MIC23060-G4YMT - Micrel, Inc.

MIC23060

Sequenced Power Management IC with

HyperLight Load™ DC/DC and

Dual Input LDO™

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

General Description

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 turn-

off 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

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.

Features

• 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 S2 S1 Sequence

X 0 0 ALL OFF

0 0 EN DC-DC ON 1st / OFF 1st

0 EN 0 LDO ON 1st / OFF 1st

1 0 EN DC-DC ON 1st / OFF 2nd

1 EN 0 LDO ON 1st / OFF 2nd

X 1 1 ALL ON

Micrel, Inc. MIC23060

April 2010 2 M9999-042210-B

> 2Mpixel Camera DSP power Supply

Ordering Information

Part Number Marking

Code

Nominal Output

Voltage1

Junction Temp.

Range Package2

MIC23060-G4YMT 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 Pin Function

1 PGND Power Ground.

2 DVIN DC/DC Supply Input Voltage.

3 AVIN Small signal circuitry and Auxiliary LDO Supply Input Voltage.

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 Analog Ground.

11 SW Switch (Output): Internal power MOSFET output switches.

12 NC Not Internally connected.

ePAD ePAD Not internally connected, connect to ground plane to maximize heat dissipation.

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April 2010 3 M9999-042210-B

Absolute Maximum Ratings(1)

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

Operating Ratings(2)

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 Typ Max Units

Supply Voltage Range 2.7 5.5 V

Under-Voltage Lockout Threshold (Rising) 2.45 2.55 2.65 V

UVLO Hysteresis 50 mV

Total Quiescent Current VS1/2 = High 43 µA

DLY Pin Current Source VDLY = 0V 0.75 1.25 1.75 µA

DLY Pin Threshold Voltage 1.25 V

Logic Low 0.2 V S1/S2/S3 Input Voltage

Logic High 1.2

VIL = < 0.2V 0.01 1 µA S1/S2/S3 Input Current

VIH = >1.2V 0.01 1 µA

DC/DC Converter

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 +2.5 %

Current Limit in PWM Mode 0.65 1 1.7 A

Output Voltage Line regulation VAVIN = VDVIN = 3.0V to 5.5V, ILOAD = 20mA 0.7 %

Output Voltage Load regulation 20mA < ILOAD DC/DC < 300mA

IOUT LDO = 0mA

0.5 %

PWM Switch ON-Resistance ISW = 100mA PMOS

ISW = -100mA NMOS

0.55

0.6



Frequency ILOAD DC/DC = 170mA, VOUT = 1.8V 4 MHz

Soft-start time VOUT = 0 to 90%, VAVIN = VDVIN = 3.6V 280 µs

Thermal Shutdown 160 oC

Thermal Shutdown Hysteresis 20 oC

Micrel, Inc. MIC23060

April 2010 4 M9999-042210-B

Parameter Condition Min Typ Max Units

LDO Regulator

Output Voltage Accuracy -3.0 +3.0 %

Load Regulation (6) I

OUT LDO = 100µA to 150mA 0.7 1.0 %

Ground Pin Current IOUT LDO = 100µA to 300mA 20 µA

70 dB Ripple Rejection F = up to 1kHz: COUT LDO = 1.0uF

F = 1kHz to 20kHz; COUT LDO = 1.0µF 45 dB

Current Limit VOUT = 0V 350 600 800 mA

Output Voltage Noise COUT LDO = 1.0µF, 10Hz to 100kHz 55 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) / JA. 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, 1.5k 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.

Micrel, Inc. MIC23060

April 2010 5 M9999-042210-B

Typical Characteristics

Voltage Accuracy

vs. Temperature

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

-40 -20 0 20 40 60 80 100 120 140

TEMPERATURE (°C)

VOUT (% of NOMINAL)

DC-DC Line Regulation

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

2.5 3.5 4.5 5.5

INPUT VOLTAGE (V)

REGULATION (%)

Quiescent Current

vs. Temperature

-40 -20 0 20 40 60 80 100 120 140

TEMPERATURE (°C)

QUIESCENT CURRENT (µA)

DC/DC P-Channel RDS

vs. Input Voltage

300

350

400

450

500

550

600

650

700

750

800

2.533.544.555.5

INPUT VOLTAGE (V)

RDSON (mΩ)

DC/DC N-Channel RDS

v s. Input Vo ltage

300

350

400

450

500

550

600

650

700

750

800

2.5 3 3.5 4 4.5 5 5.5

INPUT VOLTAG E (V)

RDSON (mΩ)

S1/S2/S3 Enable Threshold

vs. Temperature

400

500

600

700

800

900

1000

1100

-40 -20 0 20 40 60 80 100 120 140

TEMPERATURE (°C)

ENABLE THRESHOLD (mV)

UVLO

vs.Temperature

2.40

2.42

2.44

2.46

2.48

2.50

2.52

2.54

2.56

2.58

2.60

-40-200 20406080100120140

TEMPERATURE (°C)

START/STOP VOLTAGE (V)

DC/DC Load Regulation

1.72

1.74

1.76

1.78

1.80

1.82

1.84

1.86

1.88

0.1 1 10 100 1000

OUTPUT CURRENT (mA)

DC-DC OUTPUT VOLTAGE (V)

DC/DC Efficiency

vs. Output Current

100

0.1 1 10 100 1000

OUTPUT CURRENT (mA)

EFFICIENCY (%)

Delay Pin Current

vs. Input Voltage

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

2.5 3 3.5 4 4.5 5 5.5

INPUT VOLTAGE (V)

DELAY PIN CURRENT (µA)

Delay Pin Current

vs. Temperature

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

-40 -20 0 20 40 60 80 100 120 140

TEMPERATURE (°C)

DELAY PIN CURRENT (µA)

Delay Threshold

vs. Temperature

1.220

1.225

1.230

1.235

1.240

-40 -20 0 20 40 60 80 100 120 140

TEMPERATURE (°C)

DELAY THRESHOLD (V)

LDO Regulation DC-DC Regulation IOUT = 600mA

IOUT = 20mA

VIN = 3.6V

600mA

300mA

100mA

600mA

300mA

100mA

Sx(ON)

Sx(OFF)

UVLO(ON)

UVLO(OFF)

VIN=5V

VIN=4.2V

VIN=3.6V

VIN=3V VIN=5V

VIN=4.2V

VIN=3.6V

VIN=3V

T = 25°C VIN = 3.6V VIN = 3.6V

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Functional Characteristics

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April 2010 7 M9999-042210-B

Functional Characteristics (Continued)

Micrel, Inc. MIC23060

April 2010 8 M9999-042210-B

Functional Diagram

MIC23060 Block Diagram

Micrel, Inc. MIC23060

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Functional Description

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 2.2F bypass capacitor placed close to DVIN

and the power ground (PGND) pin is required. For best

performance a 4.7F capacitor is recommended, refer to

the layout recommendations for details.

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.

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

0.01A. 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.

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.

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.

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 1F is required.

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.

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.

Micrel, Inc. MIC23060

April 2010 10 M9999-042210-B

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 4.7F 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, 4.7F 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 MIC23060 was designed for use with a 2.2F or

greater ceramic output capacitor for the DC-DC section

and 1F 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, 4.7F 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.

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

• DC resistance (DCR)

The MIC23060 was designed for use with a 0.47H to

2.2H inductor. Typically, a 1H inductor is

recommended for a balance of transient response,

efficiency and output ripple. For faster transient

response, a 0.47H inductor will yield the best result. For

lower output ripple and improved regulation, a 2.2H

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:

⎥

⎦

⎤

⎢

⎣

⎡⎟

⎟

⎠

⎞

⎜

⎝

⎛

××

−

×+= Lf2

/VV1

VII INOUT

OUTOUTPEAK

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.

Compensation

The MIC23060 is designed to be stable with a 0.47H to

2.2H inductor with a minimum of 4.7F ceramic (X5R)

output capacitor for the DC/DC output (SNS) and 1F

ceramic (X5R) for the LDO (LDO). For 0.47H 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:

• S1=S2: Simultaneous (SIM)

• S3 = 0: First On/First Off (FOFO)

• S3 = 1: First On/Last Off (FOLO)

S3 is responsible for controlling the First-on/First-Off

Micrel, Inc. MIC23060

April 2010 11 M9999-042210-B

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 Sequence

X 0 0 ALL OFF

0 0 EN DC-DC ON 1st / OFF 1st

0 EN 0 LDO ON 1st / OFF 1st

1 0 EN DC-DC ON 1st / OFF 2nd

1 EN 0 LDO ON 1st / OFF 2nd

X 1 1 ALL ON

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:

DLY = VDLY.CDLY / IDLY

Where nominally: VDLY = 1.25V, IDLY = 1.25μA

∴ TDLY (ms) = CDLY (nF)

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

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.

100

(%)Efficiency

ININ

OUTOUT ×

⎟

⎠

⎞

⎜

⎝

⎛

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 N-

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.

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April 2010 12 M9999-042210-B

DC/DC Efficiency

vs. Output Current

100

0.1 1 10 100 1000

OUTPUT CURRENT (mA)

EFFICIENCY (%)

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:

100

L_PIV

1_LossEfficiency

DOUTOUT

OUTOUT ×

⎥

⎦

⎤

⎢

⎣

⎡

⎟

⎠

⎞

⎜

⎝

⎛

+×

−=

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.

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

the output voltage is over the regulation threshold, then

the error comparator turns the PMOS off for a minimum-

off-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:

(

)

⎟

⎠

⎞

⎜

⎝

⎛

××

×−

>fL2

DVV

IOUTIN

LOAD

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.

Switching Frequency

vs. Load Current

0.1

100

1000

10000

1E-05 0.0001 0.001 0.01 0.1 1

LOAD CURRENT (A)

FREQUENCY (kHz)

VIN=5V

VIN=3.6V VIN=3V

L=2.2µH

L=1µH

L=0.47µH

Micrel, Inc. MIC23060

April 2010 13 M9999-042210-B

Evaluation Board Schematic

Bill of Materials

Item Part Number Manufacturer Description Qty.

GRM188R60J475KE19D Murata(1)

C1, C2 C1608X5R0J475K TDK(2) Ceramic Capacitor, 4.7µF, 6.3V, X5R 2

C3 GRM188R71C105KA12D Murata Ceramic Capacitor, 1µF, 6.3V, X7R 1

C4 GRM188R71C103K Murata Ceramic Capacitor, 10nF, 6.3V, X7R 1

LQM2MPN2R2NG0L Murata 2mm x 1.6mm Multilayer Inductor, 2.2µH, 1.2A

L1 VLS201610ET-2R2M TDK 2mm x 1.6mm Power Inductor, 2.2µH, 1A 1

SW1 418121270803 Wurth(3) 2.54mm small SMD DIP Switch (w/raised actuator) 1

R1, R2,

R3 CRCW06031004FKEYE3 Vishay(4) Resistor, 1M, 1%. 1/16W, Size 0603 3

U1 MIC23060-G4YMT Micrel, Inc.(5) 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.

Micrel, Inc. MIC23060

April 2010 14 M9999-042210-B

PCB Layout Recommendations

Top Layer

Bottom Layer

Micrel, Inc. MIC23060

April 2010 15 M9999-042210-B

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

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