TK65025

TK65025 STEP-UP VOLTAGE CONVERTER WITH VOLTAGE MONITOR FEATURES s s s s s s s s s s Guaranteed 0.9 V Operation Very Low Quiescent Current Internal Bandgap Reference High Efficiency MOS Switching Low Output Ripple Microprocessor Reset Output Laser-Trimmed Output Voltage Laser-Trimmed Oscillator Undervoltage Lockout Regulation by Pulse Burst Modulation (PBM) APPLICATIONS s s s s s s s Battery Powered Systems Cellular Telephones Pagers Personal Communications Equipment Portable Instrumentation Portable Consumer Equipment Radio Control Systems DESCRIPTION The TK65025 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 TK65025 provides the power switch and the control circuit for a boost converter. The converter takes a DC input and boosts it up to 3 volts. This regulated 3 volt output is typically used to supply power to a microprocessor-controlled system. 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. 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...