Product category: Power Supply ICs and Controllers
News Release from: National Semiconductor | Subject: LM5574/5/6 and LM25574/5/6
Edited by the Electronicstalk Editorial Team on 31 January 2007
Buck regulators feature wide input
voltage ranges
Six new regulators feature a combination of high performance, flexibility and ease of use for DC/DC power supply designs.
National Semiconductor has added six high-frequency buck regulators to its popular Simple Switcher product family along with a "dial-in" performance enhancement to its Webench design environment The six new regulators feature a unique combination of high performance, flexibility and ease of use for DC/DC power supply designs
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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The new regulators operate with an input voltage range up to 75V and deliver up to 3A of continuous output current.
The patented emulated - current- mode technology provides superior load transient response in low duty cycle applications that are not addressable by traditional current mode control.
Operating frequency is adjustable from 50kHz to 1MHz, providing industry-leading dynamic range.
To reduce EMI, a frequency synchronisation pin allows multiple ICs from the family to self-synchronise or to synchronise to an external clock.
The new regulators guarantee robustness with cycle-by-cycle current limit, short-circuit protection and thermal shut-down.
"Combined with National's Webench suite of tools, Simple Switcher regulators allow design engineers to make decisions about their power supply design, such as the trade-off between sise and efficiency", said Mal Humphrey, Product Line Director for National's Power Management Group.
"Any engineer, including seasoned power supply designers, can create, optimise and analyse their design in just one minute.
Emulated current-mode control overcomes traditional current-mode control's noise susceptibility by emulating the buck switch current signal, which is then used for current-mode control.
The emulated buck switch current signal is the sum of an emulation ramp current and the sampled diode current just before switching occurs.
Avoiding direct buck switch current measurement minimises the effect of switching noise, while maintaining the benefits of the current-mode control.
Technical features of the new Simple Switcher buck switching regulators Six products are included in the new line of Simple Switcher regulators.
The 0.5A LM5574, 1.5A LM5575 and 3.0A LM5576 buck regulators feature a very wide input voltage range from 6 to 75V and adjustable switching frequency between 50 and 500kHz.
The 0.5A LM25574, 1.5A LM25575 and 3.0A LM25576 buck regulators feature wide input voltage range from 6 to 42V and adjustable switching frequency between 50kHz and 1MHz.
Offered in a 16-pin TSSOP, the LM5574 integrates a 75V, 750mohm, N-channel MOSFET and the LM25574 integrates a 42V, N-channel MOSFET.
Offered in a 16-pin TSSOP package with exposed pad, the LM5575 integrates a 75V, 330mohm, N-channel MOSFET and the LM25575 integrates a 42V, N-channel MOSFET.
Offered in a 20-pin TSSOP package with exposed pad, the LM5576 integrates a 75V, 170mohm, N-channel MOSFET and the LM25576 integrates a 42V, N-channel MOSFET.
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