When to Use an LRA Linear Resonant Actuator for Haptic Feedback

Updated

Use an LRA (linear resonant actuator) when you need crisp, high-definition haptic feedback and can supply a dedicated driver IC. According to Vybronics, LRA motors are "best for haptic feedback" because they combine low drive voltage and current with high vibration force — but they require a driver IC to operate. If your design can't accommodate that driver, or you're optimizing purely for cost, an ERM motor is the better fit.

What Makes an LRA Different

An LRA drives a moving mass back and forth along a single axis at its resonant frequency, rather than spinning an offset weight like an ERM motor. That linear motion is what produces the sharp, controllable "click" feel associated with HD haptics.

Vybronics lists these characteristics for its LRA line:

  • Best for haptic feedback
  • Low drive voltage and current
  • High vibration force
  • Driver IC required

The driver IC point is the key constraint. An LRA won't run from a simple DC voltage the way an ERM motor does — it needs a driver that tracks and drives the resonant frequency.

When an LRA Is the Right Choice

Choose an LRA when most of these apply:

  • Haptics are a core feature, not an afterthought — the tactile response needs to feel precise and repeatable.
  • Power budget is tight. Low drive voltage and current matter in battery-powered devices.
  • You need strong feedback in a thin package. High vibration force in a low-profile form factor suits space-constrained products.
  • Your design already includes (or can include) a haptic driver IC.

Vybronics notes its tactile actuators are used for vibratory haptic feedback in cellphones, wearables, hearables, display panels, and augmented/virtual reality hardware using HD haptics — all cases where feedback quality justifies the driver requirement.

When an LRA Is the Wrong Choice

  • Cost is the primary constraint. Vybronics describes its ERM brush-type coin motor as the "lowest cost of all vibration motors."
  • You can't add a driver IC. Without one, the LRA won't function as intended.
  • You only need basic alert vibration. A simple buzz doesn't require resonant linear motion.

Form Factors Available

Vybronics offers LRAs in more than one shape, so the choice isn't only "LRA vs. ERM" but also which LRA package fits your assembly:

Type Notes
Coin LRA Low-profile, suited to compact devices
Rectangular LRA Same haptic benefits in a different footprint

Both are described with the same core advantages: best for haptic feedback, low drive voltage and current, high vibration force, and a required driver IC.

How to Decide

  1. Confirm the feedback quality you need. If it's HD haptics, an LRA is the intended technology.
  2. Check whether a driver IC fits your design. If not, rule the LRA out.
  3. Compare against ERM if cost dominates — ERM is the lower-cost option.
  4. Pick the shape (coin or rectangular) based on your mechanical envelope.
  5. If the choice is still unclear, Vybronics states it has applications engineers who can help select the right motor or design one to specific requirements.

The short version: an LRA is the right call when haptic quality and power efficiency matter more than unit cost, and when a driver IC is part of the plan.