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MP1482DS-LF-Z

P1-P3P4-P6P7-P9P10-P12
MP1482 – 2A, 18V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
MP1482 Rev. 1.31 www.MonolithicPower.com 4
7/9/2012 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2012 MPS. All Rights Reserved.
PIN FUNCTIONS
SOIC8
Pin #
Name Description
1 BS
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET
switch. Connect a 0.01F or greater capacitor from SW to BS to power the high side switch.
2 IN
Power Input. IN supplies the power to the IC, as well as the step-down converter switches.
Drive IN with a 4.75V to 18V power source. Bypass IN to GND with a suitably large capacitor to
eliminate noise on the input to the IC. See Input Capacitor.
3 SW
Power Switching Output. SW is the switching node that supplies power to the output. Connect
the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS
to power the high-side switch.
4 GND Ground.
5 FB
Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive
voltage divider from the output voltage. The feedback threshold is 0.923V. See Setting the
Output Voltage.
6 COMP
Compensation Node. COMP is used to compensate the regulation control loop. Connect a
series RC network from COMP to GND to compensate the regulation control loop. In some
cases, an additional capacitor from COMP to GND is required. See Compensation
Components.
7 EN
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the
regulator, drive it low to turn it off. Pull up with 100k resistor for automatic startup.
8 SS
Soft-Start Control Input. SS controls the soft start period. Connect a capacitor from SS to GND
to set the soft-start period. A 0.1F capacitor sets the soft-start period to 15ms. To disable the
soft-start feature, leave SS unconnected.
MP1482 – 2A, 18V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
MP1482 Rev. 1.31 www.MonolithicPower.com 5
7/9/2012 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2012 MPS. All Rights Reserved.
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 12V, V
O
= 3.3V, L = 10µH, C1 = 10µF, C2 = 22µF, T
A
= +25°C, unless otherwise noted.
Startup through Enable
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 1A (Resistance Load)
Shutdown through Enable
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 1A (Resistance Load)
Light Load Operation
Medium Load Operation
Load Transient
Steady State Test
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 0A, I
IN
= 8.2mA
Heavy Load Operation
Short Circuit
Recovery
Short Circuit
Protection
V
EN
5V/div.
V
OUT
1V/div.
V
SW
10V/div.
I
L
1A/div.
V
EN
5V/div.
V
OUT
2V/div.
V
SW
10V/div.
I
L
1A/div.
V
IN
20mV/div.
V
OUT
20mV/div.
V
SW
10V/div.
I
L
1A/div.
V
OUT
2V/div.
I
L
2A/div.
V
OUT
2V/div.
I
L
2A/div.
V
OUT
200mV/div.
I
LOAD
1A/div.
I
L
1A/div.
V
IN, AC
200mV/div.
V
O, AC
20mV/div.
V
SW
10V/div.
I
L
1A/div.
V
IN, AC
200mV/div.
V
O, AC
20mV/div.
V
SW
10V/div.
I
L
1A/div.
V
IN, AC
20mV/div.
V
O, AC
20mV/div.
V
SW
10V/div.
I
L
1A/div.
2A Load
1A Load
No Load
MP1482 – 2A, 18V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
MP1482 Rev. 1.31 www.MonolithicPower.com 6
7/9/2012 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2012 MPS. All Rights Reserved.
OPERATION
FUNCTIONAL DESCRIPTION
The MP1482 is a synchronous rectified,
current-mode, step-down regulator. It regulates
input voltages from 4.75V to 18V down to an
output voltage as low as 0.923V, and supplies
up to 2A of load current.
The MP1482 uses current-mode control to
regulate the output voltage. The output voltage
is measured at FB through a resistive voltage
divider and amplified through the internal
transconductance error amplifier. The voltage at
the COMP pin is compared to the switch current
measured internally to control the output
voltage.
The converter uses internal N-Channel
MOSFET switches to step-down the input
voltage to the regulated output voltage. Since
the high side MOSFET requires a gate voltage
greater than the input voltage, a boost capacitor
connected between SW and BS is needed to
drive the high side gate. The boost capacitor is
charged from the internal 5V rail when SW is low.
When the MP1482 FB pin exceeds 20% of the
nominal regulation voltage of 0.923V, the over
voltage comparator is tripped and the COMP
pin and the SS pin are discharged to GND,
forcing the high-side switch off.
LOCKOUT
COMPARATOR
INTERNAL
REGULATORS
IN
EN
+
ERROR
AMPLIFIER
1.2V
OVP
RAMP
CLK
0.923V
0.3V
CURRENT
COMPARATOR
CURRENT
SENSE
AMPLIFIER
1.1V
SHUTDOWN
COMPARATOR
COMP
SS
FB
GND
OSCILLATOR
340KHz
S
R
Q
SW
BS
IN
5V
OVP
IN < 4.1V
EN OK
+
Q
+
+
1.5V
+
+
2.5V
+
+
--
--
--
--
--
--
--
Figure 1—Functional Block Diagram
P1-P3P4-P6P7-P9P10-P12

MP1482DS-LF-Z

Mfr. #:
Buy MP1482DS-LF-Z
Manufacturer:
Monolithic Power Systems (MPS)
Description:
Switching Voltage Regulators 2A, 18V Sync Step-Down DCDC
Lifecycle:
New from this manufacturer.
Delivery:
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