SOURCE: Intersil

November 15, 2005 06:00 ET

Intersil Introduces 95 Percent Efficiency Synchronous Step-Down Controller

MILPITAS, CA -- (MARKET WIRE) -- November 15, 2005 -- Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high-performance analog solutions, today expanded its power management portfolio with the introduction of a synchronous step-down controller with up to 95 percent efficiency. The ISL88 550A integrates a synchronous buck PWM (pulse width modulation) controller, a sourcing and sinking LDO (low dropout) regulator, and a 10mA reference output buffer.

The PWM controller generates VDDQ (voltage for double data rate memory), the LDO regulator generates VTT (termination voltage supply) and the reference output buffer generates VTTR (termination voltage reference). With the combined features, the ISL88550A provides a complete solution for DDR (double data rate) I and II memory power supplies. It can also be used for other applications that require voltages down to 0.7V.

"Intersil's ISL88550A uses a constant-on-time PWM architecture with a programmable switching frequency of up to 600KHz," said Majid Kafi, director of Intersil's Notebook Power group. "This control feature handles wide input/output voltage ratios with ease and provides 100ns 'instant-on' response to load transients while maintaining high efficiency and a constant switching frequency that is ideal for DDR memory applications in desktops, notebooks and graphics cards."

High Efficiency, Constant-On-Time

The ISL88550A drives two external N-Channel MOSFETs to generate output voltages down to 0.7V from a 2V to 25V input with output currents up to 20A. The LDO can sink or source up to 2.5A. Both the LDO output and the 10mA reference buffer output can be designed to track the REFIN voltage through a built-in resistive divider. This device also offers full programmable UVP/OVP and skip mode options that are well-suited for portable applications. Skip mode allows for improved efficiency at lighter loads.

The VTT and VTTR outputs of the ISL88550A track within one percent of VREFIN/2. The high bandwidth of this LDO regulator allows excellent transient response without the need for bulky capacitors, thereby reducing overall system cost and size.

Key Features

--  Constant-On-Time PWM with 100ns load-step response
--  Start-up with pre-biased output voltage
--  Up to 95 percent efficiency
--  2V to 25V input voltage range
--  1.8V/2.5V fixed or 0.7V to 3.5V adjustable output
--  200kHz / 300kHz / 450kHz / 600kHz switching frequencies
--  Programmable current limit with foldback capability
Target Applications
--  DDR I and DDR II memory power supplies
--  Desktop computers
--  Notebooks (including ultra-portable and Web tablets)
--  Graphics cards
--  Game consoles
About Intersil's Power Management Portfolio

Intersil is a recognized global leader in power management solutions, offering a broad portfolio of products that simplify a variety of power designs. Intersil's family of power management ICs ranges from building blocks such as charge pumps, to highly-integrated, multiple-output and multiphase PWMs, to quad-voltage hot-swap controllers. As a leading supplier of PWM controller ICs with over 2 billion units shipped, Intersil addresses a broad range of power management needs for applications that include computing, communications, peripherals, display, networking, telecommunications, industrial, instrumentation and battery-powered products. To learn more, visit Intersil's Power Management Web site at

Pricing and Availability

The ISL88550A is available now in a 28-pin (5mm x 5mm) thin QFN package and is priced at $2.85 in 1,000-unit quantities. More information on the ISL88550A is available at,1477,ISL88550A,0.html. A large selection of power products is supported by Intersil's iSim™ online design tool. To explore these solutions, visit To view a broad range of application block diagrams, visit Intersil's Application Design Center at

Note to editors: To view a high-resolution downloadable photo of the ISL88550A, visit Intersil's photo room at:

About Intersil

Intersil Corporation, a NASDAQ 100 Index company, is a leader in the design and manufacture of high performance analog semiconductors. The company's products address three of the industry's fastest growing markets: flat panel displays, optical storage (CD and DVD recordable) and power management. Intersil products include power management devices for battery management, hot-swap and hot-plug controllers, linear regulators, supervisory ICs, switching DC/ DC regulators and power MOSFET drivers; optical storage laser diode drivers; DSL line drivers; video and high performance operational amplifiers; data converters; interface ICs; analog switches and multiplexers; crosspoint switches; voice-over-IP devices; and ICs for military, space and rad-hard applications. For more information about Intersil or to find out how to become a member of our winning team, visit the company's web site and career page at

iSim is a trademark of Intersil Americas, Inc. All other brands or product names are trademarks or registered trademarks of their respective holders.

Contact Information

  • Media Contact
    Kim Fehrt
    Public Relations Manager
    Intersil Corporation
    (408) 546-3566
    Email Contact