
102 (4.00)
95 (3.75)
64 (2.50)3 (0.125)
76 (3.00)
6 
(0.25)
4 (0.15)
4 x 4
(0.125)
94 (3.70)
38 
(1.50)
22 (0.875)
2 x 4
(0.125)
6 
(0.25)
MICROSTEPPING  
MOTOR DRIVES
3540M Series
3540M shown 
smaller than 
3540M    
l Pulse and Direction Stepper Drive 
l 3.5 A, 40 Vdc    
l Switch Selectable Resolutions: 
400, 1000, 2000 and 
12,800 Steps/Rev
3540MO
l Stepper Drive with Digital 
Oscillator
l 3.5 A, 40 Vdc 
l Resolution: 12,800 Steps/Rev 
l Speed Range Select: 
High (25 rps) or Low (5 rps)
l 0 to 5V Analog Input, External 
Speed Signal, Pot or Joystick
l Tach Output: 5 to 24V Optically 
Isolated, 100 Pulses/Revolution
l  Acceleration/Deceleration  
Range, 1 to 250 Revs/Sec
2
Common Features   
l DC Bus Voltage 12 to 42 Vdc 
Motor Supply (Including 
Ripple) 
l Switch Selectable Motor 
Currents from 0.4 to 3.5 A/Phase
l Optically Isolated 5 Vdc Inputs 
for Step, Direction and Enable
l Enable Input to Turn Off Current 
to the Motor
l Screw Terminal Connectors 
l MOSFET, Dual H-Bridge, 
Inaudible PWM Amplifier
l 3 State, Pulse Width Modulated 
Current Control, Switching at  
20 to 30 KHz
The 3540M/MO step motor drivers are 
microstepping drives with up to 12,800 steps 
per revolution, step phase sequencer with 
MOSFET three state switching amplifiers and 
optoisolated circuits. Both drives include 5 
optically isolated inputs,  
and the 3540MO features external speed 
control, tach output, and internal pots for 
accel/decel rate along with high/low speed 
range selection.
Dimensions:  
mm (inch)
The 3540M is a step and direction drive, 
and includes an automatic feature (switch 
selectable) to reduce motor current by  
50% when the motor is left at rest for more 
than one second. Additionally there is a 
switch selectable self-test which rotates the  
motor 
100 steps/second. 
The 3540M0 has an on-board oscillator 
which allows the motor speed to be 
controlled by an analog voltage or external 
joystick. This drive is idea for continuous 
motion applications such as mixers and 
blenders. Microstepping resolution is 
selectable by DIP switch on the 3540M.
1
⁄2 revolution in each direction at 
actual size.
3540MO shown 
smaller than 
actual size.
SPECIFICATIONS
Amplifiers: Dual, bipolar MOSFET 
H-bridge, pulse width modulated three 
state switching at 20 KHz; 12 to 42 Vdc 
input; 0.4 to 3.5 A/phase output current, 
switch selectable in 0.1 A increments; 
122 W maximum output power; 
automatic idle current reduction  
(switch selectable), reduces current  
to 50% of setting after one second
Inputs (3540M): Step, direction and 
enable, optically isolated, 5V logic;  
5 mA/signal sink requirement ; motor 
steps on rising edge of step input; 
0.5 µsec minimum pulse width; 2 µsec 
minimum set up time for direction signal
D-20

MOSFET
Amplifier
Step
Direction
+5
Microstep
Sequencer
Current
0.4 to 3.5 
A/phase
Step
resolution
1/2, 1/5,
1/10 or 1/64
50% idle
current
reduction
on/off
Dir
A+ 
A– 
B+ 
B–
To 
motor
Enable
Optical
Isolator
Self test
on/off
Step
12 to 42 Vdc
Optical
Isolator
Optical 
Isolator
run
direction
Common
Ext 
speed
12 to 42 Vdc
hi/lo speed
Current
0.4 to 3.5 
A/phase
ext speed
Joystick
A+ 
A– 
B+ 
B–
To 
motor
enable 
tach out+ 
tach out-
50% idle
accel
LO
speed
HI
speed
Microstep
Sequencer
MOSFET
Amplifier
Optical
Isolation
Digital Oscillator
&
Joystick Interface
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Inputs (3540MO): Run/stop (cw limit), 
direction (ccw limit), high/low speed 
and enable inputs are optically isolated,  
5 to 24V logic. 3 to 15 mA input 
current; 2200 Ω input impedance; can 
be configured for sinking or sourcing 
signals
 Recommended External Pot/Joystick  
 Resistance: 1 to 5 K
 Joystick Dead Zone: ±80 mV 
 Potentiometer/Analog Signal 
 Dead Zone: 40 mV 
Speed Ranges (3540MO): 
 Low Speed Range: 0 to 5 rev/sec 
 High Speed Range: 0 to 25 rev/sec 
 Accel/Decel Range: 
 1 to 250 rev/sec/sec
Tach Output (3540MO):
Phototransistor, open collector, open 
emitter; 24V max, 20 mA max;  
100 pulses per motor revolution,  
50% duty cycle (square wave)
Physical: Mounted on 1⁄4 inch thick  
black anodized aluminum heat transfer 
chassis; 38.1 x 76.2 x 101.6 mm  
(1.5 x 3.0 x 4.0") overall; power on red 
LED; maximum chassis temperature: 
70°C (158°F)
Connectors (3540M): European style 
screw terminal blocks 
 Max Wire Size: 18 AWG 
 Motor: 4 position (A+, A-, B+, B-)  
 DC Input: 2 position (V+, V-) 
 Signal Input: 4 position (+5, STEP, 
 DIR, EN) 
Connectors (3540MO): European style 
screw terminal blocks 
 Power Supply and Motor: 6 position 
 Wire Size: 12 to 28 AWG 
 Signal Input: 10 position 
 Wire Size: 16 to 28 AWG 
 Motor: 4 position (A+, A-, B+, B-) 
Self Test (3540M): Switch selectable, 
rotates motor 1⁄2 revolution each  
direction at 100 steps/second,  
half step mode
Microstepping (3540M): Four switch 
selectable step resolutions with 1.8° 
motor; half Step (400 steps/rev); 
(1000 s/r); 1⁄10 step (2000 s/r); 1⁄64 step  
(12,800 s/r)
Microstepping (3540MO): 1⁄64 step  
(12,800 s/r) with 1.8° motor;  
pure sine waveform
CE Mark: Complies with EN55011A  
and EN50082-1(1992)
OPTIONAL ACCESSORIES 
Power Supply (Required for Drive 
Operation): Recommended: 
OMPS150A24; 24 Vdc, 6.3 A;  
see omega.com/ps_series
1
⁄5 step 
3540M
3540MO
D-21
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Torque vs. Speed Curves for  
3540M/MO Drive-Motor Combinations
 To Order Visit omega.com/3540m for Pricing and Details
 MODEL NO.  DESCRIPTION
3540M  Microstepping step motor drive 12 to 42 Vdc
 3540MO  Microstepping step motor drive with digital oscillator
Ordering Example: 3540M, microstepping step motor drive.
Order motors 
separately, 
see below  
for details
RECOMMENDED MOTORS FOR 3540M AND 3540MO
 MODEL NO.  g-cm (oz-in)  VOLTAGE (V)  CURRENT (A)  OHMS  MH  g-cm2 (oz-in2) 
 NEMA 17 STEP MOTOR SPECIFICATIONS ( RATINGS ARE WITH MOTOR CONNECTED IN PARALLEL)
OMHT17-075  4522 (62.8)  2.8  1.7  1.7  3.0  68 (0.37) 
 NEMA 23 STEP MOTOR SPECIFICATIONS (RATINGS ARE WITH MOTOR CONNECTED IN PARALLEL) 
 OMHT23-397  12746 (177)  2.5  2.83  0.9  2.5  300 (1.64)  
 OMHT23-400  19011 (264)  3.2  2.83  1.1  3.6  480 (2.62)
Ordering Example: 3540MO, microstepping step motor drive with digital oscillator. 
OMHT17-075, NEMA 17 step motor with 62.8 oz-in minimum holding torque. 
Visit omega.com for additional step motor information.
ACCESSORY
MODEL NO.  DESCRIPTION
 OMPS150A24  Stepper drive power supply, 24 Vdc, 6.3 A
HOLDING TORQUE  RATED  RATED  RESISTANCE  INDUCTANCE  ROTOR INERTIA 
D-22