Overview
The CD74HC238PWRG4 is a 3-to-8 line decoder/demultiplexer produced by Texas Instruments. This component is part of the HC (High-Speed CMOS) logic family and is well-suited for memory address decoding or data routing applications. It features three binary weighted address inputs (A0, A1, and A2) that decode to eight mutually exclusive outputs (Y0 to Y7). The device includes three enable inputs (G0, G1, and G2) to simplify cascading and facilitate demultiplexing operations.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage (HC types) | 2.0 | 5.0 | 6.0 | V |
| VCC Supply Voltage (HCT types) | 4.5 | 5.0 | 5.5 | V |
| Input Voltage (VI) | 0 | VCC | V | |
| Output Voltage (VO) | 0 | VCC | V | |
| Ambient Temperature Range | -40 | 125 | °C | |
| Propagation Delay (Address to Output) | 13 | 53 | ns | |
| Output Transition Time | 15 | 22 | ns | |
| Input Capacitance (Ci) | 10 | pF | ||
| Power Dissipation Capacitance (Cpd) | 67 | pF | ||
| Package Type | TSSOP | |||
| Number of Pins | 16 |
Key Features
- Select one of eight data outputs: Active high for '238.
- Three enable inputs to simplify cascading and facilitate demultiplexing.
- Typical propagation delay of 13 ns at VCC = 5 V, CL = 15 pF, TA = 25°C.
- Fanout: Bus driver outputs can drive 15 LSTTL loads, standard outputs can drive 10 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: 2 V to 6 V operation, high noise immunity.
- HCT types: 4.5-V to 5.5-V operation, direct LSTTL input logic compatibility.
Applications
The CD74HC238PWRG4 is suitable for various applications including memory address decoding, data routing, and demultiplexing. It can be used in systems requiring the selection of one out of eight outputs based on three binary address inputs. This component is particularly useful in digital circuits where multiple outputs need to be controlled based on a few input signals.
Q & A
- What is the primary function of the CD74HC238PWRG4? The primary function is to decode three binary weighted address inputs to eight mutually exclusive outputs.
- What are the supply voltage ranges for HC and HCT types? For HC types, the supply voltage range is 2.0 V to 6.0 V, and for HCT types, it is 4.5 V to 5.5 V.
- What is the typical propagation delay of the CD74HC238PWRG4? The typical propagation delay is 13 ns at VCC = 5 V, CL = 15 pF, and TA = 25°C.
- How many LSTTL loads can the bus driver outputs drive? The bus driver outputs can drive 15 LSTTL loads.
- What is the operating temperature range of the CD74HC238PWRG4? The operating temperature range is -55°C to 125°C.
- What are the package types available for the CD74HC238PWRG4? The component is available in TSSOP (Thin Shrink Small Outline Package) among other packages.
- How many pins does the CD74HC238PWRG4 have? The component has 16 pins.
- What is the significance of the three enable inputs (G0, G1, G2)? The three enable inputs simplify cascading and facilitate demultiplexing operations.
- What is the input capacitance of the CD74HC238PWRG4? The input capacitance is typically 10 pF.
- What is the power dissipation capacitance of the CD74HC238PWRG4? The power dissipation capacitance is typically 67 pF.
