Hobbyking F-40A 40A ESC

From Hobbyking's website specifications:

Constant Current: 40A
Burst Current: 50A
Battery: 2-6S Lipoly / 5-18s NiXX
BEC: 5.5v / 4A
Motor Type: Sensorless Brushless
Size: 70 x 31 x 11mm
Weight: 44g
Fig 1:

Fig 1 shows the label of a F-40A ESC.

Fig 2:

Fig 2 shows the ESC. This uses a TFQP32 package Atmega8A, so connection using the Hobbyking chip adapter (332000007) is convenient. There are a set of ISP pads on the top right of the board which could be used. The ESC uses an external resonator. The ISP pads are L-R Vcc, /Reset, Gnd, SCK, MISO, MOSI.

The three 4700pF BEMF filter capacitors in the top row have been removed.

The ESC uses three IR2101S high and low side drivers to drive the 9 P FETs and 9 N FETs.

The external wires are nominal #12 (2mm dia), but they have been replaced in this test ESC with #16 for test jig compatibility.

Fig 3:

Fig 3 shows the lower side of the ESC. It has a quite substantial heat sink to assist in cooling of the 18 P+N FETs.

Fig 4:

Fig 4 shows the ESC rewrapped

Current version: 1f75da384e5c83f83916aa752819ca6eed712565 bs_tc.hex 24/03/14


The ESC contains a SBEC rated at 4A in the manufacturers specifications.


The F-40A ESC is a sound basic ESC with integral BEC.

The ESC uses common Atmega8 TQFP32 hardware that is readily flashed with third party firmware. The tgy (SimonK) firmware delivered smoother low speed operation and lower current drawn for same motor output power.

No warranty

Advice (or a warning) to those who might try to replace the firmware on an ESC. Most FW comes with no warranty, and typically the OEM firmware is read protected so you cannot save and restore it. In most cases, changing the firmware may terminate any seller's warranty.

In making hardware or firmware modifications, you may damage the ESC, or the model may fail and cause consequential damage.

The author gives no warranty and makes no representations about the suitability of this technique or any particular products for the end user, or the accuracy of the article content, they must inform themselves and make their own judgment aware that there are risks. If you are not competent to do these things, don't do them!


The article should not be seen as a recommendation or endorsement of any products.

The products shown in this article are from Hobbyking who manufacture products under a range of brand names, possibly creating an illusion of competition. Their products tend to be low in cost and low in quality, products are not good value when you have to throw a proportion of them in the rubbish because the cost of returning them exceeds the value of the replacement which is only available after excessive delay, many follow ups and haggling. If you see the claim [o]ther stores will force you to ship the product back to China in full retail packaging every time! Hobbyking's warranty service is professional, fair and fast, don't believe it, it doesn't work that way in my experience... I get better service from most eBay sellers!




Version Date Description
1.01 07/08/2013 Initial.

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