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A4984: DMOS Microstepping Driver with Translator and Overcurrent Protection

The A4984 is a complete microstepping motor driver with built-in translator for easy operation. It is designed to operate bipolar stepper motors in full-, half-, quarter-, and eighth-step modes. Step modes are selectable by MSx logic inputs. It has an output drive capacity of up to 35 V and ±2 A. The A4984 includes a fixed off-time current regulator which has the ability to operate in slow or mixed decay modes.
The ET package meets customer requirements for no smoke no fire (NSNF) designs by adding no-connect pins between critical output, sense, and supply pins. So, in the case of a pin-to-adjacent-pin short, the device does not cause smoke or fire. Additionally, the device does not cause smoke or fire when any pin is shorted to ground or left open.
The translator is the key to the easy implementation of the A4984. Simply inputting one pulse on the STEP input drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. The A4984 interface is an ideal fit for applications where a complex microprocessor is unavailable or is overburdened.
During stepping operation, the chopping control in the A4984 automatically selects the current decay mode, Slow or Mixed. In Mixed decay mode, the device is set initially to a fast decay for a proportion of the fixed off-time, then to a slow decay for the remainder of the off-time. Mixed decay current control results in reduced audible motor noise, increased step accuracy, and reduced power dissipation.
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-on sequencing is not required.
The A4984 is supplied in three surface mount packages: two QFN packages, the 4 mm × 4 mm, 0.75 mm nominal overall height ES package, and the 5 mm × 5 mm × 0.90 mm ET package. The LP package is a 24-pin TSSOP. All three packages have exposed pads for enhanced thermal dissipation, and are lead (Pb) free (suffix –T), with 100% matte tin plated leadframes.

Product Number: A4984

Class: Integrated Circuits (ICs), Power Management (PMIC), Motor Drivers, Stepper Motor Drivers, DMOS Microstepping Driver

Tag: Stepper Motor Drivers, DMOS Microstepping Driver, Motor, Motion

Low RDS(ON) outputs
Automatic current decay mode detection/selection
Mixed and Slow current decay modes
Synchronous rectification for low power dissipation
Internal UVLO
Crossover-current protection
3.3 and 5 V compatible logic supply
Thin profile QFN and TSSOP packages
Thermal shutdown circuitry
Short-to-ground protection
Shorted load protection
Low current Sleep mode, 10 µA
No smoke no fire (NSNF) compliance (ET package)

Part Number Type Operating Supply Current Technology Mounting Style Output Current Interface Applications Output Voltage Operating Temperature Operating Supply Voltage Package Type
A4984 Microstepping 6 mA DMOS Surface Mount 2 A Logic Parallel 35 V -20 °C ~ 150 °C(TA) 8V ~ 35V 24-contact QFN with exposed thermal pad 4×4 mm × 0.75 mm(ES package)
32-contact QFN with exposed thermal pad 5×5 mm × 0.90 mm(ET package)
24-pin TSSOP with exposed thermal pad (LP Package)

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    Datasheet Download on Mar, 2022

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