Overview
The SN74HC148DRE4 is an 8-line to 3-line priority encoder produced by Texas Instruments. This device is part of the 74HC series, known for its high-speed and low-power CMOS logic. The SN74HC148DRE4 encodes eight data lines into a 3-line binary (octal) output, with priority decoding ensuring that only the highest-order data line is encoded. It features input enable (EI) and output enable (EO) signals, allowing for easy cascading of multiple stages without additional external circuitry.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage Range | -0.5 | - | 7 | V |
| Operating Temperature Range | -55 | - | 125 | °C |
| Input Clamp Current (VI < 0 or VI > VCC) | -20 | - | 20 | mA |
| Output Clamp Current (VO < 0 or VO > VCC) | -20 | - | 20 | mA |
| Continuous Output Current (VO = 0 to VCC) | -25 | - | 25 | mA |
| Propagation Delay (tpd) at VCC = 4.5V | 23 | 36 | 54 | ns |
| Propagation Delay (tpd) at VCC = 6V | 21 | 31 | 46 | ns |
| High-Level Output Voltage (VOH) at VCC = 4.5V, IOH = -20 μA | 4.4 | 4.499 | 4.4 | V |
| Low-Level Output Voltage (VOL) at VCC = 4.5V, IOL = 20 μA | 0.001 | 0.1 | 0.1 | V |
| Supply Current (ICC) at VCC = 6V | 8 | 160 | 80 | μA |
| Input Capacitance | 3 | 10 | 10 | pF |
Key Features
- Wide operating voltage range: 2 V to 6 V
- Outputs can drive up to 10 LSTTL loads
- Low power consumption, 80-μA max ICC
- Typical propagation delay (tpd) = 16 ns
- ±4-mA output drive at 5 V
- Low input current of 1 μA max
- Encode eight data lines to 3-line binary (octal)
- Input enable (EI) and output enable (EO) signals for cascading
Applications
- N-Bit encoding
- Code converters and generators
Q & A
- What is the primary function of the SN74HC148DRE4?
The primary function of the SN74HC148DRE4 is to encode eight data lines into a 3-line binary (octal) output with priority decoding.
- What is the operating voltage range of the SN74HC148DRE4?
The operating voltage range is from 2 V to 6 V.
- How many LSTTL loads can the outputs of the SN74HC148DRE4 drive?
The outputs can drive up to 10 LSTTL loads.
- What is the typical propagation delay (tpd) of the SN74HC148DRE4?
The typical propagation delay is 16 ns.
- What are the input enable and output enable signals used for in the SN74HC148DRE4?
The input enable (EI) and output enable (EO) signals are used for cascading multiple stages without additional external circuitry.
- What is the maximum supply current (ICC) of the SN74HC148DRE4 at VCC = 6V?
The maximum supply current is 80 μA.
- What is the operating temperature range of the SN74HC148DRE4?
The operating temperature range is from -55°C to 125°C.
- What are some common applications of the SN74HC148DRE4?
Common applications include n-bit encoding and code converters and generators.
- What is the package type and pin count of the SN74HC148DRE4?
The package type is SOIC (D) with 16 pins.
- Is the SN74HC148DRE4 suitable for use in safety-critical applications?
No, it is not recommended for use in safety-critical applications without proper evaluation and validation.
