Overview
The SN74HC148N is a high-speed CMOS 8-to-3 line priority encoder produced by Texas Instruments. This device is designed to accept data from up to eight active-low inputs (A0 to A7) and provide a binary representation of the highest priority active input on a 3-bit output (Y0 to Y2). The encoder features an active-low enable input (EI) and an active-low enable output (EO), which facilitate cascading multiple encoders to handle larger input sets.
Key Specifications
| Parameter | Min | Nom | Max | Unit |
|---|---|---|---|---|
| VCC Supply voltage | 2 | 5 | 6 | V |
| VIH High-level input voltage | 1.5 (VCC=2V) | 3.15 (VCC=4.5V) | 4.2 (VCC=6V) | V |
| VIL Low-level input voltage | 0.5 (VCC=2V) | 1.35 (VCC=4.5V) | 1.8 (VCC=6V) | V |
| VOH High-level output voltage | 1.9 (IOH=-20μA) | 4.4 (IOH=-4mA) | 5.9 (IOH=-5.2mA) | V |
| VOL Low-level output voltage | 0.1 (IOL=20μA) | 0.17 (IOL=4mA) | 0.26 (IOL=5.2mA) | V |
| ICC Supply current | 8 | 80 | 160 | μA |
| tpd Propagation Delay | 16 (TA=25°C, VCC=5V) | 23 (TA=25°C, VCC=4.5V) | 31 (TA=25°C, VCC=6V) | ns |
| TJ Junction temperature | - | - | 150 | °C |
| Tstg Storage temperature | -65 | - | 150 | °C |
Key Features
- Wide operating voltage range of 2V to 6V
- Outputs can drive up to 10 LSTTL loads
- Low power consumption, 80-μA max ICC
- Typical propagation delay of 16ns at VCC = 5V
- ±4-mA output drive at 5V
- Low input current of 1μA max
- Active-low enable input (EI) and active-low enable output (EO) for cascading
- Encode eight data lines to 3-line binary (Octal)
Applications
- N-Bit encoding
- Code converters and generators
- Cascading multiple stages for larger input sets
Q & A
- What is the function of the SN74HC148N?
The SN74HC148N is an 8-to-3 line priority encoder that converts eight active-low input lines into a 3-bit binary output, representing the highest priority active input.
- What is the operating voltage range of the SN74HC148N?
The operating voltage range is from 2V to 6V.
- How many LSTTL loads can the outputs drive?
The outputs can drive up to 10 LSTTL loads.
- What is the typical propagation delay of the SN74HC148N?
The typical propagation delay is 16ns at VCC = 5V.
- What are the enable inputs and outputs used for?
The active-low enable input (EI) and active-low enable output (EO) are used for cascading multiple encoders to handle larger input sets.
- What is the maximum junction temperature for the SN74HC148N?
The maximum junction temperature is 150°C.
- What is the storage temperature range for the SN74HC148N?
The storage temperature range is from -65°C to 150°C.
- Can the SN74HC148N be used in safety-critical applications?
No, it is not recommended for use in safety-critical applications without proper evaluation and validation.
- What is the package type of the SN74HC148N?
The package type is 16-Pin PDIP (Plastic Dual In-Line Package).
- Is the SN74HC148N RoHS compliant?
