Micrel mic28510 User manual

MIC28510 Evaluation Board
75V/4A Hyper Speed Control™
Synchronous DC/DC Buck Regulator
Hyper Speed Control is a trademark of Micrel, Inc
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
March 2012 M9999-030712
[email protected] or [phone]
ge is adjustable down to 0.8V with
sted the switching fre
es in in
and output
luation board are:
•Input Voltage −5V to 75V
Output Voltage −0.8V to 5V at 4A(1)
(2)
•
l
tion can be
s web site at: www.micrel.com
General Description
The MIC28510 DC/DC regulator operate
input supply range of 4.5V to 75V and
regulated output at up to 4A of output cu
output volta
s over an
provides a
rrent. The
a
uency is
quency
put voltage
typical accuracy of ±1%. The switching freq
adjustable and once adju
remains fairly constant with chang
load.
The basic parameters of the eva
•
12V at up to 4A
250kHz Switching Frequency
(Adjustable from 100kHz to 500kHz)
Notes:
1, 2. Refer to thermal de-rating curves shown in Typica
Characteristics section.
Datasheets and support documenta found
on Micrel’
nly a ngle
pab y. A
d an N
r, has been installed on the board to provide
housekeeping (VDD) for the MIC28510. The output
load can either be a passive or an active load.
Precautions
The MIC28510 evaluation board does not have
reverse polarity protection. Applying a negative
voltage to the PVIN and GND terminals may damage
the device. The maximum PVIN of the board is rated
at 75V. Exceeding 75V on the PVIN could damage the
device.
wer supply to the VIN
careful attention to the
e range (5V <VIN <
can be monitored with
ly power until Step 4.
r Output. Connect a
GND terminals. The load can
ve) or an active (as in
current meter may be
terminal and load to
re the output
OUT terminal.
s an internal 100k
tor to VDD, which allows the output to
eds its UVLO
tor is provided on the
evaluation board for users to easily access the
feature. Applying an external logic signal
N pin to pull it low or using a jumper to
will shut off the output of
n board.
4. Turn On the Power. Turn on the VIN supply and
verify that the output voltage is regulated to 3.3V.
Ordering Information
Part Number Description
Requirements
The MIC28510 evaluation board requires o
power supply with at least 10A current ca
linear regulator, which includes a Zener an
transisto
si
ilit
NP
Getting Started
1. VIN Supply. Connect a po
and GND terminals, paying
polarity and supply voltag
75V). The input current IIN
a current meter. Do not app
2. Connect Load and Monito
load to the VOUT and
be either a passive (resisti
an electronic load) type. A
placed between the VOUT
monitor the output current. Ensu
voltage is monitored at the V
3. Enable Input. The EN pin ha
pull-up resis
be turned on when VDD exce
threshold. An EN connec
enable
on the E
short the EN pin to GND
tiothe MIC28510 evalua
MIC28510 5V EV Evaluation Board up to 5V Output
MIC28510 12V EV Evaluation Board 12V Output

Micrel, Inc. MIC28510 4A Evaluation Board
Features
March 2012 2 M9999-030712
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MIC28510 evaluation
board, which is preset to 3.3V, is determined by the
feedback divider, shown in Equation 1:
Feedback Resistors
The output voltage on the
⎟
⎟
⎠
⎜
⎜
⎝+×=
BOTTOM
REFOUT R
R4
1VV
where VREF = 0.8V, and RBOTTOM is one o
which corresponds
⎞⎛ Eq. 1
f R5-R12,
to 0.9V, 1.0V, 1.2V, 1.5V, 1.8V,
2.5V, 3.3V, or 5V. Leaving the RBOTTOM open gives a
0.8V output voltage. All
above can be set by modifying RBOTTOM alu
according to Equation 2:
other voltages not listed
v e
REFOUT
REF
BOTTOM VV
R− =
Note that the output voltage should not be
VR4×Eq. 2
5V due to the 6.3V voltage rating o
mmended
hown in the MIC28510 12V/4A
e output
d for 12V
ode
ng the
t critical
nt limit
om FET.
t of
easurement
The resistor, R13, is placed in series with the reg
feedback path. The control loop gain can be
measured by connecting an impedance analyzer
across the resistor and selecting the resistor value in
between 20Ωto 50Ω.
Setting the Switching Frequency
The MIC28510 is an adjustable-frequency,
synchronous buck regulator featuring a unique
digitally modified adaptive on-time control
architecture.
be adjusted between
ng the resistor divider
connected network consisting of R18 and R19 from
PVIN to PGND.
The switching frequency can
100kHz and 500kHz by changi
Figure 1. Switching Frequency Adjustment
switching frequency: Equation 3 illustrates the estimated
set to
n theexceed
R19R18
R19
ff OSW_ADJ + ×=
output capacitors.
If higher than 5V output is desired, it is reco
to use the designs s
Eq. 3
where fO= Switching Frequency when R18 is 100k
and R19 being open, fOshould be typically 450kHz.
For more precise setting, it is recommended to use
Figure 2:
output evaluation board schematic, where th
capacitors, L1, R3, and R17 are optimize
output.
SW N
Test point J11 (VSW) is placed for monitori
switching waveform, one of the mos
waveforms for the converter.
Current Limit
The MIC28510 has internal FETs, and the curre
is implemented by sensing the RDS-ON of bott
The MIC28510 has a fixed current limi
(typical).
Loop Gain M
6.5A
ulator
Figure 2. Switching Frequency vs. R19
The evaluation board design is optimized for a
switching frequency of 250kHz. If the switching
frequency is programmed to either lower end or higher
end, the design needs optimization.

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 3 M9999-030712
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MIC28510 0.8V to 5V/4A Evaluation Board Typical Characteristics
Efficiency (V
IN
= 48V)
vs. Output Current
10
20
30
40
50
60
70
80
90
100
012345
OUTPUT CURRENT (A)
EFFICIENCY (%)
6
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
0.9V
0.8V
f
SW
= 250kHz
ThermalDerating
0
1
2
3
4
25 40 55 70 85 100
MAXIMUM AMBIENT TEMPERATURE
(°C)
LOAD CURRENT (A)
V
OUT
= 3.3V
fsw = 250kHz
L = 10µH
T
j_MAX
=125°C
V
IN
= 5V
V
IN
= 75V
V
IN
= 48V
ThermalDerating
0
1
2
3
4
25 40 55 70 85 100
MAXIMUM AMBIENT TEMPERATURE
(°C)
LOAD CURRENT (A)
V
OUT
= 5V
f
SW
= 250kHz
L = 10µH
T
j_MAX
= 125°C
V
IN
= 8V
V
IN
= 75V
V
IN
= 48V
ThermalDerating
ThermalDerating
0
1
2
3
4
25 40 55 70 85 100
MAXIMUM AMBIENT TEMPERATURE
(°C)
LOAD CURRENT (A)
V
OUT
= 3.3V
f
SW
= 250kHz
L = 10µH
T
j_MAX
= 125°C
V
IN
=18V
V
IN
= 12V
V
IN
= 24V
ThermalDerating
0
1
2
3
4
25 40 55 70 85 100
MAXIMUM AMBIENT TEMPERATURE
(°C)
LOAD CURRENT (A)
V
OUT
= 2.5V
f
SW
= 250kHz
L = 10µH
T
j_MAX
= 125°C
V
IN
=18V
V
IN
= 12V
V
IN
= 24V
0
L
1
2
3
4
25 40 55 70 85 100
MAXIMUM AMBIENT TEMPERATURE
(°C)
OAD CURRENT (A)
V
OUT
= 5V
f
SW
= 250kHz
L = 10µH
T
j_MAX
= 125°C V
IN
=18V
V
IN
= 24V
V
IN
= 12V
Die Temperature* : The temperature measurement was taken at the hottest point on the MIC28510 case mounted on a 5 square inch 4 layer, 0.62”,
FR-4 PCB with 2oz. finish copper weight per layer, see Thermal Measurement section. Actual results will depend upon the size of the PCB, ambient
temperature and proximity to other heat emitting components.

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 4 M9999-030712
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MIC28510 0.8V to 5V/4A Output Evaluation Board Schematic
MIC28510 Evaluation Board for 0.8V to 5V/4A Output

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 5 M9999-030712
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ll of 0.8V to u
Item Manufacturer Description Qty.
Bi Materials 5V/4A O tput
Part Number
C1 EEU-FC2A101B Pa or, SMD, 100V 1nasonic
(1) 100µF Aluminum Capacit
GRM32ER72A225KA M35L urata(2)
C2, C3 25KT5 TDK X7R, Size 1210, 100V 2
C3225X7R2A2 (3) 2.2µF Ceramic Capacitor,
GRM32ER60J107ME M20L urata(2)
C13 MAT2A AVX 10, 6.3V 1
12106D107 (4) 100µF Ceramic Capacitor, X5R, Size 12
06035C104KAT2A AVX(4)
GRM188R71H104KA93D Murata
(2)
C6
4K (3)
0.1µF Ceramic Capacitor, X7R, Size 0603, 50V 1
C1608X7R1H10 TDK
GRM188R72A104KA35D Murata
(2)
C10 K TDK(3) 0.1µF Ceramic Capacitor, X7R, Size 0603, 100V 1
C1608X7S2A104
0805ZC225MAT2A AVX(4)
GRM21BR71A225KA Murata(2)01L
C8, C9
1A225K
2.2µF Ceramic Capacitor, X7R, Size 0805, 10V 2
C2012X7R TDK(3)
GRM188R72A102KA01D Murata(2)
C1608X7R2A102K TDK(3)
C11
AT2A AVX
, X7R, Size 0603, 100V 1
06031C102K (4)
1nF Ceramic Capacitor
GRM188R71H472KA01D Murata(2)
C1608X7R2A472K TDK(3)
C12
AT2A AVX(4)
ramic Capacitor, X7R, Size 0603, 50V 1
06035C472K
4.7nF Ce
GRM21BR71A105K MA01L urata(2)
C16 7R1A105 R, Size 0805, 10V 1
C2012X K TDK(3) 1µF Ceramic Capacitor, X7
C4, C5, C
14, C15
7,
COpen
BAT46W-TP MCC(5)
D1 io Schottky Diode 1
BAT46W-7-F D des Inc.(6) Small Signal
MMXZ5232B-TP MCC
(5)
D2 en iode 1
CMDZ5L6 C tral Semi(7) 5.6V Zener D
L1 DR125-100-R Cooper Bussmann(8) 10µH Inductor, 5.35A RMS, 7A Saturation Current 1
Q1 FCX493 Diodes Inc/ZETEX(6) 100V NPN Transistor 1
R1 CRCW06034R75FKEA Vishay Dale(9) 4.75ΩResistor, Size 0603, 1% 1
R2, R16 CRCW08051R21FKEA Vishay Dale(9) 1.21ΩResistor, Size 0805, 1% 2
R3 CRCW060316K5FKEA Vishay Dale(9) 16.5kΩResistor, Size 0603, 1% 1
R4 CRCW060310K0FKEA Vishay Dale(9) 10kΩResistor, Size 0603, 1% 1
R5 CRCW060380K6FKEA Vishay Dale(9) 80.6kΩResistor, Size 0603, 1% 1
R6 CRCW060340K2FKEA Vishay Dale(9) 40.2kΩResistor, Size 0603, 1% 1

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 6 M9999-030712
[email protected] or [phone]
ll of Mat 8V Output (Co )
em mb Description Qty.
Bi erials 0. to 5V/4A ntinued
It Part Nu er Manufacturer
R7 0F r, Size 0603, 1% 1CRCW060320K KEA Vishay Dale(9) 20kΩResisto
R8 5F 3, 1% 1CRCW060311K KEA Vishay Dale(9) 11.5kΩResistor, Size 060
R9 06F 3, 1% 1CRCW06038K KEA Vishay Dale(9) 8.06kΩResistor, Size 060
R10 F 3, 1% 1CRCW06034K75 KEA Vishay Dale 4.75kΩ
(9) Resistor, Size 060
R11 24F istor, Size 0603, 1% 1CRCW06033K KEA Vishay Dale(9) 3.24kΩRes
R12 91F stor, Size 0603, 1% 1CRCW06031K KEA Vishay Dale(9) 1.91kΩResi
R13 CRCW06030000Z , Size 0603 10EAHP Vishay Dale(9) 0ΩResistor
R14 CRCW080510K0J 5, 1% 1NEA Vishay Dale 10kΩRes
(9) istor, Size 080
R15 CRCW060349R9 , Size 0603, 1% 1FKEA Vishay Dale 49.9ΩResistor
(9)
R17 (OP 603715R 1%EN) CRCW0 FKEA Vishay Dale(9) 715ΩResistor, Size 0603,
R18, R19 CRCW0603100KFKEAHP Vishay Dale(9) 100kΩResistor, Size 0603, 1% 2
R20 CRCW06032R00FKEA Vishay Dale(9) 2ΩResistor, Size 0603, 1% 1
R21 (OPEN) CRCW0603348RFKEA Vishay Dale(9) 348ΩResistor, Size 0603, 1%
U1 MIC28510YJL Micrel. Inc.(10) 75V/4A Synchronous Buck DC/DC Regulator 1
Notes:
1. Panasonic: www.panasonic.com.
2. Murata: www.murata.com.
3. TDK: www.tdk.com.
4. AVX: www.avx.com.
5. MCC: www.mccsemi.com.
6. Diode Inc.: www.diodes.com.
7. Central Semi: www.centralsemi.com.
8. Cooper: www.cooperbussman.com.
9. Vishay: www.vishay.com.
10. Micrel, Inc.: www.micrel.com.

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 7 M9999-030712
[email protected] or [phone]
MIC28510 12V/4A Output Evaluation Board Typical Characteristics
Efficiency
vs. Output Current
50
55
60
65
70
75
80
85
90
95
100
0123456
EFFICIENCY (%)
ThermalDerating
0
1
2
3
4
25 40 55 70 85 100 115
V
OUT
= 12V
f
SW
=250kHz
L=27μH
T
j_MAX
=125°C
18V
24V
30V
48V
75V
24V
IN
OUTPUT CURRENT (A)
V
OUT
= 12V
f
SW
= 250kHz
L = 27μH
Maximum Ambient Temperature (°C)
Load Current (A)
18V
IN
48V
IN
75V
IN
Die Temperature* : The temperature measurement was taken at the hottest point on the MIC28510 case mounted on a 5 square inch 4 layer, 0.62”,
FR-4 PCB with 2oz. finish copper weight per layer, see Thermal Measurement section. Actual results will depend upon the size of the PCB, ambient
temperature and proximity to other heat emitting components.

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 8 M9999-030712
[email protected] or [phone]
MIC28510 12V/4A Output Evaluation Board Schematic
MIC28510 Evaluation Board for 12V/4A Output

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 9 M9999-030712
[email protected] or [phone]
ll of (12V Up
Qty.
Bi Materials to 4A) Output
Item Part Number Manufacturer Description
C1 EEU-FC2A101B a or, SMD, 100V 1P nasonic
(1) 100µF Aluminum Capacit
GRM32ER61C476ME15 M (2) urata
C2, C3
76MM- iyo Yuden
R, Size 1210, 100V 2
EMK325BJ4 T Ta (3) 2.2µF Ceramic Capacitor, X7
GRM32ER61C476ME15 Murata(2)
C13, C4
476MM-T Taiyo Yuden
, X5R, Size 1210, 16V 2
EMK325BJ (3) 47µF Ceramic Capacitor
06035C104KAT2A AVX(4)
GRM188R71H104KA93D Murata
(2)
C6
C1608X7R1H104K T (5)
R, Size 0603, 50V 1
DK
0.1µF Ceramic Capacitor, X7
GRM188R72A104KA35D Murata
(2)
C10
K TDK(5)
0.1µF Ceramic Capacitor, X7R, Size 0603, 100V 1
C1608X7S2A104
0805ZC225MAT2A AVX(4)
GRM21BR71A225KA01L Murata(2)
C8, C9
5K (5)
2.2µF Ceramic Capacitor, X7R, Size 0805, 10V 2
C2012X7R1A22 TDK
GRM188R72A102KA01D Murata
(2)
C1608X7R2A102K (5) TDK
C11
06031C102KAT2A AVX
R, Size 0603, 100V 1
(4)
1nF Ceramic Capacitor, X7
GRM188R71H472KA01D Murata(2)
C1608X7R2A472K (5) TDK
C12
06035C472KAT2A AVX
Capacitor, X7R, Size 0603, 50V 1
(4)
4.7nF Ceramic
GRM21BR71A105KA M01L urata(2)
C16
X7R1A105K
1µF Ceramic Capacitor, X7R, Size 0805, 10V 1
C2012 TDK(5)
C5, C7, C
15 en
14, Op
C
BAT46W-TP MCC(6)
D1
io
Schottky Diode 1
BAT46W-7-F D des Inc.(7)
Small Signal
MMXZ5232B-TP MCC(6)
D2
CMDZ5L6 Cen
iode 1
tral Semi
(8)
5.6V Zener D
L1 7447709270 Wurth
(9) 27µH Inductor, 5.8A Saturation Current 1
Q1 FCX493 Diodes Inc./ZETEX(7) 100V NPN Transistor 1
R1 CRCW06034R75FKEA Vishay Dale(10) 4.75ΩResistor, Size 0603, 1% 1
R2, R16 CRCW08051R21FKEA Vishay Dale(10) 1.21ΩResistor, Size 0805, 1% 2
R3 CRCW060345K3FKEA Vishay Dale(10) 45.3kΩResistor, Size 0603, 1% 1
R4 CRCW060310K0FKEA Vishay Dale(10) 10kΩResistor, Size 0603, 1% 1
R5 (OPEN) CRCW060380K6FKEA Vishay Dale(10) 80.6kΩResistor, Size 0603, 1%
R6 (OPEN) CRCW060340K2FKEA Vishay Dale(10) 40.2kΩResistor, Size 0603, 1%

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 10 M9999-030712
[email protected] or [phone]
B f Mat V up utput (Conti
mbe a Description Qty.
ill o erials 12 -to 4A O nued)
Item Part Nu r M nufacturer
R7 (OPEN) CRCW060320K0FK sh or, Size 0603, 1% 1EA Vi ay Dale(10) 20kΩResist
R8 (OPEN) CRCW060311K5FK sh stor, Size 0603, 1% 1EA Vi ay Dale(10) 11.5kΩResi
R9 (OPEN) CRCW06038K06FK sh stor, Size 0603, 1% 1EA Vi ay Dale(10) 8.06kΩResi
R10 (OPEN) CRCW06034K75FK sh istor, Size 0603, 1% 1EA Vi ay Dale 4.75k
(10) ΩRes
R11 (OP 24FK sh sistor, Size 0603, 1% 1EN) CRCW06033K EA Vi ay Dale(10) 3.24kΩRe
R12 (OP 91FK sh istor, Size 0603, 1% 1EN) CRCW06031K EA Vi ay Dale(10) 1.91kΩRes
R13 00Z0 sh r, Size 0603 1CRCW060300 EAHP Vi ay Dale(10) 0ΩResisto
R14 CRCW080510K0JN sh 5, 1% 1EA Vi ay Dale 10kΩRe
(10) sistor, Size 080
R15 CRCW060349R9FKEA sh stor, Size 0603, 1% 1Vi ay Dale 49.9ΩResi
(10)
R17 603715RFK sh 1CRCW0 EA Vi ay Dale(10) 715ΩResistor, Size 0603, 1%
R18, R19 CRCW0603100KFKEAHP Vishay Dale(10) 100kΩResistor, Size 0603, 1% 2
R20 CRCW06032R00FKEA Vishay Dale(10) 2ΩResistor, Size 0603, 1% 1
R21 (OPEN) CRCW0603348RFKEA Vishay Dale(10) 348ΩResistor, Size 0603, 1%
U1 MIC28510YJL Micrel. Inc.(10) 75V/4A Synchronous Buck DC/DC Regulator 1
Notes:
1. Panasonic: www.panasonic.com.
2. Murata: www.murata.com.
3. Taiyo Yuden: www.taiyo-yuden.com.
4. AVX: www.avx.com.
5. TDK: www.tdk.com.
6. MCC: www.mccsemi.com.
7. Diode Inc.: www.diodes.com.
8. Central Semi: www.centralsemi.com.
9. Wurth: www.wurth.com.
10. Vishay Dale: www.vishay.com.
11. Micrel, Inc.: www.micrel.com.

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 11 M9999-030712
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Evaluation Board PCB Layout
MIC28510 Evaluation Board −Silkscreen Top
MIC28510 Evaluation Board −Copper Layer 1 (Top)

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 12 M9999-030712
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Evaluation Board PCB Layout (Continued)
MIC28510 Evaluation Board −Copper Layer 2
MIC28510 Evaluation Board −Copper Layer 3

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 13 M9999-030712
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Evaluation Board PCB Layout (Continued)
MIC28510 Evaluation Board −Copper Layer 4
MIC28510 Evaluation Board −Silkscreen Bottom

Micrel, Inc. MIC28510 4A Evaluation Board
March 2012 14 M9999-030712
[email protected] or [phone]
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL [phone] FAX [phone] WEB ://www.micrel.comhttp
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no
liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or
warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
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
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© 2012 Micrel, Incor
p
orated.