MP2120 – 2.5A, 5.5V SYNCHRONOUS STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS
(4)
(continued)
V
IN
= V
EN
= 3.6V, T
A
= +25C, unless otherwise noted.
Parameters
High-Side Switch Current Limit
Low-Side Switch Current Limit
Oscillator Frequency
Maximum Synch Frequency
Minimum Synch Frequency
Minimum On Time
Maximum Duty Cycle
POK Upper Trip Threshold
POK Lower Trip Threshold
POK Output Voltage Low
POK Deglitch Timer
Thermal Shutdown Threshold
Condition
Sourcing
Sinking
Min
4.2
1.2
Typ
4.5
3.5
1.5
2
1
50
90
10
-10
30
150
Max
Units
A
A
MHz
MHz
MHz
ns
%
%
%
V
μs
°C
1.8
FB respect to the nominal value
FB respect to the nominal value
I
SINK
= 5mA
Hysteresis = 20°C
0.4
Note:
4) Production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization.
PIN FUNCTIONS
Pin #
6
4, 7
3, 8
2, 9
5
1
Description
Open Drain Power Good Output. “HIGH” output indicates V
OUT
is within ±10% window.
POK
“LOW” output indicates V
OUT
is out of ±10% window. POK is pulled down in shutdown.
Input Supply. A decoupling capacitor to ground is required close to these pins to reduce
IN
switching spikes.
Switch Node Connection to the Inductor. These pins connect to the internal high and low-
SW
side power MOSFET switches. All SW pins must be connected together externally.
Ground. Connect these pins with larger copper areas to the negative terminals of the input
GND
and output capacitors.
Bootstrap. A capacitor between this pin and SW provides a floating supply for the high-side
BS
gate driver.
Feedback. This is the input to the error amplifier. An external resistive divider connects this
FB
pin between the output and GND. The voltage on the FB pin compares to the internal 0.8V
reference to set the regulation voltage.
Enable and Frequency Synchronization Input Pin. Forcing this pin below 0.4V shuts down
EN/SYNC the part. Forcing this pin above 1.6V turns on the part. Applying a 1MHz to 2MHz clock
signal to this pin synchronizes the internal oscillator frequency to the external source.
Name
10
MP2120 Rev. 0.92
9/7/2011
www.MonolithicPower.com
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3
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