August 1997
ICM7226A,
ICM7226B
8-Digit, Multi-Function,
Frequency Counter/Timer
Features
Description
• CMOS Design for Very Low Power
• Output Drivers Directly Drive Both Digits and
Segments of Large 8-Digit LED Displays
• Measures Frequencies from DC to 10MHz; Periods
from 0.5µs to 10s
• Stable High Frequency Oscillator uses either 1MHz or
10MHz Crystal
• Both Common Anode and Common Cathode Available
• Control Signals Available for External Systems
Interfacing
• Multiplexed BCD Outputs
Applications
• Frequency Counter
• Period Counter
• Unit Counter
• Frequency Ratio Counter
• Time Interval Counter
Ordering Information
TEMP.
PART NUMBER RANGE (oC)
PACKAGE
ICM7226AlJL
-25 to 85 40 Ld CERDIP
ICM7226BlPL
-25 to 85 40 Ld PDIP
PKG.
NO.
F40.6
E40.6
The ICM7226 is a fully integrated Universal Counter and
LED display driver. It combines a high frequency oscillator, a
decade timebase counter, an 8-decade data counter and
latches, a 7-segment decoder, digit multiplexer and segment
and digit drivers which can directly drive large LED displays.
The counter inputs accept a maximum frequency of 10MHz
in frequency and unit counter modes and 2MHz in the other
modes. Both inputs are digital inputs. In many applications,
amplification and level shifting will be required to obtain
proper digital signals for these inputs.
The ICM7226 can function as a frequency counter, period
counter, frequency ratio (fA/fB) counter, time interval counter
or as a totalizing counter. The devices require either a
10MHz or 1MHz quartz crystal timebase, or if desired an
external timebase can also be used. For period and time
interval, the 10MHz timebase gives a 0.1µs resolution. In
period average and time interval average, the resolution can
be in the nanosecond range. In the frequency mode, the
user can select accumulation times of 0.01s, 0.1s, 1s and
10s. With a 10s accumulation time, the frequency can be dis-
played to a resolution of 0.1Hz. There is 0.2s between mea-
surements in all ranges. Control signals are provided to
enable gating and storing of prescaler data.
Leading zero blanking has been incorporated with frequency
display in kHz and time in µs. The display is multiplexed at a
500Hz rate with a 12.2% duty cycle for each digit. The
ICM7226A is designed for common anode displays with typi-
cal peak segment currents of 25mA, and the ICM7226B is
designed for common cathode displays with typical segment
currents of 12mA. In the display off mode, both digit drivers
and segment drivers are turned off, allowing the display to
be used for other functions.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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