QT60325B Datasheet PDF - QUANTUM


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QT60325B
QUANTUM

Part Number QT60325B
Description (QT60325B - QT60645B) QMatrix KEYPANEL SENSOR ICS
Page 30 Pages

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LQ
QT60325B, QT60485B, QT60645B
32, 48, 64 KEY QMatrixKEYPANEL SENSOR ICS
Advanced second generation QMatrix controllers
Up to 32, 48 or 64 touch keys through any dielectric
Panel thicknesses to 5 cm or more
100% autocal for life - no adjustments required
Keys individually adjustable for sensitivity, response time,
and many other critical parameters
Mix and match key sizes & shapes in one panel
Passive matrix - no components at the keys
Moisture suppression capable
AKS™ - Adjacent Key Suppression feature
Synchronous noise suppression
Sleep mode with wake pin
SPI Slave or Master/Slave interface to a host controller
Low overhead communications protocol
44-pin TQFP package
MOSI
MISO
SCLK
RST
Vdd
Vss
XTO
XTI
X0
X1
X2WS
44 43 42 41 40 39 38 37 36 35 34
1 33
2 32
3 31
4 QT60325B 30
5 QT60485B 29
6 QT60645B 28
7 27
8
9
TQFP-44
26
25
10 24
11 23
12 13 14 15 16 17 18 19 20 21 22
CZ2
YS0
YS1
YS2
Aref
AGnd
AVdd
YC7
YC6
YC5
YC4
APPLICATIONS
Security keypanels
Industrial keyboards
Appliance controls
Outdoor keypads
ATM machines
Touch-screens
Automotive panels
Machine tools
The QT60325B, QT60485B, and QT60645B digital charge-transfer (“QT”) QMatrix™ ICs are designed to detect human touch on
up to 32, 48, or 64 keys respectively using a scanned, passive X-Y matrix. It will project the keys through almost any dielectric, e.g.
glass, plastic, stone, ceramic, and even wood, up to thicknesses of 5 cm or more. The touch areas are defined as simple 2-part
interdigitated electrodes of conductive material, like copper or screened silver or carbon deposited on the rear of a control panel.
Key sizes, shapes and placement are almost entirely arbitrary; sizes and shapes of keys can be mixed within a single panel of
keys and can vary by a factor of 20:1 in surface area. The sensitivity of each key can be set individually via simple functions over
the SPI port, for example via Quantum’s QmBtn program. Key setups are stored in an onboard eeprom and do not need to be
reloaded with each power-up.
These ICs are designed specifically for appliances, electronic kiosks, security panels, portable instruments, machine tools, or
similar products that are subject to environmental influences or even vandalism. They permit the construction of 100% sealed,
watertight control panels that are immune to humidity, temperature, dirt accumulation, or the physical deterioration of the panel
surface from abrasion, chemicals, or abuse. To this end the devices contain Quantum-pioneered adaptive self-calibration, drift
compensation, and digital filtering algorithms that make the sensing function robust and survivable. The devices use short dwell
times and Quantum’s patent-pending AKS™ feature to permit operation in wet environments.
The parts use a passive key matrix, dramatically reducing cost over older technologies that require an ASIC for every key. The
key-matrix can be made of standard flex material (e.g. Silver on PET plastic) or ordinary PCB material to save cost.
External circuitry consists of an opamp, R2R ladder-DAC network, a common PLD, a FET switch, and a small number of resistors
and capacitors which can fit into a footprint of roughly 8 sq. cm (1.5 sq. in). Control and data transfer is via a SPI port which can
be configured in either a Slave or Master/Slave mode.
QT60xx5B ICs make use of an important new variant of charge-transfer sensing, transverse charge-transfer, in a matrix format
that minimizes the number of required scan lines to provide a high economy of scale.
The B version is identical to the earlier QT60xx5 parts in all respects except that the device exhibits lower signal noise.
QT60xx5B replaces QT60xx5 parts with no circuit changes. After 2003, QT60xx5 devices will no longer be available.
lQ
AVAILABLE OPTIONS
TA
-400C to +1050C
-400C to +1050C
-400C to +1050C
TQFP
QT60325B-AS
QT60485B-AS
QT60645B-AS
Copyright © 2001 Quantum Research Group Ltd
Pat Pend. R1.06/0403



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© Quantum Research Group Ltd.
Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Field Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Circuit Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Matrix Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Signal Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Negative Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Positive Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Drift Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.5 Detection Recalibration Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.6 Detect Integrator (‘DI’) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.7 Positive Recalibration Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.8 Reference Guardbanding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.9 Adjacent Key Suppression (AKS™) . . . . . . . . . . . . . . . . . . . . . . . 8
2.10 Full Recalibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.11 Boundary Error Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.12 Device Status & Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Circuit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Part Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Matrix Scan Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Signal Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4 'X' Electrode Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4.1 RFI From X Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.4.2 Noise Coupling Into X lines . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.5 'Y' Gate Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.5.1 RFI From Y Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.5.2 Noise Coupling Into Y Lines . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.6 Burst Length & Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.7 Intra-Burst Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.8 Burst Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.9 PLD Circuit and Charge Sampler . . . . . . . . . . . . . . . . . . . . . . . 13
3.10 Opamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.11 Sample Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.12 R2R Resistor Ladder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.13 Water Film Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.14 Reset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.15 Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.16 Startup / Calibration Times . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.17 Sleep_Wake / Noise Sync . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.18 LED / Alert Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.19 CSR Drive Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.20 Oscilloscope Sync . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.21 Power Supply and PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . 15
3.22 ESD / Noise Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4 Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1 Serial Port specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2 Protocol Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3 SPI Slave-Only Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.4 SPI Master-Slave Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.5 Sensor Echo and Data Response . . . . . . . . . . . . . . . . . . . . . . . 19
4.6 Eeprom Corruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5 Commands & Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1 Direction Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
g 0x67 - Get Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
p 0x70 - Put Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2 Scope Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
s 0x73 - Specific Key Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
S 0x53 - All Keys Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
x 0x78 - Row Keys Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
y 0x79 - Column Keys Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.3 Status Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
0 0x30 - Signal for Single Key . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1 0x31 - Delta Signal for Single Key . . . . . . . . . . . . . . . . . . . . . . . 21
2 0x32 - Reference Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3 0x33 - R2R Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4 0x34 - Cz State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5 0x35 - Detection Integrator Counts . . . . . . . . . . . . . . . . . . . . . . 22
6 0x36 - Eeprom Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7 0x37 - General Device Status . . . . . . . . . . . . . . . . . . . . . . . . . 22
<sp> 0x20 - Signal Levels for Group . . . . . . . . . . . . . . . . . . . . . . . 22
! 0x21 - Delta Signals for Group . . . . . . . . . . . . . . . . . . . . . . . . . 22
" 0x22 - Reference Levels for Group . . . . . . . . . . . . . . . . . . . . . . 22
# 0x23 - R2R Offset for Group . . . . . . . . . . . . . . . . . . . . . . . . . . 22
$ 0x24 - Charge Cancellation for Group . . . . . . . . . . . . . . . . . . . . 22
% 0x25 - Detect Integrator Counts for Group . . . . . . . . . . . . . . . . . 22
e 0x65 - Error Code for Selected Key . . . . . . . . . . . . . . . . . . . . . 23
k 0x6B - Reporting of First Touched Key . . . . . . . . . . . . . . . . . . . . 23
K 0x4B - Key Touch Reporting for Group . . . . . . . . . . . . . . . . . . . 24
5.4 Setup Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
^A 0x01 - Negative Detect Threshold . . . . . . . . . . . . . . . . . . . . . . . 24
^B 0x02 - Positive Detect Threshold . . . . . . . . . . . . . . . . . . . . . . . 24
^C 0x03 - Negative Threshold Hysteresis . . . . . . . . . . . . . . . . . . . . 25
^D 0x04 - Positive Threshold Hysteresis . . . . . . . . . . . . . . . . . . . . . 25
^E 0x05 - Dwell Time in Machine Cycles . . . . . . . . . . . . . . . . . . . . . 25
^G 0x07 - Burst Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
^H 0x08 - Negative Drift Compensation Rate . . . . . . . . . . . . . . . . . . 26
^I 0x09 - Positive Drift Compensation Rate . . . . . . . . . . . . . . . . . . . 26
^J 0x0A - Detect Integrator Limit . . . . . . . . . . . . . . . . . . . . . . . . . 26
^K 0x0B - Positive Recalibration Delay . . . . . . . . . . . . . . . . . . . . . 26
^L 0x0C - Negative Recalibration Delay . . . . . . . . . . . . . . . . . . . . . 26
^M 0x0D - Intra-Burst Pulse Spacing . . . . . . . . . . . . . . . . . . . . . . . 27
^N 0x0E - Positive Reference Error Band . . . . . . . . . . . . . . . . . . . . 27
^O 0x0F - Negative Reference Error Band . . . . . . . . . . . . . . . . . . . 27
^P 0x10 - Adjacent Key Suppression (‘AKS’) . . . . . . . . . . . . . . . . . . 27
5.5 Supervisory / System Functions . . . . . . . . . . . . . . . . . . . . . . . . 28
6 0x36 - Eeprom Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
D 0x44 - DAC Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
L 0x4C - Lock Reference Levels . . . . . . . . . . . . . . . . . . . . . . . . . 28
b 0x62 - Recalibrate Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
l 0x6C - Return Last Command Character . . . . . . . . . . . . . . . . . . . 28
r 0x72 - Reset Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
V 0x56 - Return Part Version . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
W 0x57 - Return Part Signature . . . . . . . . . . . . . . . . . . . . . . . . . 29
Z 0x5A - Enter Sleep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
^Q 0x11 - Data Rate Selection . . . . . . . . . . . . . . . . . . . . . . . . . . 29
^R 0x12 - Oscilloscope Sync . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
^S 0x13 - Cs Clamp Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
^T 0x14 - Boundary Eqn Constant C1, MSB . . . . . . . . . . . . . . . . . . 30
^U 0x15 - Boundary Eqn Constant C1, LSB . . . . . . . . . . . . . . . . . . 30
^V 0x16 - Boundary Equation Constant C2 . . . . . . . . . . . . . . . . . . . 30
^W 0x17 - Noise Sync . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.6 Function Summary Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.7 Timing Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6 PLD Source Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.1 Absolute Maximum Specifications . . . . . . . . . . . . . . . . . . . . . . 36
7.2 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . 36
7.3 DC Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.4 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.5 Maximum Drdy Response Delays . . . . . . . . . . . . . . . . . . . . . . . 37
8 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.2 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
lQ
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Table 1.1 Device Pin List
Pin Name Type
1
MOSI
I/O PP
2
MISO
I/O PP
3
SCK
I/O PP
4 RST I
5 Vdd Pwr
6 Vss Pwr
7 XTO O
8 XTI I
9 X0 O
10 X1 O
11 X2WS O
12 X3 O
13 X4 O
14 X5 O
15 X6 O
16 XS O
17 Vdd Pwr
18 Vss Pwr
19 YC0 O
20 YC1 O
21 YC2 O
22 YC3 O
23 YC4 O
24 YC5 O
25 YC6 O
26 YC7 O
27
AVdd
Pwr
28
AGnd
Pwr
29 Aref Pwr
30 YS2 O
31 YS1 O
32 YS0 O
33 CZ2 O
34 CZ1 O
35 CSR O
36 Ain
I
37 MS I/O OD
38 Vdd Pwr
39 Vss Pwr
40 LED O
41
DRDY
O OD
42 X7 O
43 YG O
44 SS IO OD
I/O: I = Input
O = Output
Pwr = Power pin
I/O = Bi-directional line
PP = Push Pull output drive
OD = Open drain output drive
Description
Master-Out / Slave In SPI line. In Master/Slave SPI mode is used for both communication directions.
In Slave SPI mode is the data input (in only).
Master-In / Slave Out SPI line. Not used in Master/Slave SPI mode.
In Slave mode outputs data to host (out only).
SPI Clock. In Master mode is an output; in Slave mode is an input
Reset input, active low reset
+5 supply
Ground
Oscillator drive output. Connect to resonator or crystal.
Oscillator drive input. Connect to resonator or crystal, or external clock source.
X0 Drive matrix scan / R2R DAC Ladder drive
X1 Drive matrix scan / R2R DAC Ladder drive
X2 Drive matrix scan / R2R DAC Ladder drive / Wake from Sleep / Sync to noise source
X3 Drive matrix scan / R2R DAC Ladder drive
X4 Drive matrix scan / R2R DAC Ladder drive
X5 Drive matrix scan / R2R DAC Ladder drive
X6 Drive matrix scan / R2R DAC Ladder drive
X summation / R2R DAC Ladder drive
+5 supply
Ground
Y 0 Line clamp control
Y 1 Line clamp control
Y 2 Line clamp control
Y 3 Line clamp control
Y 4 Line clamp control
Y 5 Line clamp control
Y 6 Line clamp control
Y 7 Line clamp control
+5 supply for analog sections
Analog ground
Analog reference, connect to Vcc
Transfer switch control bit 2
Transfer switch control bit 1
Transfer switch control bit 0
Charge cancellation drive for CZ2 capacitor
Charge cancellation drive for CZ1 capacitor
Charge integrator reset line. Active high or active low (select polarity via Setups)
Analog input from amplifier
SPI Mode / Sync out. Connect via 10k resistor to Vcc or Gnd for mode. Scope sync yields Pulse.
+5 supply
Ground
Active low LED status drive / Activity indicator
Data ready output for Slave SPI mode; active low
X7 Drive matrix scan
Y gate control to drive Y dwell timing circuit
Slave select for SPI direction control; active low
lQ
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1 Overview
QMatrix devices are digital burst mode charge-transfer (QT)
sensors designed specifically for matrix geometry touch
controls; they include all signal processing functions
necessary to provide stable sensing under a wide variety of
changing conditions. Only a few external parts are required
for operation. The entire circuit can be built within 8 square
centimeters of PCB area.
Figure 1-2 Sample Electrode Geometries
Figure 1-1 Field flow between X and Y elements
overlying panel
X
element
Y
elem ent
PARALLEL LINES
SERPENTINE
SPIRAL
edge transitions of the X drive pulse. The charge emitted by
the X electrode is partly received onto the corresponding Y
electrode which is then processed. The parts use 8 'X'
edge-driven rows and 8 'Y' sense columns to permit up to 64
keys. Keys are typically formed from interleaved conductive
traces on a substrate like a flex circuit or PCB (Figure 1-2).
The charge flows are absorbed by the touch of a human
finger (Figure 1-3) resulting in a decrease in coupling from X
to Y. Thus, received signals decrease or go negative with
respect to the reference level during a touch.
Water films cause the coupled fields to increase slightly,
making water films easy to distinguish from touch.
QMatrix devices include charge cancellation methods which
allow for a wide range of key sizes and shapes to be mixed 1.2 Circuit Model
together in a single touch panel. These features permit the An electrical circuit model is shown in Figure 1-5. The
construction of entirely new classes of keypads never before coupling capacitance between X and Y electrodes is
contemplated, such as touch-sliders, back-illuminated keys, represented by Cx. While the reset switch is open, a sample
and complex warped panel shapes, all at very low cost.
switch is gated so that it transfers charge flows only from the
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and setup functions the device
integrator output voltage due to
can also report back actual
touch during an acquire (Section
signal strengths and error codes.
3.6) to increase gain.
QmBtn software for the PC can
be used to program the IC as
well as read back key status and
signal levels in real time.
QMatrix parts employ transverse
charge-transfer ('QT') sensing, a
new technology that senses
changes in the charge forced
across an electrode by a digital
edge.
The parts are electrically
identical with the exception of the
number of keys which may be
sensed.
1.1 Field Flows
Figure 1-1 shows how charge is
transferred across an electrode
set to permeate the overlying
panel material; this charge flow
exhibits a high dQ/dt during the
X
element
ov e rly in g pan el
Y
elem ent
Figure 1-4 Fields With a Conductive Film
The charge detector is an opamp
configured as an integrator with a
reset switch; this creates a virtual
ground input, making the Y lines
appear low impedance when the
sample switch is closed. This
configuration effectively
eliminates cross-coupling among
Y lines while greatly lowering
susceptibility to EMI. The circuit
is also highly immune to
capacitive loading on the Y lines,
since stray C from Y to ground
appears merely as a small
parallel capacitance across a
virtual ground.
The circuit uses an 8-bit ADC,
with a subranging structure to
effectively deliver a 14-bit total
conversion 'space' (see Figure
1-6 and Section 3.3). In this way
the circuit can tolerate very large
lQ
4 www.qprox.com QT60xx5B / R1.06




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Similiar Datasheets : QT60320C QT60320D QT60325 QT60325B QT60326

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