FB

GND

SW

CB

SHDN

LM2840/1/2-ADJL

5V OUT

7V to 42V IN

R1

R2

5.62k

1.02k

D1

MA2YD26

CBOOT

VIN

CIN

2.2 PF

L1

15 PH

COUT

47 PF

0.15 PF

Copyright © 2016, Texas Instruments Incorporated

14

LM2840-Q1, LM2841-Q1, LM2842-Q1

SNVSBE5 – APRIL 2019

www.ti.com

Product Folder Links: LM2840-Q1 LM2841-Q1 LM2842-Q1

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Copyright © 2019, Texas Instruments Incorporated

8.2.3 Application Curves

VIN = 12 V

IOUT = 200 mA

VOUT = 3.3 V

Top trace: VOUT, 10 mV/div, AC-Coupled

T = 1 µs/div

Bottom trace: SW, 5 V/div, DC-Coupled

Figure 10. Switching Node and Output Voltage Waveforms

VIN = 12 V

IOUT = 300 mA to 200 mA to 300 mA

VOUT = 3.3 V

Top trace: VOUT, 20 mV/div, AC-Coupled

T = 200 µs/div

Bottom trace: IOUT, 100 mA/div, DC-Coupled

Figure 11. Load Transient Waveforms

VIN = 12 V

IOUT = 50 mA

VOUT = 3.3 V

Top trace: VOUT, 1V/div, DC-Coupled

T = 40 µs/div

Bottom trace: SHDN, 2V/div, DC-Coupled

Figure 12. Start-Up Waveform

8.2.4 Other Application Circuits

Figure 13 to Figure 16 show application circuit examples using the LM284x-Q1 devices. Customers must fully

validate and test these circuits before implementing a design based on these examples. Unless otherwise noted,

the design procedures in are applicable to these designs.

Figure 13. Step-Down Converter With 5-V Output Voltage