MIC2142
Micropower Boost Converter
General Description
Features
The MIC2142 is a micropower boost switching regulator
•
2.2V to 16V input voltage
housed in a SOT23-5 package. The input voltage range is
•
Up to 22V output voltage
between 2.2V to 16V, making the device suitable for one-
•
330kHz switching frequency
cell Li Ion and 3 to 4-cell alkaline/NiCad/NiMH applica-
•
0.1µA shutdown current
tions. The output voltage of the MIC2142 can be adjusted
•
85µA quiescent current
up to 22V.
•
Implements low-power boost, SEPIC, or
flyback
The MIC2142 is well suited for portable, space-sensitive
applications. It features a low quiescent current of 85µA,
•
SOT23-5 package
and a typical shutdown current of 0.1µA. It’s 330kHz
operation allows small surface mount external components
Applications
to be used. The MIC2142 is capable of efficiencies over
85% in a small board area.
•
LCD bias supply
The MIC2142 can be configured to efficiently power a
•
White LED driver
variety of loads. It is capable of providing a few mA output
•
12V Flash memory supply
for supplying low power bias voltages; it is also capable of
•
Local 3V to 5V conversion
providing the 80mA needed to drive 4 white LEDs.
The MIC2142 is available in a SOT23-5 package with an
ambient operating temperature range from –40°C to
+85°C.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
___________________________________________________________________________________________________________
Typical Application
2.8V to 4.7V
V
IN
L1
33µH
MIC2142
VCC SW
FB
5
D1
+5V @60mA
EFFICIENCY (%)
1
3
C
IN
10µF
R2
365k
R1
124k
C
OUT
22µF
4
2
EN GND
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0
Efficiency
vs. Output Current
V
IN
= 4.2V
V
IN
= 3.0V
10 20 30 40 50 60 70
OUTPUT CURRENT (mA)
Typical Configuration
Efficiency vs. Output Current
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2007
M9999-102507
Micrel, Inc.
MIC2142
Ordering Information
Part Number
Standard
MIC2142BM5
Pb-Free
MIC2142YM5
Marking*
Standard
SBAA
Pb-Free
SBAA
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
VCC
GND
SW
FB
EN
Pin Function
Chip Supply: +2.2V to +16V.
Ground: Return for internal circuitry and internal MOSFET (switch) source.
Switch Node (Input): Internal MOSFET drain; 22V maximum.
Feedback (Input): Output voltage sense node.
Shutdown: Device shuts down to 0.1µA typical supply current.
October 2007
2
M9999-102507
Micrel, Inc.
MIC2142
Absolute Maximum Ratings
(1)
Supply Voltage (V
CC
)......................................................18V
Switch Voltage (V
SW
)......................................................24V
Enable Pin Voltage (V
EN
)
(3)
.............................................18V
Feedback Voltage (V
FB
)
Adjustable Version.....................................................8V
Ambient Storage Temperature (T
s
) ...........–65°C to +150°C
ESD Rating
(4)
Operating Ratings
(2)
Supply Voltage (V
CC
)......................................... 2.2V to 16V
Enable Pin Voltage (V
EN
)
(3)
................................... 0V to 16V
Switch Voltage (V
SW
)......................................................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
CC
= 3.6V; V
OUT
= 5V; I
OUT
= 200mA; T
A
= 25°C,
bold
values indicate –40°C< T
J
< +125°C, unless noted.
Parameter
Input Voltage
Quiescent Current
V
EN
= ON , V
FB
= 2.2V (adjustable)
V
EN
= ON , V
OUT(NOMINAL)
+ 1V (MIC2142-5.0)
V
EN
= OFF (shutdown)
Feedback Voltage (VFB)
Comparator Hysteresis
Feedback Input Bias Current,
Note 5
Enable Input Voltage
Enable Input Current
Load Regulation
Line Regulation
SW on Resistance
Switch Leakage Current
Oscillator Frequency
Duty Cycle
Notes:
1. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating
the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(Max)
, the
junction-to-ambient thermal resistance,
θ
JA
, and the ambient temperature, T
A
. The maximum allowable power dissipation will result in excessive die
temperature, and the regulator will go into thermal shutdown. The
θ
JA
of the power SOT23-5 is 220°C/W mounted on a PC board.
2. The device is not guaranteed to function outside its operating rating.
3. V
EN
must be
≤
V
IN
.
4. Devices are ESD sensitive. Handling precautions recommended.
5. The maximum suggested value of the programming resistor, whose series resistance is measured from feedback to ground, is 124kΩ. Use of larger
resistor values can cause errors in the output voltage due to the feedback input bias current.
Condition
Min
2.2
Typ
85
85
0.1
Max
16
125
125
2
1.306
1.312
Units
V
µA
µA
µA
V
V
mV
nA
µA
V
(±2%)
(±3%)
adjustable
fixed
V
IH
(turn on)
V
IL
(turn off)
1.254
1.241
1.28
18
30
20
0.6V
CC
–1
0.55V
CC
1.1
0.01
0.2
0.25
0.25
5
0.05
1
365
65
0.8
1
V
µA
%V
OUT
%/V
%/V
Ω
µA
kHz
%
200µA
≤
I
OUT
≤
20mA
2.2V
≤
V
CC
≤
16V; I
OUT
= 4mA (adjustable)
2.2V
≤
V
CC
≤
4.5V; I
OUT
= 4mA (MIC2142-5.0)
I
SW
= 100mA, V
CC
= 2.5V
V
EN
= OFF, V
SW
= 12V
295
50
330
57
October 2007
3
M9999-102507
Micrel, Inc.
MIC2142
Typical Characteristics
350
QUIESCENT CURENT (
µ
A)
300
250
200
150
100
50
0
0
2
4 6 8 10 12 14 16
INPUT VOLTAGE (V)
Quiescent Current
vs. Input Voltage
OUTPUT VOLTAGE (V)
V
OUT
= 5V
16.5
16
15.5
15
14.5
14
2
Line Regulation
I
L
= 7mA
L = 22 H
I
L
= 2mA
L = 220µH
4
6
8
10 12
INPUT VOLTAGE (V)
14
1200
OUTPUT RIPPLE (mV)
1000
800
600
400
200
0
0
2
Output Ripple
vs. Input Voltage
OUTPUT VOLTAGE (V)
I
L
= 7mA
L = 22 H
16
14
12
10
6
4
2
0
0
MIC2142 Load
Regulation
V
OUT
V
OUT
= 15V
I
L
= 2mA
L = 220µH
L = 22µH
8 V
IN
= 5V
V
REF
5
10 15 20 25 30
OUTPUT CURRENT (mA)
4
6 8 10 12 14
INPUT VOLTAGE (V)
350
300
FREQUENCY (kHz)
250
200
150
Oscillator Characteristics
vs. Input Voltage
Frequency
0.65
QUIESCENT CURRENT (
µ
A)
0.60
0.55
DUTY CYCLE
84
82
80
78
76
74
72
Quiescent Current
vs. Temperature
Duty Cycle
0.50
100 V = 15V
O
0.45
50 I
O
= 100µA
L= 220µH
0
0.40
0
2
4 6 8 10 12 14
INPUT VOLTAGE (V)
V
IN
= 3.6V
70
-50 -30 -10 10 30 50 70 90 110
TEMPERATURE
°C)
(
335
FREQUENCY (kHz)
330
325
320
315
310
305
300
295
-50 -30 -10 10 30 50 70 90 110
TEMPERATURE
°C)
(
OSCILLATOR CHARACTERISTICS
340
Frequency vs.
Temperature
3.5
Timing Characteristics
Over Temperature
3.0 T (µsec)
2.5
2.0
1.5 t
1.0
0.5
Duty Cycle
0
-50 -30 -10 10 30 50 70 90 110
TEMPERATURE
°C)
(
ON
(µsec)
October 2007
4
M9999-102507
Micrel, Inc.
MIC2142
Typical Characteristics (cont.)
7
6
5
R
DS(O N)
(Ω)
4
3
2
1
0
-50 -30 -10 10 30 50 70 90 110
TEMPERATURE
°C)
(
V
CC
= 4.5V
R
DS(ON)
vs.
Temperature
V
CC
=3.3V
DUTY CYCLE (%)
0.6
0.58
0.56
0.54
0.52
0.5
0.48
0.46
0.44
0.42
0.4
-50 -30 -10 10 30 50 70 90 110
TEMPERATURE
°C)
(
Timing Characteristics
Over Temperature
October 2007
5
M9999-102507
嵌入式系统
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