MCP16321/2
24V Input, 1A/2A Output, High Efficiency Synchronous Buck Regulator
with Power Good Indication
Features
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Up to 95% Typical Efficiency
Input Voltage Range: 6.0V to 24V
1A Output Current (MCP16321)
2A Output Current (MCP16322)
Fixed Output Voltages: 0.9V, 1.5V, 1.8V, 2.5V,
3.3V, 5V with 2% Output Voltage Accuracy
Adjustable Version Output Voltage Range:
0.9V to 5V with 1.5% Reference Voltage Accuracy
Integrated N-Channel High-Side Switch: 180 mΩ
Integrated N-Channel Low-Side Switch: 120 mΩ
1 MHz Fixed Frequency
Low Device Shutdown Current
Peak Current Mode Control
Internal Compensation
Stable with Ceramic Capacitors
Internal Soft-Start
Cycle-by-Cycle Peak Current Limit
Undervoltage Lockout (UVLO): 5.75V
Overtemperature Protection
V
OUT
Overvoltage Protection
V
OUT
Voltage Supervisor Reported at the PG Pin
Available Package: QFN-16 (3x3 mm)
Description
The MCP16321/2 is a highly integrated, high-efficiency,
fixed frequency, synchronous step-down DC-DC
converter in a 16-pin QFN package that operates from
input voltages up to 24V. Integrated features include a
high-side and low-side N-Channel switch, fixed
frequency Peak Current Mode Control, internal
compensation, peak current limit, V
OUT
overvoltage
protection and overtemperature protection. Minimal
external components are necessary to develop a
complete synchronous step-down DC-DC converter
power supply.
High converter efficiency is achieved by integrating a
high-speed, current limited, low resistance, high-side
N-Channel MOSFET, as well as a high-speed, low
resistance, low-side N-Channel MOSFET and
associated drive circuitry. High switching frequency
minimizes the size of the inductor and output capacitor,
resulting in a small solution size.
The MCP16321/2 device can supply 1A/2A of
continuous current while regulating the output voltage
from 0.9V to 5V. A high-performance peak current
mode architecture keeps the output voltage tightly
regulated, even during input voltage steps and output
current transient conditions that are common in power
supplies.
The regulator can be turned on and off with a logic level
signal applied to the EN input. The EN input is internally
pulled up to a 4.2V reference and is rated for a
maximum of 6V. With EN low, typically 5 µA of current
is consumed from the input, making the part ideal for
power shedding and load distribution applications. The
PG output is an open drain output pin used to interface
with other components of the system, and can be
pulled up to a maximum of 6V.
The output voltage can either be fixed at output
voltages of 0.9V, 1.5V, 1.8V, 2.5V, 3.3V, 5V or
adjustable using an external resistor divider. The
MCP16321/2 is offered in a 3x3 QFN-16 surface mount
package.
Applications
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PIC
®
/dsPIC
®
Microcontroller Bias Supply
12V Industrial Input DC-DC Conversion
Set-Top Boxes
DSL Cable Modems
Automotive
Wall Cube Regulation
SLA Battery Powered Devices
AC-DC Digital Control Power Source
Power Meters
Consumer
Medical and Health Care
Distributed Power Supplies
©
2011 Microchip Technology Inc.
DS22285A-page 1
MCP16321/2
1.0
ELECTRICAL
CHARACTERISTICS
† 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.
Absolute Maximum Ratings†
V
IN
.................................................................... -0.3V to 26.4V
SW ...................................................................... -1V to 26.4V
BOOST – GND ........................................... -0.3V to (V
IN
+6V)
EN,V
FB
, PG Voltage.............................................. -0.3V to 6V
Continuous Total Power Dissipation .......................................
...................................................See Thermal Characteristics
Storage Temperature ....................................-65°C to +150°C
Operating Junction Temperature...................-40°C to +125°C
ESD Protection On All Pins:
HBM ......................................................................... 3 kV
MM ..........................................................................200V
DC CHARACTERISTICS
Electrical Characteristics:
Unless otherwise indicated, T
A
= +25°C, V
IN
= 12V, V
OUT
= 3.3V, I
OUT
= 300 mA,
L = 4.7 µH, C
OUT
= 2x22 µF, C
IN
= 2x10 µF.
Boldface
specifications apply over the T
J
range of -40°C to +125°C.
Parameters
V
IN
Supply Voltage
Input Voltage
Quiescent Current
(Switching)
Quiescent Current
(Non-Switching)
Quiescent Current -
Shutdown
V
IN
Undervoltage Lockout
Undervoltage Lockout Start
Undervoltage Lockout
Hysteresis
Output Characteristics
Maximum Output Current
MCP16321
Maximum Output Current
MCP16322
Output Voltage Adjust Range
Output Voltage Tolerance
in PWM Mode
Output Voltage Tolerance
in PFM Mode
Feedback Voltage
Feedback Reference
Tolerance
PFM Mode Feedback
Comparator Threshold
Feedback Input Bias
Current
Note 1:
I
OUT
I
OUT
V
OUT
V
OUT-PWM
V
OUT-PFM
V
FB
V
FB-TOL
V
FB-PFM
I
FB
1
2
0.9
V
OUT
- 2%
—
—
—
V
OUT
—
—
5.0
V
OUT
+ 2%
A
A
V
V
V
V
%
V
nA
I
OUT
= 1A
I
OUT
= 0A
V
IN
= 6V to 24V
V
IN
= 6V to 24V
UVLO
STRT
UVLO
HYS
5.5
—
5.75
0.65
6.0
—
V
V
V
IN
Rising
Non-Switching
V
IN
I
Q
I
Q
6.0
—
—
—
5.2
2.3
24
—
—
V
mA
mA
I
OUT
= 0 mA
Closed Loop in
Overvoltage
I
OUT
= 0 mA
EN = 0
Sym
Min
Typ
Max
Units
Conditions
I
Q
—
5
10
µA
V
OUT
- 1%
V
OUT
+ 1%
V
OUT
+ 3.5%
0.886
-1.5
—
—
0.9
—
V
OUT
+ 1%
100
0.914
1.5
—
—
Regulator SW pin is forced off for 240 ns every 8 cycles to ensure the BOOST cap is replenished.
©
2011 Microchip Technology Inc.
DS22285A-page 3
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