Datasheet LT1933 (Analog Devices) - 10

LT1933
APPLICATIONS INFORMATION
Figure 1 shows the transient response of the LT1933 with drop) resulting from a larger output capacitor and a phase several output capacitor choices. The output is 3.3V. The lead capacitor. The last photo shows the response to a high load current is stepped from 100mA to 400mA and back to performance electrolytic capacitor. Transient performance 100mA, and the oscilloscope traces show the output volt- is improved due to the large output capacitance, but output age. The upper photo shows the recommended value. The ripple (as shown by the broad trace) has increased because second photo shows the improved response (less voltage of the higher ESR of this capacitor. VOUT VOUT 50mV/DIV 16.5k FB 22μF 10k IOUT 200mA/DIV 1933 F01a VOUT VOUT 50mV/DIV 16.5k 470pF FB 22μF 2x 10k IOUT 200mA/DIV 1933 F01b VOUT VOUT 50mV/DIV 16.5k + FB 100μF 10k SANYO 4TPB100M IOUT 200mA/DIV 1933 F01c
Figure 1. Transient Load Response of the LT1933 with Different Output Capacitors as the Load Current is Stepped from 100mA to 400mA. VIN = 12V, VOUT = 3.3V, L = 22μH.
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