Micrel MIC33050, MIC33050 CYHL EV, MIC33050 4YHL EV, MIC33050 GYHL EV, MIC33050 SYHL EV User Manual

MIC33050 Evaluation Board

4MHz Internal Inductor PWM Buck

Regulator with HyperLight Load®

HyperLight Load is a trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com

March 24, 2014

1

Revision 4.0

Part Number

Description

MIC33050-CYHL EV

1.0V Fixed Output Evaluation Board

MIC33050-4YHL EV

1.2V Fixed Output Evaluation Board

MIC33050-GYHL EV

1.8V Fixed Output Evaluation Board

MIC33050-SYHL EV

3.3V Fixed Output Evaluation Board

MIC33050-AYHL EV

Adjustable Output Evaluation Board

General Description

Getting Started

The MIC33050 is a 600mA 4MHz switching regulator
featuring HyperLight Load® mode. The MIC33050 is
highly efficient throughout the entire output current
range, drawing just 20µA of quiescent current in
operation. The tiny 3mm x 3mm MLF® package, in
combination with the 4MHz switching frequency, enables
a compact sub-1mm height solution with only three
external components. The MIC33050 provides accurate
output voltage regulation under the most demanding
conditions and responds extremely quickly to a load
transient with exceptionally small output voltage ripple.

Factoring in the output current, the internal circuitry of
the MIC33050 automatically selects between two modes
of operation for optimum efficiency. Under light load
conditions, the MIC33050 goes into HyperLight Load
mode. HyperLight Load uses a pulse-frequency
modulation (PFM) control scheme that controls the off
time at light load. This proprietary architecture reduces
the amount of switching needed at light load, thereby
increasing operating efficiency. The MIC33050 attains
up to 83% efficiency at 1mA output load. As the load
current increases beyond approximately 100mA, the
device operates using the pulse-width modulation
(PWM) method for up to 93% efficiency at higher load.
The two modes of operation ensure the highest
efficiency across the entire load range.

The MIC33050 operates from an input voltage range of

2.7V to 5.5V and features internal power MOSFETs that
deliver up to 600mA of output current. This step-down
regulator provides an output voltage accuracy of ±2.5%
across the junction temperature range of 40ºC to
+125ºC. The MIC33050 is available in fixed or adjustable
versions supporting an output voltage as low as 0.7V.

Requirements

The MIC33050 evaluation board requires an input power
source that is able to deliver greater than 650mA at

2.7V. The output load can either be an active (electronic)
or passive (resistive) load.

1. Connect an external supply to the VIN (J1)
terminal. Apply the desired input voltage to VIN (J1)
and ground (J2) terminals of the evaluation board,
paying careful attention to polarity and supply

voltage (2.7V ≤ V

≤ 5.5V). An ammeter may be

IN

placed between the input supply and the VIN (J1)
terminal. Be sure to monitor the supply voltage at
the VIN (J1) terminal, since the ammeter and/or
power lead resistance can reduce the voltage
supplied to the device.

2. Connect a load to the V

(J3) and ground

OUT

terminal (J4). The load can be either passive

(resistive) or active (electronic load). An ammeter
may be placed between the load and the output
terminal. Ensure the output voltage is monitored at
the V

(J3) terminal.

OUT

3. Enable the MIC33050. The MIC33050 evaluation
board has a pull-up resistor to VIN. To disable the
device, apply a voltage below 0.5V to the EN (J5)
terminal. In the absence of the pull-up resistor, the
device is enabled by applying a voltage greater than

1.2V to the EN (J5) terminal. The enable pin must be
either pulled high or low for proper operation.
Removing the pull-up resistor and leaving the pin
floating will cause the regulator to operate in an
unknown state.

Output Voltage

The MIC33050 evaluation board is available with the
following output voltage options listed in Ordering
Information.

Ordering Information

Micrel, Inc.

MIC33050 Evaluation Board

March 24, 2014

2

Revision 4.0













R3

R2

10.4VV

OUT











 1

0.4V

V

R3R2

OUT











 1

0.4V

2.5V

100kΩR2

















f2L

D)V(V

I

OUT

IN

LOAD

0.001

0.01

0.1

1

10

1 10 100 1000 10000

SW FREQUENCY (MHz)

OUTPUT CURRENT (mA)

SW Frequency

vs Output Current

L = 4.7µH
V

OUT

= 1.8V

C

OUT

= 4.7µF

VIN = 3.0V

VIN = 3.6V

VIN = 4.2V

Output Voltage (Adjustable Option Only)

The output voltage of the MIC33050-AYHL is set by the
feedback resistors R2 and R3. Follow the equation and
circuit below to determine V

OUT

:

Eq. 1

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 MIC33050 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 MIC33050 during light
load currents by only switching when it is needed. As the
load current increases, the MIC33050 goes into
continuous conduction mode (CCM) and switches at a
frequency centered at 4MHz. The equation to calculate
the load when the MIC33050 goes into continuous
conduction mode may be approximated by the following
formula:

Figure 1. Typical Circuit for MIC33050-AYHL (V

= 1.8V)

OUT

The default output voltage for the evaluation board is set
to 1.8V (R2=348kΩ, R3=100kΩ). A different output
voltage can be obtained by removing R2 and replacing it
with the desired resistance. The equation below can be
used to find R2:

Eq. 2

Changing the output voltage to 2.5V, assuming
R3=100kΩ, can be accomplished via the equation
below:

Eq. 3

The result is 523kΩ for R2 which gives an output voltage
of 2.5V.

Eq. 4

As shown in the previous equation, the load at which
MIC33050 transitions from HyperLight Load mode to
PWM mode is a function of the input voltage (VIN), output
voltage (V

), duty cycle (D), inductance (L) and

OUT

frequency (f). As shown in Figure 1, as the Output
Current increases, the switching frequency also
increases until the MIC33050 goes from HyperLight
Load mode to PWM mode at approximately 120mA. The
MIC33050 will switch at a relatively constant frequency
around 4MHz once the output current is over 120mA.

HyperLight Load Mode

MIC33050 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.

Figure 2. SW Frequency vs. Output Current

Micrel, Inc.

MIC33050 Evaluation Board

March 24, 2014

3

Revision 4.0

Item

Part Number

Manufacturer

Description

Qty.

C1, C2

C1608X5R0J475K

TDK

(1)

4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603

2

C3

C1608C0G1H561J

TDK

560pF Ceramic Capacitor, 50V, NPO, Size 0603

1

R1

CRCW0603100KFKEA

Vishay

(2)

100kΩ, Tolerance 1%, Size 0603

1

U1

MIC33050-xYHL

Micrel, Inc.

(3)

4MHz Internal Inductor PWM Buck Regulator with
HyperLight Load Mode

1

MIC33050 Typical Circuit (Fixed)

Bill of Materials

Notes:

1. TDK: www.tdk.com.

2. Vishay: www.vishay.com.

3. Micrel, Inc: www.micrel.com.

Micrel, Inc.

MIC33050 Evaluation Board

March 24, 2014

4

Revision 4.0

Item

Part Number

Manufacturer

Description

Qty.

C1, C2

C1608X5R0J475K

TDK

(1)

4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603

2

C3

C1608C0G1H121J

TDK

120pF Ceramic Capacitor, 50V, NPO, Size 0603

1

R1, R3

CRCW0603100KFKEA

Vishay

(2)

100kΩ, Tolerance 1%, Size 0603

2

R2

CRCW0603348KFKEA

Vishay

348kΩ, Tolerance 1%, Size 0603

1

U1

MIC33050-AYHL

Micrel, Inc.

(3)

4MHz Internal Inductor PWM Buck Regulator with
HyperLight Load Mode

1

MIC33050 Typical Circuit (Adjustable)

Bill of Materials

Notes:

1. TDK: www.tdk.com.

2. Vishay: www.vishay.com.

3. Micrel, Inc: www.micrel.com.

Micrel, Inc.

MIC33050 Evaluation Board

March 24, 2014

5

Revision 4.0

PCB Layout Recommendations

Top Layer

Bottom Layer

Micrel, Inc.

MIC33050 Evaluation Board

March 24, 2014

6

Revision 4.0

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL [phone] FAX [phone] WEB http://www.micrel.com

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information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,

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