UPD4701AC データシートの表示（PDF） - NEC => Renesas Technology
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UPD4701AC Datasheet PDF : 16 Pages
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µPD4701A
7. APPLICATION AREAS
Two-phase incremental signals are used for detection and measurement of a vector quantity (a quantity that has
direction and magnitude), and are widely employed in measuring instruments such as micrometers and linear scales,
control systems for digital servo motors, X-Y tables, etc., head position control for printers, magnetic disks, etc., robot
arm position control, and so on.
The µPD4701A incorporates the direction judgment circuit and count pulse generator required for 2-phase
incremental signal processing, up/down counters for counting these pulses, and a data latch to hold the read data,
in IC form, enabling an X, Y 2-axis incremental signal processing system to be implemented easily.
In addition, a 3 switch-input buffer is incorporated, enabling this device to be widely used in man-machine interface
and centronics interface application areas.
8. OPERATING PRECAUTIONS
1) As the µPD4701A incorporates two sets of 12-bit counters, large transient currents flow during a count operation.
Adecoupling capacitor of around 0.1 µF should therefore be inserted between VDD and VSS of the µPD4701A.
+5V
VDD
Tantalum electrolytic, laminated ceramic, or similar capacitor
of around 0.1 µF
(Should be mounted right next to the IC.)
VSS
µPD4701A
2) If a pulse shorter than the signal phase difference time tSAB (350 ns) is input to the A/B phase inputs (XA, XB, YA,
YB) this will result in a miscount. Therefore, if pulses shorter than tSAB are to be input because of encoder bounds,
etc., a filter should be attached to the A/B phase inputs.
PW
A or B Phase
B or A Phase
If PW ≥ tSAB (350 ns), the count value remains the same before and after pulse input.
(UP count → DOWN count or DOWN count → UP count is implemented, and therefore
the result is equivalent to no change in the count value.
8
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