• Low Radiated Emission (EMI) per EN55022, Class B
• Adjustable Current Limit
• Adjustable Output Voltage from 0.9V to 24V (Also
Limited by Duty Cycle)
• 200 kHz to 600 kHz, Programmable Switching
Frequency
• Supports Safe Start-Up into a Prebiased Output
• –40°C to +125°C Junction Temperature Range
• Available in 64-pin, 12 mm × 12 mm × 3 mm QFN
Package
General Description
MIC28303 is synchronous step-down regulator
module, featuring a unique adaptive ON-time control
architecture. The module incorporates a DC/DC
controller, power MOSFETs, bootstrap diode, bootstrap
capacitor and an inductor in a single package. The
MIC28303 operates over an input supply range from
4.5V-50V and can be used to supply up to 3A of output
current. The output voltage is adjustable down to 0.8V
with an accuracy of ±1%. The device operates with
programmable switching frequency from 200 kHz-600
kHz.
The MIC28303-1 uses HyperLight Load
®
architecture
for improved efficiency at light loads. The MIC28303-2
uses Hyper Speed Control
®
for ultra-fast transient
response.
The MIC28303 offers a full suite of protection features.
These include undervoltage lockout, internal soft-start,
foldback current limit, hiccup mode short-circuit
protection and thermal shutdown.
Applications
•
•
•
•
•
Distributed Power Systems
Industrial
Medical
Telecom
Automotive
Typical Application Circuit
MIC28303
12x12 QFN
VIN
4.5V to 50V
PVDD ANODE BSTC BSTR
PVIN
VIN
C2,C3
2.2μF
C1
100μF
EN
EN
V
OUT
5V/3A
VOUT
R3
16.5kΩ
SW
C12
2.2nF
C14
47μF
MIC28303
FREQ
R1
10kΩ
ILIM
R19
75kΩ
FB
R15
3.57kΩ C10
0.1μF
PG
PGOOD
GND PGND
C6
10pF
R11
1.91kΩ
GND
2017 Microchip Technology Inc.
DS20005464B-page 1
MIC28303
Functional Block Diagram
VIN
4.5V to 50V
C
IN
100μF
2x2.2μF
BSTR
PVIN
BSTC
D
BST
ANODE
VIN
C
VIN
VIN
PVDD
BST
DH
SW
R
BST
N2
C
BST
L
IN
VOUT
ILIM-ADJ
R1
C12
2.2nF
VIN
100k
PVDD
R
FREQ
C
VDD
CONTROLLER
ILIM
EN
N1
DL
FREQ
V
OUT
5V/3A
R15
2.7k
R3
10k
EN
PVDD
49.9k
SW
C10
16.5k
0.1μF
C
OUT
47μF
FREQ
PGOOD
R19
DNP
FB
FB
PGND
PGOOD
GND
R11
1.91k
PGND
GND
DS20005464B-page 2
2017 Microchip Technology Inc.
MIC28303
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
PV
IN
, V
IN
to P
GND
...................................................................................................................................... –0.3V to +56V
P
VDD
, V
ANODE
to P
GND
................................................................................................................................ –0.3V to +6V
V
SW
, V
FREQ
, V
ILIM
, V
EN
................................................................................................................. –0.3V to (PV
IN
+0.3V)
V
BSTC/BSTR
to V
SW
......................................................................................................................................... –0.3V to 6V
V
BSTC/BSTR
to P
GND
..................................................................................................................................... –0.3V to 56V
V
FB
, V
PG
to P
GND
......................................................................................................................... –0.3V to (P
VDD
+ 0.3V)
P
GND
to A
GND
........................................................................................................................................... –0.3V to +0.3V
)............................................................................................................................. 4.5V to 50V
Enable Input (V
EN
) ..............................................................................................................................................0V to V
IN
V
SW
, V
FREQ
, V
ILIM
, V
EN
......................................................................................................................................0V to V
IN
Power Good (V
PGOOD
).................................................................................................................................... 0V to P
VDD
† Notice:
Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the device at those or any other conditions above those indicated
in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended
periods may affect device reliability.
‡ Notice:
The device is not guaranteed to function outside its operating ratings.
Note 1:
Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5 kΩ in series
