ATA5021 ATMEL, ATA5021 Datasheet - Page 4

• Manufacturer Part Number: ATA5021
• Description: Digital Window Watchdog Timer
• Manufacturer: ATMEL

3. Functional Description
3.1
3.2
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4
Supply Voltage, Pin 6
RC Oscillator, Pin 8
ATA5021
The ATA5021 requires a stabilized supply voltage V
characteristics. An external buffer capacitor of C = 10 nF may be connected between pin 6 and
GND.
The clock frequency, f, can be adjusted by the components R
T = 0.18
(C
R
C
C
assembly. With frequency calculations of original boards, this parasitic capacitor can be omitted.
Table 3-1.
f
1
1
board
=
1
(k ) = external resistor at pin 8
(nF) = external capacitor at pin 8
R1 (k )
+ C
10.00
10.00
10.00
10.00
10.00
32.91
32.91
32.91
32.91
32.91
46.70
46.70
46.70
46.70
46.70
68.00
68.00
68.00
68.00
68.00
81.20
-- -
T
1
= 0.004 nF; this is the parasitic test board capacity caused by additional wiring on the test
with
board
(C
+ 0.016)
1
Comparison Table Clock Period Calculation versus Measurement on Test Board
+ C
C1 (nF)
10.49
10.49
10.49
10.49
board
0.23
0.47
1.04
4.75
0.23
0.47
1.04
4.75
0.23
0.47
1.04
4.75
0.23
0.47
1.04
4.75
0.23
+ 0.016) + 0.35 + [1.59 – (C
Period “T” (µs) by
New Formula
1049.85
156.30
242.10
509.25
343.03
721.70
114.25
498.94
17.26
74.40
13.45
25.99
55.57
18.92
36.69
78.63
27.38
53.22
32.61
8.20
4.36
Period “T” (µs) by
1
+ C
DD
Measurement
1020.00
= 5V ±10% to comply with its electrical
board
152.00
241.50
505.00
341.25
700.00
112.50
497.50
17.10
74.50
13.25
26.13
55.00
18.50
36.63
78.25
26.75
53.25
31.88
4.33
8.30
+ 0.016)/85]
1
and C
1
according to the formula:
Deviation of New
R
Formula versus
Measurement
1
–0.3%
–2.2%
–0.4%
–1.2%
–1.6%
–1.4%
–1.1%
9145D–AUTO–05/10
1.8%
1.4%
1.5%
1.9%
1.2%
1.2%
1.6%
0.8%
1.7%
0.6%
1.4%
1.5%
1.2%
0.0%