AK4180VT AKM [Asahi Kasei Microsystems], AK4180VT Datasheet - Page 9

• Manufacturer Part Number: AK4180VT
• Description: Touch Screen Controller
• Manufacturer: AKM [Asahi Kasei Microsystems]

[ASAHI KASEI]
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
0.1 F or larger capacitor should be connected for stable operation of the VREF circuit. Setting time depends on this external
capacitance, but 400 s or longer time is required if the external capacitance is 0.1 F.
If an external voltage reference is used, PD1 bit should be set to “0”.
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 5 s is required as tracking time. If the source impedance is large, more
tracking time is required.
<MS0195-E-01>
ADC
ADC
ADC
ADC
Voltage Reference
Battery Measurement
VREF+
VREF-
ON
ON
b)
AIN+
AIN-
Z1-Position Measurement
Differential Mode
VBAT
R0
YP
XP
XN
YN
R2=2.5K
R1=7.5K
Figure 2 Pen Pressure Measurement
Figure 3 Battery Monitoring
touch
Enable
9
ADC
ADC
ADC
ADC
VREF+
VREF-
Internal
ON
ON
VREF
AIN+
AIN-
ADC
a)
AIN+
AIN-
Z2-Position Measurement
Differential Mode
VREF+
VREF-
PD1
YP
XP
XN
YN
touch
2003/02
[AK4180]