This article takes a look at a recent range of DC-DC buck converters released by ON Semiconductor, the FAN6500xx family.

The Rise of DC-DC Buck Converters

In the past, most devices have been powered by a mains adaptor that provided a seemingly endless supply of power. Handheld devices such as radios did not integrate complex logic circuits and could handle a wide range of input voltages which meant they could run off several AA batteries. However, as electronics became more advanced and designers started to integrate logic into portable device engineers realized they could no longer get away with making portable toasters.

While linear regulators are still used, they were often the only source of regulation and this typically meant large voltage drops which directly translates to hideous amounts of power loss. One workaround is to use a DC-DC buck convert before the regulator which can take a DC source (such as 12V), and then step it down to 7V. DC-DC buck converters are incredibly efficient (as high as 95%) and are often used to reduce power consumption which can extend the life of portable devices (as well as keeping them cooler).


For those who remember, the ZX Spectrum was also a lap warmer with its 7805 regulator. Image courtesy spdns


DC-DC buck converters have come a long way from their beginnings. They can now be found in very small packages and require very few external components to work.

But DC-DC converters are not without their problems with one of the worse being EMI (electromagnetic interference). EMI is a particular pain in DC-DC buck converters because of the strict regulations on commercial products that require all electronic devices to be both immune to interference and not interfere with other devices. DC-DC converters are usually more than capable of handling external interference, but they are often the source of interference. This is mainly due to the fact that DC-DC converts rely on high-frequency power switching which can very easily emit radio waves. EMI issues can also be exaggerated in high power situations where an external MOSFET is required to handle the large voltages and currents (since the radiating component is now external to the DC-DC IC).

Other pain points for these converters include familiar hurdles like efficiency and package size. As with any component, newly released converters vie for improved stats. Here's a look at a recently released contender from ON Semiconductor, aimed at those dealing with mid-voltage DC-DC needs.


Introducing the FAN6500x family

ON Semiconductor have announced their latest family of DC-DC buck converters, the FAN6500x, that aims to provide engineers with a DC-DC buck converter that provides a balance of features to meet most power needs. They are available in a PQFN-35 IC package which is intended to help keep power circuits smaller and cooler. 

Here are some touted features:

  • Wide input voltage range (4.5V to 65V)
  • Can handle up to 10A
  • Provides up to 100W of power
  • Programmable switching frequency (100kHz to 1MHz)
  • Selectable PWM modes for adjusting to load type
  • Over current, thermal, over voltage, under voltage, and short circuit protection
  • Dual inbuilt LDOs for single supply operation
  • External compensation



The FAN6500x range of devices has been designed to help minimize external components by integrating PowerTrench MOSFET technology (i.e., no need for an external MOSFET). On the other hand, use of an integrated MOSFET also results in the FAN6500x range of DC-DC converters having better EMI performance and lower ringing that a design using an external MOSFET.

The devices also claim to offer up to a peak efficiency of 98% thanks to the extremely low parasitics. According to Richard Lu (President of the Mobile, Computing, and Cloud Division at ON Semiconductor), efficiency is a main focus for this device range, along with power density and flexibility.

The FAN6500x series of DC-DC buck converters have the potential to be in many different applications including industrial, base station power supplies, home automation, battery management, and USB power delivery.



Will you be trying out the FAN6500xx family? Let us know what you think in the comments below.


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