The TK65015 Low Power Step-Up DC-DC converter is designed for portable battery powered systems, capable of operating from a single battery cell down to 0.9 V. The output voltage is laser-trimmed to 3.0 V. An internal detector monitors the output voltage and provides an active-low microprocessor reset signal whenever the output voltage falls below an internally preset limit. An internal undervoltage lockout circuit is utilized to prevent the inductor switch from remaining in the "ON" mode when the battery voltage is too low to permit normal operation. Special care has been taken to achieve high reliability through the use of Oxide, Nitride passivation and an additional polyimide coating. The TK65015 is available in a very small plastic surface mount package. (SOT-23L) Pulse burst modulation (PBM) is used to regulate the voltage at the VOUT pin at the IC. PBM is the process in which an oscillator signal is gated or not gated to the switch drive each period. The decision is made just before the start of each cycle and is based on comparing the output voltage to an internally-generated bandgap reference. The decision is latched, so the duty ratio is not modulated within a cycle. The average duty ratio is effectively modulated by