AKM AK4180

[ASAHI KASEI]
[AK4180]
AK4180
Touch Screen Controller
Features:
General Description:
„ Sampling Frequency: 125kHz(max)
„ Pen Pressure Measurement
„ On-Chip Thermo Sensor
„ Two Auxiliary Analog Inputs
„ Direct Battery Measurement
„ 4-wire I/F
„ On-Chip Voltage Reference(2.5V)
„ 12 bit SAR type A/D Converter
„ Low Power Consumption (250µ
µA)
„ Low Voltage Operation (2.7V - 3.6V)
„ Package
16pin TSSOP
The AK4180 is a 4-wire touch screen controller that incorporates
a 12-bit 125kHz sampling SAR A/D converter. The AK4180 can
detect the pressed screen location by performing two A/D
conversions. In addition to location, the AK4180 also measures
touchscreen pressure.
On-chip VREF can be utilized for two analog auxiliary inputs
and battery monitoring, with the ability to measure voltages from
0V to 5V.
The AK4180 also has an on-chip temperature sensor.
DCLK
XP
CSN
YP
DIN
Control
Logic
XN
YN
DOUT
BUSY
IN1
Internal
VREF(2.5V)
IN2
VREF
VBAT
R1
VREF+
AIN+
R2
PENIRQN
AIN-
VREF-
12bit
ADC
(SAR type)
PEN
INTERRUPT
Temp.
Sensor
VCC
GND
Block Diagram
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
„ Ordering Guide
AK4180VT
-20°C ∼ +70°C
16pinTSSOP
„ Pin Layout
<MS0195-E-01>
VCC
1
16
DCLK
XP
2
15
CSN
YP
3
14
DIN
XN
4
13
BUSY
YN
5
12
DOUT
GND
6
11
PENIRQN
VBAT
7
10
IN2
IN1
8
9
2
VREF
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[ASAHI KASEI]
[AK4180]
Pin/Function
No.
1
2
Signal Name
VCC
XP
I/O
I/O
3
YP
I/O
4
XN
I/O
5
YN
I/O
6
7
8
9
GND
VBAT
IN1
VREF
I
I
I/O
10
11
IN2
PENIRQN
I
O
12
DOUT
O
13
BUSY
O
14
DIN
I
15
CSN
I
16
DCLK
I
<MS0195-E-01>
Description
Power Supply
Touch Screen X+ plate Voltage supply
„ X axis Measurement: Supplies the voltage
„ Y axis Measurement: This pin is used as the input for the A/D converter
„ Pen Pressure Measurement: This pin is the input to the A/D converter at Z1 measurement.
„ Temperature/VBAT/IN1/IN2 Measurement: OPEN state
„ Powerdown State: is pulled up by an internal resistor (typ.20k ohm).
Touch Screen Y+ plate Voltage supply
„ Y axis Measurement: Supplies the voltage
„ X axis Measurement: This pin is used as the input for the A/D converter
„ Pen Pressure Measurement: Supplies the voltage.
„ Temperature/VBAT/IN1/IN2 Measurement: OPEN state
„ Powerdown State: OPEN state.
Touch Screen X- plate Voltage supply
„ X axis Measurement: Supplies the voltage
„ Y axis Measurement: OPEN state
„ Pen Pressure Measurement: Supplies the voltage.
„ Temperature/VBAT/IN1/IN2 Measurement: OPEN state
„ Powerdown State: OPEN state
Touch Screen Y- plate Voltage supply
„ Y axis Measurement: Supplies the voltage
„ X axis Measurement: OPEN state
„ Pen Pressure Measurement: This pin is the input to the A/D converter at Z2 measurement.
„ Temperature/VBAT/IN1/IN2 Measurement: OPEN state
„ Powerdown State: connected to GND.
Ground
Analog Input for Battery Monitor
Auxiliary 1 Analog Input
Voltage Reference Input/Output
Outputs 2.5V
Auxiliary 2 Analog Input
Pen Interrupt Output
This pin should be pulled up via a 100k-ohm resistor.
Serial A/D Data Output
Outputs A/D data serially at the falling edge of DCLK. MSB is output at the falling edge of
BUSY signal.
DOUT is “L” at CSN=”L” except that A/D data is output.
This pin is Hi-Z state at CSN=”H”
BUSY Output
This pin goes to low at CSN = “L”. BUSY signal is “H” only for the period between the falling
edge of 8DCLK and the falling edge of 9DCLK.
This pin is Hi-Z state at CSN=”H”
Serial Data Input
Inputs 8-bit control command data serially when CSN=”L”
AK4180 latches at the rising edge of DCLK. Please keep “L” except when issuing commands.
Chip Select Input
Enables writing to the registers when CSN=”L”. CSN=”H” and DIN=”H” force the internal
registers to initial value, 00h. (Full Powerdown)
External Clock Input
3
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[ASAHI KASEI]
[AK4180]
Absolute Maximum Ratings
GND=0V
Parameter
Power Supplies
Input Current (any pins except for supplies)
Input Voltage
Touch Panel Drive Current
Ambient Temperature (power supplied)
Storage Temperature
All voltages with respect to ground.
Symbol
Min
max
Units
VCC
IIN
VIN
IOUTDRV
Ta
Tstg
-0.3
-0.3
6.0
±10
6.0(VCC+0.3)
50
70
150
V
mA
V
mA
°C
°C
-20
-65
WARNING: Operation at or beyond these limits may result in permanent damage to the device.
Normal operation is not guaranteed at these extremes.
Recommended Operating Conditions
GND=0V
Parameter
Power Supplies
Symbol
min
typ
max
Units
VCC
2.7
3.3
3.6
V
All voltages with respect to ground.
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[AK4180]
Analog Characteristics
Ta=-20°C to 70°C,VCC=2.7V, Vref=2.5V, fs=125kHz, MCLK=16*fs
Parameter
min
typ
Max
Units
ADC for Touch Screen
Resolution
12
Bits
No Missing Code
10
12
Bits
Integral Linearity Error
LSB
±5
Analog Input Voltage Range
0
Vref
V
Offset Error
0
20
LSB
Gain Error
-12
0
LSB
Touch Panel Driver
5
Ω
X+, Y+, RL=300Ω
5
X-, Y-, RL=300Ω
Ω
PSRR
70
dB
Reference Output
2.4
2.5
2.55
V
Internal Reference [email protected]=3.0V, 20°C
Load Capacitance
0.1
uF
Reference Input
Input Voltage Range
VCC
V
Input Impedance
98
196
kΩ
Battery Monitor
Input Voltage Range
5.0
V
Input Impedance (Battery Measure Mode)
10
kΩ
Accuracy *)
%
±3
Temperature Measurement
Temperature Range
-20
70
V
Resolution **)
1.6
°C
Accuracy ***)
±3
°C
Power Supply Current
Normal Mode (Internal VREF OFF)
250
500
µA
Normal Mode (Internal VREF ON)
520
800
µA
Full Power Down
0
10
µA
*) Accuracy is the difference between the output code when 5 volts is input to the VBAT pin and the “ideal” code at 1.25 volts.
**) “ideal” value derived from theory
**) Accuracy is defined as the difference between the voltage measured by two current sources, and the ideal voltage derived from
theory at specific temperatures.
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[ASAHI KASEI]
[AK4180]
DC Characteristics (Logic I/O)
Ta=-20 to 70°C,VCC=2.7V to 3.6V
Parameter
“H” level input voltage
Symbol
VIH
min
Typ
-
max
Units
0.8xVCC
“L” level input voltage
V
VIL
Input Leakage Current
“H” level output voltage (@ Iout = -250uA)
“L” level output voltage (@ Iout= 250uA)
Tri-state Leakage Current
All pins except for XP, YP, XN, YN pins
XP, YP, XN, YN pins
PENIRQN “L” level output voltage (100KΩ Pull-Up)
-
IILK
VOH
VOL
IOLK
0.2xVCC
10
-10
VCC-0.4
-
-
-10
-50
VOLP
0.4
V
uA
V
V
10
50
0.8
uA
uA
V
max
Units
125
kHz
2000
60
kHz
%
us
1/fDCLK
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Switching Characteristics
Ta=-20°C to 70°C, VCC=2.7V to 3.6V
Parameter
Touch Panel (A/D Converter)
Throughput Rate
DCLK
frequency
duty
Tracking Time (Rin=600Ω)
Conversion Time
CSN “↓” to First DCLK “↑”
CSN “↓” to BUSY Tri-State Disabled
CSN “↓” to DOUT Tri-State Disabled
DCLK High Pulse Width
DCLK Low Pulse Width
DCLK “↓” to BUSY “↑”
Data Setup Time
Data Valid to DCLK Hold Time
Data Access Time after DCLK “↓”
CSN “↑” to DCLK Ignored
CSN “↑” to BUSY High-Z state
CSN “↑” to DOUT High-Z state
Symbol
min
Typ
10
40
1.5
fDCLK
duty
tTRK
tCONV
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
t11
t12
50
12
100
200
200
200
200
200
100
10
200
0
200
200
CSN
t5
t1
t6
t4
t6
t9
t10
DCLK
t8
t7
DIN
P0
t2
t11
BUSY
t12
t3
DOUT
D11
D10
D0
AK4180 Timing Diagram
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[ASAHI KASEI]
[AK4180]
„ A/D Converter for Touch Screen
The AK4180 incorporates a12-bit successive approximation resistor A/D converter for position measurement, temperature, and
battery voltage. The architecture is based on capacitive redistribution algorithm, and an internal capacitor array functions as the
sample/hold circuit.
The A/D converter output is a straight binary format as shown below:
Input Voltage
Output Code
FFF
(∆VREF-1.5LSB)~ ∆VREF
FFE
(∆VREF-2.5LSB) ~ (∆VREF-1.5LSB)
----------------0.5LSB ~ 1.5LSB
001
0 ~ 0.5LSB
000
∆VREF: (VREF+) – (VREF-)
Table 1 Output Code
The A/D converter’s full scale measurements depend on the input mode.
„ Analog Inputs
Analog input is selected via the A2, A1, A0 and SER/ DFR bits in the control register. If the analog inputs are the X or Y-axis,
use SER/ DFR = “0”, which means differential mode, the full scale (∆VREF) is the differential voltage between the non-inverting
terminal and the inverting terminal of the measured axis (e.g. (XP) – (XN)). Analog non-inverting input to A/D converter is the
non-inverting terminal of the non-measured axis while the inverting input is the inverting terminal of the measured axis. If the
SER/ DFR bit is set to “1”, which means single-ended mode, the full scale of A/D converter (∆VREF) is the internal reference
voltage, or external reference voltage. Note that SER/ DFR bit should be set to ”0” if IN2 is selected as analog input;
nevertheless, IN2 is actually measured by single-ended mode.
Tracking time is the period from the falling edge of 5th DCLK to the falling edge of 8th DCLK after the detection of START bit.
the required settling time to charge the internal capacitors depends on the source impedance. If the source impedance, Rin, is 600
ohm, the settling time needs at least 1.5 µs (3 [email protected]). The maximum throughput of A/D converter is 125kHz.
If the source impedance of analog input is larger than 600 ohm, longer tracking time is required.
„ The Position Detection of Touch Screen
The selected touch screen position is detected by the voltage measurement of one axis when the voltage is supplied between the
two terminals of the other axis. At least two A/D conversions are needed to get the two-dimensional (X/Y axis) position.
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
ON
ON
XP
VREF+
XP
AIN+
VREF+
YP
ADC
AIN-
VREF-
AIN+
YP
ADC
VREF-
AIN-
XN
XN
ON
YN
YN
ON
a)
X-Position Measurement
b)
Differential Mode
Y-Position Measurement
Differential Mode
Figure 1 Axis Measurement
The differential mode position detection is typically more accurate than the single-ended mode. As the full scale of single-ended
mode is fixed to the internal (or external) reference voltage, input voltage may exceed the full-scale reference voltage. This
problem does not occur in differential mode. In addition to this, the differential mode is less influenced by power supply voltage
variation due to the ratio-metric measurement.
However, note that the touch screen driver switch is still ON and the current flows even for the A/D conversion time. On the other
hand, the touch screen driver switch is ON only for the tracking time, 3tDCLK. From the power consumption, single-ended mode
has more advantage.
„ The Pen Pressure Measurement
The touch screen pen pressure can be derived from the measurement of the contact resistor between two plates. The contact
resistance depends on the size of the depressed area and the pressure. The area of the spot is proportional to the contact resistance.
This resistance (Rtouch) can be calculated using two different methods.
The first method uses the total resistance of the X-plate sheet. The resistance, Rtouch, is calculated from the results of three
conversions, X-position, Z1-Position, and Z2-Position, using the following formula:
Rtouch = (Rxplate) * (Xposition/4096) * [ (Z2/Z1) – 1]
The second method uses the resistances of both the X-plate and Y-plate. The resistance, Rtouch, is calculated from the results of
three conversions, X-position, Y-Position, and Z1-Position, using the following formula:
Rtouch = (Rxplate*Xposition/4096)*[(4096/Z1) – 1] – Ryplate*[1 – (Yposition/4096)]
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
ON
ON
YP
YP
XP
VREF+
AIN+
VREF-
AIN-
touch
XP
ADC
VREF+
AIN+
VREF-
AIN-
touch
ADC
XN
XN
ON
ON
YN
b)
YN
Z1-Position Measurement
a)
Differential Mode
Z2-Position Measurement
Differential Mode
Figure 2 Pen Pressure Measurement
„ Voltage Reference
The AK4180 has an internal 2.5V voltage reference. This reference can be turned ON when PD1 = “1”, and OFF when PD1 = “0”.
This reference is used in the single-ended mode for the battery monitoring, temperature measurement, or for auxiliary input. A
0.1µF or larger capacitor should be connected for stable operation of the VREF circuit. Setting time depends on this external
capacitance, but 400µs or longer time is required if the external capacitance is 0.1µF.
If an external voltage reference is used, PD1 bit should be set to “0”.
„ Battery Measurement
The AK4180 can measure the battery voltage that is up to 5V directly while the AK4180 operates at 2.7V or 3.3V, etc. The input
voltage is internally divided down by 4. Minimum 5µs is required as tracking time. If the source impedance is large, more
tracking time is required.
Internal
VREF
PD1
VBAT
AIN+
R0
VREF+
ADC
R1=7.5K
AIN-
VREF-
R2=2.5K
Enable
Figure 3 Battery Monitoring
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[ASAHI KASEI]
[AK4180]
„ Temperature Measurement
Equation <1> describes the forward characteristics of the diode.
iD=I0exp(vD/VT) ( VT = kT/q)
<1>
I0: reverse saturation current
q : 1.602189×10-19 (electron charge)
k : 1.38054×10-23 (Boltzmann’s constant)
vD: voltage across diode
T: absolute temperature K
The diode characteristics is approximately showed As a diode junction voltage is theoretically proportional to the temperature, the
ambient temperature can be predicted by knowing this voltage.
Temp.
Sensor
I
TEMP0
82I
TEMP0
Figure 4 Temperature Measurement
As the AK4180 has two different fixed current circuits and a diode, the temperature can be measured by using two different
methods.
The first method needs two conversions, but can derive the temperature directly without knowing the voltage at a specific
temperature.
From equation <1>
(iD2 / iD1) = exp{(v(NI) - v(I))/VT} N = (iD2 / iD1) = 82 (ratio of the current)
T°C = (∆Vbe * q)/(k * ln N) – 273
∆Vbe = V(NI) – V(I)
T°C = 2.63×103 × ∆Vbe – 273
The second method needs only one conversion as the following equation, but requires knowing the junction voltage at the specific
temperature.
T = (k/q)* vD/ln(iD/I0)
<MS0195-E-01>
<2>
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[ASAHI KASEI]
[AK4180]
„ Control Command
The control command, 8 bits, provided to the AK4180 via DIN is shown in the following table. This command includes start bit,
analog input, resolution, measurement configuration, and power-down mode. The AK4180 latches the serial command at the
rising edge of DCLK.
D7
D6
D5
D4
D3
S
A2
A1
A0
MODE
BIT
7
6-4
Name
S
A2-A0
3
2
SER/ DFR
3
PD1-PD0
MODE
A1
A0
D1
D0
PD1
PD0
Function
Start Bit. This bit must be “H” because the AK4180 initiates the command recognition
Channel Selection Bits. Analog inputs to the A/D converter and the activated driver switches are
selected. Please see the following table for the detail.
Resolution of A/D converter. ”L”: 12 bit output “H”: 8 bit output
Measurement Mode (Single-Ended/Differential)
Power-down Mode (reference to “„
„ Power-down Control”)
Control Command
A2
D2
SER/ DFR
Status of Driver Switch
SER/
XP
XN
YP
YN
AIN+
AIN-
Reference Voltage
(∆VREF)
VREF+
VREF-
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
OFF
OFF
OFF
ON
OFF
ON
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
OFF
TEMP0
XP
VBAT
XP(Z1)
YN(Z2)
YP
IN1
TEMP1
GND
GND
GND
GND
GND
GND
GND
GND
VREF
VREF
VREF
VREF
VREF
VREF
VREF
VREF
GND
GND
GND
GND
GND
GND
GND
GND
OFF
OFF
ON
ON
XP
YN
YP
YN
OFF
OFF
ON
OFF
ON
ON
ON
OFF
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
XP(Z1)
YN(Z2)
YP
IN2
XN
XN
XN
GND
YP
YP
XP
VREF
XN
XN
XN
GND
ADC input (∆AIN)
Note
DFR
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
TEMP0
Y-axis
Battery Monitor
Z1 (Pen Pressure)
Z2 (Pen Pressure)
X-axis
IN1
TEMP1
NA
Y-axis
NA
Z1 (Pen Pressure)
Z2 (Pen Pressure)
IN1
TEMP1
NA
*) Note that IN2 auxiliary input is measured by single-ended mode although SER/ DFR bit is ”0”.
Table 2 Control Command List
<MS0195-E-01>
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[AK4180]
„ Power-down Control
Power-down is controlled by two bits, PD0 bit and PD1 bit. The power-down state of internal voltage reference is controlled by
PD1 bit, and is updated at the rising edge of 7th DCLK with CSN=”L”.
The power-down state of A/D converter, and touch screen driver switches is controlled by PD0 bit, and is updated at the rising
edge of 8th DCLK with CSN=”L”.
If PD0 bit is set to “1”, the state of the driver switches is maintained until the 5th DCLK↑ of the next conversion if CSN is “L”. If
CSN is “H”, all driver switches except for YN switch switches are turned off and are open states. Only YN driver switch is turned
ON and YN pin is forced to the ground in this case.
PD1
0
PD0
0
PENIRQN
Enabled
0
1
Enabled
1
0
Enabled
1
1
Disabled
Function
Auto Power-down Mode.
A/D converter is automatically powered up at the initiation of the conversion, and goes to powerdown state automatically at the end of the conversion. And the AK4180 is always powered down at
this mode if CSN=”H”. All touch screen driver switches except for YN switch are turned off and
relative pins are open state. Only YN driver switch is turned ON and YN pin is forced to the ground
in this case. PEN interrupt function is enabled except for the tracking time and conversion time even
CSN=”L”. Please see “„ PEN Interrupt” for the detail. The internal voltage reference is always
power-down state.
ADC ON Mode
A/D converter is always powered up while CSN = “L”. The internal voltage reference is always
power-down state. if X-axis or Y axis is selected as analog input, touch screen driver switches are
always turned ON and the current flows through the touch plate if CSN=”L”. This is effective if
more settling time for is required to suppress the electrical bouncing of touch plate.
VREF ON Mode
The internal voltage reference is always powered up regardless of CSN state. ADC is auto powerdown mode. PEN interrupt function is enabled at all the period except for the period from the
5DCLK↓ to 20DCLK↓ regardless of CSN state.
ADC and VREF ON Mode
A/D converter and the internal voltage reference is power-up state
PEN interrupt function is disabled and PENIRQN is forced to “H” state if CSN=”H”. The behavior
of PENIRQN is the same as “ADC ON Mode”
Table 3 Power-down Control
„ Serial Interface
The AK4180 is controlled via 4-wire serial interface, CSN, DCLK, DIN, DOUT.
Please see “„ Switching Characteristics” for the detail.
CSN
1
2
3
4
5
6
7
8
MO SER/
DFR
PD1
PD0
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
DCLK
S
DIN
BUSY
DOUT
A2
A1
A0
S
A2
A1
A0
MO SER/
DFR
2
1
0
PD1
PD0
Hi-Z
Hi-Z
11
10
9
8
7
6
5
4
3
11
Driver SW
SER/ DFR
=”1”
Driver SW
SER/ DFR
=”0”
Figure 5 Serial Interface
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[AK4180]
BUSY and DOUT goes to “L” from Hi-Z state at the falling edge of CSN. The AK4180 latches the 8bit control word serially via
DIN at the rising edge of DCLK. As the AK4180 starts the command decoding at the first “H” bit after CSN=”↓”, MSB of the
command must be “H”.
Tracking time is the period from the falling edge of 5th DCLK to the falling edge of 8th DCLK. If SER/ DFR =”1”, PD0=”0”, and
if analog input is X-axis or Y-axis (the measurement is the pen position or pen pressure), the touch screen driver switches are
turned ON for this 3DCLK period. If SER/ DFR =”0”, the switches are turned ON for the period from 5DCLK↓ to 20 DCLK↓.
BUSY is “H” for one DCLK period, which is from 8DCLK↓ to 9DCLK↓. BUSY is “L” for other period.
The AK4180 outputs A/D data with MSB first via DOUT from the falling edge of 9th DCLK.
The AK4180 can output one A/D data per 16 DCLK clock cycles for the fastest way as shown in the dotted line of the above figure.
„ Pen Interrupt
The AK4180 has pen interrupt function to detect the pen touch. Pen interrupt function is enabled at power-down state. YN pin is
connected to GND at the PEN interrupt enabled state. And XP pin is pulled up via an internal resistor (Ri), typically 20k ohm.
PENIRQN pulled up via an external resistor, 100k ohm, is also connected to XP pin. If the two plates are touched, the current
flows via <VCC> – <Ri> – <XP> –<the plates> - <YN>. The resistance of the plate is generally 1k ohm or less, PENIRQN is
forced to “L” level. If the pen is released, PENIRQN returns “H” level because two plates are disconnected, and the current
doesn’t flow via two plates.
If the plate is touched with pen or finger, PENIRQN goes to “L” at CSN=”H” unless both PD1 and PD0 is “1”. PENIRQN is
disabled and keeps “H” level regardless of the touched/non-touched state if CSN=”H”.
The operation of PENIRQN is related to PD0 bit. PD0 bit is updated at the rising edge of 8th DCLK ( please see “„ Power-down
Control “ for the detail). Therefore, the last PD0 bit is valid until this timing. (The internal voltage reference is controlled by only
PD1 bit regardless of PD0 bit and CSN state.)
i) The period from the 5th DCLK ↓to the 20th DCLK↓
The behavior of PENIRQN is related to the selected analog input. If the X-axis or Y-axis is selected as analog input,
PENIRQN is forced to “L” regardless of the touched/non-touched state. If the temperature, VBAT, or auxiliary inputs is
selected, PENIRQN is forced to “H” regardless of the touched/non-touched state.
ii) The period from CSN↓ to the 5th DCLK.
The behavior of PENIRQN is related to the combination of the last selected analog input channel, and the last PD0 bit. If the
last PD0 bit was set to “0”, PENIRQN is “H” while the plate is not pressed, and “L” while the plate is pressed regardless of the
last analog input. If the last PD0 bit was set to “1”, the last analog input decides the level of PENIRQN. If the last analog
input channel is ether X-axis or Y-axis, PENIRQN is “L” for all the time in this period regardless of the touched/non-touched
state. On the other hand, if the last analog input is temperature, VBAT, or auxiliary inputs, PENIRQN is “H” for all the time
in this period regardless of the touched/non-touched state.
iii) The period from the 20th DCLK↓ to CSN↑
The behavior of PENIRQN is related to the combination of the current selected analog input channel, and the current PD0 bit.
If the current PD0 bit is set to “0”, PENIRQN is “H” while the plate is not pressed, and “L” while the plate is pressed
regardless of the current selected analog input. If the current PD0 bit is set to “1”, the current analog input decides the
operation of PENIRQN. If the current analog input channel is ether X-axis or Y-axis, PENIRQN is “L” for all the time in this
period regardless of the touched/non-touched state. On the other hand, if the current analog input is temperature, VBAT, or
auxiliary inputs, PENIRQN is “H” for all the time in this period regardless of the touched/non-touched state..
It is recommended that microcontroller mask the pseudo-interrupts while the control command is issued or A/D data is output.
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
100kΩ
PENIRQN
EN2
20kΩ
Driver OFF
XP
EN1
YN
Driver ON
Figure 6 PENIRQ Functional Block Diagram
CSN
1
2
3
4
5
6
7
8
MO SER/
DFR
PD1
PD0
9
10
11
12
13
14
15
16
9
8
7
6
5
17
18
19
20
21
22
23
24
DCLK
DIN
S
A2
A1
A0
BUSY
11
10
4
3
2
1
0
DOUT
CONV
Internal
AXIS = ((!A2) & (!A1) & (A0))
| ((!A2) & (A1) & (A0))
| ((A2) & (!A1) & (!A0))
| ((A2) & (!A1) & (A0));
/* X-axis Measurement */
/* Z1 Measurement */
/* Z2 Measurement */
/* Y-axis Measurement */
EN1 = ((!CSN) & (!CONV) & AXIS & PD0)
/* CSN=”L”, X/Y/Z1/Z2 Measurement, PD0 = 1, NOT “CONV period” */
| ((!CSN) & AXIS & CONV);
/* CSN=”L”, X/Y/Z1/Z2 Measurement, “CONV period” */
EN2 = ((!CSN) & (!CONV) & (!PD0))
/* CSN=”L”, PD0 = 1, NOT “CONV period” */
| (CSN & (!(PD1& PD0));
/* CSN=”H”, (PD0, PD1) is not (1,1) */
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
Package
16pin TSSOP (Unit: mm)
5.00TYP
16
1.10 MAX
9
A
6.4±0.2
4.4TYP
1
8
0.22±0.08
0.65
0.17±0.05
| 0.13|M
1.10 MAX
0.07±0.04
Detail A
0.5±0.2
Seating Plane
| 0.10
0-10°
<MS0195-E-01>
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[ASAHI KASEI]
[AK4180]
Marking
AKM
4180VT
XXYYY
Contents of XXYYY
XX:
Lot #
YYY:
Date Code
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[ASAHI KASEI]
[AK4180]
IMPORTANT NOTICE
• These products and their specifications are subject to change without notice. Before considering any use
or application, consult the Asahi Kasei Microsystems Co., Ltd. (AKM) sales office or authorized
distributor concerning their current status.
• AKM assumes no liability for infringement of any patent, intellectual property, or other right in the
application or use of any information contained herein.
• Any export of these products, or devices or systems containing them, may require an export license or
other official approval under the law and regulations of the country of export pertaining to customs and
tariffs, currency exchange, or strategic materials.
• AKM products are neither intended nor authorized for use as critical components in any safety, life support,
or other hazard related device or system, and AKM assumes no responsibility relating to any such use,
except with the express written consent of the Representative Director of AKM. As used here:
(a) A hazard related device or system is one designed or intended for life support or maintenance of
safety or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to
function or perform may reasonably be expected to result in loss of life or in significant injury or
damage to person or property.
(b)A critical component is one whose failure to function or perform may reasonably be expected to result,
whether directly or indirectly, in the loss of the safety or effectiveness of the device or system
containing it, and which must therefore meet very high standards of performance and reliability.
• It is the responsibility of the buyer or distributor of an AKM product who distributes, disposes of, or
otherwise places the product with a third party to notify that party in advance of the above content and
conditions, and the buyer or distributor agrees to assume any and all responsibility and liability for and
hold AKM harmless from any and all claims arising from the use of said product in the absence of such
notification.
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