MIC45208-1/-2
26V 10A DC-to-DC Power Module
General Description
Micrel’s MIC45208 is a synchronous step-down regulator
module, featuring a unique adaptive ON-time control
architecture. The module incorporates a DC-to-DC
controller, power MOSFETs, bootstrap diode, bootstrap
capacitor, and an inductor in a single package; simplifying
the design and layout process for the end user.
This highly-integrated solution expedites system design
and improves product time-to-market. The internal
MOSFETs and inductor are optimized to achieve high
efficiency at a low output voltage. The fully-optimized
design can deliver up to 10A current under a wide input
voltage range of 4.5V to 26V, without requiring additional
cooling.
The MIC45208-1 uses Micrel’s HyperLight Load (HLL)
while the MIC45208-2 uses Micrel’s Hyper Speed
Control™ (HSC) architecture, which enables ultra-fast load
transient response, allowing for a reduction of output
capacitance. The MIC45208 offers 1% output accuracy
that can be adjusted from 0.8V to 5.5V with two external
resistors. Additional features include thermal shutdown
protection, input undervoltage lockout, adjustable current
limit, and short circuit protection. The MIC45208 allows for
safe start-up into a pre-biased output.
Datasheet and other support documentation can be found
on Micrel’s web site at:
www.micrel.com.
®
Features
No compensation required
Up to 10A output current
>93% peak efficiency
Output voltage: 0.8V to 5.5V with ±1% accuracy
Adjustable switching frequency from 200kHz to 600kHz
Enable input and open-drain power good (PG) output
Hyper Speed Control (MIC45208-2) architecture
enables fast transient response
HyperLight Load (MIC45208-1) improves light load
efficiency
Supports safe startup into pre-biased output
CISPR22, Class B compliant
–40C to +125C junction temperature range
Thermal-shutdown protection
Short-circuit protection with hiccup mode
Adjustable current limit
Available in 52-pin 10mm × 10mm × 4mm QFN package
Applications
High power density point-of-load conversion
Servers, routers, networking, and base stations
FPGAs, DSP, and low-voltage ASIC power supplies
Industrial and medical equipment
Typical Application
Efficiency (V
IN
= 12V)
vs. Output Current (MIC45208-1)
100
90
80
5.0V
OUT
3.3V
OUT
2.5V
OUT
1.8V
OUT
1.5V
OUT
1.2V
OUT
1.0V
OUT
0.8V
OUT
EFFICIENCY (%)
70
60
50
40
30
20
10
0
2
4
6
8
10
f
SW
= 600kHz
12
14
OUTPUT CURRENT (A)
Hyper Speed Control is a trademark of Micrel, Inc.
HyperLight Load is a registered 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
May 29, 2014
Revision 1.2
Micrel, Inc.
MIC45208
Ordering Information
Part Number
Switching
Frequency
Features
Junction
Temperature
Range
–40°C to +125°C
–40°C to +125°C
Package
(1)
Lead Finish
MIC45208-1YMP
200kHz to 600kHz
MIC45208-2YMP
200kHz to 600kHz
Note:
Hyper Light Load
Hyper Speed Control
52-pin
10mm × 10mm × 4mm QFN
52-pin
10mm × 10mm × 4mm QFN
Pb-Free
Pb-Free
1. QFN is a lead-free package. Lead-free lead finish is matte tin.
Pin Configuration
52-Pin 10mm × 10mm QFN (MP)
(Top View)
May 29, 2014
2
Revision 1.2
Micrel, Inc.
MIC45208
Pin Description
MIC45208
Pin Number
1, 2
3, 4
5, 6, 7
8
11
30
36
12
19
20
29
37, 38
39
40, 41
42, 43, 44
45, 52
Pin Name
Pin Function
Internal +5V linear regulator output. Powered by VIN, 5VDD is the internal supply bus for the
device. In the applications with VIN<+5.5V, 5VDD should be tied to VIN to bypass the linear
regulator.
PVDD: Supply input for the internal low-side power MOSFET driver.
Power Ground. PGND is the return path for the step-down power module power stage. The
PGND pin connects to the sources of internal low-side power MOSFET, the negative terminals of
input capacitors, and the negative terminals of output capacitors.
The SW pin connects directly to the switch node. Due to the high-speed switching on this pin, the
SW pin should be routed away from sensitive nodes. The SW pin also senses the current by
monitoring the voltage across the low-side MOSFET during OFF time.
Power Input Voltage: Connection to the drain of the internal high side power MOSFET. Connect
an input capacitor from PVIN to PGND.
Power Output Voltage: Connected to the internal inductor, the output capacitor should be
connected from this pin to PGND as close to the module as possible.
Ripple Injection Pin A. Leave floating, no connection.
Ripple Injection Pin B. Connect this pin to FB.
Anode Bootstrap Diode: Anode connection of internal bootstrap diode, this pin should be
connected to the PVDD pin.
Connection to the internal bootstrap circuitry and high side power MOSFET drive circuitry. Leave
floating, no connection.
Analog Ground. Connect bottom feedback resistor to GND. GND and PGND should be
connected together at a low impedance point.
Feedback: Input to the transconductance amplifier of the control loop. The FB pin is referenced to
0.8V. A resistor divider connecting the feedback to the output is used to set the desired output
voltage. Connect the bottom resistor from FB to GND.
Power Good: Open Drain Output. If used, connect to an external pull-up resistor of at least
10kohm between PG and the external bias voltage.
Enable: A logic signal to enable or disable the step-down regulator module operation. The EN pin
is TTL/CMOS compatible. Logic high = enable, logic low = disable or shutdown. Do not leave
floating
Internal 5V linear regulator input. A 1μF ceramic capacitor from VIN to GND is required for
decoupling.
Switching Frequency Adjust: Use a resistor divider from VIN to GND to program the switching
frequency. Connecting FREQ to VIN sets freq=600kHz.
Current Limit: Connect a resistor between ILIM and SW to program the current limit.
5VDD
PVDD
PGND
SW
PVIN
VOUT
RIA
RIB
ANODE
BST
GND
46
FB
47
PG
48
EN
49
50
51
VIN
FREQ
ILIM
May 29, 2014
3
Revision 1.2
Micrel, Inc.
MIC45208
Absolute Maximum Ratings
(2)
V
PVIN
, V
VIN
to PGND .......................................
0.3V
to +30V
V
PVDD
, V
5VDD
, V
ANODE
to PGND.........................
0.3V
to +6V
V
SW
, V
FREQ
, V
ILIM
, V
EN
to PGND ............
0.3V
to (V
IN
+0.3V)
V
BST
to V
SW
........................................................
0.3V
to 6V
V
BST
to PGND ..................................................
0.3V
to 36V
V
PG
to PGND ..................................
0.3V
to (5VDD + 0.3V)
V
FB
, V
RIB
to PGND ..........................
0.3V
to (5VDD + 0.3V)
PGND to GND ..............................................
0.3V
to +0.3V
Junction Temperature .............................................. +150°C
Storage Temperature (T
S
) .........................
65C
to +150C
Lead Temperature (soldering, 10s) ............................ 260°C
ESD Rating…………………………………….ESD Sensitive
Operating Ratings
(3)
Supply Voltage (V
PVIN
, V
VIN
) .............................. 4.5V to 26V
Output Current ............................................................... 10A
Enable Input (V
EN
) .................................................. 0V to V
IN
Power Good (V
PG
) ............................................. 0V to 5VDD
Junction Temperature (T
J
) ........................
40C
to +125C
(4)
Junction Thermal Resistance
10mm × 10mm × 4mm QFN-52 (
JA
) ............ 16.6°C/W
10mm × 10mm × 4mm QFN-52 (
JC
) ................. 4°C/W
Electrical Characteristics
(5)
V
PIN
= V
IN
= V
EN
= 12V, V
OUT
= 3.3V, V
BST
V
SW
= 5V, T
J
= +25ºC.
Bold
values indicate
40ºC
T
J
+125ºC, unless otherwise noted.
Parameter
Power Supply Input
Input Voltage Range (V
PVIN
, V
IN
)
Quiescent Supply Current (MIC45208-1)
Quiescent Supply Current (MIC45208-2)
Operating Current
Shutdown Supply Current
5VDD Output
5VDD Output Voltage
5VDD UVLO Threshold
5VDD UVLO Hysteresis
LDO Load Regulation
Reference
Feedback Reference Voltage
FB Bias Current
Enable Control
EN Logic Level High
EN Logic Level Low
EN Hysteresis
EN Bias Current
Notes:
2. Exceeding the absolute maximum ratings may damage the device.
3. The device is not guaranteed to function outside operating range.
4.
JA
and
JC
were measured using the MIC45208 evaluation board.
5. Specification for packaged product only.
Condition
Min.
Typ.
Max.
Units
4.5
V
FB
= 1.5V
V
FB
= 1.5V
V
PVIN
= V
IN
= 12V,
V
OUT
= 1.8V, I
OUT
= 0A,
f
SW
= 600kHz
MIC45208-1
MIC45208-2
2.1
0.4
26
0.75
3
V
mA
mA
mA
43
4
10
µA
SW = Unconnected, V
EN
= 0V
V
IN
= 7V to 26V, I
5VDD
= 10mA
V
5VDD
Rising
V
5VDD
Falling
I
5VDD
= 0 to 40mA
4.8
3.8
5.1
4.2
400
5.4
4.6
V
V
mV
0.6
2
3.6
%
T
J
= 25°C
40°C
≤ T
J
≤ 125°C
V
FB
= 0.8V
0.792
0.784
0.8
0.8
5
0.808
0.816
500
V
nA
1.8
0.6
200
V
EN
= 12V
5
10
V
V
mV
µA
May 29, 2014
4
Revision 1.2
Micrel, Inc.
MIC45208
Electrical Characteristics
(5)
(Continued)
V
PIN
= V
IN
= V
EN
= 12V, V
OUT
= 3.3V, V
BST
V
SW
= 5V, T
J
= +25ºC.
Bold
values indicate
40ºC
T
J
+125ºC, unless otherwise noted.
Parameter
Oscillator
Switching Frequency
Maximum Duty Cycle
Minimum Duty Cycle
Minimum Off-Time
Soft-Start
Soft-Start Time
Short-Circuit Protection
Current-Limit Threshold
Short-Circuit Threshold
Current-Limit Source Current
Short-Circuit Source Current
Leakage
SW, BST Leakage Current
FREQ Leakage Current
Power Good (PG)
PG Threshold Voltage
PG Hysteresis
PG Delay Time
PG Low Voltage
Thermal Protection
Overtemperature Shutdown
Overtemperature Shutdown Hysteresis
T
J
Rising
160
15
°C
°C
Sweep V
FB
from Low-to-High
Sweep V
FB
from High-to-Low
Sweep V
FB
from Low-to-High
V
FB
< 90% × V
NOM
, I
PG
= 1mA
85
90
6
100
70
200
95
%V
OUT
%V
OUT
µs
mV
10
10
µA
µA
V
FB
= 0.79V
V
FB
= 0V
V
FB
= 0.79V
V
FB
= 0V
30
23
50
25
14
7
70
35
0
9
90
45
mV
mV
µA
µA
3
ms
V
FB
= 1V
140
V
FREQ
= V
IN
, I
OUT
= 2A
V
FREQ
= 50%V
IN,
I
OUT
= 2A
400
600
350
85
0
200
260
750
kHz
%
%
ns
Condition
Min.
Typ.
Max.
Units
May 29, 2014
5
Revision 1.2
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