AEROSEMI
MT6273
High Performance Current Mode
PWM Controller
FEATURES
GENERAL DESCRIPTION
MT6273 is a highly integrated current mode PWM
control IC optimized for high performance, low
standby power and cost effective offline flyback
converter applications.
PWM switching frequency at normal operation is
internally fixed and is trimmed to tight range. At no
load or light load condition, the IC operates in
extended ‘burst mode’ to minimize switching loss.
Lower standby power and higher conversion
efficiency is thus achieved.
VDD low startup current and low operating current
contribute to a reliable power on startup and low
standby design with MT6273.
MT6273 offers complete protection coverage with
auto-recovery including Cycle-by-Cycle current
limiting (OCP), over load protection (OLP), over
temperature protection (OTP), over voltage (fixed or
adjustable) protection (OVP) and VDD under voltage
lockout (UVLO).
Excellent EMI performance is achieved.Frequency
shuffling technique.The tone energy at below 20KHZ
is minimized inthe design and audio noise is
eliminated duringoperation.
MT6273 is offered in SOT23-6 package.
Offline AC/DC flyback converter for
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Battery Charger
•
Power Adapter
•
Set-Top Box Power Supplies
•
Open-frame SMPS
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Power on Soft Start Reducing MOSFET Vds
Stress
Frequency shuffling for EMI
Extended Burst Mode Control For Improved
Efficiency and Minimum Standby Power
Design
Audio Noise Free Operation
Fixed 65KHZ Switching Frequency
Comprehensive Protection Coverage
o VDD Under Voltage Lockout with
Hysteresis (UVLO)
o Cycle-by-cycle over current threshold
setting for constant output power limiting
over universal input voltage range
o Overload Protection (OLP) with auto-
recovery
o Over Temperature Protection (OTP) with
auto-recovery
o VDD Over voltage Protection(OVP) with
auto-recovery
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MT6273
TYPICAL APPLICATION
GENERAL INFORMATION
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SOT23-6
(MT6273)
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MT6273
ABSOLUTE MAXIMUM RATINGS
Parameter
VDD DC Supply Voltage
VDD Zener Clamp Voltage
Note
VDD DC Clamp Current
FB Input Voltage
Sense Input Voltage
RT Input Voltage
Min/Max Operating
Junction Temperature TJ
Min/Max Storage
Temperature Tstg
Lead
Temperature
(Soldering, 10secs)
Value
35 V
VDD_Clamp+0.1V
10 mA
-0.3 to 7V
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Note:
VDD_Clamp has a nominal value of 32V.
Stresses beyond those listed under “absolute maximum
ratings” may cause permanent damage to the device. These
are stress ratings only, functional operation of the device at
these or any other conditions beyond those indicated under
“ recommended operating conditions” is not implied. Exposure
to absolute maximum-rated conditions for extended periods
may affect device reliability.
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260
℃
-40 to 150
℃
-55 to 160
℃
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-0.3 to 7V
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-0.3 to 7V
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MT6273
TERMINAL ASSIGNMENTS
Pin Name I/O
GND
FB
RT
CS
VDD
Gate
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Ground
Feedback input pin. The PWM duty cycle is determined by voltage level into this pin
and the current-sense signal at Pin 4.
Dual function pin. Either connected through a NTC resistor to ground for over
temperature shutdown/latch control or connected through Zener to VDD for
adjustable over voltage protection
Current sense input
Power Supply
Totem-pole gate driver output for power Mosfet
Description
VDD
TA
VDD Supply Voltage
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Symbol
Parameter
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Min/Max
12 to 25
-40 to 85
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RECOMMENDED OPERATING CONDITION
Unit
V
℃
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Operating Ambient Temperature
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4
MT6273
BLOCK DIAGRAM
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