mXT799T-AT/mXT799T-AB 1.0
maXTouch 798-node Touchscreen Controller
Product Brief
Description
The mXT799T-AT/mXT799T-AB uses a unique charge-transfer acquisition engine to implement Microchip’s patented capacitive
sensing method. Coupled with a state-of-the-art CPU, the entire touchscreen sensing solution can measure, classify and track a
number of individual finger touches with a high degree of accuracy in the shortest response time. The mXT799T-AT/
mXT799T-AB allows for both mutual and self capacitance measurements, with the self capacitance measurements being used
to augment the mutual capacitance measurements to produce reliable touch information.
maXTouch
®
Adaptive Sensing Touchscreen
Technology
• Up to 32 X (transmit) lines and 52 Y (receive) lines
• A maximum of 798 nodes can be allocated to the
touchscreen
• Touchscreen size 9.4 inches (16:9 aspect ratio),
assuming a sensor electrode pitch of 5.5 mm. Other
sizes may be possible with different electrode pitches
and appropriate sensor material
• Multiple touch support with up to 16 concurrent
touches tracked in real time
Touch Performance
• Moisture/Water Compensation
- No false touch with condensation or water drop up
to 22 mm diameter
- One-finger tracking with condensation or water
drop up to 22 mm diameter
• Glove Support
- Multiple-finger glove touches up to 1.5 mm
thickness (subject to stack-up design)
- Single-finger glove touch up to 5 mm thickness
(subject to stack-up design)
• Mutual capacitance and self capacitance
measurements supported for robust touch detection
• Noise suppression technology to combat ambient and
power-line noise
- Up to 240 Vpp between 1 Hz and 1 kHz
sinusoidal waveform
- Up to 20 Vpp between 1 kHz and 1 MHz
sinusoidal waveform
• Burst Frequency
- Controlled Tx burst frequency drift over process
and temperature range
• Scan Speed
- Up to 110 Hz one finger reporting rate (subject to
configuration)
- Typical report rate for 10 touches
100
Hz
(subject to configuration)
- Initial touch latency <25 ms for first touch from idle
(subject to configuration)
- Configurable to allow for power and speed
optimization
Automotive Applications
• AEC-Q100 Qualified
• Developed following Automotive SPICE
®
Level 3
certified processes
• CISPR-25 compliant (for both mutual and self
capacitance measurements)
Touch Sensor Technology
• Discrete/out-cell support including glass and PET film-
based sensors
• On-cell/touch-on display support including TFT, IPS
and OLED
• Synchronization with display refresh timing capability
• Support for standard (for example, Diamond) and
proprietary sensor patterns (review of designs by
Microchip recommended)
Front Panel Material
• Works with PET or glass, including curved profiles
(configuration and stack-up to be approved by
Microchip)
• Glass 0.4 mm to 4 mm with GFF stack, 0.55 mm to
4 mm with OGS stack (dependent on screen size,
touch size, configuration and stack-up)
• Plastic 0.2 mm to 3 mm (dependent on screen size,
touch size, configuration and stack-up)
On-chip Gestures
• Reports one-touch and two-touch gestures
2017 Microchip Technology Inc.
Product Brief
DS40001960A-page 1
MXT799T-AT/MXT799T-AB 1.0
Keys
• Up to 32 nodes can be allocated as mutual capacitance sensor keys (subject to other configurations)
• Adjacent Key Suppression (AKS) technology is supported for false key touch prevention
Enhanced Algorithms
• Lens bending algorithms to remove display noise
• Touch suppression algorithms to remove unintentional large touches, such as palm
• Palm Recovery Algorithm for quick restoration to normal state
Power Saving
• Programmable timeout for automatic transition from active to idle states
• Pipelined analog sensing detection and digital processing to optimize system power efficiency
Application Interfaces
• I
2
C-compatible slave with support for:
- Standard mode (up to 100 kHz)
- Fast mode (up to 400 kHz)
- Fast-mode Plus (up to 1 MHz)
- High-speed mode (up to 3.4 MHz)
• SPI slave interface (up to 8 MHz)
• Interrupt to indicate when a message is available
• SPI Debug Interface to read the real-time raw data for tuning and debugging purposes
Power Supply
•
•
•
•
Digital (Vdd) 3.3 V nominal
Digital I/O (VddIO) 3.3 V nominal
Analog (AVdd) 3.3 V nominal
High voltage external X line drive (XVdd) up to 9.0 V
Package
• 144-pin LQFP 20 × 20 × 1.4 mm, 0.5 mm pitch
Operating Temperature
• mXT799T-AT: –40C to +85C (Grade 3)
• mXT799T-AB: –40C to +105C (Grade 2)
Design Services
• Review of device configuration, stack-up and sensor patterns
• Custom firmware versions can be considered, such as for specific gestures or proprietary OEM host
communication protocols
• Contact your Microchip representative for more information
DS40001960A-page 2
Product Brief
2017 Microchip Technology Inc.
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