DC/DC Controller drives two external MOSFETs synchronously.

Press Release Summary:

Model LTC3736 synchronous, 2-phase, DC/DC step-down controller regulates and tracks 2 supplies. It converts input supplies ranging from 2.7-9.8 V to output voltages as low as 0.6 V at up to 95% efficiency. With 100% duty cycle capability, regulated output voltages can equal input voltage. Switching frequency is programmable up to 750 kHz. Rated for operation from -40 to 85°C, unit is housed in 24-lead SSOP or 4 x 4 mm QFN package.

Original Press Release:

2-Phase Dual 2.7VIN-9.8VIN DC/DC Controller Tracks Supplies & Requires No Sense Resistors

MILPITAS, CA - April 15, 2004 - Linear Technology Corporation introduces the LTC3736, a low input voltage synchronous 2-phase DC/DC step-down controller capable of regulating and tracking two supplies. For high operating efficiency, the LTC3736 drives two external MOSFETs (per channel) synchronously. Housed in tiny QFN and SSOP packages, this current mode controller further saves board space and cost by reducing the number of input capacitors and eliminating the need for two sense resistors. With on-board circuitry, the LTC3736 allows two output voltages to accurately track each other ensuring proper startup of systems with multiple supply rails. The IC converts input supplies as low as 2.7V and as high as 9.8V to output voltages as low as 0.6V at up to 95% efficiency. With 100% duty cycle capability, the regulated output voltages can equal the input voltage, which extends the operating time in battery powered systems. Applications include one or two cell Li-Ion-powered devices, distributed power supplies, and systems with FPGA or DSP requiring power for core and I/O.

The switching frequency is programmable up to 750kHz, allowing the use of small surface mount inductors and capacitors. Furthermore, the constant frequency current mode architecture provides excellent AC and DC load and line regulation. For noise sensitive applications, the regulators can be externally synchronized from 300kHz to 750kHz. The soft-start time is integrated, saving a capacitor. The Power Good output indicates when the outputs have reached regulation.

The LTC3736 is rated for operation from -40°C to 85°C. It is housed in a 24-lead SSOP and in a 4mm x 4mm QFN. 1,000-piece pricing starts at $3.80 each.

Summary of Features: LTC3736
No Sense Resistor: Senses VDS of MOSFET
Out-of-Phase Controllers Reduce Required Input Capacitance
Programmable Output Voltage Tracking
Constant Frequency Current Mode Architecture
Input Voltage: 2.7V to 9.8V
True PLL for Frequency Locking
±1.5% 0.6V Reference
Power Good Indicator

Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators,power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequencydevices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.

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