Information

4
Portable Power Conversion Design Guide
DC/DC Conversion
Step-Down (Buck) Switch Mode Power Converters
MCP16311/2 30V Input, High-Efficiency, Integrated Synchronous Buck Regulator
The MCP16311 is a compact, high-efficiency, fixed-frequency PWM/PFM, synchronous step-down DC-DC converter in a
8-pin MSOP or 2 × 3 TDFN package that operates from input voltage sources up to 30V. Integrated features include a high-
side and a low-side switch, fixed-frequency Peak Current Mode Control, internal compensation, peak-current limit and over-
temperature protection. The MCP16311 provides all the active functions for local DC-DC conversion, with fast transient
response and accurate regulation.
Example MCP16311 Synchronous Buck Regulator Application Circuit
Up to 95% efficiency
Wide 4.4V to 30V input
voltage range
Wide 2.0V to 24V output
voltage range
Integrated high-performance
n-channel low- and high-side
switches: 170 mΩ low-side MOSFET,
300 mΩ high-side MOSFET
Stable 0.8V reference voltage
Automatic pulse-frequency
modulation/pulse-width modulation
(PFM/PWM) operation (on
MCP16311), or 500 kHz PWM only
operation (on MCP16312)
Low 3 μA (typical) device
shutdown current
Low 44 μA device quiescent current
(when not switching in PFM Mode)
Internal compensation
Internal soft-start: 300 μs turn on
Peak current mode control
Cycle-by-cycle peak current limit
Under-voltage lockout
(UVLO) at 3.6V (typical) with
0.5V of hysteresis
Thermal shutdown at 150°C, with
25°C hysteresis
BOOST
GND
V
IN
VCC
SW
V
FB
EN
15 μH
31.2 kΩ
C
OUT
2 × 10 μF
10 kΩ
C
BOOST
100 nF
L
1
VOUT
3.3V @ 1A
CIN
2 ×10 µF
Cv
CC
1 µF
V
IN
4.5V to 30V
MCP16311 Ouput Current Capability
0
200
400
600
800
1000
1200
1400
1600
0 5 10 15 20 25 30
I
OUT
(mA)
V
IN
(V)
V
OUT
= 3.3V
V
OUT
= 5V
V
OUT
= 12V
Typical MCP16311 Efficiency, with and without
PFM Operation Enabled
0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000
Efficiency (%)
I
OUT
(mA)
V
PWM ONLY
PWM/PFM
V
IN
= 12V
OUT
= 5V
V
OUT
= 3.3V
V