SLVUA41E
6
Jumper “DIFF HALL”
Hall sensors output either a differential signal pair, or a single-ended open-drain. You can tell which
type your motor uses simply by counting the number of wires; a sensored BLDC typically has 3 phase
wires, 2 Hall power wires, and 3 or 6 Hall signal wires. 8 total mean single-ended; 11 total mean
differential (excluding optional FG or TACH wires).
The DRV8308 has differential comparators on the Hall inputs, and they can also accommodate single-
ended signals with the use of a few passive components.
When using differential Halls, directly connect the 6 Hall signals to the DRV8308 pins.
When using single-ended Halls, they require pull-ups,
and the DRV8308 comparator’s “-” pins
should be biased with a middle voltage, so that a single-
ended swing on the “+” pin is detected
like a differential voltage.
Jumper JP3 controls U7, an 8-line FET switch, and it decides when to connect the pull-ups and middle
voltage.
Install JP3 when using differential Halls. Uninstall JP3 when using single-ended Halls and
connect wires to the
“+” terminals of P3.
Figure 4. JP3 controls whether 6 connections are made
Jumper
“SMODE”
When the DRV8308 powers up, it checks if pin SMODE is High or
Low to decide whether to load register data from an external
EEPROM, or from the internal non-volatile One-Time Programmable
memory (OTP). When the OTP method is used, the DRV8308 also
accepts SPI commands to read and write registers.
Install JP4 when using the GUI and SPI.
Uninstall JP4 when using an external EEPROM
, and also install JP5a,
JP6a, JP7a, JP8a, and a 93C46B-compatible EEPROM into the DIP
socket (U6).
