ROHM Develops New Motor Driver LSI


Kyoto, Japan – Semiconductor manufacturer ROHM Co., Ltd., has developed the BD65491FV (1-channel) andBD65492MUV (2-channel) high-speed motor drivers for use in a broad range of digital camera lens drive and home appliance motor drive applications.

The company began shipping samples of the two parts in January 2011 (sample pricing: ¥150) and plans to begin mass-production at a monthly volume of 500,000 in March 2011, with production split into a pre-process handled by ROHM Hamamatsu Co., Ltd., (Shizuoka Prefecture) and a post-process handled by ROHM Electronics Philippines, Inc., (Philippines).

Increasingly advanced functionality in battery-operated mobile devices, compact office equipment, and home appliances is being accompanied by growing demand for lower power consumption. At the same time, manufacturers are under pressure to lower device drive voltages as the number of battery cells is reduced and more compact actuators developed.

To satisfy these needs, it was necessary to increase switching speeds and lower on-resistance in order to improve drive efficiency, and to eliminate switching transistors' gate drive step-up circuit (charge pump circuit) in order to lower current consumption. However, existing technologies required that the current sent to the pre-driver be boosted in order to raise the pre-driver's capacity sufficiently to accommodate the desired increase in switching speed, creating a bottleneck on the road to lower power consumption. Additionally, existing designs required a charge pump circuit in order to provide the necessary gate voltage in the operating voltage range, particularly in the low-voltage region (3 V and lower). In its new design, ROHM has combined a state-of-the-art DMOS process with proprietary circuit technology to resolve these roadblocks on the way to lower power consumption, allowing the company to deliver a high-speed drive with low current consumption and low-voltage drive performance down to 1.8 V, without a charge pump. These innovations paved the way for parts with the industry's shortest turn-on and turn-off times as well as a wide range of operating voltages, allowing their use to power mobile devices for extended periods of time as well as home appliances needing power supplies of 10 V and greater. Along with their compact packages, the ability to eliminate at least two capacitors thanks to the removal of the charge pump will contribute to smaller application systems.

ROHM, one of the world's leading motor driver LSI manufacturers, has earned high praise for meeting needs in a broad range of customer areas with an extensive portfolio of products, including system lens drivers, system motor drivers, and fan motor drivers. As manufacturers of mobile devices such as cellular phones and digital cameras produce smaller and more advanced products, ROHM will continue to contribute to the evolution of application hardware by developing cutting-edge motor driver LSIs.

Principal features of the BD65491FV and BD65492MUV motor driver LSIs

  1. Low power consumption (BD65491FV : 0.80mA / 1.30mA ; BD65492MUV : 0.95mA / 1.30mA)
  2. Industry's shortest turn-on time (BD65491FV : 150ns ; BD65492MUV : 200ns)
  3. Compact package (BD65491FV : 6.4 • 5.0 • 1.15 mm; BD65492MUV : 4.0 • 4.0 • 1.0 mm)
  4. Wide range of operating voltages (1.8V to 16.0V)
  5. Low on-resistance (BD65491FV : 0.35Ω / 0.5Ω ; BD65492MUV : 0.9Ω / 1.2Ω)

Comparison of On-resistance Motor Voltage Dependency


  1. Actuator
    A general name for a series of parts that perform a certain job. There are many different types; for example, an electrical actuator converts electrical energy into mechanical energy.
  2. Charge pump circuit
    A means of obtaining an output voltage by means of a charge conversion that is performed by superposing the input voltage with voltage stored by a capacitor. Charge pump circuits provide a simple way to obtain a higher voltage at the expense of larger current flow.
  3. Gate voltage
    Field effect transistors are semiconductor devices that generally control four pins: gate, source, drain, and body. The voltage applied to the gate controls the current that flows between the source and drain.