Datasheet
4Atmel ATA5021 [DATASHEET]
9145G–AUTO–09/12
3. Functional Description
3.1 Supply Voltage, Pin 6
The Atmel
®
ATA5021 requires a stabilized supply voltage V
DD
= 5V ±10% to comply with its electrical characteristics. An
external buffer capacitor of C = 10 nF may be connected between pin 6 and GND.
3.2 RC Oscillator, Pin 8
The clock frequency, f, can be adjusted by the components R
1
and C
1
according to the formula:
with
T = 0.18 × (C
1
+ C
board
+ 0.016) + 0.35 + [1.59 – (C
1
+ C
board
+ 0.016)/85] × R
1
×
(C
1
+ C
board
+ 0.016)
R
1
(kΩ) = external resistor at pin 8
C
1
(nF) = external capacitor at pin 8
C
board
= 0.004nF; this is the typical parasitic board capacity.
Table 3-1. Comparison Table Clock Period Calculation versus Measurement on Test Board
R1 (kΩ) C1 (nF)
Period “T” (µs) by New
Formula
Period “T” (µs) by
Measurement
Deviation of New Formula
versus Measurement
10.00 0.23 4.36 4.33 –0.9%
10.00 0.47 8.20 8.30 1.2%
10.00 1.04 17.26 17.10 –0.9%
10.00 4.75 74.40 74.50 0.1%
10.00 10.49 156.30 152.00 –2.8%
32.91 0.23 13.45 13.25 –1.5%
32.91 0.47 25.99 26.13 0.5%
32.91 1.04 55.57 55.00 –1.0%
32.91 4.75 242.10 241.50 –0.2%
32.91 10.49 509.25 505.00 –0.8%
46.70 0.23 18.92 18.50 –2.2%
46.70 0.47 36.69 36.63 –0.2%
46.70 1.04 78.63 78.25 –0.5%
46.70 4.75 343.03 341.25 –0.5%
46.70 10.49 721.70 700.00 –3.0%
68.00 0.23 27.38 26.75 –2.3%
68.00 0.47 53.22 53.25 0.0%
68.00 1.04 114.25 112.50 –1.5%
68.00 4.75 498.94 497.50 –0.3%
68.00 10.49 1049.85 1020.00 –2.8%
81.20 0.23 32.61 31.88 –2.3%
81.20 0.47 63.47 63.75 0.4%
81.20 1.04 136.32 135.00 –1.0%
81.20 4.75 595.56 592.50 –0.5%
81.20 10.49 1253.21 1240.00 –1.1%
f
1
T
---=