MIC2288
Micrel, Inc.
MIC2288
1A 1.2MHz
PWM Boost Converter in
Thin SOT-23 and 2×2 MLF™
×
General Description
The MIC2288 is a 1.2MHz PWM, DC/DC boost switching
regulator available in low-profile Thin SOT-23 and
2mm
×
2mm MLF™ package options. High power density is
achieved with the MIC2288’s internal 34V/1A switch, allow-
ing it to power large loads in a tiny footprint.
The MIC2288 implements a constant frequency, 1.2MHz
PWM, current mode control scheme with internal compensa-
tion that offers excellent transient response and output regu-
lation performance. The high frequency operation saves
board space by allowing small, low-profile, external compo-
nents. The fixed frequency PWM topology also reduces
spurious switching noise and ripple to the input power source.
The MIC2288 is available in a low-profile Thin SOT-23-5
package and a 2mm
×
2mm MLF™-8 leadless package. The
2mm
×
2mm MLF™-8 package option has an output over-
voltage protection feature.
The MIC2288 has a junction temperature range of –40°C to
+125°C.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2.5V to 10V input voltage range
Output voltage adjustable to 34V
Over 1A switch current
1.2MHz PWM operation
Stable with ceramic capacitors
High-efficiency
<1% line and load regulation
Low input and output ripple
<1µA shutdown current
UVLO
Output overvoltage protection (MIC2288BML)
Over temperature shutdown
Thin SOT-23-5 package option
2mm
×
2mm leadless MLF™-8 package option
–40°C to +125°C junction temperature range
Applications
•
•
•
•
•
•
Organic EL power supply
TFT-LCD bias supply
12V supply for DSL applications
Multi-output DC/DC converters
Positive and negative output regulators
SEPIC converters
Typical Application
V
IN
L1
10µH
V
OUT
15V
90
85
15V
OUT
Efficiency
V
IN
= 4.2V
5
VIN
EN
SW
FB
1
EFFICIENCY (%)
MIC2288BD5
R1
3
80
75
70
65
60
0
0.05
0.1
0.15
LOAD (A)
0.2
V
IN
= 3.2V
1-Cell
Li Ion
4
C1
2.2µF
GND
2
R2
C2
10µF
V
IN
= 3.6V
2mm
×
2mm MLF™ Boost Regulator
MLF and
MicroLeadFrame
are trademarks of Amkor Technology, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2005
1
M9999-042205
MIC2288
Micrel, Inc.
Ordering Information
Part Number
MIC2288BD5
MIC2288YD5
MIC2288BML
MIC2288YML
Marking
Code
SHAA
SHAA
SJA
SJA
Output
Voltage
Adjustable
Adjustable
Adjustable
Adjustable
Overvoltage
Protection
–
–
34V
34V
Junction
Temp. Range
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Package
Thin SOT-23-5
Thin SOT-23-5
2×2 MLF™-8
2×2 MLF™-8
Lead Finish
Standard
Lead Free
Standard
Lead Free
Pin Configuration
FB GND SW
1
2
3
OVP
VIN
EN
1
2
3
4
8
7
6
PGND
SW
FB
NC
4
EN
5
VIN
AGND
EP
5
TSOT-23-5 (D5)
8-Pin MLF™ (ML)
(Top View)
Fused Lead Frame
Pin Description
Pin Number
TSOT-23-5
1
2
3
6
Pin Number
2×2 MLF™-8
×
7
Pin Name
SW
GND
FB
Pin Function
Switch Node (Input): Internal power Bipolar collector.
Ground (Return): Ground.
Feedback (Input): 1.24V output voltage sense node.
R1
V
OUT
= 1.24V
1
+
R2
Enable (Input): Logic high enables regulator. Logic low shuts down regulator.
Supply (Input): 2.5V to 10V input voltage.
Output Overvoltage Protection (Input): Tie this pin to V
OUT
to clamp the
output voltage to 34V maximum in fault conditions. Tie this pin to ground if
OVP function is not required.
No Connect: No internal connection to die.
Analog ground.
Power ground.
Exposed backside pad.
4
5
3
2
1
EN
VIN
OVP
5
4
8
EP
NC
AGND
PGND
GND
M9999-042205
2
April 2005
MIC2288
Micrel, Inc.
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ..................................................... 12V
Switch Voltage (V
SW
) ..................................... –0.3V to 34V
Enable Pin Voltage (V
EN
) ................................... –0.3 to V
IN
FB Voltage (V
FB
) ............................................................. 6V
Switch Current (I
SW
) ....................................................... 2A
Storage Temperature (T
S
) ....................... –65°C to +150°C
ESD Rating
(3)
................................................................ 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
) ........................................ 2.5V to 10V
Junction Temperature Range (T
J
) ........... –40°C to +125°C
Package Thermal Impedance
2mm
×
2mm MLF™-8 (θ
JA
) ................................. 93°C/W
Thin SOT-23-5 (θ
JA
) .......................................... 256°C/W
Electrical Characteristics
(4)
T
A
= 25°C, V
IN
= V
EN
= 3.6V, V
OUT
= 10V, I
OUT
= 20mA, unless otherwise noted.
Bold
values indicate –40°C
≤
T
J
≤
±125°C.
Symbol
V
IN
V
UVLO
I
VIN
I
SD
V
FB
I
FB
Parameter
Supply Voltage Range
Under Voltage Lockout
Quiescent Current
Shutdown Current
Feedback Voltage
Feedback Input Current
Line Regulation
Load Regulation
D
MAX
I
SW
V
SW
I
SW
V
EN
I
EN
f
SW
V
OVP
T
J
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.
2. This device is not guaranteed to operate beyond its specified operating rating.
3. IC devices are inherently ESD sensitive. Handling precautions required. Human body model rating: 1.5K in series with 100pF.
4. Specification for packaged product only.
5. I
SD
= I
VIN
.
Condition
Min
2.5
1.8
Typ
Max
10
Units
V
V
mA
µA
V
V
nA
2.1
2.8
0.1
2.4
5
1
1.252
1.265
V
FB
= 2V, (not switching)
V
EN
= 0V
(5)
(±1%)
(±2%) (Over Temp)
V
FB
= 1.24V
3V
≤
V
IN
≤
5V
5mA
≤
I
OUT
≤
40mA
85
1.227
1.215
1.24
–450
0.1
0.2
90
1.2
1
%
%
%
A
mV
Maximum Duty Cycle
Switch Current Limit
Switch Saturation Voltage
Switch Leakage Current
Enable Threshold
Enable Pin Current
Oscillator Frequency
Output Overvoltage Protection
Overtemperature
Threshold Shutdown
MIC2288 MLF™ package option only
Hysteresis
I
SW
= 1A
V
EN
= 0V, V
SW
= 10V
Turn on
Turn off
V
EN
= 10V
550
0.01
1.5
0.4
20
1.05
30
1.2
32
150
10
40
1.35
34
5
µA
V
V
µA
MHz
V
°C
°C
April 2005
3
M9999-042205
MIC2288
Micrel, Inc.
Typical Characteristics
Feedback Voltage
vs. Temperature
91
89
EFFICIENCY (%)
87
85
83
81
79
77
75
0
Efficiency at V
OUT
= 12V
OUTPUT VOLTAGE (V)
12.2
12.15
12.1
12.05
12
11.95
11.9
11.85
11.8
0
Load Regulation
FEEDBACK VOLTAGE (V)
V
IN
= 4.2V
1.30
1.28
1.26
1.24
1.22
1.20
1.18
1.16
1.14
1.12
V
IN
= 3.6V
V
IN
= 3.3V
V
25
IN
=
3.6V
25 50 75 100 125 150
OUTPUT CURRENT (mA)
50 75 100 125 150
LOAD (mA)
1.10
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
1.8
1.6
CURRENT LIMIT (A)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
2.5
SWITCH SATURATION VOLTAGE (mV)
Current Limit
vs. Supply Current
1.4
1.2
CURRENT LIMIT (A)
Current Limit
vs. Temperature
300
250
200
150
100
50
Switch Saturation
vs. Supply Voltage
1.0
0.8
0.6
0.4
0.2
I
SW
= 500mA
0
2.5
4
5.5
7
8.5
SUPPLY VOLTAGE (V)
10
4
5.5
7
8.5
SUPPLY VOLTAGE (V)
10
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
SWITCH SATURATION VOLTAGE (mV)
700
600
500
400
300
200
100
0
0
SWITCH SATURATION VOLTAGE (mV)
Switch Saturation
vs. Current
700
600
500
400
300
200
100
Switch Saturation
vs. Temperature
1.4
FREQUENCY (MHz)
1.3
1.2
1.1
1.0
0.9
Frequency
vs. Temperature
V
IN
= 3.6V
200 400 600 800 1000
SWITCH CURRENT (mA)
V
IN
= 3.6V
I = 500mA
SW
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0.8
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
MAXIMUM DUTY CYCLE (%)
MAXIMUM DUTY CYCLE (%)
96
94
92
90
88
86
84
82
80
2.5
4
5.5
7
8.5
SUPPLY VOLTAGE (V)
10
97
95
93
91
89
87
V
IN
= 3.6V
FEEDBACK CURRENT (nA)
100
98
Maximum Duty Cycle
vs. Supply Voltage
99
Maximum Duty Cycle
vs. Temperature
700
600
500
400
300
200
100
FB Pin Current
vs. Temperature
85
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
M9999-042205
4
April 2005
MIC2288
Micrel, Inc.
Function Characteristics
Enable Characteristics
OUTPUT VOLTAGE
(1mV/div) AC-Coupled
Line Transient Response
OUTPUT VOLTAGE
(5V/div)
Output Voltage
ENABLE VOLTAGE
(2V/div)
Enable Voltage
INPUT VOLTAGE
(2V/div)
4.2V
3.6V
IN
12V
OUT
150mA Load
3.2V
12V
OUT
150mA Load
Time (400µs/div)
Time (400µs/div)
Load Transient Response
LOAD CURRENT
OUTPUT VOLTAGE
(100mA/div)
(100mV/div) AC-Coupled
OUTPUT VOLTAGE
(50mV/div)
Switching Waveforms
Output Voltage
INDUCTOR CURRENT
(500mA/div)
Inductor Current
(10µH)
150mA
SWITCH SATURATION
(5V/div)
V
SW
3.6V
IN
12V
OUT
150mA
10mA
3.6V
IN
12V
OUT
C
OUT
= 10µF
Time (400µs/div)
Time (400ns/div)
April 2005
5
M9999-042205
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