The ADP1972 is a constant frequency， voltage mode， pulse-width modulation （PWM） controller for buck or boost， dc-to-dc， asynchronous applications. The ADP1972 is designed for use in asynchronous battery testing applications with an external， high voltage field effect transistor （FET）， half bridge driver， and an external control device， such as the AD8450. The asynchronous device operates as a buck converter in battery charge mode and operates as a boost converter in recycle mode to recycle energy to the input bus. The ADP1972 high voltage， VIN supply pin can withstand a maximum operating voltage of 60 V and reduces the need for additional system supply voltages. The ADP1972 has integrated features such as precision enable， pin selective buck or boost mode operation， internal and external synchronization control with programmable phase shift， programmable maximum duty cycle， and programmable peak hiccup current limit. Additional protection features include soft start to limit input inrush current during startup， input voltage undervoltage lockout （UVLO）， and thermal shutdown （TSD）。 The ADP1972 also has a COMP pin to provide external control of the PWM operation and a FAULT pin that can be signaled to disable the DH and DL outputs if a fault condition occurs externally to the ADP1972. The ADP1972 is available in a 16-lead TSSOP package.