DA7282 datasheet(15/75 Pages) RENESAS

15 / 75 page

LRA/ERM Ultra-Low Power Haptic Driver with Multiple Input Triggers and Integrated Waveform Memory

R15DS0041EE0330 Rev.3.30

June 16, 2026

CFR0011-120-00

Page 15

6. Functional Description

DA7282 is a haptic driver capable of driving both LRA and ERM actuators. The power-optimized architecture

and advanced closed-loop digital algorithms achieve a very high-fidelity haptic drive. It features frequency control

within an onboard Waveform Memory and three distinct GPI inputs, for triggering up to six distinct sequences.

This helps with emulating button pressing in many applications including gaming, mobile, and wearable devices.

The device controls the level of drive across the load and senses the movement of the actuator. The driven

waveform is generated by a current regulated loop using a high-frequency PWM modulation. The differential

output drive features a switching regulator architecture with H-bridge differential drive across the load at a

frequency of 187.5 kHz. The drive level is based on the sequence from the data source selected by I2C interface,

input PWM signal, or Waveform Memory.

DA7282 is capable of closed-loop actuator monitoring while driving to enable calibration-free playback,

frequency tracking (LRA only), Active Acceleration, Rapid Stop, and actuator diagnostics.

Continuous resonant frequency tracking can be enabled while driving an LRA to track the mechanical resonance

of the actuator through closed-loop control. This maximizes electrical to mechanical energy conversion efficiency

for narrowband actuators and is especially useful in applications such as operating system notifications and

alarms.

Resonant frequency tracking can be disabled to operate DA7282 in open-loop wideband frequency operation

while driving LRAs with a wider bandwidth frequency response.

Active Acceleration and Rapid Stop features enable automated driving of both ERM and LRA loads (when

frequency tracking is enabled). This reduces the time to reach the target acceleration level and the time for the

actuator to come to a complete stop.

6.1

Features Description

6.1.1

Driving LRA and ERM Actuators

DA7282 can drive both ERMs and LRAs depending on the register configuration, see Section 6.6.2.

6.1.2

Automatic LRA Resonant Frequency Tracking

LRA resonant frequency shifts over time due to changing operating conditions, such as temperature or position,

and manufacturing spread. LRAs are high-Q systems; if driven at a fixed frequency, the consequences are loss

of electrical to mechanical energy conversion efficiency, weaker than nominal actuator acceleration output, and

significant part-to-part variation in the end-product haptic feel. Figure 5 illustrates that if the drive frequency is

fixed, for example at 200 Hz, frequency variation in the resonant peak of only 10 Hz can result in a loss of 50 %

of the output acceleration.

Frequency [Hz]

0.5

200

210

190

Typical Resonant Peak Variation

(part-to-part, across temperature, drive signal level, and manufacturing lots)

Resonant Peak

with Max Accel.

250

150

Figure 5. LRA output acceleration swept in frequency with constant power input signal

For a consistent user experience, DA7282 automatically locks onto and tracks the resonant frequency of the

LRA through active BEMF sensing and closed-loop digital control. This ensures optimal output acceleration on

every individual LRA throughout its lifetime and consistent part-to-part haptic feedback in the end product, see

Section 6.3.

DA7282 Datasheet(PDF) 15 Page - Renesas Technology Corp

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