Milpitas, Calif.Linear Technology Corp. has introduced the LTC3873, a current mode, PWM controller that reduces the size and complexity of Flyback, Boost and SEPIC power supplies.
The LTC3873 contains all the features necessary to design high efficiency single-ended isolated and non-isolated flyback converters rated up to 25 watts for telecommunications, networking equipment, Power-over-Ethernet (POE), automotive, consumer and general housekeeping power supplies.
The LTC3873 is well-suited for wide input voltage range applications in which the input can vary from 9V to 75V during start-up. It will sustain operation from 4V to 75V after start-up, enabling users to have one power supply for 48V, 24V and 12V nominal input systems.
The LTC3873-5 is a product version with a 3.9V under-voltage lockout, which allows converters to operate and start from a 5V input source up to 75V. This makes the part ideal for boost conversion from a 5V input source to 12V, 24V, 48V and higher output voltages.
A current sense resistor is optional and the current limit threshold is programmable, allowing the use of a wide variety of external MOSFETs for different topologies. The LTC3873/-5 can regulate output voltages as low as 0.8V and has an integrated soft-start function that limits inrush current, reducing output voltage overshoot.
The operating frequency is fixed at 200-kHz and constant frequency operation is maintained down to light loads, resulting in less low frequency noise generation over a wide range of load currents. With a 50-µA start-up current, the IC allows the use of a high-value input resistor and a low-value capacitor for low power dissipation and quick power supply start-up. A standby quiescent current of 300-µA makes the LTC3873 suitable for automotive applications.
Pricing: Starts at $1.25 in 1,000-piece quantities.
Availability: In an 8-lead 2mm x 3mm DFN and 8-lead TSOT-23 packages with an operating temperature range from -40°C to 85°C.
Datasheet: click here.
Linear Technology Corp., 1-408-432-1900, www.linear.com