MT3820
Dual High-Efficiency PWM Step-Down DC/DC Converter
GENERAL DESCRIPTION
The
MT3820
is
a
dual
high-efficiency
DC/DC
Pulse-Width-Modulated
(PWM)
step-down
converter. It is capable of delivering 1.2A output current
over a wide input voltage range from 2.4V to 5.5V, the
MT3820 is ideally suited for portable electronic devices
that are powered from 1-cell Li-ion battery or from other
power sources within the range such as cellular phones,
PDAs and other handheld devices. Two operational
modes are available. PWM/Low-Dropout auto-switch
and shutdown modes. Internal synchronous rectifier
with low RDS(ON) dramatically reduces conduction
loss at PWM mode. No external Schottky diode is
required in practical application.
The MT3820 enters Low-Dropout mode when normal
PWM cannot provide regulated output voltage by
continuously turning on the upper PMOS. The MT3820
enter shutdown Mode And consumes less than 0.1μA
when EN pin is pulled low.
1.5MHz Constant Frequency Operation
1.2A Output Current
No Schottky Diode Required
2.4V to 5.5V Input Voltage Range
Output Voltage as Low as 0.6V
Low Quiescent Current: 30µA
Slope Compensated Current Mode Control
for Excellent Line and Load Transient
Response
Thermal Fault Protection
Inrush Current Limit and Soft Start
<1µA Shutdown Current
Small 12-Lead WDFN package
APPLICATIONS
Cellular and Smart Phones
Personal Information Appliances
Wireless and DSL Modems
MP3 Players
Digital Still and Video Cameras
FEATURES
High Efficiency: Up to 96%
Typical Application
Figure 1. Basic Application Circuit
Aerosemi Technology Co.,LTD
1
MT3820
Package/Order Information
Part Number
SWICHING
FREQUENCY
Temp Range
-40°C to +85°C
OUTPUT
VOLTAGE (V)
OUTPUT
CURRENT (A)
MT3820-ADJ
1.5MHz
ADJ
1.2
Pin Description
PIN
1
2
3,9,EP
4
5,11
6
7
8
10
12
NAME
VIN2
LX2
GND
FB1
NC1,NC2
EN1
VIN1
LX1
FB2
EN2
Power Input of Channel2
FUNCTION
Pin for Switching of Channel2
Ground,The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
Feedback of Channel1
No connection
Chip Enable of Channel1
Power Input of Channel1
Pin for Switching of Channel1
Feedback of Channel2
Chip Enable of Channel2
Aerosemi Technology Co.,LTD
2
MT3820
Absolute Maximum Ratings
VINx Voltage ………… -0.3V to 6V
ENx,FBx Voltages….…-0.3 to (Vin+0.3V)
Operating Temperature Range … -40°C to +85°C
Lead Temperature(Soldering,10s)……....+260°C
LXx Voltage …………-0.3V to (Vin+0.3V) Storage Temperature Range ..…-65°C to 150°C
Electrical Characteristics
(Vin=3.6V,Vout=1.8V,L=2.2uH, Cin=4.7uF, Cout=10uF, Ta=25oC)
Parameter
Channel1 and Channel2
Input Voltage Range
UVLO Threshold
Input DC Supply Current
PWM Mode
PFM Mode
Shutdown Mode
Regulated Feedback
Voltage
Reference Voltage Line
Regulation
Output Voltage Line
Regulation
Output Voltage Load
Regulation
Oscillation Frequency
On Resistance of PMOS
ON Resistance of NMOS
Peak Current Limit
EN Threshold
EN Leakage Current
LX Leakage Current
V
RUN
=0V,V
IN
=Vsw=3.6V
Vout=100%
Vout=0V
I
SW
=100mA
I
SW
=-100mA
V
IN
= 3V, Vout=90%
0.40
(Note 4)
Vout = 90%, Iload=0mA
Vout = 105%, Iload=0mA
V
RUN
= 0V, V
IN
=4.2V
T
A
= 25°C
T
A
= 0°C
≤
T
A
≤
85°C
T
A
= -40°C
≤
T
A
≤
85°C
Vin=2.4V to 5.5V
V
IN
= 2.4V to 5.5V
0.588
0.586
0.585
140
30
0.1
0.600
0.600
0.600
0.04
0.04
0.5
1.5
300
0.15
0.12
2
1.0
±0.01
±0.01
1.50
±0.1
±1.0
0.22
0.2
200
60
1.0
0.612
0.613
0.615
0.40
0.4
2.4
1.7
1.8
5.5
1.9
V
µA
µA
µA
µA
V
V
V
%/V
%
%
MHz
KHz
Ω
Ω
A
V
µA
µA
Conditions
MIN
TYP
MAX
unit
Aerosemi Technology Co.,LTD
3
模拟电子
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