February 1999
PBL 3773/1
Dual Stepper Motor Driver
Description
The PBL 3773/1 is a switch-mode (chopper), constant-current driver IC with two
channels, one for each winding of a two-phase stepper motor. The circuit is similar to
Ericsson´s PBL 3771/1 and PBL 3775/1. While all Dual stepper motor drivers are
optimized for microstepping applications, PBL 3773/1 is also equipped with a Disable
input to simplify half-stepping operation.
The circuit is well suited for microstepping applications. The current control inputs
are low current, high impedance inputs, which allows the use of unbuffered Digital-to-
Analog converters or external high resistive resistor divider networks.
The PBL 3773/1 contains a clock oscillator, which is common for both driver
channels, a set of comparators and flip-flops implementing the switching control, and
two output H-bridges, including recirculation diodes.
Voltage supply requirements are +5 V for logic and +10 to +45 V for the motor.
The close match between the two driver channels guarantees consistent output
current ratios and motor positioning accuracy.
Key Features
• Dual chopper driver in a single
package.
• Down to -40°C operation
• 750 mA continuous output current per
channel.
• Low power dissipation, 2.0 W at
2 x 500 mA output current
• Close matching between channels for
high microstepping accuracy
• High impedance current control
inputs
• Digital filter on chip eliminates
external filtering components.
• Plastic 22-pin batwing DIL package,
24-pin SOIC batwing or 28-pin power
PLCC. All with lead-frame for
heatsinking through PC board
copper.
PBL 3773/1
V
CC
V
–
+
CC
R
S
Q
M
A1
Logic
M
B1
V
MM1
+
–
V
MM2
M
B2
Logic
M
A2
P
B
L
37
7
RC
+
–
S
R
Q
PB
L
/
773
3
Phase
2
Dis
2
V
R2
C
2
GND
E
2
22-pin plastic DIL package
28-pin PLCC package
24-pin SO package
Figure 1. Block diagram.
1
3/
1
Phase
1
Dis
1
V
R1
C
1
E
1
L
B /1
P 73
37
1
ERICSSON [ ERICSSON ]
