ICM7555 데이터 시트보기 (PDF) - Renesas Electronics
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ICM7555 Datasheet PDF : 13 Pages
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ICM7555, ICM7556
Schematic Diagram
P
P
R
VDD
P
P
THRESHOLD
N
CONTROL
VOLTAGE
N
R
TRIGGER
P
P
NPN
OUTPUT
R
N
N
N
N
N
N
N
R = 100kΩ ±20% (TYP)
RESET
FIGURE 2. SCHEMATIC DIAGRAM
DISCHARGE
GND
Application Information
General
The ICM7555 and ICM7556 devices are, in most instances,
direct replacements for the SE/NE 555/556 devices. However,
it is possible to effect economies in the external component
count using the ICM7555 and ICM7556. Because the bipolar
SE/NE 555/556 devices produce large crowbar currents in the
output driver, it is necessary to decouple the power supply
lines with a good capacitor close to the device. The ICM7555
and ICM7556 devices produce no such transients (see
Figure 3).
500
TA = +25°C
400
300
SE/NE 555
200
100
0
ICM7555/556
0
200
400
600
800
TIME (ns)
FIGURE 3. SUPPLY CURRENT TRANSIENT COMPARED WITH A
STANDARD BIPOLAR 555 DURING AN OUTPUT
TRANSITION
The ICM7555 and ICM7556 produce supply current spikes of
only 2mA to 3mA instead of 300mA to 400mA and supply
decoupling is normally not necessary. Also, in most instances,
the Control Voltage decoupling capacitors are not required
since the input impedance of the CMOS comparators on chip
are very high. Thus, for many applications, two capacitors can
be saved using an ICM7555 and three capacitors with an
ICM7556.
POWER SUPPLY CONSIDERATIONS
Although the supply current consumed by the ICM7555 and
ICM7556 devices is very low, the total system supply current
can be high unless the timing components are high
impedance. Therefore, use high values for R and low values for
C in Figures 4, 5, and 6.
GND
1
TRIGGER
2
3
VDD
4
RESET
R
VDD
VDD
8
10k
DISCHARGE
7
THRESHOLD
6
5
CONTROL
VOLTAGE
C
OPTIONAL
CAPACITOR
FIGURE 4. ASTABLE OPERATION
FN2867 Rev.10.01
Mar 5, 2020
Page 5 of 13
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