A3977SEDTR-T Allegro Microsystems Inc, A3977SEDTR-T Datasheet - Page 9

• Manufacturer Part Number: A3977SEDTR-T
• Description: LEAD FREE A3977SEDTR
• Manufacturer: Allegro Microsystems Inc

Specifications of A3977SEDTR-T

• Rohs Compliant: YES
• Applications: Stepper Motor Driver
• Number Of Outputs: 1
• Current - Output: ±2.5A
• Voltage - Load: 8 V ~ 35 V
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-LCC (J-Lead)
• Motor Type: Stepper
• No. Of Outputs: 2
• Output Current: 2.5A
• Output Voltage: 35V
• Supply Voltage Range: 3V To 5.5V
• Driver Case Style: LCC
• No. Of Pins: 44
• Operating Temperature Range: -20°C To +85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 620-1146-2; A3977SEDTR-T

A3977
Synchronous Rectifi cation. When a PWM off-cycle is
triggered by an internal fi xed off-time cycle, load current
will recirculate according to the decay mode selected by
the control logic. The A3977 synchronous rectifi cation fea-
ture will turn on the appropriate MOSFETs during the cur-
rent decay and effectively short out the body diodes with
the low r
signifi cantly and eliminate the need for external Schottky
diodes for most applications.
tive mode or disabled mode.
The synchronous rectifi cation can be set in either ac-
DS(on)
driver. This will reduce power dissipation
(T
A
= +25°C, V
A. Minimum Command Active Time
B. Minimum Command Active Time
C. Minimum STEP Pulse Width ...................... 1.0 μs
D. Minimum STEP Low Time ......................... 1.0 μs
E. Maximum Wake-Up Time ......................... 1.0 ms
Before Step Pulse (Data Set-Up Time) ..... 200 ns
After Step Pulse (Data Hold Time) ........... 200 ns
Microstepping DMOS Driver with Translator
Functional Description (cont’d)
DD
Timing Requirements
= 5 V, Logic Levels are V
Active Mode. When the SR input is logic low, active
mode is enabled and synchronous rectifi cation will occur.
This mode prevents reversal of the load current by turning
off synchronous rectifi cation when a zero current level is
detected. This prevents the motor winding from conduct-
ing in the reverse direction.
Disabled Mode. When the SR input is logic high, syn-
chronous rectifi cation is disabled. This mode is typically
used when external diodes are required to transfer power
dissipation from the A3977 package to the external diodes.
DD
and Ground)
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
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