ST619LB Datasheet | STMicroelectronics

DESCRIPTION The ST619LB is a step-up charge pump DC-DC converter which delivers a regulated 5V ±4% output at 30m A and over temperature. The input voltage range is 2V to 3.6V (two battery cells). It requires only four external capacitor: two 0.22µF flying capacitors, and 10µF capacitors at the input and output. Low operating supply current (typ 200µA) make the device ideal for small, portable and battery powered applications. When shut down the load is disconnected from the input and the supply current is typically 0.02µA. The ST619LB is available in SO-8 and DIP-8 packages. SCHEMATIC DIAGRAM May 2001 1/9 ST619LB SERIES OPERATING PRINCIPLE The ST619LB is able to provide a regulated 5V output from a 2V to 3.6V (two battery cells) input. Internal charge pump and external capacitors generate the 5V output, eliminating the need for inductors. The output voltage is regulated to 5V, ±4% by a pulse skipping controller that turns on the charge pump when the output voltage begins to drop. To maintain the greatest efficiency the internal charge pump of the device operates as a voltage doubler when VI ranges from 3.0V to 3.6V and as a voltage tripler when VI ranges from 2.0V to 2.5V. When VI ranges from 2.5V to 3.0V , the ST619LB switches between doubler and tripler mode on alternating cycles, making a 2.5 x VI charge pump. To further enhance the efficiency over the input range, an internal parator selects the higher of VI or VO to run the ST619LB’s circuitry. With VI = 2V and IO = 20m A the typical efficiency value is 80%. In tripler mode (see block diagram), when the S1 switches close, the S2 switches open and ABSOLUTE MAXIMUM RATINGS Symbol VI VO VSHDN IO Tstg Top DC Input Voltage Output Voltage Shutdown Input Voltage Output Current Continuous Storage Temperature Range Operating Junction Temperature Range Parameter² Value -0.3 to 5.5 -0.3 to 5.5 -0.3 to (VI + 0.3) 120 -55 to +150 -40 to +85 Unit V V V m A °C °C capacitors C1 and C2 charge up to VI. On the second half of...