Figure 2.1 Connection Diagram (32-QFN Package)
Vunreg
4.7uF
+2.8 ~ +5V
Voltage Reg
4.7uF
100nF
VDD
3
14
Note: One bypass capacitor to be
tightly wired between Vdd and Vss.
Follow recommendations from regulator
manufacturer for input and output
capacitors.
2
12
4.7nF
VDD
SNSB4
SNSB
/RST
SNSB
SNSB7
R
SNSB7
R
SNSB4
10K
4.7nF
C
KEY 7
10K
13
15
7
11
C
Sb7
4.7nF
R
SNSB6
R
SNSB3
4.7nF
SNSB3
SNSB
SNSB
8
KEY 6
10K
KEY 3
10K
C
Sb3
4.7nF
16
SNSB6
SNSB
SNSB5
10
9
C
Sb6
4.7nF
R
SNSB5
R
SNSB2
C
Sb2
4.7nF
SNSB2
SNSB
KEY 5
C
Sb5
VDD
10K
19
KEY 2
10K
17
R
SNSB1
C
Sb1
SNSB1
SNSB
KEY 1
10K
18
QT1106
32-QFN
N.C.
OSC
5
4
**Rb1
**
See the table below for
**Rb2
suggested resistor and capacitor
values, with and without spread
spectrum.
No Spread-spectrum:
Replace Css with 100K resistor and remove Rb2
*
Css
32
The wheel shows positions
at 7-bit resolution. See the
table at the end of
Section 3.5.2 for other
resolutions.
R
SNSA3
15nF
10K
SNSA3
SNSA
C
Sa3
27
127 0
30
SPREAD
SNSA1
SNSA
1
R
SNSA1
85
43
10K
15nF
C
Sa1
29
31
DRDY
SNSA2
SNSA
SCLK
MISO
MOSI
/SS
21
23
26
25
24
100K
SPI DRDY out
SPI SCLK in
SPI MISO out
SPI MOSI in
SPI /SS in
R
SNSA2
10K
15nF
C
Sa2
28
CHANGE out
6
CHANGE
100K
VSS
NOTE: Sense terminals can be twinned with any
22
e.g. SNSA1 can be paired with any SNSA terminal.
SNSA pins: 27 ,28, 29
SNSB pins: 10, 11, 12, 13, 18, 19, 20
IMPORTANT DESIGN GUIDELINES:
#
The sensitivities of the various sense channels are determined by the values of the respective Cs capacitors (i.e. Csb1,
Csb7, etc.); these values will require adjustment based on building a prototype product and testing the sensitivity
experimentally.
Rb1, Rb2 sets the oscillator frequency; recommended values are:
Vdd Range
<3V
3.0~3.6V
> 3.6V
#
#
#
Rb1
12k
12k
15k
With Spread Spectrum
Rb2
Css
27k
see note
22k
below
27k
Without Spread Spectrum
Rb1
Rb2
Css
15k
replace with
100k
not fitted
18k
resistor
20k
#
The required value of the spread-spectrum capacitor (Css) will vary according to the lengths of the acquire bursts . A
typical value is 100nF.
When the QT1106 is running the OSC pin has a DC voltage typically between 1V and 1.5V; the use of spread spectrum
will cause a small low-frequency variation in the voltage. The internal oscillator signal is not visible on this pin.
Signals DRDY and CHANGE may need pull-down resistors, see Section 5 on page 13.
Lq
7
QT1106-ISG R8I.05/0906
QUANTUM [ QUANTUM RESEARCH GROUP ]
