MIC2288YD5TR [MICROCHIP]
2A SWITCHING REGULATOR, 1350kHz SWITCHING FREQ-MAX, PDSO5, LEAD-FREE, TSOT-23, 5 PIN;
| 型号： | MIC2288YD5TR |
| 厂家： | 
MICROCHIP |
| 描述： | 2A SWITCHING REGULATOR, 1350kHz SWITCHING FREQ-MAX, PDSO5, LEAD-FREE, TSOT-23, 5 PIN 开关 光电二极管 输出元件 |
| 文件： | 总11页 (文件大小：247K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC2288
Micrel, Inc.
MIC2288
1A 1.2MHz PWM Boost Converter in
Thin SOT-23 and 2×2 MLF™
General Description
Features
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.
• 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
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
spuriousswitchingnoiseandrippletotheinputpowersource.
• <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
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.
Applications
The MIC2288 has a junction temperature range of –40°C to
+125°C.
• Organic EL power supply
• TFT-LCD bias supply
All support documentation can be found on Micrel’s web
site at www.micrel.com.
• 12V supply for DSL applications
• Multi-output DC/DC converters
• Positive and negative output regulators
• SEPIC converters
Typical Application
L1
VOUT
15V
15V
Efficiency
10µH
VIN
OUT
90
85
80
75
70
65
60
VIN = 4.2V
MIC2288BD5
5
4
1
3
VIN
SW
R1
R2
VIN = 3.2V
FB
EN
1-Cell
Li Ion
VIN = 3.6V
0.15
C1
2.2µF
C2
10µF
GND
2
0
0.05
0.1
LOAD (A)
0.2
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
Marking
Output
Overvoltage
Protection
Junction
Part Number
MIC2288BD5
MIC2288YD5
MIC2288BML
MIC2288YML
Code
SHAA
SHAA
SJA
Voltage
Temp. Range
Package
Lead Finish
Adjustable
Adjustable
Adjustable
Adjustable
–
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Thin SOT-23-5
Thin SOT-23-5
2×2 MLF™-8
2×2 MLF™-8
Standard
Lead Free
Standard
Lead Free
–
34V
34V
SJA
Pin Configuration
FB GND SW
1
3
2
OVP
1
2
3
4
8
PGND
SW
VIN
EN
7
6
5
FB
4
5
EP
AGND
NC
EN
VIN
TSOT-23-5 (D5)
8-Pin MLF™ (ML)
(Top View)
Fused Lead Frame
Pin Description
Pin Number
Pin Number
TSOT-23-5
2×2 MLF™-8
Pin Name
Pin Function
1
2
3
7
6
SW
GND
FB
Switch Node (Input): Internal power Bipolar collector.
Ground (Return): Ground.
Feedback (Input): 1.24V output voltage sense node.
R1
1+
VOUT = 1.24V
R2
4
5
3
2
1
EN
VIN
OVP
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 VOUT to clamp the
output voltage to 34V maximum in fault conditions. Tie this pin to ground if
OVP function is not required.
5
4
8
NC
No Connect: No internal connection to die.
Analog ground.
Power ground.
AGND
PGND
GND
EP
Exposed backside pad.
M9999-042205
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April 2005
MIC2288
Micrel, Inc.
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (V ) .....................................................12V
Supply Voltage (V ) ........................................ 2.5V to 10V
IN
IN
SW
Switch Voltage (V ) ..................................... –0.3V to 34V
Junction Temperature Range (T ) ........... –40°C to +125°C
J
Enable Pin Voltage (V )................................... –0.3 to V
Package Thermal Impedance
EN
IN
FB Voltage (V ) .............................................................6V
2mm × 2mm MLF™-8 (θ ) .................................93°C/W
JA
FB
Switch Current (I ) .......................................................2A
Thin SOT-23-5 (θ ) ..........................................256°C/W
JA
SW
Storage Temperature (T ) ....................... –65°C to +150°C
S
(3)
ESD Rating ................................................................ 2kV
Electrical Characteristics(4)
TA = 25°C, VIN = VEN = 3.6V, VOUT = 10V, IOUT = 20mA, unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ ±125°C.
Symbol
VIN
VUVLO
IVIN
ISD
VFB
Parameter
Condition
Min
2.5
1.8
Typ
Max
10
2.4
5
Units
V
V
mA
µA
Supply Voltage Range
Under Voltage Lockout
Quiescent Current
Shutdown Current
Feedback Voltage
2.1
2.8
0.1
VFB = 2V, (not switching)
VEN = 0V(5)
1
(±1%)
1.227
1.24
1.252
V
(±2%) (Over Temp)
1.215
1.265
V
IFB
Feedback Input Current
Line Regulation
VFB = 1.24V
3V ≤ VIN ≤ 5V
–450
0.1
nA
%
1
Load Regulation
5mA ≤ IOUT ≤ 40mA
0.2
%
DMAX
ISW
VSW
ISW
Maximum Duty Cycle
Switch Current Limit
Switch Saturation Voltage
Switch Leakage Current
Enable Threshold
85
90
1.2
550
0.01
%
A
mV
µA
ISW = 1A
VEN = 0V, VSW = 10V
5
VEN
Turn on
1.5
V
Turn off
0.4
40
1.35
34
V
IEN
Enable Pin Current
Oscillator Frequency
Output Overvoltage Protection
VEN = 10V
20
1.2
32
µA
MHz
V
fSW
VOVP
TJ
1.05
30
MIC2288 MLF™ package option only
Hysteresis
Overtemperature
150
°C
Threshold Shutdown
10
°C
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 (max),
J
the junction-to-ambient thermal resistance, θ , and the ambient temperature, T . The maximum allowable power dissipation will result in excessive
JA
A
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
= I
.
SD
VIN
April 2005
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M9999-042205
MIC2288
Micrel, Inc.
Typical Characteristics
Feedback Voltage
vs. Temperature
Efficiency at V
= 12V
Load Regulation
OUT
91
89
87
85
83
81
79
77
75
12.2
12.15
12.1
12.05
12
11.95
11.9
11.85
11.8
1.30
1.28
1.26
1.24
1.22
1.20
1.18
1.16
1.14
1.12
1.10
VIN = 4.2V
VIN = 3.6V
VIN = 3.3V
VIN = 3.6V
-40 -20
0
20 40 60 80 100 120
0
25 50 75 100 125 150
OUTPUT CURRENT (mA)
0
25 50 75 100 125 150
LOAD (mA)
TEMPERATURE (°C)
Current Limit
Switch Saturation
vs. Supply Voltage
Current Limit
vs. Supply Current
vs. Temperature
1.8
1.6
1.4
1.2
1
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
300
250
200
150
100
50
0.8
0.6
0.4
0.2
0
ISW = 500mA
0
2.5
4
5.5
7
8.5
10
-40 -20
0
20 40 60 80 100 120
2.5
4
5.5
7
8.5
10
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
Switch Saturation
vs. Current
Switch Saturation
vs. Temperature
Frequency
vs. Temperature
700
700
600
500
400
300
200
100
0
1.4
1.3
1.2
1.1
1.0
0.9
0.8
600
500
400
300
200
100
0
VIN = 3.6V
ISW = 500mA
VIN = 3.6V
0
200 400 600 800 1000
SWITCH CURRENT (mA)
-40 -20
0
20 40 60 80 100 120
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
Maximum Duty Cycle
vs. Temperature
Maximum Duty Cycle
vs. Supply Voltage
FB Pin Current
vs. Temperature
100
98
96
94
92
90
88
86
84
82
80
99
97
95
93
91
89
87
85
700
600
500
400
300
200
100
0
VIN = 3.6V
-40 -20
0
20 40 60 80 100 120
-40 -20
0
20 40 60 80 100 120
2.5
4
5.5
7
8.5
10
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
M9999-042205
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April 2005
MIC2288
Micrel, Inc.
Function Characteristics
Enable Characteristics
Line Transient Response
Output Voltage
4.2V
Enable Voltage
3.2V
3.6VIN
12VOUT
150mA Load
12VOUT
150mA Load
Time (400µs/div)
Time (400µs/div)
Switching Waveforms
Load Transient Response
Output Voltage
Inductor Current
(10µH)
150mA
VSW
3.6VIN
12VOUT
150mA
10mA
3.6VIN
12VOUT
COUT = 10µF
Time (400ns/div)
Time (400µs/div)
April 2005
5
M9999-042205
MIC2288
Micrel, Inc.
Functional Diagram
VIN
FB
OVP*
EN
OVP*
SW
PWM
Generator
gm
VRE
F
1.24V
Σ
CA
1.2MHz
Oscillator
Ramp
Generator
GND
*
OVP available on MLFTM package option only.
Figure 1. MIC2288 Block Diagram
Theg erroramplifiermeasuresthefeedbackvoltagethrough
Functional Description
m
the external feedback resistors and amplifies the error be-
tween the detected signal and the 1.24V reference voltage.
The MIC2288 is a constant frequency, PWM current mode
boost regulator. The block diagram is shown in Figure 1. The
MIC2288 is composed of an oscillator, slope compensation
The output of the g error amplifier provides the voltage-loop
m
signal that is fed to the other input of the PWM generator.
When the current-loop signal exceeds the voltage-loop sig-
nal, thePWMgeneratorturnsoffthebipolaroutputtransistor.
The next clock period initiates the next switching cycle,
maintaining the constant frequency current-mode PWM con-
trol.
ramp generator, current amplifier, g error amplifier, PWM
m
generator, and a 1A bipolar output transistor. The oscillator
generates a 1.2MHz clock. The clock’s two functions are to
trigger the PWM generator that turns on the output transistor,
and to reset the slope compensation ramp generator. The
current amplifier is used to measure the switch current by
amplifying the voltage signal from the internal sense resistor.
The output of the current amplifier is summed with the output
of the slope compensation ramp generator. This summed
current-loop signal is fed to one of the inputs of the PWM
generator.
M9999-042205
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April 2005
MIC2288
Micrel, Inc.
Applications Information
Component Selection
DC-to-DC PWM Boost Conversion
Inductor
The MIC2288 is a constant-frequency boost converter. It
operates by taking a DC input voltage and regulating a higher
DC output voltage. Figure 2 shows a typical circuit. Boost
regulation is achieved by turning on an internal switch, which
draws current through the inductor (L1). When the switch
turns off, the inductor’s magnetic field collapses, causing the
current to be discharged into the output capacitor through an
external Schottky diode (D1). Voltage regulation is achieved
by modulating the pulse width or pulse-width modulation
(PWM).
Inductor selection is a balance between efficiency, stability,
cost, size, and rated current. For most applications a 10µH is
therecommendedinductorvalue. Itisusuallyagoodbalance
between these considerations.
Larger inductance values reduce the peak-to-peak ripple
current, affecting efficiency. This has the effect of reducing
both the DC losses and the transition losses. There is also a
secondary effect of an inductor’s DC resistance (DCR). The
DCR of an inductor will be higher for more inductance in the
same package size. This is due to the longer windings
required for an increase in inductance. Since the majority of
inputcurrent(minustheMIC2288operatingcurrent)ispassed
through the inductor, higher DCR inductors will reduce effi-
ciency.
L1
D1
VIN
10µH
VOUT
MIC2288BML
VIN
SW
OVP
FB
To maintain stability, increasing inductor size will have to be
met with an increase in output capacitance. This is due to the
unavoidable “right half plane zero” effect for the continuous
current boost converter topology. The frequency at which the
right half plane zero occurs can be calculated as follows:
R1
R2
C1
C2
2.2µF
10µF
EN
GND
GND
GND
2
Figure 2. Typical Application Circuit
V
IN
F
=
rhpz
Duty Cycle Considerations
VOUT ×L ×IOUT × 2π
Duty cycle refers to the switch on-to-off time ratio and can be
The right half plane zero has the undesirable effect of
increasing gain, while decreasing phase. This requires that
the loop gain is rolled off before this has significant effect on
the total loop response. This can be accomplished by either
reducing inductance (increasing RHPZ frequency) or in-
creasing the output capacitor value (decreasing loop gain).
calculated as follows for a boost regulator:
V
IN
VOUT
D = 1−
Thedutycyclerequiredforvoltageconversionshouldbeless
than the maximum duty cycle of 85%. Also, in light load
conditions where the input voltage is close to the output
voltage, the minimum duty cycle can cause pulse skipping.
This is due to the energy stored in the inductor causing the
outputtoovershootslightlyovertheregulatedoutputvoltage.
Duringthenextcycle, theerroramplifierdetectstheoutputas
being high and skips the following pulse. This effect can be
reduced by increasing the minimum load or by increasing the
inductor value. Increasing the inductor value reduces peak
current, which in turn reduces energy transfer in each cycle.
Output Capacitor
Output capacitor selection is also a trade-off between perfor-
mance, size, and cost. Increasing output capacitance will
lead to an improved transient response, but also an increase
insizeandcost. X5RorX7Rdielectricceramiccapacitorsare
recommended for designs with the MIC2288. Y5V values
may be used but to offset their tolerance over temperature,
more capacitance is required. The following table shows the
recommended ceramic (X5R) output capacitor value vs.
output voltage.
Overvoltage Protection
Output Voltage
<6V
Recomended Output Capacitance
For the MLF™ package option, there is an overvoltage
protection function. If the feedback resistors are discon-
nected from the circuit or the feedback pin is shorted to
ground, the feedback pin will fall to ground potential. This will
cause the MIC2288 to switch at full duty cycle in an attempt
to maintain the feedback voltage. As a result, the output
voltage will climb out of control. This may cause the switch
node voltage to exceed its maximum voltage rating, possibly
damagingtheICandtheexternalcomponents.Toensurethe
highest level of protection, the MIC2288 OVP pin will shut the
switch off when an overvoltage condition is detected, saving
itself and other sensitive circuitry downstream.
22µF
10µF
4.7µF
<16V
<34V
Table 1. Output Capacitor Selection
Diode Selection
The MIC2288 requires an external diode for operation. A
Schottky diode is recommended for most applications due to
their lower forward voltage drop and reverse recovery time.
Ensure the diode selected can deliver the peak inductor
current and the maximum reverse voltage is rated greater
than the output voltage.
April 2005
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M9999-042205
MIC2288
Micrel, Inc.
Input capacitor
Feedback Resistors
A minimum 1µF ceramic capacitor is recommended for
designing with the MIC2288. Increasing input capacitance
will improve performance and greater noise immunity on the
source. The input capacitor should be as close as possible to
the inductor and the MIC2288, with short traces for good
noise performance.
The MIC2288 utilizes a feedback pin to compare the output
to an internal reference. The output voltage is adjusted by
selecting the appropriate feedback resistor network values.
The R2 resistor value must be less than or equal to 5kΩ
(R2 ≤ 5kΩ).The desired output voltage can be calculated
as follows:
R1
R2
VOUT = VREF
where V
×
+1
is equal to 1.24V.
REF
M9999-042205
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April 2005
MIC2288
Micrel, Inc.
Application Circuits
L1
10µH
L1
4.7µH
VIN
3V to 4.2V
VOUT
15V @ 100mA
VIN
3V to 4.2V
VOUT
5V @ 400mA
D1
D1
MIC2288BML
MIC2288BML
R1
54.9k
R1
5.62k
VIN
SW
OVP
FB
VIN
SW
OVP
FB
C1
2.2µF
10V
C2
10µF
16V
C1
4.7µF
6.3V
C2
22µF
6.3V
EN
EN
GND
R2
5k
GND
R2
1.87k
GND
GND
GND
GND
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
AVX
AVX
ON Semi.
C1 4.7µF, 6.3V, 0805 X5R Ceramic Capacitor 08056D475MAT
C2 22µF, 6.3V, 0805 X5R Ceramic Capacitor 12066D226MAT
AVX
AVX
ON Semi.
C2 10µF, 16V, 1206 X5R Ceramic Capacitor
D1 1A, 40V Schotty Diode
1206YD106MAT
MBRM140T3
D1 1A, 40V Schotty Diode
L1 4.7µH, 650mA Inductor
MBRM140T3
LQH32CN4R7M11 Murata
L1 10µH, 650mA Inductor
LQH43CN100K03 Murata
Figure 6. 3.3V – 4.2V to 15V
@ 100mA
Figure 3. 3.3V to 5V
@ 400mA
OUT
IN
IN
OUT
IN
L1
10µH
VIN
3V to 4.2V
VOUT
24V @ 50mA
L1
10µH
VIN
3V to 4.2V
VOUT
9V @ 180mA
D1
D1
MIC2288BML
MIC2288BML
R1
VIN
SW
OVP
FB
R1
VIN
SW
OVP
FB
18.2k
C1
2.2µF
10V
C2
4.7µF
25V
31.6k
C1
2.2µF
10V
C2
10µF
16V
EN
EN
GND
R2
1k
GND
R2
5k
GND
GND
GND
GND
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
C2 4.7µF, 25V, 1206 X5R Ceramic Capacitor 12063D475MAT
AVX
AVX
ON Semi.
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
AVX
AVX
ON Semi.
C2 10µF, 16V, 1206 X5R Ceramic Capacitor
D1 1A, 40V Schotty Diode
1206YD106MAT
MBRM140T3
D1 1A, 40V Schotty Diode
L1 10µH, 650mA Inductor
MBRM140T3
LQH43CN100K03 Murata
L1 10µH, 650mA Inductor
LQH43CN100K03 Murata
Figure 7. 3.3V – 4.2V to 24V @ 50mA
OUT
IN
IN
Figure 4. 3.3V – 4.2V to 9V
@ 180mA
IN
IN
OUT
L1
10µH
VIN
5V
VOUT
9V @ 330mA
D1
L1
10µH
VIN
3V to 4.2V
VOUT
12V @ 100mA
D1
MIC2288BML
MIC2288BML
R1
VIN
SW
OVP
FB
31.6k
R1
C1
2.2µF
10V
C2
VIN
SW
OVP
FB
42.3k
10µF
16V
C1
2.2µF
10V
C2
10µF
16V
EN
EN
GND
R2
5k
GND
R2
5k
GND
GND
GND
GND
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
AVX
AVX
ON Semi.
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
AVX
AVX
ON Semi.
C2 10µF, 16V, 1206 X5R Ceramic Capacitor
D1 1A, 40V Schotty Diode
1206YD106MAT
MBRM140T3
C2 10µF, 16V, 1206 X5R Ceramic Capacitor
D1 1A, 40V Schotty Diode
1206YD106MAT
MBRM140T3
L1 10µH, 650mA Inductor
LQH43CN100K03 Murata
L1 10µH, 650mA Inductor
LQH43CN100K03 Murata
Figure 8. 5V to 9V
@ 330mA
IN
OUT
Figure 5. 3.3V – 4.2V to 12V @ 100mA
OUT
IN
IN
April 2005
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M9999-042205
MIC2288
Micrel, Inc.
L1
10µH
L1
10µH
VIN
5V
VOUT
24V @ 80mA
VIN
5V
VOUT
12V @ 250mA
D1
D1
MIC2288BML
MIC2288BML
R1
18.2k
R1
43.2k
VIN
SW
OVP
FB
VIN
SW
OVP
FB
C1
C2
4.7µF
25V
C1
C2
10µF
16V
2.2µF
2.2µF
10V
10V
EN
EN
GND
R2
1k
GND
R2
5k
GND
GND
GND
GND
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
C2 4.7µF, 25V, 1206 X5R Ceramic Capacitor 12066D475MAT
AVX
AVX
ON Semi.
C1 2.2µF, 10V, 0805 X5R Ceramic Capacitor 08052D225KAT
AVX
AVX
ON Semi.
C2 10µF, 16V, 1206 X5R Ceramic Capacitor
D1 1A, 40V Schotty Diode
1206YD106MAT
MBRM140T3
D1 1A, 40V Schotty Diode
L1 10µH, 650mA Inductor
MBRM140T3
LQH32CN4R7M11 Murata
L1 10µH, 650mA Inductor
LQH43CN100K03 Murata
Figure 10. 5V to 24V
@ 80mA
OUT
Figure 9. 5V to 12V
@ 250mA
IN
IN
OUT
M9999-042205
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April 2005
MIC2288
Micrel, Inc.
Package Information
All Dimensions are in millimeters
5-Pin TSOT (D5)
8-Pin MLF™ (ML)
MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com
This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
April 2005
11
M9999-042205
相关型号：
MIC2288YMLTR
2A SWITCHING REGULATOR, 1350kHz SWITCHING FREQ-MAX, PDSO8, 2 X 2 MM, LEAD-FREE, MLF-8
MICROCHIP
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