Analog Angle Article

MOSFET half-bridge yields over 90% efficiency at 25A, despite far smaller size

Dallas, Texas—Targeting higher-current, multiphase, point-of-load (POL) converters and similar applications, a pair of MOSFETs in an H-bridge configuration, Texas Instruments claims their CSD86350Q5D NexFET Power Block provides efficiency that is two percentage points higher than comparable solutions, and with 20% less power loss, at 25 A, Figure 1 . (Although 2% may seem small, it has significant energy-cost and thermal-dissipation implications.)

Efficiency versus current for Texas Instruments CSD86350Q5D NexFET Power Block

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The Power Block has a footprint which is about half the size of discrete MOSFETs (providing a reduction of up to 30 mm2 ), and also simplifies PCB layout issues while improving EMI performance due to easier placement of input capacitors, a low-impedance high-side gate-drive path, reduced source inductance and other parasitics, and a grounded lead frame with exposed ground pad which is placed directly on the PCB, Figure 2 . It is capable of handling up to 40A and switching at up to 1.5 MHz –Bill Schweber

Half bridge comprised of stacked MOSFETs in single package yields improved PCB layout and smaller footprint

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Price and availability : The CSD86350Q5D, in a 5×6 mm SON package, is available in volume now. It is priced at $1.75 each in 1000-piece lots. Evaluation modules are also available for the device.

For more information : contact Texas Instruments,

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