A3955SLB-T Allegro Microsystems Inc, A3955SLB-T Datasheet - Page 2

• Manufacturer Part Number: A3955SLB-T
• Description: IC MOTOR DRIVER PWM FULL 16-SOIC
• Manufacturer: Allegro Microsystems Inc

Specifications of A3955SLB-T

• Applications: Stepper Motor Driver
• Number Of Outputs: 1
• Current - Output: ±1.5A
• Voltage - Load: 4.5 V ~ 50 V
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Motor Type: Full Bridge
• No. Of Outputs: 2
• Output Current: 1.5A
• Output Voltage: 50V
• Supply Voltage Range: 4.5V To 5.5V
• Driver Case Style: SOIC
• No. Of Pins: 16
• Operating Temperature Range: -20°C To
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 620-1068

Features and Benefits
▪ ±1.5 A continuous output current
▪ 50 V output voltage rating
▪ Internal PWM current control
▪ 3-bit nonlinear DAC
▪ Fast, mixed fast/slow, and slow current-decay modes
▪ Internal transient-suppression diodes
▪ Internal thermal shutdown circuitry
▪ Crossover-current and UVLO protection
Packages:
29319.41G
Package B, 16-pin DIP
with exposed tabs
Not to scale
PFD
GROUND
PHASE
12
13
7
4
5
1
Full-Bridge PWM Microstepping Motor Driver
COMPARATOR
MIXED-DECAY
Package LB, 16-pin SOIC
with internally fused pins
+
–
V
CC
BLANKING
UVLO
& TSD
Functional Block Diagram
R T
PWM LATCH
Q
RC
3
C T
R
S
V
CC
6
BLANKING
GATE
+ –
Description
The A3955 is designed to drive one winding of a bipolar
stepper motor in a microstepping mode. The outputs are
rated for continuous output currents to ±1.5 A and operating
voltages to 50 V. Internal pulse width modulated (PWM) current
control combined with an internal three-bit nonlinear digital-
to-analog converter allows the motor current to be controlled
in full-, half-, quarter-, or eighth-step (microstepping) modes.
Nonlinear increments minimize the number of control lines
necessary for microstepping. Microstepping provides increased
step resolution, and reduces torque variations and resonance
problems at low speed.
Internal circuitry determines whether the PWM current-control
circuitry operates in a slow (recirculating) current-decay
mode, fast (regenerative) current-decay mode, or in a mixed
current-decay mode in which the off-time is divided into a
period of fast current decay and with the remainder of the
fixed off-time spent in slow current decay. The combination of
user-selectable current-sensing resistor and reference voltage,
digitally selected output current ratio; and slow, fast, or mixed
current-decay modes provides users with a broad, variable
range of motor control.
Continued on the next page…
V TH
÷3
CURRENT-SENSE
2
COMPARATOR
10
8
V
BB
D/A
9
15
+
–
14
16
DISABLE
SENSE
Dwg. FP-042
11
R S
A3955