AK4186 Datasheet, PDF (29/33 Pages) Asahi Kasei Microsystems – Low Power Touch Screen Controller with I2C Interface

[AK4186]
AK4186EN <5-wire Touch Screen Input>
Digital Ground
Analog Ground
5 -wi re
Touch Screen
13 ^NC
NC ₈
AK4186EN
14 ^VSS
VDD ₇
Top View
15 ^{T EST}
WIPER ₆
16 ^{N C}
NC ₅
0.001µ *
0.001µ *
0.001µ *
0.001µ *
Analog Supply
+ ^{1.6∼3.6V}
10µ
0.1 µ
0.001µ *
Rp
Rp
µP
“L” or “H”
Figure 38. Typical Connection Diagram (5-wire, AK4186EN)
Notes:
- VSS of the AK4186 should be distributed separately from the ground of external controllers.
- All digital input pins (SCL, SDA, CAD0 pins) must not be left floating.
1. Grounding and Power Supply Decoupling
The AK4186 requires careful attention to power supply and grounding arrangements. VDD is usually supplied from the
system’s analog supply. VSS of the AK4186 must be connected to the analog ground plane. System analog ground and
digital ground should be connected together near to where the supplies are brought onto the printed circuit board.
Decoupling capacitors should be as near to the AK4186 as possible, with the small value ceramic capacitor being the
nearest.
2. Analog Inputs
When an EMI source is close to the touch panel analog signal line, EMI noise affects analog characteristics
performance. Connect noise canceling capacitors (*) as close as possible to each pin (XP, XN, YP, YN pins) of the
AK4186 to avoid this noise. (Figure 35, Figure 36, Figure 37, Figure 38)
MS1068-E-04
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2011/03