February 22, 2006

Unipolar Two-Phase Stepping Motor Driver ICs
SLA7070MPR Series
Built-in current sensing resistors cut its footprint in half and simplify circuit design

Sanken Electric has developed SLA7070MPR series, unipolar 2-phase stepping motor driver ICs with a total of 8 types (4 types of rated currents: 1A, 1.5A, 2A, 3A, each with 2 excitation versions of full/half stepping and microstepping)
The ICs will be launched in March 1, CY06 starting with 50k pcs/month, then ramping up to 500k pcs/month by the end of CY06. (Sample price: 400 Yen to 800 Yen)
SLA7070MPR Series Phot

1. Development background and product outline
  In recent years, Office Automation (OA) and Factory Automation (FA) equipment have become more intelligent, and the motor count has been increasing especially in Plain Paper Copiers (PPCs) and Laser Beam Printers (LBPs) to support color printing and higher-speed printing. Accordingly, the motor driver IC count has also been increasing.
As a result, this leads to additional control signal lines for motor drivers, more complex discrete circuits and an increase in the footprint of these parts. Thus a further downsizing and a higher reliability are required on the motor drivers.

In Sanken's conventional unipolar 2-phase stepping motor driver ICs, current sensing resistors to detect and control the motor currents are connected externally. Since the motor currents flow directly through the resistors, they are required to be power resistors (multi-watt level) and therefore occupy a large footprint on a printed circuit board (PCB).
In the new SLA7070MPR Series, these current sensing resistors are built in Sanken's proprietary compact package (plastic molding dimensions: 31 × 16 × 5 mm), thereby reducing the discrete component count and realizing a space-saving (about a half footprint on a Sanken's evaluation board).

The SLA7070MPR Series employs a clock input method as a control signal input method, enabling to control the operation only with a few signal lines, while the conventional phase input method requires about 10 signal lines. This allows to simplify the circuit design and to reduce a workload on a control microprocessor.

The conventional driver ICs may possibly be damaged by an excessive energy caused by a breaking of load (motor coil) wires. In contrast, the SLA7070MPR series has a built-in protection circuit that detects the excessive energy and protects it. It also has a built-in overcurrent protection circuit to protect it from the overcurrent at a short-circuiting of load (motor coil) wires.

In addition, the SLA7070MPR series is improved in its reliability by preventing the IC from damaging at abnormal conditions, such as having a flag output terminal to signal that a protection circuit is operated.

All the SLA7070MPR Series ICs, being compatible in their pin layouts and interface specifications, allow customers to choose flexibly the IC optimal for the target equipment characteristics.

< Applications >
 • LBPs, PPCs, ATMs, industrial robots, etc.

2. Features
Built-in current sensing resistors: Realizes reduction of discrete components and space-saving (about a half footprint on a Sanken's evaluation board).
Clock input method: Reduces the control signal line count to approx. 1/3, simplifies the circuit design and reduces the control microprocessor's workload.
Built-in protection circuit for open and short-circuited load: Realizes a higher reliability.
Compatible pin layouts and the same interface specifications among the series ICs: Enables customers to simplify discrete circuit designs and to improve flexibility in choosing the ICs optimal for their target equipment.
3. Specifications
Parameter Rated Value Version (Sample Price in Parentheses)
Full/Half driving Microstepping
Main supply voltage 46V    
Output current 1.0A SLA7070MPR (¥400) SLA7075MPR (¥500)
1.5A SLA7071MPR (¥500) SLA7076MPR (¥600)
2.0A SLA7072MPR (¥600) SLA7077MPR (¥700)
3.0A SLA7073MPR (¥700) SLA7078MPR (¥800)
Maximum power dissipation 4.7W    
Output MOS FET ON resistance 0.7Ωtyp SLA7070MPR SLA7075MPR
0.45Ωtyp SLA7071MPR SLA7076MPR
0.257Ωtyp SLA7072MPR SLA7077MPR
0.18Ωtyp SLA7073MPR SLA7078MPR
Sensing resistance 0.305Ωtyp SLA7070MPR SLA7075MPR
0.305Ωtyp SLA7071MPR SLA7076MPR
0.205Ωtyp SLA7072MPR SLA7077MPR
0.155Ωtyp SLA7073MPR SLA7078MPR

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