Product category:
Power Supply ICs and Controllers
News Release from: International Rectifier | Subject: IR3621M and IR3621F
Edited by the Electronicstalk Editorial
Team on 31 August 2005
Buck controllers are efficient at point
of load
The IR3621M and IR3621F are voltage-mode dual-output biphase synchronous buck controller-driver ICs for high performance point-of-load buck convertors.
International Rectifier has introduced the IR3621M and IR3621F voltage-mode, dual-output biphase synchronous buck controller-driver ICs for high performance point-of-load (POL) buck convertors The IR3621 includes a full suite of power management features, including pre-bias protection, sequencing capability, hiccup current limit protection and tight voltage reference accuracy demanded by today's systems
This article was originally published on Electronicstalk on 15 Feb 2001 at 8.00am (UK)
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The IR3621 is offered in two package styles: the IR3621F is housed in a 28-lead TSSOP package and the IR3621M is housed in a 32-pin 5 x 5mm MLPQ package for improved thermal performance.
The IR3621M provides +/-1% output voltage accuracy, and the IR3621F provides +/-1.35% output voltage accuracy.
Both provide prebias protection, and are ideal for nonisolated 0.8 to 3.3V output DC/DC POL convertors with either dual output rails up to 15A each, or single output rails up to 30A.
Further reading
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With high radiation hardness and unparalleled single event effect (SEE) immunity, International Rectifier's new R5 MOSFETs are well suited for systems that must survive penetrating gamma rays.
The prebias feature included in the IR3621 prevents the discharge of any pre-existing output voltage during the startup of the POL, eliminating negative voltage spikes on the output.
A negative voltage spike during startup in many cases can cause damage to expensive network processor units (NPUs) and application-specific ICs (ASICs), so when a prebias condition occurs, it is critical that the output voltage charges to its required regulation voltage without going through the initial discharge cycle during soft-start initiation.
For single-output biphase configurations, the IR3621 uses the output inductor DC resistance as a current sharing reference, eliminating external shunt resistors.
The IR3621 features 180-degree out-of-phase operation with programmable switching frequency up to 500kHz, reducing input and output filtering requirements and results in lower component count.
Two independently programmable soft-start functions allow system level sequencing of output voltages in various configurations, critical for system level startup protocols.
The IR3621 includes a "power good" output signal, which can be used to trigger a sequential rise of output voltages across multiple POL convertors.
Protection features such as selectable hiccup or latched current limit, thermal shutdown, and under- and overvoltage protection ensure system level security during fault conditions.
A design kit - the IRDC3621 - featuring the new IR3621M is also available and demonstrates the complete DC/DC convertor performance, while showcasing its full range of power management features.
For 12V input, 2.5V output, the convertor achieves up to 86% efficiency at 15A full load and 400kHz switching frequency when the IR3621M is used with two optimised HEXFET MOSFETs, such as the IRF7821 and IRF8113.
Typical applications include powering dual logic application-specific ICs (ASICs), DDR memory power management or other multirail or two-phase requirements.
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