NJM3517
DIR
INH
HSM
STEP
OB
LB
PB1
PB2
PA1
PA2
LA
OA
H
L
H
P
L
P
P
P
P
P
P
L
DIR
INT
HSM
STEP
OB
LB
PB1
PB2
PA1
PA2
LA
OA
L
L
H
P
L
P
P
P
P
P
P
L
Figure 7. Full-step mode, forward. 4-step sequence. Gray-code Figure 8. Full-step mode, reverse. 4-step sequence. Gray-
+90° phase shift.
code -90° phase shift.
DIR
INH
HSM
STEP
OB
LB
PB1
PB2
PA1
PA2
LA
OA
H
L
L
P
C
DIR
INH
HSM
STEP
OB
LB
PB1
PB2
PA1
PA2
LA
OA
L
L
L
P
C
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Figure 9. Half-step mode, forward. 8-step sequence.
DIR
INH
HSM
STEP
OB
LB
PB1
PB2
PA1
PA2
LA
OA
L
H
L
P
C
Figure 10. Half-step mode, reverse. 8-step sequence.
P
P
H
H
H
H
P
P
Figure 11. Half-step mode, inhibit.
s
APPLICATIONS INFORMATION
Logic inputs
If any of the logic inputs are left open, the circuit will treat it as a high-level input. Unused inputs should be con-
nected to proper voltage levels in order to get the highest noise immunity.
Phase outputs
Phase outputs use a current-sinking method to drive the windings in a unipolar way. A common resistor in the
center tap will limit the maximum motor current.
Fast free-wheeling diodes must be used to protect output transistors from inductive spikes.
Series diodes in V
MM
supply, prevent V
SS
voltage from shorting through the V
MM
power supply. However, these
may be omitted if no bi-level is used. The V
SS
pin must not be connected to a lower voltage than V
MM
, but can be left
unconnected.
Zero outputs
Ø
A
and Ø
B
, “zero A” and “zero B,” are open-collector outputs, which go high when the corresponding phase output
is inhibited by the half-step-mode circuitry. A pull-up resistor should be used and connected to a suitable supply
voltage (5 kohms for 5V logic). See “Bipolar phase logic output.”
Interference
To avoid interference problems, a good idea is to route separate ground leads to each power supply, where the
only common point is at the NJM3517’s GND pin. Decoupling of V
SS
and V
MM
will improve performance. A 5 kohm
pull-up resistor at logic inputs will improve level definitions, especially when driven by open-collector outputs.
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