Details, datasheet, quote on part number: UC2843
CategorySemiconductors => Power Management => Offline and Isolated DC/DC Controllers and Converters => PWM and Resonant Controller
Part familyUC2843 Current-Mode PWM Controller
TitleCurrent Mode PWM Controllers
DescriptionCurrent-Mode PWM Controller 14-SOIC -40 to 85
CompanyTexas Instruments, Inc.
DatasheetDownload UC2843 datasheet
Cross ref.Similar parts: MAX887HESA, MAX887HESA+, MAX887HESA+T, MAX887HESA-T, NCP1010AP130, NCP1011AP130, NCP1011AP130G, UCC2800PW, UCC2801PW, UCC2802PW
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Duty Cycle(Max)(%)100
Control MethodPeak Current Mode
Operating Temperature Range(C)-40 to 85
UVLO Thresholds On/Off(V)8.4/7.6
Special FeaturesError Amplifier,Multi-topology
Package GroupPDIP,SOIC
Gate Drive(Typ)(A)1
  Mecanical Data
Pin nbPackage typeInd stdJEDEC codePackage qtyCarrierDevice markWidth (mm)Length (mm)Thick (mm)Pitch (mm)
14DSOICR-PDSO-G50TUBEUC2843D 3.918.651.581.27
Application notes
• DN-26 UC3842A Low-Cost Start-up and Fault Protection Circuit
The UC1842/3/4/5 family of control ICs can implement off-line or DC-to-DC fixed-frequency current-mode control schemes with a minimal external parts count. This design note describes a circuit with low startup current (less than 0.5mA), MOSFET-compatible u | Doc
• Conditioning a Switch-mode Power Supply Current Signal Using TI Op Amps
The switch-mode power supply primary current is often sensed using a power resistor. Using an op amp to amplify the current-sense signal can reduce cost and improve noise performance and efficiency. This report reviews the advantages of using an op amp cir | Doc
• U-111, Practical Considerations in Current Mode Power Supplies
This application note explains the numerous PWM functions and ways to maximize their usefulness. It covers practical circuit design considerations, such as slope compensation, gate drive circuitry, external control functions, synchronization, and paralleli | Doc
• UCC38C42 Family of High-Speed BiCMOS Current-Mode PWM Controllers
Since their introduction in the mid 1980?s, the bipolar UC3842 family of Pulse width modulation (PWM)controllers has grown to become the most widely-used control strategy in the power supply industry. [1] The reasons for success are quite clear, the device | Doc
• Understanding Buck Power Stages In Switchmode Power Supplies
A switching power supply consists of the power stage and the control circuit. The power stage performs the basic power conversion from the input voltage to the output voltage and includes switches and the output filter. This report addresses the buck power | Doc
• DN-42A Design Considerations for Transitioning from UC3842 to the New UCC3802
The UCC3802 offers numerous advantages that allow the power supply design engineer to meet requirements for lower power for battery-operated equipment, higher switching frequencies for reduced magnetics size, higher levels of circuit integration for improv | Doc
• DN-65 Considerations in Powering BiCMOS ICs
Bipolar linear integrated circuits have been with us for years in the form of PWM and PFC controllers, supervisory circuits, and other circuits. Since these devices have traditionally used relatively high-voltage (35V) bipolar processes, powering was not a | Doc
• Understanding Buck-Boost Power Stages in Switchmode Power Supplies (Rev. A) | Doc
• Understanding Boost Power Stages In Switchmode Power Supplies
A switching power supply consists of the power stage and the control circuit. The power stage performs the basic power conversion from the input voltage to the output voltage and includes switches and the output filter. This report addresses the boost powe | Doc
• DN-40 The Effects of Oscillator Discharge Current Variations on Maximum Duty
This design note details programming frequency and maximum duty cycle using the UC3842 and UC3842-A PWM oscillator ICs. Simplified equations are used to develop obtainable ranges for parameters over IC tolerances. | Doc
• U-100A UC3842/3/4/5 Provides Low-Cost Current-Mode Control
The fundamental challenge of power supply design is to realize simultaneously two conflicting objectives: good electrical performance and low cost. The UC3842/3/4/5 control ICs are integrated pulse-width modulators (PWMs). These inexpensive IC controllers | Doc
Spice Model
UCC28C43 PSpice Transient Model - ZIP (12/09/2008)
UCCx8C43 Unencrypted PSpice Transient Model - ZIP (02/18/2016)


Features, Applications

FEATURES Optimized For Off-line And To DC Converters Low Start Up Current (<1mA) Automatic Feed Forward Compensation Pulse-by-pulse Current Limiting Enhanced Load Response Characteristics Under-voltage Lockout With Hysteresis Double Pulse Suppression High Current Totem Pole Output Internally Trimmed Bandgap Reference 500khz Operation Low RO Error Amp DESCRIPTION The UC1842/3/4/5 family of control ICs provides the necessary features to implement off-line to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start up current less than 1mA, 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. Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC1842 and UC1844 have UVLO thresholds of 16V (on) and 10V (off), ideally suited to off-line applications. The corresponding thresholds for the UC1843 and UC1845 are 8.4V and 7.6V. The UC1842 and UC1843 can operate to duty cycles approaching 100%. A range of zero 50% is obtained by the UC1844 and UC1845 by the addition of an internal toggle flip flop which blanks the output off every other clock cycle.

= DIL-8 Pin Number. = SO-14 and CFP-14 Pin Number. Toggle flip flop used only in 1844 and 1845.

Supply Voltage (Low Impedance Source). 30V Supply Voltage (ICC < 30mA). Self Limiting Output Current. 1A Output Energy (Capacitive Load). 5J Analog Inputs (Pins to +6.3V Error Amp Output Sink Current. 10mA Power Dissipation (DIL-8). 1 Power Dissipation (SOIC-14). 725mW Storage Temperature Range. to +150C Lead Temperature (Soldering, 10 Seconds). 300C Note 1: All voltages are with respect to Pin 5. All currents are positive into the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.

DIL-8, SOIC-8 (TOP VIEW) or J Package, D8 Package PLCC-20 (TOP VIEW) Q Package


Package TA 25C Power Rating 700 mW Derating Factor Above 25C 5.5 mW/C TA 70C Power Rating TA 85C Power Rating TA 125C Power Rating 150 mW

Unless otherwise stated, these specifications apply for TA 125C for the TA 85C for the TA 70C for the 384X; VCC = 15V (Note = 3.3nF, TA=TJ. TEST CONDITIONS UC1842/3/4/5 UC2842/3/4/5 MIN Reference Section Output Voltage Line Regulation Load Regulation Temp. Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Oscillator Section Initial Accuracy Voltage Stability Temp. Stability Amplitude Error Amp Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth PSRR Output Sink Current Output Source Current VOUT High VOUT Low Current Sense Section Gain Maximum Input Signal PSRR Input Bias Current Delay to Output VPIN to 2V (Note 2) (Notes 3 and 4) VPIN = 5V (Note 3) 12 VCC 25V (Note 3) (Note V/V VO 4V (Note 25C 12 VCC 25V VPIN = 2.7V, VPIN = 1.1V VPIN = 2.3V, VPIN = 5V VPIN 15k to ground VPIN 15k to Pin VPIN A dB MHz = 25C (Note 6) 12 VCC 25V TMIN TA TMAX (Note 2) VPIN 4 peak to peak (Note kHz 1mA 12 VIN I0 20mA (Note 2) (Note 7) Line, Load, Temp. (Note 125C, 1000Hrs. (Note V mV mV/C mV mA TYP MAX UC3842/3/4/5 MIN TYP MAX UNITS

These parameters, although guaranteed, are not 100% tested in production. Parameter measured at trip point of latch with VPIN = 0. Gain defined as VPIN , 0 VPIN 3 0.8V VPIN 3 Adjust VCC above the start threshold before setting at 15V. Output frequency equals oscillator frequency for the UC1842 and UC1843. Output frequency is one half oscillator frequency for the UC1844 and UC1845. Temperature stability, sometimes referred to as average temperature coefficient, is described by the equation: V (max ) - VREF (min ) Temp Stability = REF TJ (max - TJ (min ) VREF (max) and VREF (min) are the maximum and minimum reference voltages measured over the appropriate temperature range. Note that the extremes in voltage do not necessarily occur at the extremes in temperature.


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