MICREL MIC23060

MIC23060
Sequenced Power Management IC with
HyperLight Load™ DC/DC and
Dual Input LDO™
General Description
Features
The MIC23060 is a highly efficient power management IC
integrating a high frequency DC/DC converter with
HyperLight Load™ mode and a low input voltage capable
LDO. The MIC23060 offers two output voltages at very
high efficiency on both outputs while maintaining a low
total system cost.
The MIC23060 also provides sequencing of the two
outputs in every potential combination of turn-on and turnoff sequencing by connecting two pins either high or low,
and using a single GPIO to enable and disable the device.
The LDO is designed both to post regulate from the output
of the DC/DC converter for high system efficiency, and/or
power directly from the battery. For sequences where the
LDO is enabled prior to the DC/DC output, the LDO is first
powered by the input voltage (typically the battery source)
and then after the DCDC soft start is complete, seamlessly
transition LDO input power to draw from the output of the
DC/DC converter for higher efficiency operation through
post-regulation.
The DC/DC converter in the MIC23060 is a HyperLight
Load™ converter with very high efficiency at light load and
at full operating current, maintaining high efficiency across
all operating modes in portable electronics.
The MIC23060 is a µCap design, operating with small
ceramic output capacitors and tiny inductors for stability,
reducing required board space and component cost and is
available in the tiny 2.5mm x 2.5mm Thin MLF® package.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• 2.7V to 5.5V supply voltage range
• Tiny 12-pin 2.5mm x 2.5mm Thin MLF® package
• Integrated sequencing
– Dual Input LDO™ can turn-on prior to DC/DC
converter and automatically switch to post regulation
from the DC/DC converter after it starts
– Power for LDO from input during start-up
– Adjustable delay time between outputs
• Zero-current off mode
• Current-limit and thermal shutdown protection
HyperLight Load™ DC/DC Converter
• Up to 600mA output current in PWM mode (shared
between switcher and linear LDO regulator outputs)
• 4MHz frequency in continuous PWM mode
• Tiny 2.2µH inductor, 4.7µF capacitor
• 85% Efficiency at 1mA output current
• >90% peak efficiency
• Low output voltage ripple across all loads
LDO Regulator
• Low Input voltage LDO regulator
• Stable with ceramic output capacitors
• Regulates from the output of the DC/DC converter
• 300mA output current capability
• High Accuracy: ±3% over temperature
• High PSRR: greater than 60dB
• Very low quiescent current: 16µA
Applications
• Mobile phones
• PDAs/pocket PCs
• Digital cameras/DSP power supply
_______________________________________________________________________________________________________________________________________
Typical Application
S3
X
0
0
1
S2
0
0
EN
0
S1
0
EN
0
EN
1
X
EN
1
0
1
Sequence
ALL OFF
DC-DC ON 1st / OFF 1st
LDO ON 1st / OFF 1st
DC-DC ON 1st / OFF 2nd
LDO ON 1st / OFF 2nd
ALL ON
HyperLight Load and Dual Input LDO are trademarks of Micrel, Inc
MLF and MicroLead frame are registered 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 2010
M9999-042210-B
Micrel, Inc.
MIC23060
> 2Mpixel Camera DSP power Supply
Ordering Information
Part Number
MIC23060-G4YMT
Marking
Code
Nominal Output
Voltage1
Junction Temp.
Range
Package2
XG4
1.8V/1.2V
–40° to +125°C
12-Pin 2.5mm x 2.5mm Thin MLF®
Note:
1. Refers to output voltage of DC/DC & LDO respectively. Other voltage options available. Contact Micrel for details.
a. DC/DC Converter Voltage Range: 1.7V to 2.5V
b. LDO Output Voltage Range: 0.8V to 2.5V
®
2. Thin MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
®
12-Pin 2.5mm x 2.5mm Thin MLF (MT)
(Top View)
Pin Description
Pin Number
Pin Name
1
PGND
Power Ground.
2
DVIN
DC/DC Supply Input Voltage.
3
AVIN
Small signal circuitry and Auxiliary LDO Supply Input Voltage.
April 2010
Pin Function
4
LDO
LDO Regulator Output.
5
SNS
Main LDO input supply and feedback for DC-DC converter. Connect to DC/DC VOUT to
sense output voltage.
6
DLY
Delay. Capacitor to AGND sets a delay time between the first regulator reaching 90% of
its regulated voltage and enabling the second regulator. Also programs the turn-off delay,
setting the time between the disable of each output. The on/off sequence of the
regulators is set by pins S1, S2 and S3. Do not ground.
7
S3
SET Input (3). Active High Input. Logic High = On; Logic Low = Off; do not leave floating.
See applications information for set pin configurations.
8
S2
SET Input (2). Active High Input. Logic High = On; Logic Low = Off; do not leave floating.
See applications information for set pin configurations.
9
S1
SET Input (1). Active High Input. Logic High = On; Logic Low = Off; do not leave floating.
See applications information for set pin configurations.
10
AGND
11
SW
12
NC
ePAD
ePAD
Analog Ground.
Switch (Output): Internal power MOSFET output switches.
Not Internally connected.
Not internally connected, connect to ground plane to maximize heat dissipation.
2
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MIC23060
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VAVIN, VDVIN).................................. 0V to 6V
Switch Voltage (VSW).............................................. 0V to 6V
Switch Current (ISW) .........................................................2A
Logic Input Voltage (VS1/2/3).......................... 0V to VIN+0.3V
Lead Temperature (soldering, 10sec.)....................... 260°C
Storage Temperature (Ts)..........................-65°C to +150°C
ESD Rating(4) ................................................. ESD Sensitive
Supply Voltage (VAVIN, VDVIN)........................ +2.7V to +5.5V
Output Voltage (VLDO).......................................... 0V to 5.5V
Logic Input Voltage (VS1/2/3).................................... 0V to VIN
Ambient Temperature (TJ)(3) ...................... –40°C to +125°C
Thermal Resistance
2.5mmx2.5mm Thin MLF-12L (θJA) ...................66°C/W
2.5mmx2.5mm Thin MLF-12L (θJC) ...................37°C/W
Electrical Characteristics(5)
VAVIN = VDVIN = 3.6V; IDC-DC = 20mA, ILDO = 100µA; L = 2.2µH; COUT = 4.7µF; COUTLDO = 1µF; TA = 25°C.
Bold values indicate –40°C≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min
2.7
Supply Voltage Range
Under-Voltage Lockout Threshold
2.45
(Rising)
UVLO Hysteresis
Total Quiescent Current
VS1/2 = High
DLY Pin Current Source
VDLY = 0V
0.75
DLY Pin Threshold Voltage
S1/S2/S3 Input Voltage
Typ
2.55
Max
Units
5.5
V
2.65
V
50
mV
43
µA
1.25
1.75
1.25
Logic Low
µA
V
0.2
V
1.2
Logic High
VIL = < 0.2V
0.01
1
µA
VIH = >1.2V
0.01
1
µA
Quiescent Current, Hyper LL mode
IOUT = 0mA
25
35
µA
Shutdown Current
S1 = S2 = S3 = 0V
0.01
5
µA
Output Voltage Accuracy
Nominal VOUT tolerance
+2.5
%
1.7
A
S1/S2/S3 Input Current
DC/DC Converter
-2.5
0.65
Current Limit in PWM Mode
Output Voltage Line regulation
Output Voltage Load regulation
1
VAVIN = VDVIN = 3.0V to 5.5V, ILOAD = 20mA
0.7
%
20mA < ILOAD DC/DC < 300mA
0.5
%
ISW = 100mA PMOS
0.55
Ω
ISW = -100mA NMOS
0.6
IOUT LDO = 0mA
PWM Switch ON-Resistance
Frequency
ILOAD DC/DC = 170mA, VOUT = 1.8V
Soft-start time
VOUT = 0 to 90%, VAVIN = VDVIN = 3.6V
Thermal Shutdown
Thermal Shutdown Hysteresis
April 2010
3
4
MHz
280
µs
160
o
C
20
o
C
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Micrel, Inc.
MIC23060
Parameter
Condition
Min
Typ
Max
Units
+3.0
%
1.0
%
LDO Regulator
-3.0
Output Voltage Accuracy
Load Regulation
(6)
IOUT LDO = 100µA to 150mA
0.7
Ground Pin Current
IOUT LDO = 100µA to 300mA
20
µA
Ripple Rejection
F = up to 1kHz: COUT LDO = 1.0uF
70
dB
F = 1kHz to 20kHz; COUT LDO = 1.0µF
45
dB
Current Limit
VOUT = 0V
350
Output Voltage Noise
COUT LDO = 1.0µF, 10Hz to 100kHz
600
55
800
mA
µVRMS
Notes:
1. Exceeding maximum rating may damage the device.
2. The device is not guaranteed to work outside its operating rating.
3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) - TA) / θJA. Exceeding the maximum allowable power
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
5. Specification for packaged product only.
6. Regulation is measured at constant junction temperature using low duty cycle pulse testing; changes in the output voltage due to heating effects are
covered by the thermal regulation specification.
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MIC23060
Typical Characteristics
Voltage Accuracy
v s. Tem perature
50
0.04
45
0.03
1.0
0.5
0.0
-0.5
-1.0
LDO Regulation
DC-DC Regulation
IOUT = 20mA
0.02
REGULATION (%)
0.01
0.00
-0.01
-0.02
IOUT = 600mA
-0.03
-1.5
-0.04
-2.0
0
20 40 60 80 100 120 140
T EM PERAT URE (°C)
2.5
800
800
750
750
300mA
550
500
100mA
450
300mA
450
350
300
100mA
500
350
5
5.5
2.5
1.88
2.58
1.86
DC-DC OUTPUT VOLTAGE (V)
START/STOP VOLTAGE (V)
2.60
2.56
2.54
UVLO(ON)
2.50
2.48
2.46
UVLO(OFF)
2.44
2.42
2.40
3
3.5
4
4.5
INPUT VOLT AGE (V)
5
0
1.78
VIN=3.6V
1.15
1.10
T = 25°C
1.00
1000
5.5
70
60
VIN=3.6V
VIN=4.2V
50
VIN=5V
40
30
0.1
1.30
1.25
1.20
1.15
1.10
1.05
1
10
100
O UT PUT CURRENT (mA)
1000
Delay Threshold
v s. Temperature
Delay Pin Current
v s. Temperature
1.240
1.235
1.230
1.225
VIN = 3.6V
1.00
5
VIN=3V
0
1
10
100
OUT PUT CURRENT (mA)
DELAY THRESHOLD (V)
DELAY PIN CURRENT (µA)
1.20
0 20 40 60 80 100 120 140
T EM PERAT URE (°C)
10
0.1
1.35
April 2010
500
20
1.74
1.40
3.5
4
4.5
INPUT VOLT AGE (V)
Sx(OFF)
600
80
VIN=3V
1.76
1.35
3
700
-40 -20
VIN=4.2V
1.80
1.40
2.5
800
DC/DC Efficiency
v s. Output Current
1.82
Delay Pin Current
v s. Input Voltage
1.05
Sx(ON)
900
90
VIN=5V
T EM PERAT URE (°C)
1.25
20 40 60 80 100 120 140
T EM PERAT URE (°C)
100
1.84
20 40 60 80 100 120 140
1.30
0
1000
5.5
1.72
-40 -20
VIN = 3.6V
5
DC/DC Load Regulation
UVLO
v s.Tem perature
2.52
10
400
300
3.5
4
4.5
INPUT VOLT AGE (V)
15
1100
550
400
3
20
S1/S2/S3 Enable Threshold
v s. Temperature
600
400
2.5
25
600mA
650
600mA
600
30
-40 -20
5.5
700
RDSON (mΩ)
RDSON (mΩ)
650
35
DC/DC N-Channel RDS ON
v s. Input Voltage
DC/DC P-Channel RDS ON
v s. Input Voltage
700
3.5
4.5
INPUT VO LT AG E (V)
ENABLE THRESHOLD (mV)
-40 -20
40
0
-0.05
EFFICIENCY (%)
VOUT (% of NO M INAL)
1.5
0.05
QUIESCENT CURRENT (µA)
2.0
DELAY PIN CURRENT (µA)
Quiescent Current
v s. Tem perature
DC-DC Line Regulation
VIN = 3.6V
1.220
-40 -20
0
20 40 60 80 100 120 140
T EM PERAT URE (°C)
5
-40 -20
0 20 40 60 80 100 120 140
T EM PERAT URE (°C)
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MIC23060
Functional Characteristics
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MIC23060
Functional Characteristics (Continued)
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MIC23060
Functional Diagram
MIC23060 Block Diagram
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MIC23060
Functional Description
SNS
The feedback (SNS) pin is connected to the output of the
DC/DC converter 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.
DVIN
The main input supply (DVIN) provides power to the
internal MOSFETs for the switch mode regulator. The
DVIN 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 DVIN
and the power ground (PGND) pin is required. For best
performance a 4.7μF capacitor is recommended, refer to
the layout recommendations for details.
LDO
The LDO Output (LDO) pin is the output of the Dual
Input LDO™. Power is provided by the DC/DC output
during normal operation and briefly by VAVIN during some
start-up and Shutdown sequences. A ceramic bypass
capacitor of at least 1μF is required.
AVIN
The Analog input supply (AVIN) provides power to the
low power, biasing and control circuitry. Due to the high
switching speed of the DC/DC converter, this should
ideally be connected away from the DVIN bypass
capacitor at the input supply. Refer to layout
recommendations for more details.
DLY
The delay (DLY) pin is connected to an external
capacitor and AGND to set the delay time between the
first regulator output reaching 90% of its regulated
voltage and enabling the second regulator. The same
delay time is also used during shutdown.
S1/S2/S3
A logic high signal on the Set pins activates the output
voltage of the devices in various sequencing modes. A
logic low signal on the Set pins deactivates the outputs
in various sequences and reduces supply current to
0.01μA. Full details of start-up/shutdown sequencing are
given in the Application Information section. The
MIC23060 features built-in soft-start circuitry that
reduces in-rush current and prevents the output voltage
from overshooting at start up. Do not leave these pins
floating.
AGND
The analog ground (AGND) is the ground path for the
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.
PGND
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.
SW
The switch (SW) pin 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.
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MIC23060
The MIC23060 was designed for use with a 0.47μH to
2.2μH inductor. 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 and improved regulation, a 2.2μH
inductor is recommended.
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 MIC23060 is a high performance DC/DC step down
regulator plus Dual input Low Dropout linear regulator
offering a small solution size. Supporting a
recommended maximum output current of 300mA and
300mA respectively inside a tiny 2.5mm x 2.5mm Thin
MLF® package and requiring only four external
components, the MIC23060 meets today’s miniature
portable electronic device needs. Using the HyperLight
Load™ switching scheme, the MIC23060 DC/DC
converter 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.
Input Capacitor
A 4.7μF ceramic capacitor should be placed close to the
DVIN pin and PGND pin for decoupling the high di/dt
pulses of the DC-DC section from the LDO section. 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.
⎡
⎛ 1 − VOUT /VIN
IPEAK = ⎢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.
Output Capacitor
The MIC23060 was designed for use with a 2.2μF or
greater ceramic output capacitor for the DC-DC section
and 1μF for the LDO. 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 MIC23060 is designed to be stable with a 0.47μH to
2.2μH inductor with a minimum of 4.7μF ceramic (X5R)
output capacitor for the DC/DC output (SNS) and 1μF
ceramic (X5R) for the LDO (LDO). For 0.47μH inductors,
a 10µF capacitor is recommended to reduce ripple and
improve stability.
Enable Sequencing (S1/S2/S3)
The MIC23060 offers complete flexibility of start-up
sequencing of its two outputs. The sequence mode is set
in hardware (pin-strapping) which requires that only a
single GPIO be used for enable toggling. The Dual Input
LDO™ can turn-on prior to the DC/DC converter and
automatically switch to post regulation from the DC/DC
converter after it starts.
There are 3 modes available:
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
•
•
S1=S2: Simultaneous (SIM)
DC resistance (DCR)
•
S3 = 0: First On/First Off (FOFO)
• S3 = 1: First On/Last Off (FOLO)
S3 is responsible for controlling the First-on/First-Off
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MIC23060
modes, S2 controls the LDO sequence and S1 controls
the DC/DC sequence. Here is a Truth Table followed by
a flow chart of the sequencing events:
S3
S2
S1
X
0
0
0
0
EN
0
EN
0
1
0
EN
1
EN
0
LDO ON 1st / OFF 2nd
X
1
1
ALL ON
For example, an application where the LDO should be
enabled 50ms before the DC/DC and disabled 50ms
after the DC-DC, the pins should be set as follows:
S1 = 0
S3 = 1
CDLY = 50nF
S2 = Enable stimulus
Sequence
ALL OFF
st
st
DC-DC ON 1 / OFF 1
LDO ON 1st / OFF 1st
DC-DC ON 1st / OFF 2nd
Detail of the delay timer circuit.
Duty Cycle
The typical maximum duty cycle of the MIC23060 is
80%.
Efficiency Considerations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied.
⎛V
×I
Efficiency(%) = ⎜⎜ OUT OUT
⎝ VIN × IIN
⎞
⎟⎟ × 100
⎠
Maintaining high efficiency serves two purposes. It
reduces power dissipation in the power supply,
simplifying thermal design considerations, and it reduces
current consumption 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 Nchannel 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.
Flow Chart of the Enable & Disable sequence
DLY
The value of capacitor on this pin is used to program the
enable and disable delay times. The delay time follows
the following equation:
TDLY = VDLY.CDLY / IDLY
Where nominally: VDLY = 1.25V, IDLY = 1.25μA
∴ TDLY (ms) = CDLY (nF)
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MIC23060
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 MIC23060 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
MIC23060 during light load currents by only switching
when it is needed. As the load current increases, the
MIC23060 goes into continuous conduction mode (CCM)
and switches at a frequency centred at 4MHz. The
equation to calculate the load when the MIC23060 goes
into continuous conduction mode may be approximated
by the following formula:
DC/DC Efficiency
v s. Output Current
100
VIN=3.6V
90
VIN=3V
EFFICIENCY (%)
80
70
60
50
VIN=5V
40
30
20
10
0
0.1
1
10
100
OUT PUT CURRENT (mA)
1000
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 HyperLight Load™ mode, the
MIC23060 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 drive at 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:
DCR Loss = IOUT2 X DCR
From that, the loss in efficiency due to inductor
resistance can be calculated as follows:
⎡ ⎛
VOUT × IOUT
Efficiency_Loss = ⎢1 − ⎜⎜
⎢⎣ ⎝ VOUT × IOUT + L_PD
⎛ (V − VOUT ) × D ⎞
⎟⎟
ILOAD > ⎜⎜ IN
2×L× f
⎠
⎝
As shown in the previous equation, the load at which
MIC23060 transitions from HyperLight Load™ mode to
PWM mode is a function of the input voltage (VDVIN),
output voltage (VOUT), duty cycle (D), inductance (L)
and frequency (f). As shown in the figure below, as the
Output Current increases, the switching frequency also
increases until the MIC23060 goes from HyperLight
Load™ mode to PWM mode at approximately 120mA.
The MIC23060 will switch at a relatively constant
frequency around 4MHz once the output current is over
120mA.
⎞⎤
⎟⎥ × 100
⎟
⎠⎥⎦
Switching Frequency
v s. Load Current
10000
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.
L=1µH
FREQUENCY (kHz)
1000
HyperLight Load™ Mode
MIC23060 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
minimum-on-time. This increases the output voltage. If
April 2010
L=2.2µH
100
10
L=0.47µH
1
0.1
1E-05 0.0001 0.001
0.01
0.1
LOAD CURRENT (A)
12
1
M9999-042210-B
Micrel, Inc.
MIC23060
Evaluation Board Schematic
Bill of Materials
Item
C1, C2
Part Number
GRM188R60J475KE19D
Manufacturer
Murata
2
Murata
Ceramic Capacitor, 1µF, 6.3V, X7R
1
GRM188R71C103K
Murata
Ceramic Capacitor, 10nF, 6.3V, X7R
1
LQM2MPN2R2NG0L
Murata
2mm x 1.6mm Multilayer Inductor, 2.2µH, 1.2A
VLS201610ET-2R2M
TDK
TDK(2)
C3
GRM188R71C105KA12D
C4
SW1
R1, R2,
R3
U1
Qty.
Ceramic Capacitor, 4.7µF, 6.3V, X5R
C1608X5R0J475K
L1
Description
(1)
418121270803
Wurth
(3)
CRCW06031004FKEYE3
Vishay(4)
MIC23060-G4YMT
Micrel, Inc.(5)
2mm x 1.6mm Power Inductor, 2.2µH, 1A
1
2.54mm small SMD DIP Switch (w/raised actuator)
1
Resistor, 1M, 1%. 1/16W, Size 0603
3
Sequenced digital power management IC
1
Notes:
1. Murata: www.murata.com
2. TDK: www.tdk.com
3. Wurth Elektrik: www.we-online.com
4. Vishay: www.vishay.com.
5. Micrel, Inc.: www.micrel.com.
April 2010
13
M9999-042210-B
Micrel, Inc.
MIC23060
PCB Layout Recommendations
Top Layer
Bottom Layer
April 2010
14
M9999-042210-B
Micrel, Inc.
MIC23060
Package Information
®
12-Pin 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.
© 2009 Micrel, Incorporated.
April 2010
15
M9999-042210-B