Datasheet UC1846, UC1847, UC2846 UC2847, UC3846, UC3847 (Texas Instruments) - 3

UC1846, UC1847 , UC2846 UC2847, UC3846 , UC3847 www.ti.com
SLUS352C – JANUARY 1997 – REVISED DECEMBER 2015
5 Pin Configuration and Functions J or N, DW Packages 16-Pin CDIP or PDIP, SOIC Top View FN or FK Packages 20-Pin PLCC or LCCC Top View Pin Functions PIN I/O DESCRIPTION PLCC, LCC DIL, SOIC NO. NAME NO.
1 2 C/S SS I Current limit/soft-start programming 2 3 VREF O 5.1-V reference voltage output 3 4 C/S – I Current sense comparator inverting input 4 5 C/S + I Current sense comparator non-inverting input 5 7 E/A + I Error amplifier inverting input 6 8 E/A – I Error amplifier inverting input 7 9 COMP I/O Error amplifier output and input to the PWM comparator 8 10 CT I Oscillator frequency programming capacitor pin 9 12 CR I Oscillator frequency programming resistor pin 10 13 Sync I/O Synchronization out from master controller or input of slave controller 11 14 A Out O PWM drive signal output A, Pin11 and P14 are complementary 12 15 GND G All signals are referenced to this node 13 17 VC I Bias supply input for output stage 14 18 B Out O PWM drive signal output B, Pin11 and P14 are complementary 15 19 VIN I Bias supply input 16 20 Shutdown I External shutdown signal input — 1, 6, 11, 16 N/C Copyright © 1997–2015, Texas Instruments Incorporated Submit Documentation Feedback 3 Product Folder Links: UC1846 UC1847 UC2846 UC2847 UC3846 UC3847 Document Outline 1 Features 2 Applications 3 Description Table of Contents 4 Revision History 5 Pin Configuration and Functions 6 Specifications 6.1 Absolute Maximum Ratings 6.2 ESD Ratings 6.3 Recommended Operating Conditions 6.4 Thermal Information 6.5 Electrical Characteristics 6.6 Typical Characteristics 7 Detailed Description 7.1 Overview 7.2 Functional Block Diagram 7.3 Feature Description 7.3.1 Current Sense Amplifier 7.3.2 Oscillator 7.4 Device Functional Modes 7.4.1 Current Limit 7.4.2 Shutdown 8 Application and Implementation 8.1 Application Information 8.2 Typical Application 8.2.1 Design Requirements 8.2.2 Detailed Design Procedure 8.2.2.1 Design Switching Frequency 8.2.2.2 Error Amplifier Output Configuration 8.2.2.3 Parallel Operation Configuration 8.2.2.4 Design Pulse by Pulse Current Limit Threshold 8.2.2.5 Soft-Start and Shutdown, Restart Function Design 8.2.3 Application Curves 9 Power Supply Recommendations 10 Layout 10.1 Layout Guidelines 10.2 Layout Example 11 Device and Documentation Support 11.1 Related Links 11.2 Community Resources 11.3 Trademarks 11.4 Electrostatic Discharge Caution 11.5 Glossary 12 Mechanical, Packaging, and Orderable Information