MIC2174-1YMM-3A Evaluation Board User Guide

MIC2174 3A Evaluation Board
Constant Frequency, Synchronous
Buck Controller Featuring Adaptive OnTime Control
Hyper Speed ControlTM Family
General Description
TM
MIC2174, a member of the new Hyper Speed Control
family of buck controllers introduced by Micrel, is a
synchronous, adaptive on-time buck controller. This
controller is targeted for cost sensitive applications
requiring high performance. The MIC2174 operates over
an input supply range of 3V to 40V, and is independent of
the IC supply voltage.
Data sheets support documentation can be found on
Micrel’s web site at www.micrel.com.
Requirements
The MIC2174 evaluation board requires two power
supplies: one to provide VIN (connect to HSD pin of
MIC2174), and the other to provide VDD (connect to IN pin
of the MIC2174) for the control circuitry. The VIN power
supply should be able to deliver greater than 3.0V at over
3A. The VDD power source, which is recommended to be
5.0V typical, should be able to deliver greater than 3.0V.
The typical VDD current is a few milliamps. An external
20mA minimum power supply is recommended for VDD.
Precautions
The evaluation board does not have reverse polarity
protection. Applying a negative voltage to the VIN or VDD
terminal may damage the device. In addition, the
maximum VIN operating voltage of the MIC2174
evaluation board is 40V, and the maximum VDD operation
voltage is 5.5V. Exceeding 42V on VIN or exceeding 6V on
VDD could damage the device.
An external VDD power supply is required and it should be
turned on no earlier than VIN power supply to make sure
the soft-start behavior properly.
Getting Started
1. Connect an external supply to VIN terminal. Apply
desired input voltage to the VIN (J1) and ground (J4)
terminals of the evaluation board, paying careful attention
to polarity and supply voltage (3.0V<VIN<40V). An
ammeter may be placed between the input supply and the
VIN terminal to the evaluation board. Ensure the supply
voltage is monitored at the VIN terminal. The ammeter
and/or power lead resistance can reduce the voltage
supplied to the input.
2. Connect an external supply to VDD terminal. Apply
desired input voltage to the VDD (J6) and ground (J5)
terminals of the evaluation board, paying careful attention
to polarity and supply voltage (3.0V<VDD<5.5V). The VDD
power supply should be turned on no earlier than VIN
power supply. The recommended voltage for VIN is 5V.
3. Connect the load to the VOUT and ground terminals.
The load can be either passive (resistive) or active (as in
an electronic load). An ammeter can be placed between
the load and the VOUT (J2) terminal. Ensure the output
voltage is monitored at the VOUT terminal. The default
VOUT is set to 1.8V. This can be adjusted by changing the
feedback resistors. See “Output Voltage.”
4. Enable the MIC2174. The enable pin is floating by
default. The output of the MIC2174 turns on when VDD
exceeds the UVLO threshold. The output of the MIC2174
may be turned off by shorting the enable pin to ground or
bringing the enable pin below the enable threshold. An
external connection on the board provides easy access to
the enable pin.
Output Voltage
The output voltages on the MIC2174 evaluation board are
adjustable. The output voltage is controlled by the
feedback resistors (R4 and R6) and can be calculated as
follows:
VOUT = VREF × (1 +
R4
)
R6
where VREF = 0.8V.
The evaluation board is preset at a 1.8V output, but can
easily be modified by removing R6 and replacing it with the
value that yields the desired output voltage.
R6 =
R 4 × VREF
VOUT − VREF
For VREF = 0.8V, this reduces to:
Hyper Speed Control is a trademark of Micrel, 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
December 2009
M9999-122309-A
Micrel, Inc.
MIC2164 5A Evaluation Board
R 4 × 0 .8 V
VOUT − 0.8 V
Ensure the output voltage set does not exceed 5V, since
the output capacitor has a 6.3V voltage rating. When the
output voltage greater than 5V is desired, the output
capacitor should be replaced with higher voltage rating.
Ordering Information
R6 =
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Part Number
Description
Package
MIC2174-1YMM
MIC2174-1YMM
3A EV
IC
10-pin MSOP
Evaluation Board
10-pin MSOP
M9999-122309-A
Micrel, Inc.
MIC2174 3A Evaluation Board
Bill of Materials
Item
C1
C2
C4,C5,C13
Part Number
B41112A8336M
12105C475KAZ2A
GRM32ER71H475KA88L
12106D107MAT2A
GRM32ER60J107ME20L
06035C104KAT2A
C3, C6, C8, C10
GRM188R71H104KA93D
C1608X7R1H104K
0805ZC225MAT2A
C7
GRM21BR71A225KA01L
C2012X7R1A225K
06035C102KAT2A
C11
C12
D1
L1
December 2009
GRM188R71H102KA01D
Manufacturer
EPCOS
(1)
Qty
33µF Aluminum Capacitor, SMD, 63V
1
4.7µF Ceramic Capacitor, X7R, Size 1210, 50V
1
100µF Ceramic Capacitor, X5R, Size 1210, 6.3V
3
0.1µF Ceramic Capacitor, X7R, Size 0603, 50V
4
2.2µF Ceramic Capacitor, X7R, Size 0805, 10V
1
1nF Ceramic Capacitor, X7R, Size 0603, 50V
1
10nF Ceramic Capacitor, X7R, Size 0603, 50V
1
Small Signal Schottky Diode
1
10µH Inductor, 3.8A Saturation Current
1
(2)
AVX
Murata
(3)
AVX
Murata
AVX
Murata
TDK
(4)
AVX
Murata
TDK
AVX
Murata
C1608X7R1H102K
TDK
06035C103KAZ2A
AVX
GRM188R71H103K
Murata
C1608X7R1H103K
TDK
SD103AWS-7
Description
Diodes Inc
(5)
(6)
SD103AWS
Vishay
CDRH104RNP-100
Sumida
(7)
3
M9999-122309-A
Micrel, Inc.
MIC2174 3A Evaluation Board
60V 7.5A N-Channel MOSFET 26.5mΩ Rds(on)
@ 4.5V
1
Vishay Dale
2.21Ω Resistor, Size 0603, 1%
1
CRCW06031R21FKEA
Vishay Dale
1.21Ω Resistor, Size 0603, 1%
1
R3
CRCW060319K6FKEA
Vishay Dale
19.6kΩ Resistor, Size 0603, 1%
1
R4
CRCW060310K0FKEA
Vishay Dale
10kΩ Resistor, Size 0603, 1%
1
R5
CRCW060320R0FKEA
Vishay Dale
20Ω Resistor, Size 0603, 1%
1
R6
CRCW06038K06FKEA
Vishay Dale
8.06kΩ Resistor, Size 0603, 1%
1
300kHz Buck Controller
1
Q1,Q2
FDS5682
R1
CRCW06032R21FKEA
R2
U1
MIC2174YMM
Fairchild
(8)
(9)
Micrel. Inc.
Notes:
1. EPCOS: www.epcos.com
2. AVX: www.avx.com
3. Murata: www.murata.com
4. TDK: www.tdk.com
5. Diodes Inc: www.diodes.com
6. Vishay: www.vishay.com
7. Sumida: www.sumida.com
8. Fairchild: www.fairchildsemi.com
9. Micrel, Inc.: www.micrel.com
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Micrel, Inc.
MIC2174 3A Evaluation Board
Printed Circuit Board Layouts
Figure 1a. Top Layer
Figure 1b. Bottom Layer
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M9999-122309-A
Micrel, Inc.
MIC2174 3A Evaluation Board
Figure 1c. Mid Layer 1 (GND Plane)
Figure 1d. Mid Layer 2
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M9999-122309-A
Micrel, Inc.
MIC2174 3A Evaluation Board
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.
December 2009
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