QT1081 Datasheet, PDF (7/20 Pages) Quantum Research Group – 8-KEY QTOUCH SENSOR IC

Figure 1.2 Connection Diagram - Simplified Mode
Vunreg
*4.7uF
+2.8 ~ +5V
Voltage Reg
*4.7uF
VDD
*100nF
* Note: one bypass capacitor to be tightly wired
between Vdd and Vss. Follow manufacturer’s
recommendations for input and output capacitors.
KEY 3
KEY 4
KEY 5
KEY 6
KEY 7
LP IN
DETECT OUT
Keep these parts
close to the IC
1nF ¹²
RSNS3 _{CS3 13}
10K _1nF
RSNS4 _CS4
15
10K
1nF 16
RSNS5
CS5 17
10K
1nF ¹⁸
RSNS6 _CS6
19
10K
SMR
1M
20
RSNS7 ^1nF
CS7 ₂₁
10K
SNS3
3
VDD
SNS3K
SNS4
SNS4K
SNS5
SNS5K
2
/RST
SNS2K
SNS2
SNS1K
SNS1
SNS0K
SNS0
SNS6
SNS6K
QT1081 ^OSC
SNS7 ^32-QFN
SNS7K
SS
Keep these parts
close to the IC
11 ^{1nF RSNS2}
10
10K
CS2
RSNS1
9 1nF
8
CS1 ^10K
7
1nF ^RSNS0
6
10K
CS0
KEY 2
KEY 1
KEY 0
AKS_0
1M ^{Vdd / Vss}
VDD
Recommended Rb1, Rb2 Values
Rb1
4
Rb2
Vdd Range Rb1 Rb2
2.8 ~ 3.59V 12K 22K
3.6 ~ 5V 15K 27K
The required value of spread-spectrum capacitor CSS
will vary according to the lengths of the acquire bursts,
see Section 3.2. A typical value of CSS is 100nF.
CSS
1
22
VSS
23
SYNC/LP
24 _DETECT
OUT_7 ³²
OUT_6 ³¹
OUT_5 ³⁰
OUT_4 ²⁹
OUT_3 ²⁸
OUT_2 ²⁷
OUT_1 ²⁶
OUT_0 ²⁵
OUT_7
OUT_6
OUT_5
OUT_4
OUT_3
OUT_2
OUT_1
OUT_0
Table 1.6
AKS Resistor Options
AKS_0
Vss
Vdd
AKS MODE
Off
On, global
FAST-DETECT
Enabled
Off
Table 1.7
Functions in Simplified Mode
Function
Output Drive, Polarity
SYNC/LP pin
Max on-duration delay
Detect Pin
Parameter
One-per-key outputs, push-pull, active high
180ms nom LP function; sync not available
60 seconds (nom)
Active high on any detect
lQ
7
QT1081_1R0.04_0307