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NXP Semiconductors
UMxxxxx
Install Guide
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Preliminary 1
— September 6, 2013
© NXP B.V. 2013. All rights reserved.
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Fig 6.6 Push switches
6.2.3 Bias Circuit
Each channel requires three reference voltages (VL, VC, and VH), from the Bias Circuit. A resistor
divider chain (R01, R02, R03, and R04) divides the supply voltage to produce one-third (VL), one half
(VC) and two-thirds (VH). Each value is buffered by an op amp (sections of IC80). Test points are
provided as PCB pads for VH (high), VC (center), and VL (low). The fourth section of the quad op amp
(IC80) is not used. Noise spikes on each bias supply are removed by capacitors (C89, C90, and C91),
power supply variations are removed by capacitors (C86 and C87). See figure 6.7.
Содержание OM13260
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