Overview
The CD74HCT238M96G4, produced by Texas Instruments, is a high-speed CMOS logic 3-to-8 line decoder/demultiplexer. This integrated circuit is part of the 74HCT series, which is known for its compatibility with TTL (Transistor-Transistor Logic) inputs and its low power consumption. The device is well-suited for applications requiring memory address decoding or data routing.
It features three address select inputs (A2, A1, and A0) and three enable inputs (G2, G1, and G0) to simplify cascading and demultiplexing operations. The outputs are normally high when selected, making it an inverting decoder/demultiplexer.
Key Specifications
| Parameter | Test Conditions | Unit | Min | Max | |
|---|---|---|---|---|---|
| VCC (Operating Voltage) | V | 4.5 | 5.5 | ||
| VIH (High-level input voltage) | VCC = 5 V | V | 2 | ||
| VIL (Low-level input voltage) | VCC = 5 V | V | 0.8 | ||
| VOH (High-level output voltage) | IOH = –20 μA, VCC = 5 V | V | 4.4 | ||
| Propagation Delay (tpd) | Address to output, CL = 50 pF, VCC = 5 V | ns | 14 | 35 | |
| Output Transition Time (tt) | CL = 50 pF, VCC = 5 V | ns | 15 | 22 | |
| Input Capacitance (Ci) | pF | 10 | |||
| Power Dissipation Capacitance (Cpd) | CL = 15 pF | pF | 67 | ||
| Operating Temperature Range | °C | -55 | 125 | ||
| Package Type | SOIC (16 pins) |
Key Features
- Select one of eight data outputs with active high outputs for the CD74HCT238.
- Three enable inputs (G2, G1, and G0) to simplify cascading and demultiplexing.
- Typical propagation delay of 13 ns at VCC = 5 V, CL = 15 pF, TA = 25°C.
- Fanout capability: can drive up to 10 LSTTL loads.
- Wide operating temperature range: -55°C to 125°C.
- High noise immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5 V.
- Direct LSTTL input logic compatibility.
- CMOS input compatibility with low input current (Il ≤ 1µA at VOL, VOH).
- Significant power reduction compared to LSTTL logic ICs.
Applications
- Memory address decoding.
- Data routing applications.
- Demultiplexing operations.
- I/O port or memory selector functions.
- Cascading decoders for larger decoding requirements.
Q & A
- What is the primary function of the CD74HCT238M96G4?
The primary function is to act as a 3-to-8 line decoder/demultiplexer, selecting one of eight data outputs based on the input address.
- What are the operating voltage ranges for the CD74HCT238M96G4?
The operating voltage range is from 4.5 V to 5.5 V.
- What is the typical propagation delay of the CD74HCT238M96G4?
The typical propagation delay is 13 ns at VCC = 5 V, CL = 15 pF, and TA = 25°C.
- How many LSTTL loads can the CD74HCT238M96G4 drive?
The device can drive up to 10 LSTTL loads.
- What is the operating temperature range of the CD74HCT238M96G4?
The operating temperature range is from -55°C to 125°C.
- Does the CD74HCT238M96G4 have high noise immunity?
Yes, it has high noise immunity with NIL = 30%, NIH = 30% of VCC at VCC = 5 V.
- Is the CD74HCT238M96G4 compatible with LSTTL input logic?
Yes, it is directly compatible with LSTTL input logic.
- What is the package type of the CD74HCT238M96G4?
The package type is SOIC (16 pins).
- Can the CD74HCT238M96G4 be used for demultiplexing operations?
Yes, it can be used for demultiplexing operations by using the select inputs and one of the strobe inputs as the data input.
- How does the CD74HCT238M96G4 simplify cascading?
The device simplifies cascading through its three enable inputs (G2, G1, and G0).
