NE56632-XX 查看數據表（PDF） - Philips Electronics
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NE56632-XX Datasheet PDF : 16 Pages
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Philips Semiconductors
Active-LOW system reset with adjustable delay time
Product data
NE56632-XX
APPLICATION INFORMATION
A typical application circuit for the NE56632-XX is shown in
Figure 24. Note that a pull-up resistor, RPU is necessary since the
output is an open collector. The value of RPU is calculated by the
following expression.
RPU ≥ (VCC – VRESET) / IOL
where:
VCC = VS(min) – 0.05 V (for a 3 V reset this is 2.905 V)
VRESET = 0.4 V (this is VOL(max))
IOL = 5 mA; minimum output current at Tamb = 25 °C
Substituting these values into the expression and calculating, finds
RPU should be greater than or equal to 510 Ω. To ensure that the
Active-LOW level is sufficient, a value of 4.7 kΩ is chosen in the test
and application examples.
TO VCC
RPU
5
4
TO RESET
TERMINAL
OF CPU
NE56632-XX
1
2
3
CD
SL01605
Figure 24. Typical application.
Figure 25 (NE56632-20 CD versus tPLH) and Figure 26
(NE56632-44 CD versus tPLH) show how tPHL, the “H” transmission
delay or reset release delay time varies as a function of the external
delay capacitance, CD. From Figure 26, typical range of the delay
capacitance is 1 pF to 10 nF which yields typical delays from 200 µs
to 200 ms.
The following formula can be used to find the approximate delay
time based on external delay capacitance, CD and the delay time
coefficient, d shown in Table 2.
tPLH (ms) ≈ CD (µF) × d
For example, a NE56632-44 using an external capacitor,
CD = 1 nF = 1000 pF yields:
tPLH (ms) ≈ (1 × 10–3) (1.85 × 104) ≈ 18.5 ms
Compare this to the value of tPLH ≈ 17 ms for CD = 1000 pF that is
extracted from Figure 26.
1.0E+00
1.0E–01
1.0E–02
1.0E–03
1.0E–04
1.0E–05
1.0E+00
1.0E+01
1.0E+02
CD (pF)
1.0E+03
1.0E+04
SL01611
Figure 25. NE56632-20 CD versus tPLH characteristics.
1.0E+00
1.0E–01
1.0E–02
1.0E–03
1.0E–04
1.0E–05
1.0E+00
1.0E+01
1.0E+02
CD (pF)
1.0E+03
1.0E+04
SL01612
Figure 26. NE56632-44 CD versus tPLH characteristics.
Table 2. Delay time coefficient
Device
NE56632–46
NE56632–45
NE56632–44
NE56632–43
NE56632–42
NE56632–31
NE56632–30
NE56632–29
NE56632–28
NE56632–27
NE56632–20
NE56632–19
d
1.95 × 104
1.90 × 104
1.85 × 104
1.80 × 104
1.75 × 104
1.20 × 104
1.15 × 104
1.10 × 104
1.05 × 104
1.00 × 104
0.65 × 104
0.60 × 104
2002 Mar 25
11
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