MICREL MIC23031-FYMT

MIC23031
4MHz PWM 400mA Buck Regulator
with Hyper Light Load™
General Description
Features
The MIC23031 is a high efficiency 4MHz 400mA
synchronous buck regulator with Hyper Light Load™
mode. Hyper Light Load™ provides very high efficiency at
light loads and ultra-fast transient response which is
perfectly suited for supplying processor core voltages. An
additional benefit of this proprietary architecture is very low
output ripple voltage throughout the entire load range with
the use of small output capacitors. The tiny 1.6mm x
1.6mm Thin MLF® package saves precious board space
and requires only three external components.
The MIC23031 is designed for use with a very small
inductor, down to 0.47µH, and an output capacitor as small
as 2.2 µF that enables a sub-1mm height.
The MIC23031 has a very low quiescent current of 21µA
and achieves as high as 88% efficiency at 1mA. At higher
loads, the MIC23031 provides a constant switching
frequency around 4MHz while achieving peak efficiencies
up to 93%.
The MIC23031 is available in a 6-pin 1.6mm x 1.6mm Thin
MLF® package with an operating junction temperature
range from –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
•
•
•
•
•
•
•
•
•
•
•
•
•
Input voltage range: 2.7V to 5.5V
400mA output current
Up to 93% efficiency and 88% at 1mA
21µA typical quiescent current
4MHz PWM operation in continuous mode
Ultra fast transient response
Low voltage output ripple
o 20mVpp ripple in Hyper Light LoadTM mode
o 3mV output voltage ripple in full PWM mode
Fully integrated MOSFET switches
0.01µA shutdown current
Thermal shutdown and current limit protection
Fixed and adjustable output voltage options available
6-pin 1.6mm x 1.6mm Thin MLF®
–40°C to +125°C junction temperature range
Applications
•
•
•
•
•
•
•
•
Mobile handsets
Portable media/MP3 players
Portable navigation devices (GPS)
WiFi/WiMax/WiBro modules
Digital Cameras
Wireless LAN cards
USB powered devices
Portable applications
Typical Application
Efficiency VOUT = 2.5V
U1 - MIC23031
100
L1
VIN
VIN
SW
VOUT
= 3.6V
C1
SNS
EN
C2
EN
AGND
GND
= 3.0V
90
80
= 4.2V
70
PGND
60
L
GND
50
1
10
100
1000
OUTPUT CURRENT (mA)
Hyper Light Load is a trademark of Micrel, Inc
MLF and MicroLead Frame are registered trademark 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
May 2008
M9999-051608-A
Micrel Inc.
MIC23031
Ordering Information
Part Number
Marking
Code
Nominal Output
Voltage
Junction
Temperature Range
Package
MIC23031-AYMT
GEA
ADJ
-40°C to +125°C
6-Pin 1.6x1.6 Thin MLF®
Pb-Free
-40°C to +125°C
6-Pin 1.6x1.6 Thin MLF
®
Pb-Free
-40°C to +125°C
6-Pin 1.6x1.6 Thin MLF
®
Pb-Free
-40°C to +125°C
6-Pin 1.6x1.6 Thin MLF®
Pb-Free
-40°C to +125°C
®
Pb-Free
MIC23031-GYMT
GEG
1.8V
MIC23031-FYMT
GEF
1.5V
MIC23031-4YMT
GE4
1.2V
MIC23031-CYMT
GEC
1.0V
6-Pin 1.6x1.6 Thin MLF
Lead Finish
1. Other options available. Contact Micrel for details.
2. Thin MLF® is GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
VIN
1
6
PGND
VIN
1
6
GND
SW
2
5
AGND
SW
2
5
FB
SNS
3
4
EN
SNS
3
4
EN
Fixed
(Top View)
1.6 x 1.6mm Thin MLF (MT)
Adjustable
(Top View)
1.6 x 1.6mm Thin MLF (MT)
Pin Description
Fixed Option
ADJ Option
Pin Name
1
1
VIN
Input Voltage: Connect a capacitor to ground to decouple the
noise.
2
2
SW
Switch (Output): Internal power MOSFET output switches.
3
3
SNS
Sense: Connect to VOUT as close to output capacitor as possible
to sense output voltage
4
4
EN
5
-
AGND
-
5
FB
6
-
PGND
-
6
GND
E-PAD
E-PAD
HS PAD
May 2008
Pin Function
Enable (Input): Logic high enables operation of the regulator.
Logic low will shut down the device. Do not leave floating.
Analog Ground: Connect to central ground point where all high
current paths meet (CIN, COUT, PGND) for best operation.
Feedback (Input): Connect resistor divider at this node to set
output voltage. Resistors should be selected based on a nominal
VFB of 0.62V.
Power Ground
Ground
Connect to PGND or GND
2
M9999-051608-A
Micrel Inc.
MIC23031
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) . ……………………………………….6V
Sense (VSNS).. ..................................................................6V
Output Switch Voltage ..................................................6V
Enable Input Voltage (VEN).. ..............................-0.3V to VIN
Storage Temperature Range .. ……………-65°C to +150°C
ESD Rating(3) ................................................. ESD Sensitive
Supply Voltage (VIN)... …………………………..2.7V to 5.5V
Enable Input Voltage (VEN) .. ……………………….0V to VIN
Output Voltage Range (VSNS) ………………….0.7V to 3.6V
Junction Temperature Range (TJ)... ….-40°C ≤ TJ ≤ +125°C
Thermal Resistance
1.6 x 1.6mm Thin MLF®-6 (θJA).......................92.4°C/W
Electrical Characteristics(4)
TA = 25°C; VIN = VEN = 3.6V; L = 1µH; COUT = 4.7µF unless otherwise specified.
Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min
Supply Voltage Range
2.7
Under-Voltage Lockout Threshold
(turn-on)
Quiescent Current
IOUT = 0mA , SNS > 1.2 * VOUT Nominal
Shutdown Current
VEN = 0V
Output Voltage Accuracy
Typ
2.45
VIN = 5.5V
VIN = 3.6V; ILOAD = 20mA
Max
Units
5.5
V
2.55
2.65
V
21
35
µA
0.01
4
µA
+2.5
%
-2.5
Feedback Voltage
Adjustable Option Only
Current Limit
SNS = 0.9*VOUTNOM
Output Voltage Line Regulation
VIN = 3.0V to 5.5V, VOUT = 1.2V, ILOAD = 20mA,
0.3
%/V
Output Voltage Load Regulation
20mA < ILOAD < 400mA, VOUT = 1.2V, VIN =
3.6V
0.7
%
ISW = 100mA PMOS
0.65
ISW = -100mA NMOS
0.8
PWM Switch ON-Resistance
Frequency
IOUT = 120mA
SoftStart Time
VOUT = 90%
0.62
0.41
Enable Threshold
0.7
V
1
A
Ω
4
MHz
100
µs
0.9
1.2
V
Enable Input Current
0.1
2
µA
Over-temperature Shutdown
160
°C
Over-temperature Shutdown Hysteresis
20
°C
0.5
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
May 2008
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MIC23031
Typical Characteristics
Efficiency VOUT = 2.5V
Efficiency VOUT = 1.8V
100
Efficiency VOUT = 1.2V
100
100
= 3.0V
90
90
= 3.0V
= 2.7V
90
80
= 3.0V
= 2.7V
= 3.6V
80
80
= 4.2V
= 4.2V
70
= 3.6V
70
70
= 4.2V
= 3.6V
60
L
50
1
100
10
60
100
1000
OUTPUT CURRENT (mA)
Efficiency
with Various Inductors
Quiescent Current
vs Input Voltage
40
1.86
1.84
1.82
30
L = 2.2
25
15
1.76
1.74
1.72
10
60
5
50
1
10
100
1000
OUTPUT CURRENT (mA)
Output Voltage
vs Output Current
2
0
2.7
L
10
100
1000
OUTPUT CURRENT (mA)
Output Voltage
vs Input Voltage
50mA
1.8
1.78
20
L = 1.0
L = 0.47
50
1
1.9
1.88
35
80
70
50
1
10
100
1000
OUTPUT CURRENT (mA)
L = 4.7
90
60
L
3.2 3.7 4.2 4.7 5.2
INPUT VOLTAGE (V)
5.7
Output Voltage
vs Temperature
1.9
1.7
2.7
5
150mA
10mA
1mA
400mA
300mA
L
3.2 3.7 4.2 4.7 5.2
INPUT VOLTAGE (V)
5.7
Frequency vs
Temperature
= 1.8V
1.95
1.9
1.85
1.8
4.5
1.7
4
= 4.2V
1.8
= 3.6V
1.75
= 3.0V
1.6
1.7
1.65
1.6
1
10
100
1000
OUTPUT CURRENT (mA)
10
SW FREQUENCY (MHz)
3.5
L
L
1.5
20 40 60 80
TEMPERATURE (C°)
SW Frequency
vs Output Current
SW Frequency
vs Output Current
10
1.2
20 40 60 80
TEMPERATURE (C°)
Enable Threshold
vs. Input Voltage
Enable ON
1
= 3.0V
=
= 3.6V
1
3
1
= 4.2V
0.8
Enable OFF
=
=
0.1
=
0.1
L
0.01
1
May 2008
10
100
1000
OUTPUT CURRENT (mA)
0.01
0.001
1
0.6
0.4
0.2
10
100
1000
OUTPUT CURRENT (mA)
4
0
2.7
3.2 3.7 4.2 4.7 5.2
INPUT VOLTAGE (V)
5.7
M9999-051608-A
Micrel Inc.
1.2
MIC23031
Enable Threshold
vs Temperature
800
1
700
0.8
600
500
0.6
400
0.4
300
200
0.2
0
May 2008
900
Current Limit
vs Input Voltage
100
20 40 60 80
TEMPERATURE (C°)
0
2.7
3.2 3.7 4.2 4.7 5.2
INPUT VOLTAGE (V)
5
5.7
M9999-051608-A
Micrel Inc.
MIC23031
Functional Characteristics
May 2008
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Micrel Inc.
May 2008
MIC23031
7
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Micrel Inc.
May 2008
MIC23031
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MIC23031
Functional Diagram
VIN
EN
CONTROL
LOGIC
Timer &
Softstart
UVLO
Gate
Drive
Reference
SW
Current
Limit
ERROR
COMPARATOR
ZERO 1
ISENSE
PGND
SNS
AGND
Simplified MIC23031 Fixed Functional Block Diagram
VIN
EN
CONTROL
LOGIC
Timer &
Softstart
UVLO
Gate
Drive
Reference
SW
Current
Limit
ERROR
COMPARATOR
ZERO 1
ISENSE
SNS
FB
GND
Simplified MIC23031 Adjustable Functional Block Diagram
May 2008
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Micrel Inc.
MIC23031
biasing and control circuitry. The current loop for the
signal ground should be separate from the power ground
(PGND) loop. Refer to the layout recommendations for
more details.
Functional Description
VIN
The input supply (VIN) provides power to the internal
MOSFETs for the switch mode regulator along with the
internal control circuitry. The VIN operating range is 2.7V
to 5.5V so an input capacitor, with a minimum voltage
rating of 6.3V, is recommended. Due to the high
switching speed, a minimum 2.2µF bypass capacitor
placed close to VIN and the power ground (PGND) pin is
required. Refer to the layout recommendations for
details.
FB (Adjustable Output Only)
The feedback pin (FB) allows the regulated output
voltage to be set by applying an external resistor
network. The internal reference voltage is 0.62V and the
recommended value of R2 is 200kΩ. The output voltage
is calculated from the equation below.
⎛ R1
⎞
VOUT = 0.62V ⎜
+ 1⎟
⎝ 200 kΩ
⎠
EN
A logic high signal on the enable pin activates the output
voltage of the device. A logic low signal on the enable
pin deactivates the output and reduces supply current to
0.01µA. MIC23031 features built-in soft-start circuitry
that reduces in-rush current and prevents the output
voltage from overshooting at start up. Do not leave
floating.
MIC23031
VIN
SW
C1
SW
The switch (SW) connects directly to one end of the
inductor and provides the current path during switching
cycles. The other end of the inductor is connected to the
load, SNS pin and output capacitor. Due to the high
speed switching on this pin, the switch node should be
routed away from sensitive nodes whenever possible.
EN
SNS
EN
VOUT
L1
R1
C2
FB
GND
R2
GND
GND
Figure 1. MIC23031-AYMT Schematic
SNS
The sense (SNS) pin is connected to the output of the
device to provide feedback to the control circuitry. The
SNS connection should be placed close to the output
capacitor. Refer to the layout recommendations for more
details.
PGND / GND
The power ground pin is the ground path for the high
current in PWM mode. The current loop for the power
ground should be as small as possible and separate
from the analog ground (AGND) loop as applicable.
Refer to the layout recommendations for more details.
AGND (Fixed Output Only)
The analog ground (AGND) is the ground path for the
May 2008
VIN
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M9999-051608-A
Micrel Inc.
MIC23031
Maximum current ratings of the inductor are generally
given in two methods; permissible DC current and
saturation current. Permissible DC current can be rated
either for a 40°C temperature rise or a 10% to 20% loss
in inductance. Ensure the inductor selected can handle
the maximum operating current. When saturation current
is specified, make sure that there is enough margin so
that the peak current does not cause the inductor to
saturate. Peak current can be calculated as follows:
Application Information
The MIC23031 is a high performance DC/DC step down
regulator offering a small solution size. Supporting an
output current up to 400mA inside a tiny 1.6mm x 1.6mm
Thin MLF® package and requiring only three external
components, the MIC23031 meets today’s miniature
portable electronic device needs. Using the Hyper Light
Load™ switching scheme, the MIC23031 is able to
maintain high efficiency throughout the entire load range
while providing ultra-fast load transient response. The
following sections provide additional device application
information.
⎡
⎛ 1 − VOUT /VIN
I PEAK = ⎢IOUT + VOUT ⎜
⎝ 2 ×f ×L
⎣
As shown by the calculation above, the peak inductor
current is inversely proportional to the switching
frequency and the inductance; the lower the switching
frequency or the inductance the higher the peak current.
As input voltage increases, the peak current also
increases.
The size of the inductor depends on the requirements of
the application. Refer to the Typical Application Circuit
and Bill of Materials for details.
DC resistance (DCR) is also important. While DCR is
inversely proportional to size, DCR can represent a
significant efficiency loss. Refer to the Efficiency
Considerations.
Input Capacitor
A 2.2µF ceramic capacitor or greater should be placed
close to the VIN pin and PGND / GND pin for bypassing.
A TDK C1608X5R0J475K, size 0603, 4.7µF ceramic
capacitor is recommended based upon performance,
size and cost. A X5R or X7R temperature rating is
recommended for the input capacitor. Y5V temperature
rating capacitors, aside from losing most of their
capacitance over temperature, can also become
resistive at high frequencies. This reduces their ability to
filter out high frequency noise.
Output Capacitor
The MIC23031 was designed for use with a 2.2µF or
greater ceramic output capacitor. Increasing the output
capacitance will lower output ripple and improve load
transient response but could increase solution size or
cost. A low equivalent series resistance (ESR) ceramic
output capacitor such as the TDK C1608X5R0J475K,
size 0603, 4.7µF ceramic capacitor is recommended
based upon performance, size and cost. Both the X7R or
X5R temperature rating capacitors are recommended.
The Y5V and Z5U temperature rating capacitors are not
recommended due to their wide variation in capacitance
over temperature and increased resistance at high
frequencies.
Compensation
The MIC23031 is designed to be stable with a 0.47µH to
4.7µH inductor with a minimum of 2.2µF ceramic (X5R)
output capacitor.
Duty Cycle
The typical maximum duty cycle of the MIC23031 is
80%.
Efficiency Considerations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied.
Inductor Selection
When selecting an inductor, it is important to consider
the following factors (not necessarily in the order of
importance):
•
Inductance
•
Rated current value
•
Size requirements
⎛V
×I
Efficiency % = ⎜⎜ OUT OUT
V
IN × IIN
⎝
⎞
⎟ × 100
⎟
⎠
Maintaining high efficiency serves two purposes. It
reduces power dissipation in the power supply, reducing
the need for heat sinks and thermal design
considerations and it reduces consumption of current for
battery powered applications. Reduced current draw
from a battery increases the devices operating time and
is critical in hand held devices.
There are two types of losses in switching converters;
DC losses and switching losses. DC losses are simply
the power dissipation of I2R. Power is dissipated in the
high side switch during the on cycle. Power loss is equal
to the high side MOSFET RDSON multiplied by the Switch
Current squared. During the off cycle, the low side N-
• DC resistance (DCR)
The MIC23031 was designed for use with an inductance
range from 0.47µH to 4.7µH. Typically, a 1µH inductor is
recommended for a balance of transient response,
efficiency and output ripple. For faster transient
response, a 0.47µH inductor will yield the best result. For
lower output ripple, a 4.7µH inductor is recommended.
May 2008
⎞⎤
⎟⎥
⎠⎦
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Micrel Inc.
MIC23031
minimum-on-time. This increases the output voltage. If
the output voltage is over the regulation threshold, then
the error comparator turns the PMOS off for a minimumoff-time until the output drops below the threshold. The
NMOS acts as an ideal rectifier that conducts when the
PMOS is off. Using a NMOS switch instead of a diode
allows for lower voltage drop across the switching device
when it is on. The asynchronous switching combination
between the PMOS and the NMOS allows the control
loop to work in discontinuous mode for light load
operations. In discontinuous mode, the MIC23031 works
in pulse frequency modulation (PFM) to regulate the
output. As the output current increases, the off-time
decreases, thus provides more energy to the output.
This switching scheme improves the efficiency of
MIC23031 during light load currents by only switching
when it is needed. As the load current increases, the
MIC23031 goes into continuous conduction mode (CCM)
and switches at a frequency centered at 4MHz. The
equation to calculate the load when the MIC23031 goes
into continuous conduction mode may be approximated
by the following formula:
channel MOSFET conducts, also dissipating power.
Device operating current also reduces efficiency. The
product of the quiescent (operating) current and the
supply voltage represents another DC loss. The current
required driving the gates on and off at a constant 4MHz
frequency and the switching transitions make up the
switching losses.
Efficiency VOUT = 2.5V
100
= 3.0V
90
= 3.6V
80
= 4.2V
70
60
50
1
L
10
100
1000
OUTPUT CURRENT (mA)
The figure above shows an efficiency curve. From no
load to 100mA, efficiency losses are dominated by
quiescent current losses, gate drive and transition
losses. By using the Hyper Light Load™ mode, the
MIC23031 is able to maintain high efficiency at low
output currents.
Over 100mA, efficiency loss is dominated by MOSFET
RDSON and inductor losses. Higher input supply voltages
will increase the Gate-to-Source threshold on the
internal MOSFETs, thereby reducing the internal RDSON.
This improves efficiency by reducing DC losses in the
device. All but the inductor losses are inherent to the
device. In which case, inductor selection becomes
increasingly critical in efficiency calculations. As the
inductors are reduced in size, the DC resistance (DCR)
can become quite significant. The DCR losses can be
calculated as follows:
L Pd = IOUT2 × DCR
From that, the loss in efficiency due to inductor
resistance can be calculated as follows:
⎡ ⎛
VOUT × I OUT
Efficiency Loss = ⎢1 − ⎜⎜
⎢⎣ ⎝ VOUT × I OUT + L _ PD
⎛ (V − VOUT ) × D ⎞
I LOAD = ⎜⎜ IN
⎟⎟
2L × f
⎠
⎝
As shown in the previous equation, the load at which
MIC23031 transitions from Hyper Light Load™ mode to
PWM mode is a function of the input voltage (VIN), output
voltage (VOUT), duty cycle (D), inductance (L) and
frequency (f). This is illustrated in the graph below. Since
the inductance range of MIC23031 is from 0.47µH to
4.7µH, the device may then be tailored to enter Hyper
Light Load™ mode or PWM mode at a specific load
current by selecting the appropriate inductance. For
example, in the graph below, when the inductance is
4.7µH the MIC23031 will transition into PWM mode at a
load of approximately 4mA. Under the same condition,
when the inductance is 1µH, the MIC23031 will transition
into PWM mode at approximately 70mA.
⎞⎤
⎟⎥ × 100
⎟
⎠⎥⎦
10
=
1
Efficiency loss due to DCR is minimal at light loads and
gains significance as the load is increased. Inductor
selection becomes a trade-off between efficiency and
size in this case.
=
=
0.1
=
0.01
Hyper Light Load™ Mode
MIC23031 uses a minimum on and off time proprietary
control loop (patented by Micrel). When the output
voltage falls below the regulation threshold, the error
comparator begins a switching cycle that turns the
PMOS on and keeps it on for the duration of the
May 2008
SW Frequency
vs Output Current
0.001
1
12
10
100
1000
OUTPUT CURRENT (mA)
M9999-051608-A
Micrel Inc.
MIC23031
MIC23031 Typical Application Circuit (Fixed 1.8V)
U1 MIC23031
VIN
2.7 to 5.5V
1
VIN
SW 2
EN
SNS 3
C1
EN
VOUT
L1
C2
4
AGND
5
GND
PGND
6
GND
Bill of Materials
Item
C1, C2
L1
Part Number
(1)
Description
C1608X5R0J475K
TDK
4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603
LQM21PN1R0M00
Murata(2)
1µH, 0.8A, 190mΩ, L2mm x W1.25mm x H0.5mm
LQH32CN1R0M33
Murata(2)
1µH, 1A, 60mΩ, L3.2mm x W2.5mm x H2.0mm
LQM31PN1R0M00
(2)
Murata
1µH, 1.2A, 120mΩ, L3.2mm x W1.6mm x H0.95mm
GLF251812T1R0M
TDK(1)
1µH, 0.8A, 100mΩ, L2.5mm x W1.8mm x H1.35mm
LQM31PNR47M00
Murata(2)
0.47µH, 1.4A, 80mΩ, L3.2mm x W1.6mm x H0.85mm
MIPF2520D1R5
U1
Manufacturer
MIC23031-xYMT
FDK
(3)
Micrel, Inc.
Qty.
2
1
1.5µH, 1.5A, 70mΩ, L2.5mm x W2mm x H1.0mm
(4)
4MHz 400mA Buck Regulator with Hyper Light Load™ Mode
1
Notes:
1. TDK: www.tdk.com
2. Murata: www.murata.com
3. FDK: www.fdk.co.jp
4. Micrel, Inc.: www.micrel.com
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MIC23031
MIC23031 Typical Application Circuit (Adjustable 1.8V)
U1 - MIC23031
VIN
1
SW
VIN
C1
EN
4
VOUT
2
L1
SNS 3
FB 5
EN
GND
6
GND
R1
383k
R2
200k
C2
GND
Bill of Materials
Item
C1, C2
R1
R2
L1
Part Number
Manufacturer
Description
C1608X5R0J475K
TDK(1)
4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603
2
383kΩ, 1%, Size 0603
1
1
CRCW06033833FT1
Vishay
(2)
CRCW06032003FT1
Vishay
200kΩ, 1%, Size 0603
LQM21PN1R0M00
Murata(3)
1µH, 0.8A, 190mΩ, L2mm x W1.25mm x H0.5mm
LQH32CN1R0M33
Murata(3)
1µH, 1A, 60mΩ, L3.2mm x W2.5mm x H2.0mm
LQM31PN1R0M00
(3)
Murata
TDK
LQM31PNR47M00
Murata(3)
MIC23031-AYMT
1µH, 1.2A, 120mΩ, L3.2mm x W1.6mm x H0.95mm
(1)
GLF251812T1R0M
MIPF2520D1R5
U1
(2)
Qty.
1
1µH, 0.8A, 100mΩ, L2.5mm x W1.8mm x H1.35mm
0.47µH, 1.4A, 80mΩ, L3.2mm x W1.6mm x H0.85mm
(4)
1.5µH, 1.5A, 70mΩ, L2.5mm x W2mm x H1.0mm
FDK
(5)
Micrel, Inc.
4MHz 400mA Buck Regulator with Hyper Light Load™ Mode
1
Notes:
1. TDK: www.tdk.com
2. Vishay: www.vishay.com
3. Murata: www.murata.com
4. FDK: www.fdk.co.jp
5. Micrel, Inc.: www.micrel.com
May 2008
14
M9999-051608-A
Micrel Inc.
MIC23031
PCB Layout Recommendations (Fixed)
Fixed Top Layer
Fixed Bottom Layer
May 2008
15
M9999-051608-A
Micrel Inc.
MIC23031
PCB Layout Recommendations (Adjustable)
Adjustable Top Layer
Adjustable Bottom Layer
May 2008
16
M9999-051608-A
Micrel Inc.
MIC23031
Package Information
6-pin 1.6mm x 1.6mm Thin MLF® (MT)
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
The 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.
© 2008 Micrel, Incorporated.
May 2008
17
M9999-051608-A