Datasheet ADP2121 (Analog Devices) - 9

Data Sheet ADP2121 180 ) A 160 (m OUTPUT VOLTAGE (50mV/DIV) D PWM OPERATION L 140 O H S E 120 HR T 100 NG HI C 80 LOAD CURRENT (100mA/DIV) IT PFM OPERATION W 60 S DE O 40 M O 20 AUT VOUT = 1.82V
2 -02
0
7
2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
14 40 0
TIME (20µs/DIV)
7- 07
INPUT VOLTAGE (V)
40 07 Figure 22. Auto Mode Switching Threshold vs. Input Voltage Figure 25. Load Transient Response, 0 mA to 150 mA (VIN = 2.5 V, Auto Mode)
A) 190 m ( VOUT = 1.8V D V L 180 OUT = 1.82V O VOUT = 1.85V OUTPUT VOLTAGE (50mV/DIV) H VOUT = 1.875V 170 VOUT = 2.3V HRES T G 160 IN H C 150 IT W LOAD CURRENT (100mA/DIV) S 140 NG ISI R 130 DE PFM OPERATION O 120 M O T
3
AU 110
-02 7
2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
4 05 40
TIME (20µs/DIV)
7- 07
INPUT VOLTAGE (V)
740 0 Figure 23. Auto Mode Rising Switching Threshold vs. Input Voltage for All Figure 26. Load Transient Response, 0 mA to 150 mA Voltage Options (VIN = 3.6 V, Auto Mode)
) A 200 m D ( L 180 OUTPUT VOLTAGE (50mV/DIV) HO S 160 HRE T PWM OPERATION NG 140 CHI IT 120 W LOAD CURRENT (100mA/DIV) S 100 ING L AL 80 F VOUT = 1.8V V DE OUT = 1.82V O 60 VOUT = 1.85V M VOUT = 1.875V O V
4
OUT = 2.3V
-02
40
7
AUT 2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
5 40
TIME (20µs/DIV)
-05 07 07
INPUT VOLTAGE (V)
74 0 Figure 24. Auto Mode Falling Switching Threshold vs. Input Voltage for All Figure 27. Load Transient Response, 0 mA to 150 mA Voltage Options (VIN = 4.5 V, Auto Mode) Rev. C | Page 9 of 20 Document Outline FEATURES APPLICATIONS TYPICAL APPLICATION CIRCUIT GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL DATA THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION OVERVIEW MODE SELECTION Pulse-Width Modulation (PWM) Mode Auto Mode (PFM and PWM Switching) Pulse Frequency Modulation (PFM) Mode Transition ENABLE/SHUTDOWN INTERNAL CONTROL FEATURES Overcurrent Protection Soft Start Synchronous Rectification Compensation Undervoltage Lockout (UVLO) Output Short-Circuit Protection Thermal Shutdown (TSD) Protection APPLICATIONS INFORMATION INDUCTOR SELECTION INPUT CAPACITOR SELECTION OUTPUT CAPACITOR SELECTION PCB LAYOUT GUIDELINES OUTLINE DIMENSIONS ORDERING GUIDE