MIC22205 Evaluation Board
2A Integrated Switch High-Efficiency
Synchronous Buck Regulator
General Description
The Micrel MIC22205 is a high-efficiency, 2A, integrated
switch, synchronous buck (step-down) regulator. It is
frequency programmable up to 4MHz. The MIC22205
achieves more than 95% efficiency and switches at
1MHz. The ultra-high-speed control loop keeps the
output voltage within regulation even under the extreme
transient load swings commonly found in FPGAs and
low-voltage ASICs. The output voltage is pre-bias safe
and is adjustable down to 0.7V.
The MIC22205 offers a full range of sequencing and
tracking options. The Enable/Delay (EN/DLY) and
Power Good (PG) inputs allow versatile turn-on and
turn-off sequencing across multiple devices. The Ramp
Control™ (RC) input allows start-up voltage tracking,
either directly or ratio-metrically.
The MIC22205 is available in a 12-pin 3mm x 3mm
®
MLF with a junction operating range from –40°C to
+125°C.
Data sheets and support documentation are available
on the Micrel web site:
www.micrel.com.
Requirements
The MIC22205YML EV requires a power supply of 2.9V
to 5.5V, and a test load. Make sure that the power
supply can provide the wattage needed for the chosen
test load. The load can be active (electronic load) or
passive (resistor). Additionally, monitor the Power Good
output (PG) with a multimeter or an oscilloscope.
Precautions
There is no reverse input protection on this board. While
connecting supplies and signals, make sure that correct
polarities are observed.
Getting Started
1. V
IN
Supplies
Connect the V
IN
supply (2.9V to 5.5V) across the VIN
and PGND terminals. Monitor V
IN
at the VIN and PGND
terminals with a voltmeter. TP9 is a 4-pin header test
point provided for monitoring VIN.
2. Enable
The enable input EN is internally pulled up with a 1µA
current source.
3. Monitor Outputs
Monitor the output V
OUT
with a scope or DVM connected
across the VOUT and PGND terminals. TP11 is a 4-pin
header test point provided for monitoring VOUT.
4. Output Load
Connect a load across the VOUT and PGND terminals.
Use an active or passive load.
5. Turn On the Power
Turn on the power supply and verify that V
OUT
= 1.8V.
Ordering Information
Part Number
MIC22205YML EV
Description
Evaluation Board for the MIC22205YML
Ramp Control 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 +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
September 2012
M9999-092112-A
Micrel, Inc.
MIC22205 Evaluation Board
Evaluation Board Features
See the
MIC22205YML Data Sheet
for detailed
explanations of these functions.
Enable/Delay (EN/DLY)
Enable/Delay allows delayed turn-on of the MIC22205.
Install a capacitor in location C7 to increase the start-up
delay of the MIC22205.
t
EN/DLY
=
1.24
×
C
7
1
×
10
−
6
Ramp Control (RC)
Ramp control allows slowing the slew rate of the
MIC22205 output. Increase the value of capacitor C6 to
reduce the slew rate.
t
RAMP
=
0.7
×
C
6
1
×
10
−
6
Power On Reset Output (POR)
Open drain output POR pulls low when the output
voltage of the MIC22205 is out of specification. POR is
pulled up to V
IN
by a 47.5kΩ resistor.
Switch Voltage (V
SW
)
Test point V
SW
is provided to monitor the internal
switching node. V
SW
is isolated from the switch node by
49.9Ω resistor R7. TP10 is a 2-pin header test point
provided for monitoring switch voltage.
September 2012
2
M9999-092112-A
Micrel, Inc.
MIC22205 Evaluation Board
Typical Characteristics
Efficiency (V
IN
= 5.0V)
vs. Output Current
100
95
0.72
IC Power Dissipation (V
IN
= 5.0V)
vs. Output Current
POWER DISSIPATION (W)
0.60
0.48
0.36
0.24
0.12
0.00
90
3.3V
OUT
2.5V
OUT
1.8V
OUT
1.5V
OUT
1.2V
OUT
1.0V
OUT
0.9V
OUT
0.8V
OUT
V
IN
= 5V
0.7V
OUT
EFFICIENCY (%)
85
80
75
70
65
60
55
50
0
0.6
1.2
1.8
Curves Top to Bottom
3.3V
OUT
1.2V
OUT
0.7V
OUT
2.4
3
0
0.4
0.8
1.2
1.6
2
OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
September 2012
3
M9999-092112-A
Micrel, Inc.
MIC22205 Evaluation Board
Evaluation Board Schematic
Bill of Materials
Item
C1
Part Number
C2012X5R0J106K
GRM2196R60J106K
08056D106KAT2A
C1608X5R0J225M
C2
GRM188R60J225M
06036D225MAT2A
C1608X7RH471K
C3
GRM188R71H471KA01D
06035C471KAT2A
C1608C0G1H470J
C5
GQM1885C1H470JB01D
06035A470JAT2A
C1608C0G1H221J
C6
GRM1885C1H221JA01D
06035A221JAT2A
C1608C0G1H102J
C7, C8
GRM1885C1H102JA01D
06035A102KAT2A
Manufacturer
TDK
(1)
Murata
(2)
AVX
(3)
TDK
Murata
AVX
TDK
Murata
AVX
TDK
Murata
AVX
TDK
Murata
AVX
TDK
Murata
AVX
Capacitor, 1nF, 50V, NPO, Size 0603
2
Capacitor, 220pF, 50V, NPO, Size 0603
1
Capacitor, 47pF, 50V, NPO, Size 0603
1
Capacitor, 470pF, 50V, X7R, Size 0603
Capacitor, 2.2µF, 6.3V, X5R, Size 0603
1
Capacitor, 10µF, 6.3V, X5R, Size 0805
1
Description
Qty.
September 2012
4
M9999-092112-A
Micrel, Inc.
MIC22205 Evaluation Board
Bill of Materials (Continued)
Item
C9
C10
D.N.P.
C3216X5R0J476M
GRM31CR60J476ME19L
1206D476MAT2A
C1608C0G1H101J
C11
C12
L1
R1
R2, R3
R4
R5
R6
U1
Notes:
Part Number
Manufacturer
TDK
Murata
AVX
TDK
Murata
AVX
Epcos
(4)
Vishay
(5)
AVX
AVX
AVX
AVX
AVX
Micrel
(6)
Description
Qty.
Capacitor, 47µF, 6.3V, X5R, Size 1206
1
GRM1885C1H101JA01D
06035A101JAT2A
B41125A3477M
IHLP1616BZER1R0M11
CRCW06031602FKEA
CRCW06031002FKEA
CRCW060320K0FKEA
CRCW06032R20FKEA
CRCW060349R9FKEA
MIC22205YML
Capacitor, 100pF, 50V, NPO Size 0603
470µF, 10V, Electrolytic, 8x10 case
Inductor, 1µH, 5A
Resistor, 16K, 1%, Size 0603
Resistor, 10K, 1%, Size 0603
Resistor, 20K, 1%, Size 0603
Resistor, 2.2Ω, 1%, Size 0603
Resistor, 49.9Ω, 1%, Size 0603
Integrated 2A Synchronous Buck Regulator
1
1
1
1
2
1
1
1
1
1. TDK:
www.tdk.com.
2. Murata:
www.murata.com.
3. AVX:
www.avx.com.
4. Epcos:
www.epcos.com.
5. Vishay:
www.vishay.com.
6.
Micrel, Inc.:
www.micrel.com
.
September 2012
5
M9999-092112-A
嵌入式系统
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