74192 IC Up/Down Decade Counter
The IC 74192 is a synchronous 4-bit BCD (Binary-Coded Decimal) up/down counter designed for counting in both directions (up or down) from 0000 (0) to 1001 (9). It includes an Up/Down control input to select the counting direction.
This counter features an asynchronous clear (CLR) that resets the outputs to zero immediately, regardless of the clock, and a parallel load (LOAD) that allows presetting a specific count value. When LOAD is active, the counter loads the preset data instead of counting.
The 74192 includes carry (TCU) and borrow (TCD) outputs for cascading multiple counters to create multi-decade counters. It operates synchronously with the clock for all outputs, ensuring glitch-free transitions.
It is widely used in digital clocks, counters, numerical display systems, and sequencing applications.
Pin Configuration (DIP-16)
| Pin | Name | Description |
|---|---|---|
| 1 | B0 | Parallel Data Input (LSB) |
| 2 | B1 | Parallel Data Input |
| 3 | B2 | Parallel Data Input |
| 4 | B3 | Parallel Data Input (MSB) |
| 5 | U/D | Up/Down Control (HIGH = Up, LOW = Down) |
| 6 | CPU | Clock Pulse Up Input |
| 7 | CPD | Clock Pulse Down Input |
| 8 | GND | Ground |
| 9 | Q0 | Output Bit 0 |
| 10 | Q1 | Output Bit 1 |
| 11 | Q2 | Output Bit 2 |
| 12 | Q3 | Output Bit 3 (MSB) |
| 13 | TCD | Terminal Count Down (Borrow) Output |
| 14 | TCU | Terminal Count Up (Carry) Output |
| 15 | LOAD | Parallel Load (active LOW) |
| 16 | CLR | Asynchronous Clear (active LOW) |
Key Features
Synchronous up/down counting (0–9 BCD)
Separate up and down clock inputs
Asynchronous clear for immediate reset
Parallel load for preset values
Carry and borrow outputs for cascading
TTL-compatible logic levels
Standard DIP-16 or SOIC-16 package
Applications
Design decade up/down counters for digital clocks.
Drive BCD-to-7-segment display decoders.
Implement programmable countdown or count-up timers.
Create reversible event counters in automation systems.
Build cascaded counters for multi-digit counting.
Develop frequency dividers with up/down control.
Use in numerical control panels for scoring.
Create up/down counters in elevators and robotics.
Implement bidirectional sequencing in logic systems.
Teach advanced counters in digital electronics labs.
Specifications Table
| Parameter | Value |
|---|---|
| Logic Family | TTL |
| Function | Synchronous Up/Down BCD Counter |
| Count Range | 0–9 (mod-10) |
| Inputs | CLR, LOAD, CPU, CPD, U/D, B0–B3 |
| Outputs | Q0–Q3, TCU, TCD |
| Input HIGH Voltage | ≥ 2.0V |
| Input LOW Voltage | ≤ 0.8V |
| Output HIGH Voltage | ≥ 2.4V |
| Output LOW Voltage | ≤ 0.4V |
| Propagation Delay | ~25 ns ‘ |
| Max Clock Frequency | ~35 MHz |
| Supply Voltage (Vcc) | 4.75V to 5.25V |
| Operating Temp | 0°C to 70°C |
| Package Type | DIP-16 / SOIC-16 |
| Number of Pins | 16 |
