Information

6
Portable Power Conversion Design Guide
DC/DC Conversion
Step-Down (Buck) Switch Mode Power Converters
MCP16323 3A Synchronous Buck DC/DC Converter
The MCP16323 is a fully integrated synchronous buck dc/dc converter that operates from 6V to 18V input, regulates the
output voltage to any level between 0.9V to 5V, and supplies load currents up to 3A. Operating at a fixed 1 MHz switching
frequency offers small external inductor and capacitor sizes, minimizing board space. Integrating both high- and low-side
switches results in a compact, high-efficiency converter circuit. The device is available in a 3 × 3 mm QFN package with
exposed pad to reduce the thermal resistance from junction to case. With both adjustable and fixed output voltage
options, this device provides flexibility for generating custom output voltages or minimizing external resistor dividers and
obtaining fixed output voltages. The internal peak current mode control architecture results in fast transient response,
minimizing the change in output voltage with dynamic load conditions. Small ceramic capacitors are used at the input and
output for space-constrained applications.
■ Up to 95% typical efficiency
■ Wide 6.0V to 18V input
voltage range
■ 3A output current
■ Multiple fixed output voltage options:
0.9V, 1.5V, 1.8V, 2.5V, 3.3V, 5.0V
with 2% output voltage accuracy
■ Adjustable version output voltage
range: 0.9V to 5.0V with 1.5%
reference voltage accuracy
■ Integrated 180 mΩ n-channel
high-side switch
■ Integrated 120 mΩ n-channel low-
side switch
■ 1 MHz fixed frequency operation
with pulse skipping for efficient
operation in light load conditions
■ Low device shutdown current
■ Peak current mode control
■ Internal compensation
■ Stable with ceramic capacitors
■ Internal soft-start
■ Cycle-by-cycle peak current limit
■ Under-voltage lockout (UVLO)
at 5.75V
■ Over-temperature protection
■ Over-voltage protection will tri-state
the SW outputs to prevent damage
if the output exceeds 103% of the
regulation voltage
■ Vout voltage status reported with
the power good output pin
■ Available in 16-pin QFN (3 × 3 mm)
package with exposed thermal pad
MCP16323 Typical Application Circuit
BOOST
S
GND PGND
VIN SW
V
FB
VOUT
EN
PG
4.7 μH
C
OUT
2 × 22 μF
10 kΩ
CBOOST
22 nF
L
1
VOUT
3.3V @ 3A
CIN
2 ×10 µF
V
IN
6.0V to 18V
Typical MCP16323 Efficiency with a 5V Fixed Output
50
55
60
65
70
75
80
85
90
95
100
0.0 0.6 1.2 1.8 2.4 3.0
Efficiency (%)
I
OUT
(A)
V
IN
= 6V
V
IN
= 18V V
IN
= 12V
V
OUT
= 5V