UC3843AN Datasheet
Switching Reg Control Circuit, Single Ended, 1000mA, 8.2V To 30V, 8 Lead DIP
Download: UC3843AN Datasheet 
UC3843AN
Switching Reg Control Circuit, Single Ended, 1000mA, 8.2V To 30V, 8 Lead DIP
Voltage Regulators and Switching Regulators
Voltage Regulators (Continued)
ON Semiconductor
Linear Voltage Regulators (Continued)
Fixed Output (Continued)
Case 29/TO-92
Mc78l08acp Mc78l12acp Mc78l15acp Mc78l24acp
Positive Regulator
Case 221A
Case 369A
Lm340at-5.0 Mc78t05ct Mc78t05act Lm323at Mc7806ct Mc78m08ct Mc7808ct Mc78t08ct Mc78m12ct
Mc7812ct Mc7812act Lm340t-12 Lm340at-12 Mc78t12ct Mc78t12act Mc78m15ct Mc7815bt Mc7815ct
Mc7815act Lm340t-15 Lm340at-15 Mc78t15ct Mc7818ct Mc78m20ct Mc78m24ct Mc7824bt Mc7824ct
MC78M08CDT MC78M12CDT
Mfr.'s Type
Case 751/SO-8
MC78L12ACD
Case 29/TO-92
MC79L12ACP MC79L15ACP
Negative Regulator
Case 221A
Case 369A
MC7906CT
MC7908CT
MC7912CT
MC7915CT
MC7915ACT
MC7918CT
UC3843AN Datasheet
SMPS Controller
Download: UC3843AN Datasheet
UC3843AN
SMPS Controller
UC3842A/UC3843A
FEATURES
Low Start Current 0.2mA (typ)
Operating Range Up To 500KHz
Cycle by Cycle Current Limiting
Under Voltage Lock Out With Hysteresis
Short Shutdown Delay Time: typ.100ns
High Current Totem-pole Output
Output Swing Limiting: 22V
Description
The UC3842A/UC3843A are fixed PWM controller for OffLine and DC to DC converter
Applications. The Internal Circuits Include Uvlo, Low Start Up Current Circuit, Temperature
Compensated Reference, High Gain Error Amplifier, Current Sensing Comparator, And High Current
Totem-pole Output For Driving A Power Mosfet. Also Uc3842a/ Uc3843a Provide Low Start Up Current
Below 0.3ma And Short Shutdown Delay Time Typ. 100ns. The Uc3842a Has Uvlo Threshold Of 16v(on) And
10v(off). The Uc3843a Is 8.4v(on) And 7.6v(off). The Uc3842a And Uc3843a Can Operate Within 100%
duty cycle.
Internal Block Diagram
1 8-SOP
VREF 8
Internal Bias
5V VREF
SET/ RESET
Good LOGIC
VFB 2 COMP 1
1/2VREF
Error Amp + -
1/3 1V
C.S PWM Comp. LATCH
RT/CT 4
OSCILLATOR
7 VCC 29V
UC3843AN Datasheet
HIGH PERFORMANCE CURRENT MODE CONTROLLERS
Download: UC3843AN Datasheet
UC3843AN
HIGH PERFORMANCE CURRENT MODE CONTROLLERS
Order this document by UC3842A/D
High Performance
Current Mode Controllers
The Uc3842a, Uc3843a Series Of High Performance Fixed Frequency Current Mode Controllers Are
specifically designed for off-line and dc-to-dc converter
Applications Offering The Designer A Cost Effective Solution With Minimal 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
totem pole output ideally suited for driving a power MOSFET.
Also included are protective
Features Consisting Of Input And Reference Undervoltage Lockouts Each With Hysteresis,
Cycle-by-cycle Current Limiting, Programmable Output Deadtime, And A Latch For Single Pulse
metering.
These Devices Are Available In An 8-pin Dual-in-line Plastic Package As Well As The 14-pin Plastic
Surface Mount (so-14). The So-14 Package Has Separate Power And Ground Pins For The Totem Pole
output stage.
The Ucx842a Has Uylo Thresholds Of 16 V (on) And 10 V (off), Ideally Suited For Off-line Converters.
The UCX843A is tailored for lower voltage
Applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
Trimmed Oscillator Discharge Current for Precise Duty Cycle Control
Current Mode Operation to 500 kHz
Automatic Feed Forward Compensation
Latching PWM for Cycle-By-Cycle Current Limiting
Internally Trimmed Reference with Undervoltage Lockout
High Current Totem Pole Output
Undervoltage Lockout with Hysteresis
Low Startup and Operating Current
Direct Interface with Motorola SENSEFET Products
4(7) Voltage Feedback
Input 2(3)
Output Compensation
Simplified Block Diagram
VCC 7(12)
5.0V Reference
VCC Undervoltage
Lockout
Vref Undervoltage
Lockout
Oscillator
+ - Error Amplifier
Latching PWM
UC3843AN Datasheet
High Performance Current Mode Controllers
Download: UC3843AN Datasheet
UC3843AN
High Performance Current Mode Controllers
UC3842A, UC3843A, UC2842A, UC2843A
The Uc3842a, Uc3843a Series Of High Performance Fixed Frequency Current Mode Controllers Are
specifically designed for off-line and dc-to-dc converter
Applications Offering The Designer A Cost Effective Solution With Minimal 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
totem pole output ideally suited for driving a power MOSFET.
Also included are protective
Features Consisting Of Input And Reference Undervoltage Lockouts Each With Hysteresis,
Cycle-by-cycle Current Limiting, Programmable Output Deadtime, And A Latch For Single Pulse
metering.
These Devices Are Available In An 8-pin Dual-in-line Plastic Package As Well As The 14-pin Plastic
Surface Mount (so-14). The So-14 Package Has Separate Power And Ground Pins For The Totem Pole
output stage.
The Ucx842a Has Uylo Thresholds Of 16 V (on) And 10 V (off), Ideally Suited For Off-line Converters.
The UCX843A is tailored for lower voltage
Applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
Trimmed Oscillator Discharge Current for Precise Duty Cycle
Control
Current Mode Operation to 500 kHz
Automatic Feed Forward Compensation
Latching PWM for Cycle-By-Cycle Current Limiting
Internally Trimmed Reference with Undervoltage Lockout
High Current Totem Pole Output
Undervoltage Lockout with Hysteresis
Low Startup and Operating Current
Direct Interface with ON Semiconductor SENSEFET Products
PDIP-8 N SUFFIX CASE 626
SO-14 D SUFFIX CASE 751A
SO-8 D1 SUFFIX CASE 751
PIN CONNECTIONS
Compensation 1 Voltage Feedback 2
Current Sense 3 RT/CT 4
8 Vref 7 VCC 6 Output 5 Gnd
(Top View)
Compensation 1 NC 2
Voltage Feedback 3 NC 4
Current Sense 5 NC 6
RT/CT 7
14 Vref 13 NC 12 VCC 11 VC 10 Output 9 Gnd 8 Power Ground
(Top View)
UC3843AN Datasheet
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
Download: UC3843AN Datasheet
UC3843AN
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
UC2842A/3A/4A/5A
UC3842A/3A/4A/5A
. TRIMMED OSCILLATOR DISCHARGE CURRENT
. CURRENT MODE OPERATION TO 500kHz . AUTOMATIC FEED FORWARD COMPENSA-
. LATCHING PWM FOR CYCLE-BY-CYCLE CURRENT LIMITING
. INTERNALLY TRIMMED REFERENCE WITH UNDERVOLTAGE LOCKOUT
. HIGH CURRENT TOTEM POLE OUTPUT . UNDERVOLTAGE LOCKOUT WITH HYSTER-
. LOW START-UP CURRENT (< 0.5mA) . DOUBLE PULSE SUPPRESSION
Description
The UC384xA family of control ICs provides the necessary
Features To Implement Off-line Or Dc To Dc Fixed Frequency Current Mode Control Schemes With A
Minimal External Parts Count. Internally Implemented Circuits Include A Trimmed Oscillator For
Precise Duty Cycle Control Under Voltage Lockout Featuring Start-up Current Less Than 0.5ma, A
Precision Reference Trimmed For Accuracy At The Error Amp Input, Logic To Insure Latched Operation,
a PWM
Minidip
Comparator Which Also Provides Current Limit Control, And A Totem Pole Output Stage Designed To
Source Or Sink High Peak Current. The Output Stage, Suitable For Driving N-channel Mosfets, Is Low
in the offstate.
Differences Between Members Of This Family Are The Under-voltage Lockout Thresholds And Maximum Duty
Cycle Ranges. The Uc3842a And Uc3844a Have Uvlo Thresholds Of 16v (on) And 10v (off), Ideally Suited
off-line
Applications The Corresponding Thresholds For The Uc3843a And Uc3845a Are 8.5 V And 7.9v. The
Uc3842a And Uc3843a Can Operate To Duty Cycles Approaching 100%. A Range Of The Zero To < 50 % Is
Obtained By The Uc3844a And Uc3845a By The Addition Of An Internal Toggle Flip Flop Which Blanks The
output off every other clock cycle.
BLOCK DIAGRAM (toggle flip flop used only in UC3844A and UC3845A)
5 GROUND
4 RT/CT
1 COMP CURRENT 3 SENSE
5V REF
2.50V OSC
VREF GOOD LOGIC
INTERNAL BIAS
8 VREF 5V 50mA
6 OUTPUT
ERROR AMP.
CURRENT SENSE
COMPARATOR
PWM LATCH
UC3843AN Datasheet
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
Download: UC3843AN Datasheet
UC3843AN
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
UC284XA UC384XA
NOT FOR NEW DESIGN
FEATURES
TRIMMED OSCILLATOR DISCHARGE CURRENT
CURRENT MODE OPERATION TO 500kHz AUTOMATIC FEED FORWARD COMPENSATION
LATCHING PWM FOR CYCLE-BY-CYCLE CURRENT LIMITING
INTERNALLY TRIMMED REFERENCE WITH UNDERVOLTAGE LOCKOUT
HIGH CURRENT TOTEM POLE OUTPUT UNDERVOLTAGE LOCKOUT WITH HYSTERESIS
LOW START-UP CURRENT (< 0.5mA) DOUBLE PULSE SUPPRESSION
Description
The UC384xA family of control ICs provides the necessary
Features To Implement Off-line Or Dc To Dc Fixed Frequency Current Mode Control Schemes With A
Minimal External Parts Count. Internally Implemented Circuits Include A Trimmed Oscillator For
Precise Duty Cycle Control Under Voltage Lockout Featuring Start-up Current Less Than 0.5ma, A
Precision Reference Trimmed For Accuracy At The Error Amp Input, Logic To Insure Latched Operation,
A Pwm Comparator Which Also Provides Current Limit Control, And A Totem Pole Output Stage Designed
To Source Or Sink High Peak Current. The Output Stage, Suitable For Driving N-channel Mosfets, Is
low in the off-state.
Figure 1. Package
Table 1. Order Codes
Part Number Uc2842ad1; Uc3842ad1; Uc2843ad1; Uc3843ad1; Uc2844ad1; Uc3844ad1; Uc2845ad1; Uc3845ad1
UC2842AN; UC3842AN; UC2843AN; UC3843AN; UC2844AN; UC3844AN; UC2845AN; UC3845AN
SO-8 Package SO-8 DIP-8
Differences Between Members Of This Family Are The Under-voltage Lockout Thresholds And Maximum Duty
Cycle Ranges. The Uc3842a And Uc3844a Have Uvlo Thresholds Of 16v (on) And 10v (off), Ideally Suited
off-line
Applications The Corresponding Thresholds For The Uc3843a And Uc3845a Are 8.5 V And 7.9v. The
Uc3842a And Uc3843a Can Operate To Duty Cycles Approaching 100%. A Range Of The Zero To < 50 % Is
Obtained By The Uc3844a And Uc3845a By The Addition Of An Internal Toggle Flip Flop Which Blanks The
output off every other clock cycle.
Figure 2. Block Diagram (toggle flip flop used only in UC3844A and UC3845A)
5 GROUND
4 RT/CT
1 COMP CURRENT 3 SENSE
5V REF
VREF GOOD LOGIC
INTERNAL BIAS
ERROR AMP.
UC3843AN Datasheet
Current Mode PWM, 0.5mA Start-up Supply Current, DIP
Download: UC3843AN Datasheet
UC3843AN
Current Mode PWM, 0.5mA Start-up Supply Current, DIP
UC2842A/3A/4A/5A
UC3842A/3A/4A/5A
HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
. TRIMMED OSCILLATOR DISCHARGE CURRENT
. CURRENT MODE OPERATION TO 500kHz . AUTOMATIC FEED FORWARD COMPENSA-
. LATCHING PWM FOR CYCLE-BY-CYCLE CURRENT LIMITING
. INTERNALLY TRIMMED REFERENCE WITH UNDERVOLTAGE LOCKOUT
. HIGH CURRENT TOTEM POLE OUTPUT . UNDERVOLTAGE LOCKOUT WITH HYSTER-
. LOW START-UP CURRENT (< 0.5mA) . DOUBLE PULSE SUPPRESSION
Description
TheUC384xA family ofcontrolICs providesthe necessary
Features To Implement Off-line Or Dc To Dc Fixed Frequency Current Mode Control Schemes With A
Minimal External Parts Count. Internally Implemented Circuits Include A Trimmed Oscillator For
Precise Duty Cycle Control Under Voltage Lockoutfeaturingstart-up Current Less Than0.5ma,a Precision
Reference Trimmed For Accuracy At The Error Amp Input, Logicto Insure Latched Operation,a Pwm
Minidip
Comparatorwhich Alsoprovidescurrent Limit Control, And A Totem Pole Output Stage Designed To Source
Or Sink High Peakcurrent. The Outputstage, Suitable For Driving N-channel Mosfets, Is Low In The
offstate.
Differences Between Members Of This Family Are The Under-voltagelockout Thresholds And Maximum Duty
Cycle Ranges. The Uc3842a And Uc3844a Have Uvlo Thresholds Of 16v (on) And 10v (off), Ideally Suited
off-line
Applications The Corresponding Thresholds For The Uc3843a And Uc3845a Are 8.5 V And 7.9v. The
Uc3842a And Uc3843a Can Operate To Dutycycles Approaching100%.a Range Of The Zeroto < 50 % Is
Obtainedby Theuc3844aand Uc3845aby The Addition Of An Internal Toggle Flip Flopwhich Blanks The
output off every otherclock cycle.
BLOCK DIAGRAM (toggle flip flop used only in UC3844A and UC3845A)
5 GROUND
4 RT/CT
1 COMP CURRENT 3 SENSE
5V REF
2.50V OSC
VREF GOOD LOGIC
INTERNAL BIAS
8 VREF 5V 50mA
6 OUTPUT
ERROR AMP. +
CURRENT SENSE
COMPARATOR
UC3843AN Datasheet
Current Mode PWM Controller 8-PDIP 0 To 70
Download: UC3843AN Datasheet
UC3843AN
Current Mode PWM Controller 8-PDIP 0 To 70
PACKAGE OPTION ADDENDUM
29-Oct-2009
PACKAGING INFORMATION
Orderable Device
5962-8670405pa 5962-8670405xa 5962-8670406pa 5962-8670406xa 5962-8670407pa 5962-8670407xa
5962-8670408PA 5962-8670408XA
UC1842AJ UC1842AJ883B UC1842AL883B
UC1843AJ UC1843AJ883B UC1843AL883B
UC1844AJ UC1844AJ883B UC1844AL883B
UC1845AJ UC1845AJ883B UC1845AL883B
UC2842AD
UC2842AD8
UC2842AD8G4
UC2842AD8TR
UC2842AD8TRG4
UC2842ADG4
UC2842ADTR
UC2842ADTRG4
UC2842ADW
UC2842ADWG4
UC2842ADWTR
UC2842ADWTRG4
UC2842AJ UC2842AN
Status (1)
ACTIVE
Package Type Cdip Lccc Cdip Lccc Cdip Lccc Cdip Lccc Cdip Lccc Cdip Lccc Cdip Lccc Cdip Lccc Soic
Package Drawing
JG FK JG FK JG FK JG FK JG FK JG FK JG FK JG FK D
ACTIVE
OBSOLETE CDIP
ACTIVE
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3) Qty
N / A for Pkg Type
POST-PLATE N / A for Pkg Type
N / A for Pkg Type
UC3843AN Datasheet
UC3843 - Current Mode PWM Controller 8-PDIP 0 To 70
Download: UC3843AN Datasheet
UC3843AN
UC3843 - Current Mode PWM Controller 8-PDIP 0 To 70
PACKAGE OPTION ADDENDUM
25-Sep-2013
PACKAGING INFORMATION
Orderable Device 5962-8670405PA
Status Package Type Package Pins Package
Drawing
ACTIVE
Eco Plan
Lead/Ball Finish A42
MSL Peak Temp
N / A for Pkg Type
Op Temp ( C) -55 to 125
5962-8670405XA
ACTIVE
POST-PLATE N / A for Pkg Type -55 to 125
5962-8670406PA 5962-8670406XA
ACTIVE
CDIP LCCC
N / A for Pkg Type
POST-PLATE N / A for Pkg Type
-55 to 125 -55 to 125
5962-8670407PA 5962-8670407XA
ACTIVE
CDIP LCCC
UC3843AN Datasheet
PMIC - Voltage Regulators - DC DC Switching Controllers, Integrated Circuits (ICs),
Download: UC3843AN Datasheet
UC3843AN
PMIC - Voltage Regulators - DC DC Switching Controllers, Integrated Circuits (ICs),
UC3842A, UC3843A, UC2842A, UC2843A
High Performance Current Mode Controllers
The Uc3842a, Uc3843a Series Of High Performance Fixed Frequency Current Mode Controllers Are
specifically designed for off line and DC to DC converter
Applications Offering The Designer A Cost Effective Solution With Minimal 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
totem pole output ideally suited for driving a power MOSFET.
Also included are protective
Features Consisting Of Input And Reference Undervoltage Lockouts Each With Hysteresis, Cycle By
Cycle Current Limiting, Programmable Output Deadtime, And A Latch For Single Pulse Metering.
These Devices Are Available In An 8 Pin Dual In Line Plastic Package As Well As The 14 Pin
Plastic Surface Mount (soic 14). The Soic 14 Package Has Separate Power And Ground Pins For The
totem pole output stage.
The Ucx842a Has Uylo Thresholds Of 16 V (on) And 10 V (off), Ideally Suited For Off Line
converters. The UCX843A is tailored for lower voltage
Applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
FEATURES
Trimmed Oscillator Discharge Current for Precise Duty Cycle
Control
Current Mode Operation to 500 kHz
Automatic Feed Forward Compensation
Latching PWM for Cycle By Cycle Current Limiting
Internally Trimmed Reference with Undervoltage Lockout
High Current Totem Pole Output
Undervoltage Lockout with Hysteresis
Low Startup and Operating Current
Direct Interface with ON Semiconductor SENSEFET Products
Pb Free Packages are Available
PDIP 8 N SUFFIX CASE 626
SOIC 14 D SUFFIX CASE 751A
SOIC 8 D1 SUFFIX CASE 751
PIN CONNECTIONS
Compensation 1 Voltage Feedback 2
Current Sense 3 RT/CT 4
8 Vref 7 VCC 6 Output 5 GND
(Top View)
Compensation 1 NC 2
Voltage Feedback 3 NC 4
Current Sense 5 NC 6
UC3843AN Datasheet
PMIC - Voltage Regulators - DC DC Switching Controllers, Integrated Circuits (ICs),
Download: UC3843AN Datasheet
UC3843AN
PMIC - Voltage Regulators - DC DC Switching Controllers, Integrated Circuits (ICs),
PACKAGE OPTION ADDENDUM
PACKAGING INFORMATION
Orderable Device 5962-8670405PA
Status Package Type Package Pins Package
Drawing
ACTIVE
Eco Plan
5962-8670405XA
ACTIVE
5962-8670406PA 5962-8670406XA
ACTIVE
CDIP LCCC
5962-8670407PA 5962-8670407XA
ACTIVE
CDIP LCCC
5962-8670408PA 5962-8670408XA
ACTIVE
CDIP LCCC
UC1842AJ UC1842AJ883B UC1842AL883B
ACTIVE
CDIP LCCC
UC1843AJ UC1843AJ883B
ACTIVE
Lead/Ball Finish