MIC2141
Micropower Boost Converter
General Description
Features
The MIC2141 is a micropower boost switching regulator
•
Implements low-power boost, SEPIC, or flyback
that can operate from 3- or 4-cell nickel-metal-hydride
•
2.2V to 14V input voltage
batteries or a single Li-ion cell. This regulator employs a
•
330kHz switching frequency
constant 330kHz, fixed 18% duty-cycle, gated-oscillator
•
<2µA shutdown current
architecture.
•
70µA quiescent current
The MIC2141 can be used in applications where the
•
1.24V bandgap reference
output voltage must be dynamically adjusted. The device
features a control signal input which is used to
•
Typical output current 1mA to 10mA
proportionally adjust the output voltage. The control signal
•
SOT23-5 package
input has a gain of 6, allowing a 0.8V to 3.6V control signal
to vary a 4.8V to 22V output.
Applications
The MIC2141 requires only three external components to
operate and is available in a tiny 5-pin SOT-23 package for
•
LCD bias supply
space and power-sensitive portable applications. The
•
CCD digital camera supply
MIC2141 draws only 70µA of quiescent current and can
operate with an efficiency exceeding 85%.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
___________________________________________________________________________________________________________
Typical Application
10µH
V
C
*
(from DAC)
MIC2141
1
2
3
4
5
Variable
V
OUT
Control Voltage
vs. Output Voltage
4.0
3.5
3.0
V
C
(V)
2.5
2.0
1.5
1.0
0.5
0
0
5
10
15
V
OUT
(V)
20
25
10µF
DAC-Controlled LCD Bias Voltage Supply
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
December 2006
1
M9999-122006
Micrel, Inc.
MIC2141
Ordering Information
Part Number
Standard
MIC2141BM5
Marking*
Standard
SAAA
Pb-Free
MIC2141YM5
Pb-Free
SAAA
Voltage
Adj.
Ambient
Temperature Range
–40° to +85°C
Package
5-Pin SOT23
* Under bar symbol (_) may not be to scale.
Pin Configuration
5-Pin SOT23 (BM5)
5-Pin SOT23 (YM5)
Pin Description
Pin Number
1
2
3
4
5
Pin Name
IN
GND
SW
FB
VC
Pin Function
Input: +2.5V to +14V supply for internal circuity.
Ground: Return for internal circuitry and internal MOSFET (switch) source.
Switch Node (Input): Internal MOSFET drain; 22V maximum.
Feedback (Input): Output voltage sense node. Compared to VC control input
voltage.
Control (Input): Output voltage control signal input. Input voltage of 0.8V to3.6V
is proportional to 4.8V to 22V output voltage (gain of 6). If the pin is not
connected, the output voltage will be V
IN
– 0.5V.
December 2006
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M9999-122006
Micrel, Inc.
MIC2141
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .......................................................18V
Switch Voltage (V
SW
)......................................................24V
Feedback Voltage (V
FB
) .................................................24V
Control Input Voltage (V
C
)
(3)
............ V
IN
– 200mV
≤
V
C
≤
4V
ESD Rating
(4)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
).......................................... 2.5V to 14V
Switch Voltage (V
SW
)............................................ 3V to 22V
Ambient Temperature (T
A
) .......................... –40°C to +85°C
Junction Temperature Range (T
J
)............. –40°C to +125°C
Package Thermal Impedance
SOT23-5 (θ
JA
) ..................................................220°C/W
Electrical Characteristics
V
IN
= 3.6V; V
OUT
= 5V; I
OUT
= 1mA; T
J
= 25°C,
bold
values indicate –40°C< T
A
< +85°C, unless noted.
Parameter
Input Voltage
Quiescent Current
Comparator Hysteresis
Control Voltage Gain (V
OUT
/V
C
)
Controlled Output Voltage,
Note 3
2.5V
≤
V
IN
≤
12V, V
OUT
= 15V
V
C
= 0.8V; 2.5V
≤
V
IN
≤
4.2V
V
C
= 2.5V; 2.7V
≤
V
IN
≤
12V
V
C
= 3.4V; 3.6V
≤
V
IN
≤
12V
Load Regulation
Line Regulation
Switch on Resistance
Oscillator Frequency
Oscillator Duty Cycle
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating
3. V
C
= 4V sets V
OUT
to 24V (absolute maximum level on V
SW
); V
C
must be
≤
V
IN
– 200mV.
4. Devices are ESD sensitive. Handling precautions recommended.
Condition
Switch off, V
IN
= 3.6V
Min
2.5
Typ
70
10
6
Max
14
100
Units
V
µA
mV
4.85
14.55
19.4
5
15
20
0.25
0.05
4
2.5
5.15
15.45
20.6
1
0.2
V
V
V
%
%/V
Ω
Ω
100µA
≤
I
OUT
≤
1mA, V
OUT
= 15V
2.5V
≤
V
IN
≤
12V; I
OUT
≤
1mA
I
SW
= 100mA, V
IN
= 3.6V
I
SW
= 100mA, V
IN
= 12V
300
15
330
18
360
kHz
%
December 2006
3
M9999-122006
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