ADP2121Data SheetABSOLUTE MAXIMUM RATINGS Table 3. The junction temperature (TJ) of the device is dependent on the ParameterRating ambient temperature (TA), the power dissipation of the device VIN to GND −0.3 V to +6 V (PD), and the junction-to-ambient thermal resistance of the package (θ EN, MODE to GND −0.3 V to VIN JA). Maximum junction temperature (TJ) is calculated from the ambient temperature (T FB, SW to GND −0.3 V to VIN + 0.2 V A) and power dissipation (PD) using the following formula: Operating Ambient Temperature Range –40°C to +85°C (ILOAD ≤ 600 mA) TJ = TA + (PD × θJA) Operating Junction Temperature Range –40°C to + 125°C The junction-to-ambient thermal resistance (θJA) of the package Storage Temperature –45°C to +150°C is based on modeling and calculation using a 2- and 4-layer Soldering Conditions JEDEC J-STD-020 board. The junction-to-ambient thermal resistance is highly ESD (Electrostatic Discharge) dependent on the application and board layout. In applications Human Body Model ±4 kV where high maximum power dissipation exists, close attention Stresses at or above those listed under Absolute Maximum to thermal board design is required. Ratings may cause permanent damage to the product. This is a The value of θJA may vary, depending on PCB material, layout, stress rating only; functional operation of the product at these and environmental conditions. Refer to JEDEC JESD51-9 for or any other conditions above those indicated in the operational detailed information about board construction. section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may THERMAL RESISTANCE affect product reliability. The junction-to-ambient thermal resistance of the system (θJA) THERMAL DATA is specified for worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages. Absolute maximum ratings apply individually only, not in combination. The ADP2121 can be damaged when the junction Table 4. temperature limits are exceeded. Monitoring ambient tempera- Package TypeθJAUnit ture does not guarantee that the junction temperature (TJ) is 6-Ball WLCSP within the specified temperature limits. In applications with 2-Layer Board 198 °C/W high power dissipation and poor PCB thermal resistance, the 4-Layer Board 105 °C/W maximum ambient temperature may need to be derated. In applications with moderate power dissipation and low PCB thermal resistance, the maximum ambient temperature can ESD CAUTION exceed the maximum limit as long as the junction temperature is within specification limits. Rev. C | Page 4 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