LTC Unveils LTC3448 Synchronous Step-Down Regulator
Linear Technology Corp. (LTC, Milpitas, CA) announced its new LTC3448, a high-efficiency, 2.25 MHz (or 1.5 MHz) synchronous buck regulator, which can deliver up to 600 mA of continuous output current. Using a current-mode architecture, the LTC3448 operates from an input-voltage range of 2.5 V to 5.5 V, making it suitable for single-cell, lithium-ion; multi-cell alkaline; or nickel-metal hydride applications. It can generate output voltages as low as 0.6 V, enabling it to power the latest generation of low voltage DSPs and microcontrollers.
When output current is greater than 3 mA, the LTC3448 switches at a constant frequency of 2.25 MHz. If output current drops to 3 mA or below, it automatically transitions into a low-noise LDO mode consuming 32 µA of quiescent current. Output ripple is less than 5 mVp-p in switching mode and is low noise in LDO mode, making it suitable for low-noise applications such as hand-held wireless applications.
The LTC3448's switching frequency can be set to either 1.5 MHz or 2.25 MHz, and can synchronize the device up to 4 MHz allowing the utilization of tiny, low-cost ceramic capacitors and inductors less than 1.2 mm in height. The LTC3448 uses internal synchronous switches with an RDS(ON) of 0.35 Ω and 0.40 Ω to deliver efficiencies as high as 96 percent. It also utilizes low-dropout, 100-percent, duty cycle operation to allow output voltages approaching VIN, further extending battery run time. Light load quiescent current is only 32 µA and <1 µA in shutdown ensuring maximum battery life.
The LTC3448EDD is available in a 3 mm x 3 mm DFN-8 package while the LTC3448EMS8E is available in a thermally enhanced MSOP-8 package. Both are available from stock. Pricing starts at $2.05 each for both package options in 1,000-piece quantities.
