ST STMT05E User Manual
5-inch multi-touch capacitive touchscreen controller
Features
■ True multi-touch:
– Independent XY tracking with 10
simultaneous touches in real time
– Up to 12 force and 20 sense channels
■ Single chip solution:
– Up to 5 inches screen size
– Supports multiple touchscreen
configurations including touch keys with no
external components on touch channels
■ High SNR:
– Common mode charger noise rejection up
to 40 Vpp
– Advanced filtering techniques for strong
noise immunity
■ Fast report rate: > 150 Hz
■ High response time: < 2x report rate
■ Power consumption:
– 7 mW in active mode (multi-touch)
– 5 µW in sleep mode
■ 32-bit RISC processor
– Flexibility for customer code
implementation
– Allows customization of proprietary touch
pattern and gestures
■ Multiple input types: finger and stylus pen
– Up to 2 mm stylus
– Simultaneous finger and stylus
– Stylus recognition with palm rejection
Table 1. Device summary
STMT05E
S-Touch® FingerTip
Data brief
QFN48
(6 x 6 mm)
■ Large area recognition and rejection
■ Advanced signal processing and calibration:
– Water recovery, self-calibration with auto-
drift compensation and fast start-up
– Hardware coordinate scalar to match
touchscreen and display resolution
– Supports axis flipping and axis switch-over
for portrait and landscape modes
■ Sensor types:
– Works with plastic or glass sensors, with
different types of sensor patterns with or
without ground shield
– Supports on-cell, laminated and touch-on-
lens touch display
■ Power supply scheme:
– 2.8 V to 5 V A
■
Serial interface:
– Supports high speed I
– 3.3 V tolerant interface for I
■ I/Os: RESETB, INTB hardware pins to host
interface and 4 GPIOs with full programmability
■ High ESD protection:
– ±8 KV HBM ESD protection on all the force
and sense pins
and 1.8 V D
VDD
2
C and SPI
2
C and SPI
VDD
Order code Package Packing
STMT05EN1QTR
August 2011 Doc ID 022155 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
QFN48 (6 x 6 mm);
0.4 mm pitch and 0.55 mm thick
Tape and reel
www.st.com
4
Description STMT05E
1 Description
The STMT05E device represents a marked improvement over competing technologies by
providing an optimal mix of low power, small size, feature flexibility with unmatched true
multi-touch performance in a single-chip touchscreen controller.
The FingerTip STMT05E uses a unique capacitance to voltage conversion acquisition
engine to implement the S-Touch
®
capacitive sensing method. Coupled with the flexibility
offered by the internal processor engine, the entire touchscreen sensing solution can
measure, classify and track a single finger touch with fast report rate and response times on
240 nodes. Built-in movement tracking engine tracks greater than 10 independent touch
movements.
The acquisition engine uses an optimal measurement approach to ensure almost complete
immunity from parasitic capacitance on the receiver inputs (sense lines). The engine
includes sufficient dynamic range to cope with touchscreens of different size and
configuration. This offers great flexibility to use with multiple touchscreens with different ITO
designs and overlay materials. One and two layer ITO sensors are possible using glass or
PET substrates.
The STMT05E's capacitive analog front-end provides enhanced noise suppression
capabilities for various noise sources such as display, human body captured noise, system
generated noise and severe common mode noise introduced by battery chargers. ST’s
advanced capacitive sensing technology coupled with a powerful digital 32-bit DSP engine
is able to address common mode noise to provide high level of noise immunity without
reducing the overall touch performance in terms of response time, frame rate and power
consumption.
The device has an external SYNC pin for LCD noise filtering for an "on-cell" display
touchscreen technology. The synchronization of the signal acquisition with the LCD SYNC
signal helps in removal of LCD noise. This benefits the touch module maker to employ glass
screens with ITO to be used without any GND shield that can significantly reduce the cost of
the touch module.
The STMT05E supports multiple input types including stylus detection (up to 2 mm) for
smooth handwriting capability on touchscreens while detecting and rejecting large area
such as palm or hand. The device also supports touchkeys using the same ITO.
The main processor engine offers flexibility with required performance by an efficient preprocessing, post-processing and house-keeping. This gives ample scope for sensing
algorithm, touch tracking or advanced shape based filtering, area definition and event
reporting. Built-in associated processor memory (ROM, RAM) is optimized to run the
desired fixed program codes in the ROM and to maintain the data, event stack and system
variables in a RAM. An additional patch RAM can be used for implementing customized
codes or algorithms.
Besides I
2
I
C bus and providing more flexibility.
2/4 Doc ID 022155 Rev 1
2
C serial interface, the device supports a SPI interface freeing up the overloaded
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