1. Overview & Functionality:

️· What they are: These are synchronous decade counters. They count in binary from 0 to 10 (decimal), then reset to 0.
️· LS390 vs. LS393:
- LS390: Is a single decade counter.
- LS393: Is a dual decade counter (two counters in a single package, they function independently).
️· Synchronous Counting: They change state on the rising edge of the clock pulse.
️· Key Inputs:
- CP (Clock Input): The clock pulse drives the counting operation.
- CP0: (LS390 only) – A second clock input for cascade counting.
- CP1: (LS390 & 393) - A second clock input for cascading or other functions.
- MR (Master Reset): Asynchronously resets the counter to 0.
- TO (Terminal Output): Indicates when the count reaches 10 (decimal). It goes high for one clock cycle.

2. Electrical Characteristics:

️· Supply Voltage (VCC): Typically 5V.
️· Input Voltages: Specific voltage ranges are required for logic HIGH and LOW.
️· Output Voltages: VOH (High-level output voltage) and VOL (Low-level output voltage) are defined based on supply voltage and load conditions.
️· Input Currents: Limits on input currents (IIH, IIL) are specified.
️· Power Supply Current (ICC): A maximum value is given for the current drawn from the supply.
️· Short Circuit Currents: Limits are provided for the currents that can flow if an output is shorted to ground or VCC.

3. AC Characteristics (Timing):

️· Maximum Clock Frequency: Limits are given for the maximum frequency of the clock signal. LS393 has a slightly higher max frequency.
️· Propagation Delays: Indicate how long it takes for a signal to propagate from input to output (CP to Q0, CP0 to Q0, etc.).
️· Pulse Width Requirements: The minimum width of the clock pulses (tW) to ensure proper operation.
️· Recovery Time: Time needed after reset to ensure proper counting.

4. Physical Characteristics & Packaging:

️· Package Types: These counters are available in:
- 16-Pin Plastic SOIC
- 16-Pin Plastic DIP (Dual In-Line Package)
- 16-Pin Ceramic DIP
️· Suffix Codes: These indicate the package type and temperature range (e.g., "N" suffix).

5. Important Notes & Warnings:

️· Application Limitations: A significant warning emphasizes that these devices are *not* suitable for life-sustaining or critical applications where failure could cause injury or death. Motorola disclaims liability for such uses.
️· Short Circuit Precautions: If any output is shorted, it should be done for a short time only.
️· Typical Parameters: "Typical" values can vary in different applications, so they need to be validated.