UC2843A – High Performance Current Mode Controllers

Part Number : UC2843A

Function : High Performance Current Mode Controllers

Manufactures : ON Semiconductor

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Description :

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 http://onsemi.com 8 1 14 1 PDIP−8 N SUFFIX CASE 626 SOIC−14 D SUFFIX CASE 751A 8 1 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 RT/CT 7 14 Vref 13 NC 12 VCC 11 VC 10 Output 9 GND 8 Power Ground (Top View) © Semiconductor Components Industries, LLC, 2005 November, 2005 − Rev. 8 ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 15 of this data sheet. DEVICE MARKING INFORMATION See general marking information in the device marking section on page 16 of this data sheet. 1 Publication Order Number: UC3842A/D UC3842A, UC3843A, UC2842A, UC2843A Vref 8(14) RTCT 4(7) Voltage Feedback Input 2(3) Output Compensation 1(1) VCC 7(12) R 5.0V Reference VCC Undervoltage Lockout R Vref Undervoltage Lockout Oscillator + − Error Amplifier Latching PWM GND 5(9) Pin numbers in parenthesis are for the D suffix SOIC−14 package. VC 7(11) Output 6(10) Power Ground 5(8) Current Sense 3(5) Input Figure 1. Simplified Block Diagram MAXIMUM RATINGS Rating Symbol Value Unit Bias and Driver Voltages (Zero Series Im […]

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UC2843A Datasheet


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