2015 Microchip Technology Inc.
DS00001622B-page 1
General Description
The CAP1128, which incorporates RightTouch
®
tech-
nology, is a multiple channel Capacitive Touch sensor
with multiple power LED drivers. It contains eight (8)
individual capacitive touch sensor inputs with program-
mable sensitivity for use in touch sensor applications.
Each sensor input automatically recalibrates to com-
pensate for gradual environmental changes.
The CAP1128 also contains two (2) LED drivers that
offer full-on / off, variable rate blinking, dimness con-
trols, and breathing. Each of the LED drivers may be
linked to one of the sensor inputs to be actuated when
a touch is detected. As well, each LED driver may be
individually controlled via a host controller.
The CAP1128 includes Multiple Pattern Touch recogni-
tion that allows the user to select a specific set of but-
tons to be touched simultaneously. If this pattern is
detected, then a status bit is set and an interrupt gen-
erated.
Additionally, the CAP1128 includes circuitry and sup-
port for enhanced sensor proximity detection.
The CAP1128 offers multiple power states operating at
low quiescent currents. In the Standby state of opera-
tion, one or more capacitive touch sensor inputs are
active and all LEDs may be used. If a touch is detected,
it will wake the system using the WAKE/SPI_MOSI pin.
Deep Sleep is the lowest power state available, draw-
ing 5uA (typical) of current. In this state, no sensor
inputs are active. Driving the WAKE/SPI_MOSI pin or
communications will wake the device.
Applications
• Desktop and Notebook PCs
• LCD Monitors
• Consumer Electronics
• Appliances
Features
• Eight (8) Capacitive Touch Sensor Inputs
- Programmable sensitivity
- Automatic recalibration
- Individual thresholds for each button
• Proximity Detection
• Multiple Button Pattern Detection
• Calibrates for Parasitic Capacitance
• Analog Filtering for System Noise Sources
• Press and Hold feature for Volume-like Applica-
tions
• Multiple Communication Interfaces
- SMBus / I
2
C compliant interface
- SPI communications
- Pin selectable communications protocol and
multiple slave addresses (SMBus / I
2
C only)
• Low Power Operation
- 5uA quiescent current in Deep Sleep
- 50uA quiescent current in Standby (1 sensor
input monitored)
- Samples one or more channels in Standby
• Two (2) LED Driver Outputs
- Open Drain or Push-Pull
- Programmable blink, breathe, and dimness
controls
- Can be linked to Capacitive Touch Sensor
inputs
• Dedicated Wake output flags touches in low
power state
• System RESET pin
• Available in 20-pin 4mm x 4mm QFN RoHS com-
pliant package
CAP1128
8 Channel Capacitive Touch Sensor with 2 LED Drivers
CAP1128
DS00001622B-page 2
2015 Microchip Technology Inc.
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2015 Microchip Technology Inc.
DS00001622B-page 3
CAP1128
Table of Contents
1.0 Block Diagram ................................................................................................................................................................................. 4
2.0 Pin Description ................................................................................................................................................................................ 5
3.0 Electrical Specifications .................................................................................................................................................................. 9
4.0 Communications ........................................................................................................................................................................... 12
5.0 General Description ...................................................................................................................................................................... 23
6.0 Register Description ...................................................................................................................................................................... 29
7.0 Package Information ..................................................................................................................................................................... 67
Appendix A: Device Delta ................................................................................................................................................................... 72
Appendix B: Data Sheet Revision History ........................................................................................................................................... 74
The Microchip Web Site ...................................................................................................................................................................... 76
Customer Change Notification Service ............................................................................................................................................... 76
Customer Support ............................................................................................................................................................................... 76
Product Identification System ............................................................................................................................................................. 77
CAP1128
DS00001622B-page 4
2015 Microchip Technology Inc.
1.0
BLOCK DIAGRAM
SMBus /
BC-Link /
SPI Slave
Protocol
SMCLK/ BC_CLK /
SPI_CLK
SMDATA / BC_DATA/ SPI_MSIO /
SPI_MISO
VDD
GND
ALERT# / BC_IRQ#
Capacitive Touch Sensing Algorithm
LED1
CS1
CS2
CS3
CS4
CS5
CS6
LED Driver, Breathe,
and Dimness control
WAKE / SPI_MOSI
CS7
CS8
RESET
ADDR_COMM
SPI_CS#
LED2
2015 Microchip Technology Inc.
DS00001622B-page 5
CAP1128
2.0
PIN DESCRIPTION
FIGURE 2-1:
CAP1128 Pin Diagram (20-Pin QFN)
TABLE 2-1:
PIN DESCRIPTION FOR CAP1128
Pin
Number
Pin Name
Pin Function
Pin Type
Unused
Connection
1
SPI_CS#
Active low chip-select for SPI bus
DI (5V)
Connect to
Ground
2
WAKE / SPI_-
MOSI
WAKE - Active high wake / interrupt output
Standby power state - requires pull-down resistor
DO
Pull-down
Resistor
WAKE - Active high wake input - requires pull-down
resistor
Deep Sleep power state
DI
SPI_MOSI - SPI Master-Out-Slave-In port when used in
normal mode
DI (5V)
Connect to
Ground
1
2
3
4
15
14
13
12
20
19
18
17
6
7
8
9
GND
AL
ERT#
/ BC_
IRQ#
WAKE / SPI_MOSI
SPI_CS#
SMCLK / BC_CLK / SPI_CLK
SMDAT / BC_DATA / SPI_MSIO /
SPI_MISO
CS7
RESET
CS5
CS6
5
10
11
16
VDD
CS1
CS2
CS4
CS8
CS3
N/C
*
LE
D2
LE
D1
ADDR_COMM
CAP1128
20 pin QFN
N/C
*
*
N/C pins must be connected to ground
CAP1128
DS00001622B-page 6
2015 Microchip Technology Inc.
3
SMDATA /
SPI_MSIO /
SPI_MISO
SMDATA - Bi-directional, open-drain SMBus data -
requires pull-up resistor
DIOD (5V)
n/a
SPI_MSIO - SPI Master-Slave-In-Out bidirectional port
when used in bi-directional mode
DIO
SPI_MISO - SPI Master-In-Slave-Out port when used in
normal mode
DO
4
SMCLK / SPI_-
CLK
SMCLK - SMBus clock input - requires pull-up resistor
DI (5V)
n/a
SPI_CLK - SPI clock input
DI (5V)
5
N/C
Not Internally Connected
n/a
Connect to
Ground
6
LED1
Open drain LED 1 driver (default)
OD (5V)
Connect to
Ground
Push-pull LED 1 driver
DO
leave open or
connect to
Ground
7
LED2
Open drain LED 2 driver (default)
OD (5V)
Connect to
Ground
Push-pull LED 2 driver
DO
leave open or
connect to
Ground
8
N/C
Not Internally Connected
n/a
Connect to
Ground
9
RESET
Active high soft reset for system - resets all registers to
default values. If not used, connect to ground.
DI (5V)
Connect to
Ground
10
ALERT#
ALERT# - Active low alert / interrupt output for SMBus
alert or SPI interrupt
OD (5V)
Connect to
Ground
ALERT# - Active high push-pull alert / interrupt output
for SMBus alert or SPI interrupt
DO leave
open
11
ADDR_COMM
Address / communications select pin - pull-down resis-
tor determines address / communications mechanism
AI
n/a
12
CS8
Capacitive Touch Sensor Input 8
AIO
Connect to
Ground
13
CS7
Capacitive Touch Sensor Input 7
AIO
Connect to
Ground
14
CS6
Capacitive Touch Sensor Input 6
AIO
Connect to
Ground
15
CS5
Capacitive Touch Sensor Input 5
AIO
Connect to
Ground
16
CS4
Capacitive Touch Sensor Input 4
AIO
Connect to
Ground
TABLE 2-1:
PIN DESCRIPTION FOR CAP1128 (CONTINUED)
Pin
Number
Pin Name
Pin Function
Pin Type
Unused
Connection
2015 Microchip Technology Inc.
DS00001622B-page 7
CAP1128
APPLICATION NOTE: When the ALERT# pinis configured as an active low output, it will be open drain. When it is
configured as an active high output, it will be push-pull.
APPLICATION NOTE: For the 5V tolerant pins that have a pull-up resistor, the pull-up voltage must not exceed 3.6V
when the CAP1128 is unpowered.
APPLICATION NOTE: The SPI_CS# pin should be grounded when SMBus, or I
2
C,communications are used.
The pin types are described in
Table 2-2
. All pins labeled with (5V) are 5V tolerant.
17
CS3
Capacitive Touch Sensor Input 3
AIO
Connect to
Ground
18
CS2
Capacitive Touch Sensor Input 2
AIO
Connect to
Ground
19
CS1
Capacitive Touch Sensor Input 1
AIO
Connect to
Ground
20
VDD
Positive Power supply
Power
n/a
Bottom Pad
GND
Ground
Power
n/a
TABLE 2-2:
PIN TYPES
Pin Type
Description
Power
This pin is used to supply power or ground to the device.
DI
Digital Input - This pin is used as a digital input. This pin is 5V tolerant.
AIO
Analog Input / Output -This pin is used as an I/O for analog signals.
DIOD
Digital Input / Open Drain Output - This pin is used as a digital I/O. When it is used as an out-
put, it is open drain and requires a pull-up resistor. This pin is 5V tolerant.
OD
Open Drain Digital Output - This pin is used as a digital output. It is open drain and requires a
pull-up resistor. This pin is 5V tolerant.
DO
Push-pull Digital Output - This pin is used as a digital output and can sink and source current.
DIO
Push-pull Digital Input / Output - This pin is used as an I/O for digital signals.
TABLE 2-1:
PIN DESCRIPTION FOR CAP1128 (CONTINUED)
Pin
Number
Pin Name
Pin Function
Pin Type
Unused
Connection
CAP1128
DS00001622B-page 8
2015 Microchip Technology Inc.
3.0
ELECTRICAL SPECIFICATIONS
Note 3-1
Stresses above those listed could cause permanent damage to the device. This is a stress rating
only and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied.
Note 3-2
For the 5V tolerant pins that have a pull-up resistor, the voltage difference between V
5VT_PIN
and V
DD
must never exceed 3.6V.
Note 3-3
The Package Power Dissipation specification assumes a recommended thermal via design consisting
of a 3x3 matrix of 0.3mm (12mil) vias at 1.0mm pitch connected to the ground plane with a 2.5 x
2.5mm thermal landing.
Note 3-4
Junction to Ambient (
θ
JA
) is dependent on the design of the thermal vias. Without thermal vias and
a thermal landing, the
θ
JA
is approximately 60°C/W including localized PCB temperature increase.
TABLE 3-1:
ABSOLUTE MAXIMUM RATINGS
Voltage on 5V tolerant pins (V
5VT_PIN
)
-0.3 to 5.5
V
Voltage on 5V tolerant pins (|V
5VT_PIN
- V
DD
|)
Note 3-2
0 to 3.6
V
Voltage on VDD pin
-0.3 to 4
V
Voltage on any other pin to GND
-0.3 to VDD + 0.3
V
Package Power Dissipation up to T
A
= 85°C for 20 pin QFN
(see
Note 3-3
)
0.9
W
Junction to Ambient (
θ
JA
) (see
Note 3-4
)
58
°C/W
Operating Ambient Temperature Range
-40 to 125
°C
Storage Temperature Range
-55 to 150
°C
ESD Rating, All Pins, HBM
8000
V
2015 Microchip Technology Inc.
DS00001622B-page 9
CAP1128
TABLE 3-2:
ELECTRICAL SPECIFICATIONS
V
DD
= 3V to 3.6V, T
A
= 0°C to 85°C, all typical values at T
A
= 27°C unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
Conditions
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Supply Current
I
STBY
120
170
uA
Standby state active
1 sensor input monitored
No LEDs active
Default conditions (8 avg, 70ms
cycle time)
I
STBY
50
uA
Standby state active
1 sensor input monitored
No LEDs active
1 avg, 140ms cycle time,
I
DSLEEP
5
15
uA
Deep Sleep state active
LEDs at 100% or 0% Duty Cycle
No communications
T
A
< 40°C
3.135 < V
DD
< 3.465V
I
DD
500
600
uA
Capacitive Sensing Active
No LEDs active
Capacitive Touch Sensor Inputs
Maximum Base
Capacitance
C
BASE
50
pF
Pad untouched
Minimum Detectable
Capacitive Shift
Δ
C
TOUCH
20
fF
Pad touched - default conditions (1
avg, 35ms cycle time, 1x sensitiv-
ity)
Recommended Cap
Shift
Δ
C
TOUCH
0.1
2
pF
Pad touched - Not tested
Power Supply Rejec-
tion
PSR
±3
±10
counts /
V
Untouched Current Counts
Base Capacitance 5pF - 50pF
Maximum sensitivity
Negative Delta Counts disabled
All other parameters default
Timing
RESET Pin Delay
t
RST_DLY
10
ms
Time to communica-
tions ready
t
COMM_DLY
15
ms
Time to first conver-
sion ready
t
CONV_DLY
170
200
ms
LED Drivers
Duty Cycle
DUTY
LED
0
100
%
Programmable
Drive Frequency
f
LED
2
kHz
Sinking Current
I
SINK
24
mA
V
OL
= 0.4
Sourcing Current
I
SOURCE
24
mA
V
OH
= V
DD
- 0.4
Leakage Current
I
LEAK
±5
uA
powered or unpowered
TA < 85°C
pull-up voltage < 3.6V if unpowered
I/O Pins
Output Low Voltage
V
OL
0.4
V
I
SINK_IO
= 8mA
Output High Voltage
V
OH
V
DD
- 0.4
V
I
SOURCE_IO
= 8mA
CAP1128
DS00001622B-page 10
2015 Microchip Technology Inc.
Note 3-5
The ALERT pin will not glitch high or low at power up if connected to VDD or another voltage.
Note 3-6
The SMCLK and SMDATA pins will not glitch low at power up if connected to VDD or another voltage.
Input High Voltage
V
IH
2.0
V
Input Low Voltage
V
IL
0.8
V
Leakage Current
I
LEAK
±5
uA
powered or unpowered
T
A
< 85°C
pull-up voltage < 3.6V if unpowered
RESET Pin Release
to conversion ready
t
RESET
170
200
ms
SMBus Timing
Input Capacitance
C
IN
5
pF
Clock Frequency
f
SMB
10
400
kHz
Spike Suppression
t
SP
50
ns
Bus Free Time Stop to
Start
t
BUF
1.3
us
Start Setup Time
t
SU:STA
0.6
us
Start Hold Time
t
HD:STA
0.6
us
Stop Setup Time
t
SU:STO
0.6
us
Data Hold Time
t
HD:DAT
0
us
When transmitting to the master
Data Hold Time
t
HD:DAT
0.3
us
When receiving from the master
Data Setup Time
t
SU:DAT
0.6
us
Clock Low Period
t
LOW
1.3
us
Clock High Period
t
HIGH
0.6
us
Clock / Data Fall Time
t
FALL
300
ns
Min = 20+0.1C
LOAD
ns
Clock / Data Rise
Time
t
RISE
300
ns
Min = 20+0.1C
LOAD
ns
Capacitive Load
C
LOAD
400
pF
per bus line
SPI Timing
Clock Period
t
P
250
ns
Clock Low Period
t
LOW
0.4 x t
P
0.6 x t
P
ns
Clock High Period
t
HIGH
0.4 x t
P
0.6 x t
P
ns
Clock Rise / Fall time
t
RISE
/ t
FALL
0.1 x t
P
ns
Data Output Delay
t
D:CLK
10
ns
Data Setup Time
t
SU:DAT
20
ns
Data Hold Time
t
HD:DAT
20
ns
SPI_CS# to SPI_CLK
setup time
t
SU:CS
0
ns
Wake Time
t
WAKE
10
20
us
SPI_CS# asserted to CLK assert
TABLE 3-2:
ELECTRICAL SPECIFICATIONS (CONTINUED)
V
DD
= 3V to 3.6V, T
A
= 0°C to 85°C, all typical values at T
A
= 27°C unless otherwise noted.
Characteristic
Symbol
Min
Typ
Max
Unit
Conditions