Overview
The CD74HC390EE4, produced by Texas Instruments, is a high-speed CMOS logic dual decade ripple counter. This device includes two independent 4-bit decade counters, each divided into two sections: a divide-by-2 and a divide-by-5 counter. Each counter has an independent clock input, allowing for flexible configuration. The device is part of the HC and HCT series, known for their low power consumption and high noise immunity.
Key Specifications
| Parameter | Unit | HC Types (Min - Max) | HCT Types (Min - Max) |
|---|---|---|---|
| Supply Voltage Range | V | 2 - 6 | 4.5 - 5.5 |
| Input Voltage Range | V | 0 - VCC | 0 - VCC |
| Operating Temperature Range | °C | -55 to 125 | -55 to 125 |
| Maximum Clock Frequency | MHz | 35 (at VCC = 6V) | 27 (at VCC = 5V) |
| Propagation Delay (nCLK to Q) | ns | 30 - 45 (at VCC = 6V) | 31 - 48 (at VCC = 5V) |
| Output Transition Times | ns | 75 (at CL = 15 pF, VCC = 5V) | 75 (at CL = 15 pF, VCC = 5V) |
| Input Current (per input pin) | μA | ±1 (at VCC = 5V) | ±1 (at VCC = 5V) |
| Output Source/Sink Current (per output pin) | mA | ±25 | ±25 |
| Junction Temperature | °C | -65 to 150 | -65 to 150 |
Key Features
- Two BCD decade or bi-quinary counters in one package, configurable to divide-by-2, 4, 5, 10, 20, 25, 50, 100.
- Two controller reset inputs to clear each decade counter individually.
- Fanout capability: Standard outputs can drive 10 LSTTL loads, bus driver outputs can drive 15 LSTTL loads.
- Wide operating temperature range: -55°C to 125°C.
- Balanced propagation delay and transition times.
- Significant power reduction compared to LSTTL logic ICs.
- HC types: 2V to 6V operation, high noise immunity.
- HCT types: 4.5V to 5.5V operation, direct LSTTL input logic compatibility.
Applications
The CD74HC390EE4 is suitable for a variety of applications requiring high-speed counting and division, such as:
- Digital counters and timers.
- Frequency dividers.
- Event counters.
- Sequential logic circuits.
- Automotive and industrial control systems.
Q & A
- What is the CD74HC390EE4?
The CD74HC390EE4 is a high-speed CMOS logic dual decade ripple counter produced by Texas Instruments.
- What are the key features of the CD74HC390EE4?
It includes two independent 4-bit decade counters, configurable reset inputs, wide operating temperature range, and low power consumption.
- What are the operating voltage ranges for HC and HCT types?
HC types operate from 2V to 6V, while HCT types operate from 4.5V to 5.5V.
- What is the maximum clock frequency for the CD74HC390EE4?
The maximum clock frequency is up to 35 MHz for HC types at VCC = 6V and up to 27 MHz for HCT types at VCC = 5V.
- How many LSTTL loads can the outputs drive?
Standard outputs can drive 10 LSTTL loads, and bus driver outputs can drive 15 LSTTL loads.
- What is the operating temperature range of the CD74HC390EE4?
The device operates over a temperature range of -55°C to 125°C.
- What are some common applications for the CD74HC390EE4?
It is used in digital counters, timers, frequency dividers, event counters, and sequential logic circuits.
- How do I ensure proper power supply for the CD74HC390EE4?
Each VCC terminal should have a good bypass capacitor, typically a 0.1-μF capacitor, installed close to the power terminal.
- Can the inputs of the CD74HC390EE4 be left floating?
No, all unused inputs must be held at VCC or GND to ensure proper device operation.
- What is the significance of the reset inputs on the CD74HC390EE4?
The reset inputs (1CLR and 2CLR) are active-High asynchronous inputs that can clear each decade counter individually.
