NO NF-A4X20 PWM - Noctua NF-A4x20 PWM fan, 40 mm

The NF-A4x20 is a highly optimized, quiet 40x20mm fan in premium quality, which draws on future-oriented aerodynamic design measures such as Flow Acceleration Channels and Noctua's AAO frame system. The PWM version uses Noctua's specially designed NE-FD1 IC for fully automatic speed control via 4-pin connections and is supplied with a low-noise adapter, through which the maximum speed in PWM operation can be reduced from 5000 to 4400rpm. Its outstanding smoothness, the SSO2 reference class bearing and Noctua's proven premium quality make the NF-A4x20 PWM a choice for the highest demands.

40x20 mm format
Compared to Noctua's award-winning NF-A4x10, the NF-A4x20 has twice the depth of its construction. This enables higher pressure performance and makes the NF-A4x20 the perfect choice for applications with higher air resistance.

Flow Acceleration Channels
The impeller of the NF-A4x20 is equipped with so-called flow acceleration channels on the suction side. The acceleration of the air flow in the critical outer regions of the fan blades reduces the suction-side vortex-ablation, resulting in higher efficiency and lower turbulence-related noise emission.

AAO frame system
Noctua's AAO (Advanced Acoustic Optimization) frames have built-in vibration buffers and a stepped inlet design (stepped inlet Design) and an interior microstructure (Inner surface Microstructures), which enable even better performance/noise efficiency.

Stepped Inlet Design
The stepped inlet area of the stepped inlet design creates more turbulence in the inlet. This facilitates the transition from laminar to turbulent flow, which is better attached to the frame (flow attachment) and thus increases the suction capacity of the fan, especially when the intake area is limited.

Inner Surface Microstructures
The microstructure inside the frame (Inner surface Microstructures) creates a boundary layer through which the tips of the fan blades move. This reduces the current separation from the suction side of the leaf tips, which results in a significant reduction of the rotton and an increase in the efficiency of the pressure and airflow.

Anti-Vibration Pads
The anti-vibration pads, made from extra-soft silicone, reduce the transmission of minimal vibrations and are compatible with all standard screws as well as standard mounting systems or fan clips used in CPU coolers.

PWM IC WITH SCD
The fan supports fully automatic speed control via PWM and uses Noctua's specially designed NE-FD3 chip for this purpose. This 5V PWM IC integrates Noctua's smooth commutation Drive (SCD) technology, which minimizes PWM switching noise and makes the fan even quieter at low speeds.

OmniJoin Adapter set
Since many devices, in which 40 mm fans are used, have proprietary fan connectors, the NF-A4x20 is supplied with Noctuas OmniJoin... ...