Data SheetADP2138/ADP2139PIN CONFIGURATION AND FUNCTION DESCRIPTIONSVINEN14SW MODE25GND VOUT36TOP VIEW 02 -0 (BALL SIDE DOWN) 96 Not to Scale 94 0 Figure 2. Pin Configuration (Top View) Table 5. Pin Function Descriptions Pin No.Mnemonic Description 1 VIN Power Source Input. VIN is the source of the PFET high-side switch. Bypass VIN to GND with a 4.7 μF or greater capacitor as close to the ADP2138/ADP2139 as possible. 2 SW Switch Node Output. SW is the drain of the P-channel MOSFET switch and N-channel synchronous rectifier. Connect the output LC filter between SW and the output voltage. 3 GND Ground. Connect the input and output capacitors to GND. 4 EN Buck Activation. To turn on the buck, set EN to high. To turn off the buck, set EN to low. 5 MODE Mode Input. Drive the MODE pin high for the operating mode to force continuous PWM switching. Drive the MODE pin low to allow automatic PWM/PSM operating mode. 6 VOUT Output Voltage Sensing Input. Rev. C | Page 5 of 20 Document Outline Features Applications General Description Typical Applications Circuit Revision History Table of Contents Specifications Input and Output Capacitor, Recommended Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Control Scheme PWM Mode Power Save Mode Power Save Mode Current Threshold Enable/Shutdown Short-Circuit Protection Undervoltage Lockout Thermal Protection Soft Start Current Limit 100% Duty Operation Discharge Switch Applications Information ADIsimPower Design Tool External Component Selection Inductor Thermal Considerations PCB Layout Guidelines Evaluation Board Evaluation Board Layout Outline Dimensions Ordering Guide