Shenzhen Retechip Electronics Co., Ltd
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A3977 Microstepping DMOS Driver with Translator CHIP
Description
The A3977 is a complete microstepping motor driver with built-in translator. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes, with output drive capability of 35 V and ±2.5 A. The A3977 includes a fixed off-time current regulator that has the ability to operate in slow-, fast-, or mixed-decay modes. This currentdecay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.
The translator is the key to the easy implementation of the A3977. Simply inputting one pulse on the STEP input drives the motor one step (two logic inputs determine if it is a full-, half-, quarter-, or eighth-step). There are no phase-sequence tables, high-frequency control lines, or complex interfaces to program. The A3977 interface is an ideal fit for applications where a complex microprocessor is unavailable or overburdened.
Internal synchronous-rectification control circuitry is provided to improve power dissipation during PWM operation. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power-up sequencing is not required. The A3977 is supplied in a thin (<1.2 mm) 28-pin TSSOP with an exposed thermal pad (suffix LP).
The A3977 is lead (Pb) free, with 100% matte tin leadframe plating
Features
• ±2.5 A, 35 V output rating
• Low RDS(on) outputs, 0.28 Ω source, 0.22 Ω sink typical
• Automatic current decay mode detection/selection
• 3.0 to 5.5 V logic supply voltage range
• Mixed, fast, and slow current decay modes
• Home output
• Synchronous rectification for low power dissipation
• Internal UVLO and thermal shutdown circuitry
• Crossover-current protection
Applications
When a PWM off-cycle is triggered by an internal fixed off-time cycle, load current will recirculate according to the decay mode selected by the control logic. The A3977 synchronous rectification feature will turn on the appropriate MOSFETs during the current decay and effectively short out the body diodes with the low RDS(on) driver. This will reduce power dissipation significantly and eliminate the need for external Schottky diodes for most applications. The synchronous rectification can be set in either active mode or disabled mode. Active Mode When the SR input is logic low, active mode is enabled and synchronous rectification will occur. This mode prevents reversal of the load current by turning off synchronous rectification when a zero current level is detected. This prevents the motor winding from conducting in the reverse direction. Disabled Mode When the SR input is logic high, synchronous rectification is disabled. This mode is typically used when external diodes are required to transfer power dissipation from the A3977 package to the external diodes
Date Sheet
| Product Attribute | Attribute Value |
|---|---|
| Allegro MicroSystems | |
| Product Category: | Motor / Motion / Ignition Controllers & Drivers |
| Brushed DC Motor Drivers | |
| Microstepping | |
| 8 V to 35 V | |
| 2.5 A | |
| 8 mA | |
| - 20 C | |
| + 85 C | |
| SMD/SMT | |
| TSSOP-28 | |
| Reel | |
| Cut Tape | |
| MouseReel | |
| Brand: | Allegro MicroSystems |
| Load Voltage Rating: | 35 V |
| Moisture Sensitive: | Yes |
| Number of Outputs: | 2 Output |
| Operating Frequency: | 500 kHz |
| Product Type: | Motor / Motion / Ignition Controllers & Drivers |
| Factory Pack Quantity: | 4000 |
| Subcategory: | PMIC - Power Management ICs |
Quality Assurance
1: Before the products are put into storage, we will preliminarily verify the external packaging,labels,
quantity, etc. of the products;
2: After the preliminary inspection, the products will enter the inspection waiting area,and thenwe will
use professional equipment for inspection Equipment such as X-RAY gold sample detection, silk
screen contrast detection with magnifying glass, and alcohol detection,The silk screen shall be
checked, and the qualified ones shall be printed and put into storage.
3: The product will be stored in a constant temperature and humidity environment, and aspecially
assigned person will check, confirm and record it every day.
4: Before the products are delivered from the warehouse, the first and second tests will be repeated
according to the customer's order to ensure that the outgoing products reviewthe customer's
requirements.
Transportations & Payments
Frequently Asked Questions
Shipping:
1, We can shipping all over the world by DHL, UPS, FEdex, TNT and EMS.The packaging is very
safe and strong. Please nitfy me you have any special needs
2, It will take around 3-5 days to reach your hands.
Product Type & condition:
Because of the fluctuant sales situation. the stock parts are always changing and the stock list cannot
be, promptly updated.So please consult the stock situation when you inquire.
Buyer Reading:
1. Please confirm receipt of products if the items you received,and if the goods was damaged please
contact us immediately. send the photo to us that we can check and give you best solution
2. We only guarantee delivery in time but we couldn't control the express delivery time. Our related
sales person will be responsible to send the AWB for the delivered goods in the next workday.
you can check the AWB in the website which we send to you. For the AWByou also can call to the
local branch of the express company in your company.
Pre-sales service :
1. Our team design and make solutions based on different requirements from different customers.
2. We provide 24-hours service,and every message you quote inquiry will be replied within12 hours