V
IN
Power On
70
4.5
0.01
V
OUT
112%
400
CONDITIONS
Min.
2.5
588
Typ.
Max.
6
612
1
UNIT
V
mV
µ
A
V
1
µ
A
µ
A
MHz
%
V
V
mV
µ
A
O
O
600
0.05
2.1
0.1
100
1.2
90
OTP Hystersis
Output Switch
R
ON
C
C
I
LEAK
SW Leakage Current
Open Circuit Protection
MST9220B
t
ss
Soft Start Time (Note 3)
1
mΩ
A
µ
A
V
µ
S
Note3: Guaranteed by design.
Typical Performance Characteristics
Current Load Vs Efficiency
94
Current Load Vs Efficiency
93
92
92
91
Efficiency / %
90
Efficiency / %
90
89
88
87
86
85
88
86
Vin=3.6V,Vout=5V
84
Vin=3.6V,Vout=5V
0
0.5
1
1.5
2
2.5
82
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
I Load / A
I Load / A
Fig 1 Efficiency Vs Light Load
Fig 2 Efficiency Vs Heavy Load
Page3-8
Rev. 1.3 Nov.14, 2013
A fabless company serves market with technology innovation
MST9220B
Milestone Semiconductor Inc.
1.2MHz, 2A Output Current, Boost Converter
Fig 3 Startup with V
in
Fig 4 SW Waveform
Fig 5 Transient Response
(V
IN
=3.6V, Vout=5V, I
load
=0.15A to 0.9A)
Fig 6 Transient Response
(V
IN
=3.6V, Vout=5V, I
load
=0.9A to 0.15A)
I Quiescent Vs Temperature
110
105
Current /uA
100
95
90
85
80
-40
-20
0
20
40
60
80
100
Temperature / oC
Fig 7 Vout Ripple
Fig 8
Quiescent Current Vs Temperature
Typical Application Circuit
VIN
L1
2.2uH
Schottky
C
FB
22pF
R1
440K
EN
GND
FB
VOUT
C
IN
22uF
OFF/ON
IN
SW
C
OUT1
22uF2
C
OUT2
100 nF
R2
60K
Typical application
Page4-8
Rev. 1.3 Nov.14, 2013
A fabless company serves market with technology innovation
MST9220B
Milestone Semiconductor Inc.
1.2MHz, 2A Output Current, Boost Converter
Operation Description
The MST9220B adopts fixed frequency, peak current mode boost regulator architecture to regulate output voltage. The
operating principle of the MST9220B can be easily understood by referring to the functional block diagram. At the
beginning of each oscillator cycle the MOSFET is turned on by the control circuit. To prevent sub-harmonic oscillations at
duty cycle larger than 50 percent, a stabilizing ramp is added to the output of the current sense amplifier and the result is
fed into the negative input of the PWM comparator. When this voltage equals the output voltage of the error amplifier, the
power MOSFET is turned off. The voltage at the output of the error amplifier is an amplified result of the difference
between the 0.6V reference voltage and the feedback voltage. In this way the peak current level keeps the output voltage
in regulation. If the feedback voltage starts to drop, the output of the error amplifier increases, resulting in more current to
flow through the power MOSFET, thus increasing the power delivered to the output. The MST9220B has internal soft
start to avoid rush input current during the startup and also to avoid overshoot on the output.
Application Information
Because of the high integration in the MST9220B, the application circuit based on this regulator IC is rather simple. Only
input capacitor C
IN
, output capacitor C
OUT1
and C
OUT2
, inductor L, schottky diode and feedback resistors (R1 and R2) need
to be selected for the targeted applications.
Feedback Resistor Divider R1 and R2:
Choose R1 and R2 to program the proper output voltage. To minimize the power consumption under light loads, it is
desirable to choose large resistance values for both R1 and R2. A value of between 30K
Ω
and 500K
Ω
is recommended for
both resistors. If R1=440K
Ω
is chosen and VOUT is 5V then R2 can be calculated to be 60K
Ω based on the followin g
,
equation
:
R2 = (R1×0.6V)/(VOUT - 0.6V)
Feedback Capacitor C
FB
:
In order to enhance response speed of the convertor, feedback capacitor C
FB
should be added to the loop. Its value should
not be less than 22pF.
Input Capacitor C
IN
:
To minimize the potential noise problem, place a typical X5R or better grade ceramic capacitor really close to the IN and
GND pins. Care should be taken to minimize the loop area formed by CIN, and IN/GND pins. In this case a 10uF low
ESR ceramic is recommended.
Output Capacitor C
OUT1
And C
OUT2
:
The output capacitor is selected to meet the output ripple noise requirements. Both steady state ripple and transient
requirements must be taken into consideration when selecting this capacitor. For the best performance, it is recommended
C
OUT1
should be X5R or better grade ceramic capacitor with 10V rating and more than two pieces of 22uF Capacitor. Only
when C
OUT1
is big enough, it can absorb the energy of inductor
and prevent the voltage of output up to too high when
current load suddenly be shut. It is recommended C
OUT2
is 100nF. It can also reduce the ripple of output voltage.
Page5-8
Rev. 1.3 Nov.14, 2013
A fabless company serves market with technology innovation
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