Diodes AM4951/R/2 - Manual (Page 9)

Data Sheet
BTL Drive Single-phase Full-wave Fan Motor Driver AM4951/R/2
Apr. 2012 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
9
Typical Application
Note 2: Adding D1 can protect the IC from destruction by reverse connection. If D1 is used, it is necessary to
insert a capacitor C1 to provide a regenerative current route. Similarly, if there is no nearby capacitor on the fan
power supply line, C1 will also be necessary to improve reliability. Its capacity should be larger than 2.2
µF.
Note 3: If the Hall sensor bias is taken from V
CC
, A 1/2 V
CC
bias, as shown in the figure must be used. Adjusting
the value of R1 and R2 may achieve better startup characteristics and efficiency, even quiet operation.
Note 4: This pin must be left open if unused.
Note 5: If the line between Hall sensor output and Hall sensor input of IC is long, the noise may occur in this line.
But it can be eliminated by adding a capacitor C3.
Note 6: Each of R2, R3, R4 and R5 (AM4951/R only) is recommended to be 51k
Ω typical. R1 is recommended
to be 2k and must be added when V
CC
is larger than 20V.
Note 7: The package of AH920 is SOT-23-3. If it is packaged in TO-92S-3，please exchange IN- with IN+.
Figure 9. Typical Application of AM4951/R