Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - voltage regulators - DC DC switch controllers Automotive/AEC-Q100 SOIC 8

FEATURES

D PACKAGE

(TOP VIEW)

COMP

SENSE

REF

OUTPUT

GND

DESCRIPTION/ORDERING INFORMATION

UC2843A-Q1

www.ti.com

........................................................................................................................................................................................................ SGLS384 – MAY 2008

CURRENT-MODE PWM CONTROLLER

• Qualified for Automotive Applications

• Extended Temperature Performance of

– 40 ° C to 125 ° C

• Optimized for Off-Line and DC-to-DC

Converters

• Low Start-Up Current (<0.5 mA)

• Trimmed Oscillator-Discharge Current

• 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

• 500-kHz Operation

• Low R

Error Amp

The UC2843A control IC is a pin-for-pin compatible improved version of the UC2843. Providing the necessary

features to control current mode switched mode power supplies, this device has the following improved features.

Start up current is specified to be less than 0.5 mA. Oscillator discharge is trimmed to 8.3 mA. During

undervoltage lockout, the output stage can sink at least 10 mA at less than 1.2 V for V

over 5 V.

MAXIMUM DUTY

PART NUMBER UVLO ON UVLO OFF

CYCLE

UC2843A 8.5 V 7.9 V <100%

ORDERING INFORMATION

(1)

PACKAGE

(2)

ORDERABLE PART NUMBER TOP-SIDE MARKING

– 40 ° C to 125 ° C SOIC-8 – D8 Reel of 2500 UC2843AQD8RQ1 UC2843AQ

(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

web site at www.ti.com.

(2) Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at

www.ti.com/sc/package.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (12 pages)

PAGE 1
UC2843A-Q1 www.ti.com........................................................................................................................................................................................................ SGLS384 – MAY 2008 CURRENT-MODE PWM CONTROLLER FEATURES 1 • • • • • • • • • • • • • • D PACKAGE (TOP VIEW) Qualified for Automotive Applications Extended Temperature Performance of –40°C to 125°C Optimized for Off-Line and DC-to-DC Converters Low Start-Up Current (<0.
PAGE 2
UC2843A-Q1 SGLS384 – MAY 2008........................................................................................................................................................................................................ www.ti.com FUNCTIONAL BLOCK DIAGRAM VCC 7 34 V UVLO S/R GND 5 5-V REF 8 VREF 5V 50 mA 7 VC 6 Output 5 GND 2.
PAGE 3
UC2843A-Q1 www.ti.com........................................................................................................................................................................................................ SGLS384 – MAY 2008 ELECTRICAL CHARACTERISTICS TA = –40°C to 125°C, VCC = 15 V (1), RT = 10 kΩ, CT = 3.3 nF, TA = TJ (unless otherwise stated) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 4.95 5.0 5.
PAGE 4
UC2843A-Q1 SGLS384 – MAY 2008........................................................................................................................................................................................................ www.ti.com ELECTRICAL CHARACTERISTICS (continued) TA = –40°C to 125°C, VCC = 15 V, RT = 10 kΩ, CT = 3.3 nF, TA = TJ (unless otherwise stated) PARAMETER TEST CONDITIONS MIN TYP MAX IOUT = 20 mA 0.1 0.4 IOUT = 200 mA 15 2.
PAGE 5
UC2843A-Q1 www.ti.com........................................................................................................................................................................................................ SGLS384 – MAY 2008 PARAMETER MEASUREMENT INFORMATION 2.5 V 0.5 mA VFB Zi Comp Zf A. 2 1 The error amplifier can source up to 0.5 mA and sink up to 2 mA. Figure 1. Error Amp Configuration ICC VCC On/Off Command to Rest of IC <17 mA UC2843A VON 8.4 V VOFF 7.6 V < 0.
PAGE 6
UC2843A-Q1 SGLS384 – MAY 2008........................................................................................................................................................................................................ www.ti.
PAGE 7
UC2843A-Q1 www.ti.com........................................................................................................................................................................................................ SGLS384 – MAY 2008 APPLICATION INFORMATION Oscillator Frequency vs Timing Resistance Maximum Duty Cycle vs Timing Resistor Figure 6. Oscillator VREF RT 4.7 kW 1 kW Error Amp Adjust 4.
PAGE 8
UC2843A-Q1 SGLS384 – MAY 2008........................................................................................................................................................................................................ www.ti.com UC2843A VREF 8 RT 0.1 µF A fraction of the oscillator ramp can be resistively summed with the current sense signal to provide slope compensation for converters requiring duty cycles over 50%.
PAGE 9
PACKAGE OPTION ADDENDUM www.ti.
PAGE 10
PACKAGE OPTION ADDENDUM www.ti.
PAGE 11
PAGE 12
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.