80ns/div

C013

SW1

SW2

SW3

SW4

10s/div

C013

VOUT1

50mV/div

IOUT

500mA/div

40s/div

C014

VOUT1

50mV/div

VIN

1V/div

200s/div

C001

VOUT1

100mV/div

SW_B1

5V/div

Inductor

current

500mA/div

100s/div

C012

EN_B1

PG_B1

VOUT1

1V/div

LP8728B-Q1

www.ti.com

SNVSA70 – FEBRUARY 2015

8.2.3 Application Performance Plots

Unless otherwise noted, VIN = 5 V, TA = 25°C, inductor type: TOKO MDT2520-CN1R5M, input and output capacitor type:

MuRata GRM21BR71A106KE51L.

Figure 16. Short-Circuit Waveforms

Figure 17. Start-up Delay

IOUT from 0 mA to 1A, tRISE = tFALL = 1 µs

VIN from 4.5 V To 5.5 V, tRISE = tFALL = 10 µs

Figure 18. Load Transient Response

Figure 19. Line Transient Response

Figure 20. Switch Turn-on Phase Shifting

9 Power Supply Recommendations

The LP8728B-Q1 is designed to operate from an input voltage supply range between 4.5 V and 5.5 V. This input

supply must be well regulated and capable to supply the required input current. If the input supply is located far

from the device, additional bulk capacitance may be required in addition to the ceramic bypass capacitors.

Copyright © 2015, Texas Instruments Incorporated

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