Datasheet ADP2127 (Analog Devices) - 10

ADP2126/ADP2127 Data Sheet NO LOAD ILOAD = 100mA OUTPUT VOLTAGE (20mV/DIV) OUTPUT VOLTAGE (500mV/DIV) 1.20V OFFSET 1 INDUCTOR CURRENT (200mA/DIV) 1 INDUCTOR CURRENT (200mA/DIV) 4 4 SW PIN VOLTAGE (5V/DIV) EXTCLK PIN VOLTAGE (5V/DIV) 2 2
-024 -027
TIME (100µs/DIV) TIME (400ns/DIV)
09658 09658 Figure 23. Startup, No Load Figure 26. Typical PFM Mode Operation, ILOAD = 100 mA
RLOAD = 3.6Ω ILOAD = 150mA OUTPUT VOLTAGE (500mV/DIV) OUTPUT VOLTAGE (10mV/DIV) 1.20V OFFSET 1 1 INDUCTOR CURRENT (200mA/DIV) 4 INDUCTOR CURRENT (200mA/DIV) 4 SW PIN VOLTAGE (5V/DIV) EXTCLK PIN VOLTAGE (5V/DIV) 2 4
025 028 8- 8-
TIME (100µs/DIV) TIME (100ns/DIV)
0965 0965 Figure 24. Startup, RLOAD = 3.6 Ω Figure 27. Typical PWM Mode Operation, ILOAD = 150 mA
5.50 5.45 ) Hz M 5.40 ( NCY UE 5.35 Q RE F 5.30 5.25 –2.0 –1.5 –1.0 –0.5 0 0.5 1.0 1.5 2.0
26 0 8-
TIME (ns)
65 09 Figure 25. Spread Spectrum Switching Frequency Rev. B | Page 10 of 20 Document Outline FEATURES APPLICATIONS TYPICAL APPLICATIONS CIRCUIT GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING DIAGRAMS ABSOLUTE MAXIMUM RATINGS THERMAL CONSIDERATIONS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION OVERVIEW EXTERNAL CLOCK (EXTCLK) ENABLE SPREAD SPECTRUM OSCILLATOR MODE SELECTION Pulse-Width Modulation (PWM) Mode Auto Mode (PFM and PWM Switching) Pulse Frequency Modulation (PFM) Mode Mode Transition INTERNAL CONTROL FEATURES Synchronous Rectification Soft Start PROTECTION FEATURES Overcurrent Protection Output Short-Circuit Protection (SCP) Thermal Shutdown (TSD) Protection Undervoltage Lockout (UVLO) TIMING CONSTRAINTS Shutdown Time Power-Off Time APPLICATIONS INFORMATION INDUCTOR SELECTION INPUT CAPACITOR SELECTION OUTPUT CAPACITOR SELECTION THERMAL CONSIDERATIONS PCB LAYOUT GUIDELINES OUTLINE DIMENSIONS ORDERING GUIDE