MT2484
Rev.V1.2
1.4MHz, 18V，3A Synchronous Step-Down Converter
FEATURES
High Efficiency: Up to 94%
1.4MHz Frequency Operation
3A Output Current
No Schottky Diode Required
4.7V to 18V Input Voltage Range
Output Voltages from 0.923V to 15V
Slope Compensated Current Mode
Control for Excellent Line and Load
Transient Response
Integrated internal compensation
Low RDS(ON) Internal Power
MOSFETs
OCP, SCP, OVP, UVP Protection
Thermal Shutdown
Inrush Current Limit and Soft Start
Available in SOP8 Package
-40°C to +85°C Temperature Range
Flat Panel Television and Monitors
Wireless and DSL Modems
Notebook Computer
GENERAL DESCRIPTION
The MT2484 is a fully integrated, high–
efficiency
3A
synchronous
rectified
step-down converter. The MT2484 operates
at high efficiency over a wide output current
load range.
This device offers two operation modes,
PWM control and PFM Mode switching
control, which allows a high efficiency over
the wider range of the load.
The MT2484 requires a minimum number of
readily
available
standard
external
components and is available in an 8-pin
APPLICATIONS
Distributed Power Systems
Digital Set Top Boxes
SOIC ROHS compliant package.
Typical Application
Figure 1. Basic Application Circuit
MT2484 Datasheet V1.2
October 2011
1
Aerosemi Technology Co.,LTD
MT2484
Rev.V1.2
Absolute Maximum Ratings
(Note 1)
Input Supply Voltage …… -0.3V to 20V
EN,FB Voltages
……….…-0.3 to 6V
SW Voltage …………-0.3V to (Vin+0.5V)
BS Voltage ………….. (Vsw-0.3) to (Vsw+6V)
Operating Temperature Range … -40°C to +85°C
Lead Temperature(Soldering,10s) ….…....+300°C
Storage Temperature Range ….…-65°C to 150°C
Pin Description
PIN
NAME
FUNCTION
Bootstrap. A capacitor connected between SW and BST pins is
required to form a floating supply across the high-side switch driver.
Power supply Pin
Switching Pin
Ground
Adjustable version feedback input. Connect FB to the center point of
the external resistor divider.
No Connect
Enable Pin
Soft-Start Control Input. SS controls the soft-start period. Connect a
1
BS
2
3
4
5
6
7
VIN
SW
GND
FB
NC
EN
8
SS
capacitor from SS to GND to set the soft-start period. A 0.1μF
capacitor sets the soft-start period to 15ms. To disable the soft-start
feature, leave SS unconnected.
Pin Configuration
MT2484 Datasheet V1.2 October 2011
2
Aerosemi Technology Co.,LTD
MT2484
Rev.V1.2
Electrical Characteristics
Parameter
Input Voltage Range
UVLO Threshold
Supply Current
Regulated Feedback
Voltage
Feedback Overvoltage
Threshold
Error Amplifier Voltage
Gain
High-Side/Low-Side
Switch
On-Resistance
High-Side Switch
Leakage Current
Upper Switch Current
Limit
Lower Switch Current
Limit
Oscillation Frequency
EN Lockout Threshold
Voltage
Soft-Start Current
Thermal Shutdown
Vss=0V
2.2
V
EN
=2.0V, V
FB
=1.0V
T
A
= 25°C, 4.7V≤V
IN
≤18V
(Note 3)
(V
IN
=12V, V
OUT
=3.3V, T
A
= 25°C, unless otherwise noted.)
Conditions
MIN
4.7
3.8
TYP
MAX unit
18
V
V
mA
V
V
V/V
m
Ω
10
uA
A
A
MHz
2.7
V
uA
℃
4.2
1.3
4.5
1.5
0.900 0.925 0.950
1.1
500
100
V
EN
=0V, V
SW
=0V
Minimum Duty Cycle
From Drain to Source
3
0
3.5
0.9
1.4
2.5
6
160
MT2484 Datasheet V1.2 October 2011
3
Aerosemi Technology Co.,LTD
MT2484
Rev.V1.2
Typical Performance Characteristics
VIN = 12V, VOUT = 1.2V, L = 4.7μH, TA = +25ºC, unless otherwise noted.
Enable Supply Current vs Input Voltage
Disable Supply Current vs Input Voltage
VCC Regulator Line Regulation
Load Regulation
Efficiency
V
OUT
=1.2V
Efficiency
V
OUT
=1.8V
MT2484 Datasheet V1.2 October 2011
4
Aerosemi Technology Co.,LTD
MT2484
Rev.V1.2
Efficiency
V
OUT
=2.5V
Efficiency
V
OUT
=3.3V
Power Up without Load
Power up with 2A Load
Enable Startup with 2A Load
Output Ripple Voltage
I
OUT
=2A
MT2484 Datasheet V1.2 October 2011
5
Aerosemi Technology Co.,LTD
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