Datasheet

STEP
DIR
RESET
nENBL
nHOME
OUT1
OUT2
OUT3
OUT4
Lookup
Table
(translator)
Counter
SM0
SM1
RESET
CLK
DIR
3.3V
DRV8805
www.ti.com SLVSAW3C –JULY 2011–REVISED MARCH 2012
FUNCTIONAL DESCRIPTION
Output Drivers
The DRV8805 contains four protected low-side drivers. Each output has an integrated clamp diode connected to
a common pin, VCLAMP.
VCLAMP can be connected to the main power supply voltage, VM. It can also be connected to a zener or TVS
diode to VM, allowing the switch voltage to exceed the main supply voltage VM. This connection can be
beneficial when driving loads that require very fast current decay, such as unipolar stepper motors.
In all cases, the voltage on the outputs must not be allowed to exceed the maximum output voltage specification.
Indexer Operation
The DRV8805 integrates an indexer to allow motor control with a simple step and direction interface. Logically,
the indexer is shown in Figure 2.
Figure 2. Indexer Operation
Step Modes
The SM0 and SM1 pins select the stepping mode of the translator as shown in Table 2.
Table 2. Step Modes
SM1 SM0 MODE
0 0 2-phase drive (full step)
0 1 1-2 phase drive (half step)
1 0 1-phase excitation (wave drive)
1 1 Reserved
In all modes, during a fault condition, the STEP input will be ignored. See the Protection Circuits section below.
The sequence of the outputs is shown in Table 3 through Table 5.
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Product Folder Link(s): DRV8805