UC3843N

UC3843N Datasheet

UC3842/UC3843/UC3844/UC3845

Part	Datasheet
UC3843N	UC3843N (pdf)

Related Parts	Information
UC3845D	UC3845D
UC3843DX	UC3843DX
UC3843D	UC3843D
UC3844DX	UC3844DX
UC3842D	UC3842D
UC3844D	UC3844D
UC3842N	UC3842N
UC3844N	UC3844N

PDF Datasheet Preview
UC3842/UC3843/UC3844/UC3845 SMPS Controller • Low Start up Current • Maximum Duty Clamp • UVLO With Hysteresis • Operating Frequency up to 500KHz Internal Block Diagram The UC3842/UC3843/UC3844/UC3845 are fixed frequencycurrent-mode PWM controller. They are specially designed for Off-Line and DC to DC converter applications with minimum external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator and a high current totempole output for driving a Power MOSFET. The UC3842 and UC3844 have UVLO thresholds of 16V on and 10V off . The UC3843 and UC3845 are 8.5V on and 7.9V off . The UC3842 and UC3843 can operate within 100% duty cycle. The UC3844 and UC3845 can operate with 50% duty cycle. 8-DIP 8-SOP 14-SOP * NORMALLY 8DIP/8SOP PIN NO. * IS 14SOP PINNO. * TOGGLE FLIP FLOP USED ONLY IN UC3844, UC3845 2002 Fairchild Semiconductor Corporation UC3842/UC3843/UC3844/UC3845 Absolute Maximum Ratings Parameter Value Supply Voltage Output Current Analog Inputs Pin Error Amp Output Sink Current Power Dissipation at 8DIP Power Dissipation at 8SOP Power Dissipation at 14SOP Storage Temperature Range Lead Temperature Soldering, 10sec VCC IO V ANA ISINK E.A PD Note1,2 PD Note1,2 PD Note1,2 TSTG TLEAD 30 ±1 to 10 1200 460 680 -65 ~ +150 +300 Note Board Thickness 1.6mm, Board Dimension 76.2mm x114.3mm, Reference EIA / JSED51-3, 51-7 Do not exceeed PD and SOA Safe Operation Area Unit V A V mA mW °C °C Power Dissipation Curve POWER DISSIPATION mW 1200 1100 8DIP 1000 14SOP 600 8SOP 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 AMBIENT TEMPERATURE ℃ Thermal Data Characteristic Thermal Resistance Junction-ambient Symbol Rthj-amb MAX 8-DIP 100 8-SOP 265 Pin Array 8DIP,8SOP 14SOP 14-SOP 180 Unit °C/W Ordering Information Product Number UC3842N UC3843N UC3844N UC3845N UC3842D1 UC3843D1 UC3844D1 UC3845D1 UC3842D UC3843D UC3844D UC3845D Package 8-DIP 8-SOP 14-SOP UC3842/UC3843/UC3844/UC3845 Operating Temperature 0 ~ + 70°C UC3842/UC3843/UC3844/UC3845 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 2/19/02 0.0m 001 2002 Fairchild Semiconductor Corporation

PDF Datasheet Preview

UC3842/UC3843/UC3844/UC3845

SMPS Controller
• Low Start up Current
• Maximum Duty Clamp
• UVLO With Hysteresis
• Operating Frequency up to 500KHz

Internal Block Diagram

The UC3842/UC3843/UC3844/UC3845 are fixed frequencycurrent-mode PWM controller. They are specially designed for Off-Line and DC to DC converter applications with minimum external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator and a high current totempole output for driving a Power MOSFET. The UC3842 and UC3844 have UVLO thresholds of 16V on and 10V off . The UC3843 and UC3845 are 8.5V on and 7.9V off . The UC3842 and UC3843 can operate within 100% duty cycle. The UC3844 and UC3845 can operate with 50% duty cycle.
8-DIP
8-SOP
14-SOP
* NORMALLY 8DIP/8SOP PIN NO. * IS 14SOP PINNO. * TOGGLE FLIP FLOP USED ONLY IN UC3844, UC3845
2002 Fairchild Semiconductor Corporation

UC3842/UC3843/UC3844/UC3845

Absolute Maximum Ratings

Parameter

Value

Supply Voltage Output Current Analog Inputs Pin Error Amp Output Sink Current Power Dissipation at 8DIP Power Dissipation at 8SOP Power Dissipation at 14SOP Storage Temperature Range Lead Temperature Soldering, 10sec

VCC IO

V ANA ISINK E.A PD Note1,2 PD Note1,2 PD Note1,2

TSTG TLEAD
30 ±1 to 10 1200 460 680 -65 ~ +150 +300

Note Board Thickness 1.6mm, Board Dimension 76.2mm x114.3mm, Reference EIA / JSED51-3, 51-7 Do not exceeed PD and SOA Safe Operation Area

Unit V A V mA
mW °C °C

Power Dissipation Curve

POWER DISSIPATION mW
1200 1100
8DIP
1000
14SOP
600 8SOP
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

AMBIENT TEMPERATURE ℃

Thermal Data

Characteristic Thermal Resistance Junction-ambient

Symbol Rthj-amb MAX
8-DIP 100
8-SOP 265

Pin Array
8DIP,8SOP
14SOP
14-SOP 180

Unit °C/W
Ordering Information

Product Number UC3842N UC3843N UC3844N UC3845N UC3842D1 UC3843D1 UC3844D1 UC3845D1 UC3842D UC3843D UC3844D UC3845D

Package 8-DIP 8-SOP 14-SOP

UC3842/UC3843/UC3844/UC3845

Operating Temperature
0 ~ + 70°C

UC3842/UC3843/UC3844/UC3845

DISCLAIMER

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:

Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.

A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
2/19/02 0.0m 001 2002 Fairchild Semiconductor Corporation

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived UC3843N Datasheet file may be downloaded here without warranties.

Datasheet ID: UC3843N 634813