Datasheet

Table Of Contents
DA7280
LRA/ERM Haptic Driver with Multiple Input Triggers,
Integrated Waveform Memory and Wideband Support
Datasheet
Revision 3.0
30-Jul-2019
CFR0011-120-00
15 of 76
© 2019 Dialog Semiconductor
For a consistent user experience, DA7280 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 5.3.
Wideband LRA Support
Wideband LRAs respond across a frequency range typically several times wider than narrowband
ones, as demonstrated in Figure 6, and can be used in combination with DA7280 to a create richer
haptic feedback experience by utilizing the increased vibrational frequency range, see Section 5.5.
Frequency [Hz]
Acceleration Output [g]
1
0.5
200
Wideband LRA
Standard
Narrowband LRA
Figure 6: Narrowband and Wideband LRA Response across Frequency
Dual mode actuators (DMA) consist of two modes of vibration in different axes around different
resonance points, depending on actuator construction. The two resonant points, wide response
frequency, and different direction of vibration allow immersive gaming experience with multiple
unique feedback effects. Figure 8 shows a typical DMA response, vibration in the y-axis occurs if the
DMA is driven at 100 Hz and vibration in the x-axis occurs if the DMA is driven at 200 Hz.
Frequency [Hz]
Acceleration Output [g]
1
0.5
200
X-axis Resonance
100
Y-axis Resonance
Useful Operating Range
X-axis Vibration
Y-axis Vibration
Dual Mode LRA
Figure 7: Dual Mode LRA Response across Frequency
The ability of DA7280 to control the frequency (25 Hz to 1000 Hz) and amplitude of the drive over
time as well as the type of output wave allows the use of wideband sequences fully utilizing the
capabilities of wideband and dual mode actuators for creating a richer user experience, see
Section 5.7.5. Example use cases in DMAs are excitation of both resonant peaks simultaneously for
maximum perceptible vibration or distinct single-frequency event-signaling clicks at different resonant
frequencies and physical directions. Both DMAs and wideband LRAs can also be used to augment
user audio experience by playing audio-derived haptic sequences over their useful frequency
operating range.
DA7280 supports all of the above use cases and drives wideband LRAs via I
2
C or wideband
Waveform Memory sequences triggered by I
2
C or GPIs. The output drive can be configured as either
square wave, sine wave, or custom wave to create different end effects, see Section 5.7.6.
Usually, LRA resonant frequency tracking is disabled during wideband operation. However, it can be
enabled to either locate the resonant peak of wideband actuators, or to operate at a selected DMA