ST5R00 Datasheet | STMicroelectronics

DESCRIPTION The ST5R00 is an high efficiency VFM Step-up DC/DC converter for small, low input voltage or battery powered systems with ultra low quiescent supply current. The ST5Rxx accept a positive input voltage from start-up voltage to VOUT and convert it to a higher output voltage in the 2.5 to 5V range. The ST5R00 bine ultra low quiescent supply current and high efficiency to give maximum battery life. The high switching frequency and the internally limited peak inductor current, permits the use of small, low cost inductors. Only three external ponents are nedeed: an inductor a diode and an output capacitor. The ST5R00 is suitable to be used in a battery powered equipment where low noise, low ripple and ultra low supply current are required. The ST5R00 is available in very small packages: SOT23-5L, SOT-89. Typical applications are pagers, cameras & video camera, cellular telephones, wireless telephones, palmtop puter, battery backup supplies, battery powered equipment. SCHEMATIC DIAGRAM June 2001 1/13 ABSOLUTE MAXIMUM RATING Symbol V OUT V IN V LX I LX P tot T st g T op Output Voltage Input Voltage LX Pin Voltage LX Pin Output Current Power Dissipation @ 25o C for SOT23-5L Storage Temperature Range Operating Junction Temperature Range Parameter Value 5.5 5.5 5.5 Internally limited 170 (- ) - 55 to 125 - 25 to 85 m W o o Unit V V V (- ) Reduced by 1.7 m W for increasing in TA of 1o C over 25o C THERMAL DATA Symbol Parameter SOT23-5L 63 SOT-89 17 Unit °C/W R thj-case Therma l Resistance Junction-case OPERATION The ST5Rxx architecture is built around a VFM CONTROL logic core: switching frequency is set through a built in oscillator: TON time is fixed (Typ. 5µs) while TOFF time is determined by the error amplifier output, a logic signal ing from the parison made by the Error Amplifier Stage between the signal ing from the output voltage divider network and the internal Band-Gap voltage reference (Vref). TOFF reaches a minimum (Typ. 1.7µs) when heavy...