LTC1872 Datasheet | Linear Technology

LTC1872 Constant Frequency Current Mode Step-Up DC/DC Controller in SOT-23 Features s s s s s s s DESCRIPTIO s s s s High Efficiency: Over 90% High Output Currents Easily Achieved Wide VIN Range: 2.5V to 9.8V VOUT Limited Only by External ponents Constant Frequency 550k Hz Operation Burst Mode TM Operation at Light Load Current Mode Operation for Excellent Line and Load Transient Response Low Quiescent Current: 270µA Shutdown Mode Draws Only 8µA Supply Current ± 2.5% Reference Accuracy Tiny 6-Lead SOT-23 Package The LTC®1872 is a constant frequency current mode stepup DC/DC controller providing excellent AC and DC load and line regulation. The device incorporates an accurate undervoltage lockout feature that shuts down the LTC1872 when the input voltage falls below 2.0V. The LTC1872 boasts a ± 2.5% output voltage accuracy and consumes only 270µA of quiescent current. For applications where efficiency is a prime consideration, the LTC1872 is configured for Burst Mode operation, which enhances efficiency at low output current. In shutdown, the device draws a mere 8µA. The high 550k Hz constant operating frequency allows the use of a small external inductor. The LTC1872 is available in a small footprint 6-lead SOT-23. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. U APPLICATIO S s s s s s Lithium-Ion-Powered Applications Cellular Telephones Wireless Modems Portable puters Scanners TYPICAL APPLICATION R1 0.03Ω 147k 220p F 80.6k 1 ITH/RUN LTC1872 2 3 GND VFB SENSE - NGATE 422k C1: TAIYO YUDEN CERAMIC EMK325BJ106MNT C2: MURATA GRM42-2X5R226K6.3 D1: IR10BQ015 L1: MURATA LQN6C4R7M04 M1: IRLMS2002 R1: DALE 0.25W 4 6 M1 D1 VIN 5 L1 4.7µH C1 10µF 10V VIN 3.3V 100 95 VOUT 5V 1A EFFICIENCY (%) + C2 2× 22µF 6.3V 85 80 75 70 65 1872 TA01 Figure 1. LTC1872 High Output Current 3.3V to 5V Boost Converter Efficiency vs Load Current VIN = 3.3V VOUT = 5V 1 10 100 LOAD CURRENT (m...