LTC3558 Datasheet | Linear Technology

Features Battery Charger n Standalone USB Charger n Up to 950m A Charge Current Programmable via Single Resistor n HPWR Input Selects 20% or 100% of Programmed Charge Current n NTC Input for Temperature Qualified Charging n Internal Timer Termination n Bad Battery Detection Switching Regulators (Buck and Buck-Boost) n Up to 400m A Output Current per Regulator n 2.25MHz Constant-Frequency Operation n Power Saving Burst Mode® Operation n Low Profile, 20-Lead, 3mm × 3mm QFN Package APPLICATIONS n SD/Flash-Based MP3 Players n Low Power Handheld Applications Linear USB Battery Charger with Buck and Buck-Boost Regulators DESCRIPTION The LTC®3558 is a USB battery charger with dual high efficiency switching regulators. The device is ideally suited to power single-cell Li-Ion/Polymer based handheld applications needing multiple supply rails. Battery charge current is programmed via the PROG pin and the HPWR pin with capability up to 950m A of current at the BAT pin. The CHRG pin allows battery status to be monitored continuously during the charging process. An internal timer controls charger termination. The part includes monolithic synchronous buck and buckboost regulators that can provide up to 400m A of output current each and operate at efficiencies greater than 90% over the entire Li-Ion/Polymer battery range. The buckboost regulator can regulate its programmed output voltage at its rated deliverable current over the entire Li-Ion range without drop out, increasing battery runtime. The LTC3558 is offered in a low profile (0.75mm), thermally enhanced, 20-lead (3mm × 3mm) QFN package. , LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION USB Charger Plus Buck Regulator and Buck-Boost Regulator USB (4.3V TO 5.5V) VCC 1μF 1.74k PROG BAT PVIN1 PVIN2 NTC SW1 CHRG SUSP FB1 SWAB2 DIGITAL CONTROL HPWR MODE SWCD2 VOUT2 EN1 10μF 4.7μH 2.2μH...