Datasheet
Resistive Type Touch Screen Controller ICs
BU21024FV-M
General Description
Unlike most resistive touch screen controllers, the
BU21024 4-wire resistive touch screen controller
enables dual-touch detection and gesture recognition.
These intelligent controllers expose a set of registers to
a HOST processor and are configured through software.
The controllers can detect single point coordinates, dual
coordinates, pinch, spread, rotate left and rotate right
gestures, enabling pan and zoom operations in
applications that previously had to rely exclusively on
capacitive touch technology. Resistive touch does not
require custom screen development which reduces
development cost, and results in faster time to market
across a family of products.
Packages
SSOP-B28
W(Typ) x D(Typ) x H(Max)
10.0mm x 7.60mm x 1.35mm
Features
Enables single touch, dual touch & gesture
recognition using standard 4-wire resistive touch
screens
Adjustable touch detection threshold allows fine
tuning of pressure sensitivity for an application
Enables measurement of single point touch
pressure
SPI- and I
2
C interface for interfacing to HOST
processor
Programmable interrupt polarity
10-bit ADC provides sufficient resolution for finger
or stylus inputs
Firmware for internal CPU may be downloaded
from HOST processor or from an EEPROM
Includes filtering options to eliminate false
coordinates
Built in support for intelligent calibration
Easy to swap X & Y coordinates or adapt to
different touch screen connections
Single 3V power supply
Available in small packages and temperature
ranges
Ideally suited for large volume automotive,
consumer, and industrial applications
AEC-Q100 Qualified
Applications
Products with an LCD can benefit from pan and
zoom operations.
Smart phones, Digital Cameras, Video Cameras,
GPS Receivers, Printers,
Copiers, automotive navigation screens, touch
kiosks
Tablet PCs , Notebook computers, LCD displays
(with USB interface)
Car navigation system, Car Audio
Key Specifications and Lineup
Parameter
Screen
Maximum Detection Point
Integrated Filter Process
Gesture Detection
Supplied Voltage Range(V)
Temperature Range(°C)
Host I/F
Pakage
○Product
structure：Silicon monolithic integrated circuit
.
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ22111・14・001
BU21024FV-M
4-wire resistive
touch screens
2
Yes
Yes
2.7 to 3.6
-40 to +85
4-wire SPI
2-wire serial
SSOP-B28
○This
product has no designed protection against radioactive rays
1/16
TSZ02201-0L5L0F300190-1-2
31.Mar.2014 Rev.003
BU21023GUL BU21023MUV
BU21024FV-M
BU21024FV-M
Datasheet
Pin Configuration and Pin Description
CLK_EXT
DVDD_EXT
15
TOP VIEW
SCL_SCK
SDA_SI
SEL_CSB
IFSEL
RSTB
T3
T2
T1
VDD
16
VSS
17
INT
25
SO
24
28
27
26
23
22
21
20
19
18
10
11
12
13
PVDD
ECL
XPM
YPM
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
1.
2.
3.
Pin Name
EDA
ECL
YNM
XNM
YPM
XPM
YN
XN
YP
XP
T4
PVDD
AVDD
DVDD
DVDD_EXT
VDD
VSS
RSTB
CLK_EXT
T1
T2
T3
IFSEL
SO
INT
SEL_CSB
SDA_SI
SCL_SCK
I/O
I/O
O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
I/O
I
-
-
I
I
I
I
I
I
O
O
I
I/O
I
Function
EEPROM SDA
EEPROM SCL
Screen interface (Test input)
Screen interface (Test input)
Screen interface (Test input)
Screen interface (Test input)
Screen interface
Screen interface
Screen interface
Screen interface
Test pin
Regulator output (for supply screen voltage)
Regulator output (for supply analog block)
Regulator output (for supply digital block) or supply digital voltage
Digital voltage enable (H=Hi-Z , L=DVDD enable)
Supply voltage
Ground
H/W reset
Supply external clock for debug
Test pin
Test pin
Test pin
Interface select pin (L=SPI, H=2-wire serial)
SPI
Serial data output
2-wire
-
Interrupt output
SPI
Chip select
2-wire Slave address select
SPI
Serial data input
2-wire Serial data in-out
SPI
Serial clock input
2-wire Serial clock input
DVDD
AVDD
XNM
YNM
EDA
XN
YN
XP
YP
T4
14
1
2
3
4
5
6
7
8
9
TOP VIEW
Figure
C
C
E
E
E
E
E
E
E
E
E
-
-
-
E
-
-
E
A
A
A
A
A
F
C
C
C
C
4.
5.
6.
7.
8.
9.
10.
Please use
1.0µF
capacitors between AVDD and DVDD to GND, and leave PVDD terminal open.
If DVDD_EXT=”H “, the DVDD pin can be connected to an external 1.8V power source.
Please pull up the ECL, EDA, and INT pins using 10k ohm resistors as shown in the application diagram at the end of this document.
ECL and EDA pins may be directly connected to GND if an external EEPROM is not being used. Please connect a
0.1µF
capacitor between
T4 and GND. T1, T2 & T3 pins should be connected to GND.
When using the 2 wire serial interface, please pull up the SCL_SCK, SDA_SI pins via 10k ohms and leave SO unconnected.
Please note that the values of resistors and capacitors mentioned here are only recommended values.
RSTB should be held low until supply voltage VDD has ramped up and has reached a stable level.
The polarity of INT pin is programmable via register 0x30
Connect CLK_EXT to GND for normal use
Please leave the XPM, XNM, YPM, YNM terminals open if they are not being used.
INT terminal is used as input pin in test mode.
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
2/16
TSZ02201-0L5L0F300190-1-2
31.Mar.2014 Rev.003
BU21023GUL BU21023MUV
BU21024FV-M
I/O equivalence circuit
BU21024FV-M
Datasheet
PAD
PAD
Figure A
Figure B
PAD
PAD
Figure C
Figure D
PAD
CIN
PAD
Figure E
Figure F
Figure I/O Equivalent Circuit
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
3/16
TSZ02201-0L5L0F300190-1-2
31.Mar.2014 Rev.003
BU21023GUL BU21023MUV
BU21024FV-M
BU21024FV-M
Datasheet
Block Diagram and Description of each Block
Screen I/F
ADC
OSC
Regulator
Clock Generator
CPU Core
Work Memory
Program Memory
EEPROM I/F
Host I/F
4-wire or 8-wire resistive touch screen interface
10-bit A/D converter
Internal 20MHz oscillator block with optional external clock input
Internal regulator provides 1.8V DVDD supply. DVDD can also be supplied from an
external source if DVDD_EXT pin is tied high.
System clock and timing generation (10MHz CPU clock)
For dual touch processing, programmability and HOST interface
Data memory for CPU
Program memory for CPU. Code can be downloaded by HOST processor or from an
external EEPROM
To connect to external EEPROM when downloading program memory from EEPROM.
Use of external EEPROM is optional.
4-wire SPI or 2-wire I
2
C interface provides access to registers
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
4/16
TSZ02201-0L5L0F300190-1-2
31.Mar.2014 Rev.003
BU21023GUL BU21023MUV
BU21024FV-M
Absolute Maximum Ratings
Parameter
Power Supply Voltage
Input Voltage
Power Dissipation
Storage Temperature Range
BU21024FV-M
Datasheet
Symbol
V
DD
V
IN
Pd
Tstg
Rating
-0.3 to +4.5
-0.3 to V
DD
+0.3
0.85
(Note 1)
Unit
V
V
W
°C
Conditions
-50 to +125
(Note 1) Derate by 8.50mW /°C centigrade when ambient temperature exceeds 25°C. Measured using PCB(1 layer) measuring 70x70x1.6mm
3
.
Caution:
Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over
the absolute maximum ratings.
Recommended Operating Conditions
Parameter
Power Supply Voltage
Digital Core Power Supply
Operating Temperature Range
Symbol
V
DD
DV
DD
Topr
Rating
Min
2.70
1.62
-40
Typ
3.00
1.80
+25
Max
3.60
1.98
+85
Unit
V
V
°C
DVDD_EXT=H
Conditions
Note: The BU21024 controllers can be operated with a single 3V V
DD
supply.
It is also possible to supply 1.8V DV
DD
from an external source if the DVDD_EXT pin is connected to logic high.
Electrical Characteristics
(Ta=25°C, V
DD
=3.00V)
Parameter
Low-Level Input Voltage
High-Level Input Voltage
Low-Level Output Voltage
High-Level Output Voltage
Standby Current
Sleep Current1
Sleep Current2
Operating Current
Oscillation Frequency
Resolution
Differential Non-Linearity Error
Integral Non-Linearity Error
Symbol
V
IL
V
IH
V
OL
V
OH
I
ST
I
CC1
I
CC2
I
DD
Freq
Ad
DNL
INL
-3.0
-3.0
Limit
Min
-0.5
0.8xV
DD
-
V
DD
-0.4
-
-
-
-
18
Typ
-
-
-
-
-
60
10
4
20
1024x1024
-
-
+3.0
+3.0
Max
0.2xV
DD
V
DD
+0.5
0.4
-
1
100
20
6
22
Unit
V
V
V
V
µA
µA
µA
mA
MHz
Bit
LSB
LSB
RSTB=L
DVDD_EXT =L
DVDD_EXT =H
No Load
Conditions
www.rohm.com
© 2014 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
5/16
TSZ02201-0L5L0F300190-1-2
31.Mar.2014 Rev.003
京公网安备 11010802033920号
EEWORLD
