Datasheet LT1614 (Analog Devices) - 9

LT1614
U OPERATIO
VOUT 100mV/DIV VOUT AC COUPLED 20mV/DIV AC COUPLED VSW 200mA I 5V/DIV LOAD 50mA 500µs/DIV 1614 F08 500ns/DIV 1614 F09
Figure 8. Load Step Response of LT1614 Figure 9. 33
µ
F “B” Case Tantalum Capacitor Has ESR Resulting with 33
µ
F Tantalum Output Capacitor in 40mVP-P Voltage Ripple at Output with 200mA Load
VOUT VOUT 100mV/DIV 10mV/DIV AC COUPLED AC COUPLED VSW 200mA I 5V/DIV LOAD 50mA 500µs/DIV 1614 F10 500ns/DIV 1614 F11
Figure 10. Replacing C3 with 22
µ
F Ceramic Capacitor Figure 11. 22
µ
F Ceramic Capacitor at Lowers Output Voltage Ripple. 1nF Phase-Lead Capacitor Output Reduces Output Ripple Voltage in Parallel with R1 Lowers Transient Excursion
C1 + SHUTDOWN VIN 1 8 RC R1 R2 2 7 CC 3 6 L1 4 5 D1 GND + C3 C2 1614 F12 L2 VOUT
Figure 12. Suggested Component Placement. Note: Cut in Ground Copper at D1’s Cathode
9