qt60161b Quantum Research Group, qt60161b Datasheet - Page 30

• Manufacturer Part Number: qt60161b
• Description: 16 Key Qmatrix Keypanel Sensor Ic
• Manufacturer: Quantum Research Group

5.7 Timing Limitations
The device requires processing time between bursts, as well
as time to handle communications with the host. With short
burst spacings, long burst lengths, and long intra-burst pulse
spacings, the device can simply run out of available
processing time. When this happens, burst timing and host
communications slow down and become erratic.
5.8 Erratta / Notes
4 April 2003 - The QT60xx5 version 1.05 datasheet erroneously showed negative recalibration timeouts in the range from
1..255 seconds. The correct range is 0.1..25.5 seconds. From datasheet version 1.06 on, this document change has been
made. The devices themselves are not affected.
lQ
Spacing
Spacing
1,000
2,000
1,000
2,000
Pulse Spacing = 2µs
Pulse Spacing = 7µs
Burst
Burst
500
500
Max BL
Max BL
64
64
64
30
50
64
Spacing
Spacing
1,000
2,000
1,000
2,000
Pulse Spacing = 3µs
Pulse Spacing = 8µs
Burst
Burst
500
500
Table 5-2 Permissible Burst Lengths (BL’s)
Cs = 4.7nF, Cx = 5pF, Rs = 180K; 100µs ramp time
Max BL
Max BL
64
64
64
25
50
64
©Quantum Research Group Ltd.
Spacing
Spacing
1,000
2,000
1,000
2,000
Pulse Spacing = 4µs
Pulse Spacing = 9µs
Burst
Burst
500
500
30
It is important that burst spacings be verified on an
oscilloscope with an actual keymatrix during development to
be certain that the device timings are preserved and are
constant. If not, the burst length and/or pulse spacing should
be reduced.
Max BL
Max BL
50
64
64
20
40
64
Spacing
Spacing
Pulse Spacing = 10µs
1,000
2,000
1,000
2,000
Pulse Spacing = 5µs
Burst
Burst
500
500
www.qprox.com QT60161B / R1.03
Max BL
Max BL
40
64
64
20
40
64
Spacing
Pulse Spacing = 6µs
1,000
2,000
Burst
500
Max BL
30
64
64