ICM7228_15 Datasheet, PDF (16/19 Pages) Intersil Corporation – 8-Digit, Microprocessor-Compatible, LED Display Decoder Driver

ICM7228
V_DD
V_DD
1K
V_DD
1.4A_PEAK
2N6034
100
ICM7228B
V_DD
SEGMENT
OUTPUT
DIGIT ^300
OUTPUT
N
15
1K _25
(100mA_PEAK)
2N2219
1K
Power Supply Bypassing
Connect a minimum of 47F in parallel with 0.1F capacitors
between V_DD and V_SS 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.
V_SS
V_SS
FIGURE 16. DRIVING HIGH CURRENT DISPLAY, COMMON
CATHODE ICM7228B TO COMMON ANODE
DISPLAY
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
16