High-integration 8 &3A synchronous regulators with phased slaving

High-integration 8 &3A synchronous regulators with phased slaving

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Five high efficiency DC/DC converters step-down 5V rails to point-of-load (POL) rails as low as 0.6V for FPGAs, DSPs and microprocessors. ISL8018 delivers up to 8A of continuous output current from a 2.7V to 5.5V input supply, while offering up to 97% efficiency and higher integration than competitive devices.
By eeNews Europe


The 2 x 2 mm ISL8003x family of devices delivers up to 3A of continuous output current from a 2.7V to 5.5V input supply and offers up to 95% peak efficiency for delivering general POL conversions in telecom, cloud computing, industrial, instrumentation and medical equipment.

The ISL8018 provides a SYNCIN and SYNCOUT feature that connects and synchronises multiple regulators at the same switching frequency in a master/slave configuration using a phase shifting time delay. This prevents ON time overlapping and reduces RMS current, ripple and input capacitance requirements to improve EMI and efficiency. With the ISL8018’s VSET feature, the voltage output margining can be set at ±10% to compensate for output voltage IR drop. The ISET feature provides programmable output current limits to support 8A, 5A and 3A applications. This allows designers to make the most of one design with smaller inductors for reduced costs and board area. ISL8018’s programmable switching frequency from 500 kHz up to 4MHz enables the use of smaller passive components for faster transient response and further board space savings.

The ISL80030, ISL80030A, ISL80031, and ISL80031A are pin-compatible and integrate very low RDS(ON) high-side PMOS and low-side NMOS MOSFETs, which reduces external component count and power losses. With lower die temperatures, these buck regulators allow the system to operate without cooling fans or heatsinks and still deliver a continuous 3A to the load, significantly increasing reliability. They also offer internal compensation, which eliminates additional external components to reduce design complexity. The complete converter occupies less than 64 mm² of board space. ISL80031 and ISL80031A offer a light load mode to improve efficiency over all load currents when the system switches to a low power state.

The ISL8018 8A synchronous buck regulator is available in a 3 x 4 mm, 20-lead QFN package and is priced at $1.60 (1000). The ISL8018DEMO1Z demonstration board is $20 and the full-featured ISL8018EVAL3Z evaluation board is $115.

Intersil; www.intersil.com/products/isl8018

next page; specification table

Specifications of ISL8018

Delivers high peak efficiency up to 97%

Complete converter occupies less than 97 mm² of board space

±10% output voltage margining

Output voltage is adjustable from 0.6V to Vin, with a fixed output voltage option

Adjustable current limit

External synchronisation up to 4 MHz, with master-to-slave phase shifting capability

Adjustable switching frequency from 500 kHz to 4 MHz, with default at 1 MHz

Start-up with pre-bias output, internal soft-start – 1 msec or adjustable, internal/external compensation

Soft-stop output discharge during disabled

Peak current limiting, hiccup mode short circuit protection and over-temperature protection

Specifications of ISL80030, ISL80030A, ISL80031, ISL80031A

Deliver high peak efficiency up to 95%, with 3A maximum output current

Switching frequency up to 2 MHz

Provides quiescent current as low as 35 µA

Selectable PFM or PWM operation

Short-circuit protection, and over-current, negative current, over-temperature/thermal protection

Internal soft-start and soft-stop

Vin under-voltage lockout and Vout over-voltage protection

These synchronous buck regulators can be combined with the ISL85033 dual 3A output synchronous buck regulator in POL applications, and the ISL85003 4.5V to 18V, 3A synchronous buck regulator for a two-stage solution converting a 12V rail to a 5V rail. The ISL85403 also can be used for a two-stage solution to step-down a 24V rail to a 5V rail.

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