MIC2165
Adaptive On-Time DC-DC Controller
Featuring HyperLight Load®
Hyper Speed Control™ Family
General Description
Features
The Micrel MIC2165 is a synchronous adaptive on-time
buck controller targeting high-performance, cost-sensitive
applications such as set-top boxes, gateways, routers,
computing
peripherals,
and
telecom/networking
equipment.
The MIC2165 operates over a supply range of 4.5V to
28V. It has an internal linear regulator which provides a
regulated 5V supply to power the internal control circuitry.
MIC2165 operates at a constant 600kHz switching
frequency and can be used to drive up to 25A of output
current. The output voltage is adjustable from 0.8V to
5.5V.
A unique Hyper Speed Control™ architecture enables
ultra-fast transient response while reducing the output
capacitance and also makes High VIN/Low VOUT operation
possible.
A UVLO feature is provided to ensure proper operation
under power-sag conditions to prevent the external power
MOSFET from over heating. Also, a soft start feature is
provided to reduce the inrush current. Short current
sensing on the bottom MOSFET with hiccup mode current
limiting ensures protection in case of an output short
circuit. Further, the MIC2165 includes an EN pin to shut
down the converter and a Power Good (PGOOD) pin to
allow simple sequencing.
The MIC2165 is available in a 10-pin MSOP ePad
package with a junction operating temperature ranging
from –40°C to +125°C. All support documentation can be
found on Micrel’s web site at: www.micrel.com.
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Hyper Speed Control™ architecture enables
High VIN Low VOUT operation (VIN=28V & VOUT=0.8V)
Small output capacitance
HyperLight Load® Efficiency
Built-in 5V regulator for single-supply operation
Any CapacitorTM stable
- Zero ESR to high ESR
Power-Good output
Input voltage range: 4.5V to 28V
5μA typical shutdown current
25A output current drive capability
Adjustable output from 0.8V to 5.5V with ±1% FB
Accuracy
600kHz switching frequency
Internal 5ms digital Soft Start
Thermal shutdown and hiccup current-limit protection
No external current-sense resistor required
Safe start-up into pre-biased loads
10-pin MSOP ePad package
–40°C to +125°C junction temperature range
Applications
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Set-top box, gateways, routers and DSL modems
Printers, scanners, graphic and video cards
Servers, PCs and processor core supply
Low-Voltage Distributed Power
Typical Application
12V to 3.3V Efficiency
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
10
0
0.01
MIC2165 Adjustable Output 600kHz Buck Converter
0.10
1.00
10.00
OUTPUT CURRENT (A)
MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc.
HyperLight Load is a registered trademark of Micrel, Inc.
Hyper Speed Control and Any Capacitor are trademarks 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
September 2010
M9999-092410-E
Micrel, Inc.
MIC2165
Ordering Information
Part Number
Voltage
Switching Frequency
Junction Temp. Range
Package
Lead Finish
Adj.
600kHz
–40° to +125°C
10-pin ePad MSOP
Pb-Free
MIC2165YMME
Pin Configuration
10-Pin ePad MSOP (MME)
Pin Description
Pin
Number
Pin Name
1
FB
2
PGOOD
3
EN
Enable (Input): A logic level control of the output. The EN pin is CMOS-compatible. Logic high = enable,
logic low = shutdown. In the off state, supply current of the device is greatly reduced (typically 5µA). The
EN pin should not be left open. Connect to VIN if sequencing not required.
4
VIN
Supply Voltage: Input voltage for the internal +5V linear regulator. The VIN operating voltage range is
from 4.5V to 28V. A 0.1µF capacitor between VIN and the ground is required.
5
VDD
Pin Function
Feedback (Input): Input to the transconductance amplifier of the control loop. The FB pin is regulated to
0.8V. A resistor divider connecting the output to FB is used to set the desired output voltage.
Power Good (Output): Open Drain Output. The PGOOD pin is externally tied with a resistor to VDD.
High output when VOUT>90% nominal.
5V Internal Linear Regulator (Output): VDD is the external MOSFET gate drive supply voltage and an
internal supply bus for the IC. VDD is created by internal LDO from VIN. When VIN 20mV
R1 + R2
Figure 9. Voltage-Divider Configuration
The output voltage is determined by the equation:
VOUT = VREF × (1 +
Figure 8c. ΔVOUT < 20mV
The process of sizing the ripple injection resistor and
capacitors is:
Step 1. Select Cff to feed all output ripples into the
feedback pin and make sure the large time constant
assumption is satisfied. Typical choice of Cff is 1nF to
100nF if R1 and R2 are in kΩ range.
Step 2. Select Rinj according to the expected feedback
voltage ripple. According to Equation 37:
K div =
ΔVFB(PP )
VIN
×
f SW × τ
D × (1 − D)
(39)
Then the value of Rinj is obtained as:
R inj = (R1 // R2) × (
1
K div
− 1)
R1
)
R2
(41)
where VREF = 0.8V. If R1 is too large, it may allow noise to
be introduced into the voltage feedback loop. If R1 is too
small, it will decrease the efficiency of the power supply,
especially at light loads. The total voltage divider
resistance R1+R2 is recommended to be 7.5kΩ. Once R1
is selected, R2 can be calculated using:
R2 =
VREF × R1
VOUT − VREF
(42)
In addition to the external ripple injection added at the FB
pin, internal ripple injection is added at the inverting input
of the comparator inside the MIC2165, as shown in Figure
10. The inverting input voltage VINJ is clamped to 1.2V. As
VOUT is increased, the swing of VINJ will be clamped. The
clamped VINJ reduces the line regulation because it is
reflected back as a DC error on the FB terminal. Therefore,
the maximum output voltage of the MIC2165 should be
limited to 5.5V to avoid this problem.
(40)
Step 3. Select Cinj as 100nF, which could be considered
as short for a wide range of the frequencies.
Setting Output Voltage
The MIC2165 requires two resistors to set the output
voltage, as shown in Figure 9.
Figure 10. Internal Ripple Injection
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Micrel, Inc.
PCB Layout Guidelines
Warning!!! To minimize EMI and output noise, follow
these layout recommendations.
PCB Layout is critical to achieve reliable, stable and
efficient performance. A ground plane is required to control
EMI and minimize the inductance in power, signal and
return paths.
The following guidelines should be followed to insure
proper operation of the MIC2165 converter.
IC
•
Place the IC and MOSFETs close to the point of load
(POL).
•
Use fat traces to route the input and output power
lines.
•
Signal and power grounds should be kept separate
and connected at only one location.
•
The exposed pad (ePad) on the bottom of the IC must
be connected to the ground through several vias.
•
The feedback resistors should be placed close to the
FB pin. The top feedback resistor should connect
directly to the output node. Run this trace away from
the switch node (SW).
Input Capacitor
MIC2165
Inductor
•
Keep the inductor connection to the switch node (SW)
short.
•
Do not route any digital lines underneath or close to
the inductor.
•
Keep the switch node (SW) away from the feedback
(FB) pin.
•
The SW pin should be connected directly to the drain
of the low-side MOSFET to accurate sense the voltage
across the low-side MOSFET.
•
To minimize noise, place a ground plane underneath
the inductor.
Output Capacitor
•
Use a wide trace to connect the output capacitor
ground terminal to the input capacitor ground terminal.
•
Phase margin will change as the output capacitor
value and ESR changes. Contact the factory if the
output capacitor is different from what is shown in the
BOM.
•
The feedback trace should be separate from the power
trace and connected as close as possible to the output
capacitor. Sensing a long high current load trace can
degrade the DC load regulation.
Schottky Diode
•
Place the VIN input capacitor next.
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Place the VIN input capacitors on the same side of the
board and as close to the MOSFETs as possible.
Place the Schottky diode on the same side of the
board as the MOSFETs and VIN input capacitor.
•
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Keep both the VIN and PGND connections short.
•
The connection from the Schottky diode’s Anode to the
input capacitors ground terminal must be as short as
possible.
Place several vias to the ground plane close to the VIN
input capacitor ground terminal.
•
Use either X7R or X5R dielectric input capacitors. Do
not use Y5V or Z5U type capacitors.
•
Do not replace the ceramic input capacitor with any
other type of capacitor. Any type of capacitor can be
placed in parallel with the input capacitor.
•
If a Tantalum input capacitor is placed in parallel with
the input capacitor, it must be recommended for
switching regulator applications and the operating
voltage must be derated by 50%.
•
In “Hot-Plug” applications, a Tantalum or Electrolytic
bypass capacitor must be used to limit the overvoltage spike seen on the input supply with power is
suddenly applied.
•
The 2.2µF (minumum) capacitors, which connect to
the VDD terminal, must be located right at the IC. The
VDD terminal is very noise sensitive and placement of
the capacitor is very critical. Connections must be
made with wide trace.
September 2010
•
The diode’s Cathode connection to the switch node
(SW) must be keep as short as possible.
RC Snubber
•
Place the RC snubber on the same side of the board
and as close to the MOSFETs as possible.
MOSFETs
•
Low-side MOSFET gate drive trace (DL pin to
MOSFET gate pin) must be short and routed over a
ground plane. The ground plane should be the
connection between the MOSFET source and PGND.
•
Chose a low-side MOSFET with a high CGS/CGD ratio
and a low internal gate resistance to minimize the
effect of dv/dt inducted turn-on.
•
Do not put a resistor between the LSD output and the
gate.
•
Use a 4.5V VGS rated MOSFET. Its higher gate
threshold voltage is more immune to glitches than a
2.5V or 3.3V rated MOSFET. MOSFETs that are rated
for operation at less than 4.5V VGS should not be used.
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Micrel, Inc.
MIC2165
Evaluation Board Schematic
Figure 11. Schematic of MIC2165 8-24 VIN to 1.2 VOUT/10A Evaluation Board
September 2010
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Micrel, Inc.
MIC2165
Bill of Materials
Item
Part Name
B41125A7227M
C1
222215095001E3
C2,C3
12105C475KAZ2A
GRM32ER71H475KA88L
06035C104KAT2A
C6, C8, C10
C7
GRM188R71H104KA93D
C12
C13
C15
Q2
(5)
10µF Ceramic Capacitor, X5R, Size 0805, 10V
(4)
Murata
AVX(3)
1nF Ceramic Capacitor, X7R, Size 0603, 50V
4.7nF Ceramic Capacitor, X7R, Size 0603, 50V
(4)
Murata
TDK(5)
12106D107MAT2A
AVX(3)
1
1
Murata(4)
C1608X7R1H472K
100µF Ceramic Capacitor, X5R, Size 1210, 6.3V
(4)
GRM32ER60J107ME20L
Murata
6SEPC560MX
SANYO(6)
FDS8672S
0.1µF Ceramic Capacitor, X7R, Size 0603, 50V
Murata
AVX(3)
FDS6298
2
3
(4)
06035C472KAT2A
HCF1305-1R0-R
Q1
AVX(3)
TDK(5)
GRM188R71H472KA01D
1
4.7µF Ceramic Capacitor, X7R, Size 1210, 50V
Murata(4)
C1608X7R1H102K
SD103BWS
L1
AVX(3)
AVX(3)
SD103BWS-7
D1
Vishay
TDK
GRM188R71H102KA01D
Qty
220µF Aluminum Capacitor, SMD, 35V
(2)
0805ZD106KAT2A
06035C102KAT2A
Description
EPCOS(1)
C1608X7R1H104K
GRM21BR61A106KE19L
C11
Manufacturer
Diodes Inc
560µF OSCON Capacitor, 6.3V
1
Small Signal Schottky Diode
Vishay
Cooper Bussmann(8)
1
1
(7)
(2)
1
1.0µH Inductor, 24A Saturation Current
1
(9)
30V 13A N-Channel MOSFET 12mΩ Rds(on) @ 4.5V
1
(9)
Fairchild
Fairchild
30V 18A N-Channel MOSFET 7mΩ Rds(on) @ 4.5V
1
(2)
R1, R14
CRCW06032R21FKEA
Vishay/Dale
2.21Ω Resistor, Size 0603, 1%
2
R2
CRCW08051R21FKEA
Vishay/Dale(2)
1.21Ω Resistor, Size 0805, 1%
1
CRCW060319K6FKEA
(2)
19.6kΩ Resistor, Size 0603, 1%
1
(2)
R3
Vishay/Dale
R4
CRCW06032K49FKEA
Vishay/Dale
2.49kΩ Resistor, Size 0603, 1%
1
R5
CRCW06034K99FKEA
Vishay/Dale(2)
4.99kΩ Resistor, Size 0603, 1%
1
CRCW060320R0FKEA
(2)
20Ω Resistor, Size 0603, 1%
1
(2)
10kΩ Resistor, Size 0603, 1%
2
(2)
R13
R15, R16
CRCW060310K0FKEA
Vishay/Dale
Vishay/Dale
R17
CRCW060349R9FKEA
Vishay/Dale
49.9Ω Resistor, Size 0603, 1%
1
U1
MIC2165YMME
Micrel Inc.(10)
600kHz Buck Controller
1
Notes:
1.
EPCOS: www.epcos.com.
2.
Vishay: www.vishay.com.
3.
AVX: www.avx.com.
4.
MuRata: www.murata.com.
5.
TDK: www.tdk.com.
6.
Sanyo: www.sanyo.com.
7.
Diode Inc.: www.diodes.com.
8.
Cooper Bussmann: www.cooperbussmann.com.
9.
Fairchild: www.fairchildsemi.com.
10. Micrel, Inc: www.micrel.com.
September 2010
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M9999-092410-E
Micrel, Inc.
MIC2165
PCB Layout Recommendations
Figure 12. MIC2165 10A Evaluation Board Top Layer
Figure 13. MIC2165 10A Evaluation Board Bottom Layer
September 2010
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M9999-092410-E
Micrel, Inc.
MIC2165
PCB Layout Recommendations (Continued)
Figure 14. MIC2165 10A Evaluation Board Mid-Layer 1 (GND Plane)
Figure 15. MIC2165 10A Evaluation Board Mid-Layer 2
September 2010
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M9999-092410-E
Micrel, Inc.
MIC2165
Package Information
10-Pin ePad MSOP (MME)
September 2010
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M9999-092410-E
Micrel, Inc.
MIC2165
Recommended Landing Pattern
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
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 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.
© 2010 Micrel, Incorporated.
September 2010
28
M9999-092410-E
