Summary of 40V SYNCHRONOUS BUCK CONVERTERS FROM DIODES DELIVER HIGH EFFICIENCY WITH LOW EMI
Diodes Incorporated announced the AP64350Q/AP64351Q/AP64352Q series: automotive-compliant, 3.5A synchronous buck converters for point-of-load use with 3.8V–40V input, integrated MOSFETs, low quiescent current (22 μA), PFM mode, FSS jitter ±6%, and EMI-reducing gate driver. Variants offer adjustable switching frequency (100 kHz–2.2 MHz) and sync (AP64350Q, AP64352Q), programmable soft-start (AP64351Q, AP64352Q), and external compensation (AP64350Q, AP64351Q).
Parts used in the AP6435xQ Series:
- AP64350Q synchronous buck converter
- AP64351Q synchronous buck converter
- AP64352Q synchronous buck converter
- 75 mΩ high-side integrated MOSFET (within devices)
- 45 mΩ low-side integrated MOSFET (within devices)
Diodes Incorporated announces the AP64350Q/AP64351Q/AP64352Q series of automotive-compliant, 3.5A, synchronous buck converters for point of load (POL) applications.
Diodes Incorporated today announced the AP64350Q/AP64351Q/AP64352Q series of automotive-compliant, 3.5A, synchronous buck converters for point of load (POL) applications. The AP6435xQ combines a low quiescent current with a wide input voltage range of 3.8V to 40V. The devices have been developed for use in automotive applications including infotainment systems, instrument clusters, telematics, advanced driver assistance systems (ADAS), and forward lighting.
With a fully integrated 75mΩ high-side power MOSFET and 45mΩ low-side power MOSFET, AP6435xQ provides high-efficiency step-down DC-DC conversion. The design of the AP6435xQ’s gate drive/bootstrap enables the devices to operate in low drop out (LDO) mode, allowing near 100% duty cycle.
To increase efficiency as the load current approaches zero, the devices enter pulse frequency modulation (PFM), resulting in a quiescent current of just 22μA. They also feature frequency spread spectrum (FSS) with a switching frequency jitter of ±6% and a proprietary gate driver scheme, which reduces high frequency radiated EMI noise caused by MOSFET switching.
The AP64350Q, AP64351Q, and AP64352Q have distinct additional feature sets that optimize performance in slightly different ways. The AP64350Q and AP64352Q have an adjustable switching frequency (100kHz – 2.2MHz) and can also be synchronized to an external clock. This provides the design flexibility to deliver a choice of low frequency with extremely high efficiency, or high frequency for small form factor solutions whose switching frequency is outside the AM band. The AP64351Q and AP64352Q have programmable soft-start, which reduces in-rush currents, while the AP64350Q and AP64351Q have external compensation to optimize loop response.
Read more: 40V SYNCHRONOUS BUCK CONVERTERS FROM DIODES DELIVER HIGH EFFICIENCY WITH LOW EMI
- What input voltage range do the AP6435xQ devices support?
The devices support a wide input voltage range of 3.8V to 40V. - What is the maximum output current of these converters?
Each device provides up to 3.5A output current. - Do the AP6435xQ devices include integrated MOSFETs?
Yes, they include a 75 mΩ high-side MOSFET and a 45 mΩ low-side MOSFET integrated. - How low is the quiescent current and how is it achieved?
The quiescent current is 22 μA, achieved by entering pulse frequency modulation as load current approaches zero. - Do any devices offer adjustable switching frequency or synchronization?
Yes, AP64350Q and AP64352Q have adjustable switching frequency from 100 kHz to 2.2 MHz and can be synchronized to an external clock. - Which devices provide programmable soft-start?
AP64351Q and AP64352Q include programmable soft-start to reduce in-rush currents. - Which models support external compensation?
AP64350Q and AP64351Q provide external compensation to optimize loop response. - What features reduce EMI and switching noise?
The devices use frequency spread spectrum with ±6% switching frequency jitter and a proprietary gate driver scheme to reduce high frequency radiated EMI noise. - Can the converters operate in near 100% duty cycle?
Yes, the gate drive/bootstrap design enables low dropout mode allowing near 100% duty cycle.
