7228AIBIZ Ver la hoja de datos (PDF) - Renesas Electronics
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7228AIBIZ Datasheet PDF : 19 Pages
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ICM7228
Three Level Input, ICM7228C
As mentioned before, pin 9 is a three level input and controls
three functions: Hexadecimal display decoding, Code B display
decoding and shutdown mode. In many applications, pin 9 will
be left open or permanently wired to one state. When pin 9 can
not be permanently left in one state, the circuits illustrated in
Figure 17 can be used to drive this three level input.
HIGH = HEX
LOW = SHUTDOWN
74C126 THREE-STATE BUFFER
PIN 9
HIGH = HEX OR SHUTDOWN
LOW = CODE B
HIGH = HEX
LOW = SHUTDOWN
HIGH = HEX OR SHUTDOWN
LOW = CODE B
HIGH = CODE B
LOW = HEX
CD4016
CD4066
CONTROL
CD4069 1N4148
PIN 9
PIN 9
HIGH = SHUTDOWN
LOW = CODE B
CD4069 1N4148
PIN 9
HIGH = SHUTDOWN
LOW = HEX
HIGH = SHUTDOWN
LOW = CODE B
CD4069
PIN 9
OPEN DRAIN OR OPEN
COLLECTOR OUTPUT
PIN 9
FIGURE 17. ICM7228C PIN 9 DRIVE CIRCUITS
Test Circuit
Power Supply Bypassing
Connect a minimum of 47F in parallel with 0.1F capacitors
between VDD and VSS of ICM7228. These capacitors should
be placed in close proximity to the device to reduce the power
supply ripple caused by the multiplexed LED display drive
current pulses.
VDD
+
5V
-
VSS
FN3160 Rev 9.00
August 19, 2015
1
28
2
27
3
26
4
25
ID6 (HEXA/CODE B)
5
24
ID5 (DECODE)
6
23
ID7 (DATA COMING)
7
22
WRITE
8
ICM7228A
21
MODE
9
20
ID4 (SHUTDOWN)
10
19
ID1 11
18
ID0
12
17
ID2
13
16
ID3
14
15
VDD
47F
+0.1F
VSS
f
d
g
a
c
D8
D7 D6 D5 D4 D3 D2 D1
e
COMMON ANODE DISPLAY
b
DP
FIGURE 18. FUNCTIONAL TEST CIRCUIT #1
Page 16 of 19
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