Overview
The MC74AC138DTR2, produced by ON Semiconductor, is a high-speed 1-of-8 decoder/demultiplexer. This device is particularly suited for high-speed bipolar memory chip select address decoding. It features three binary weighted input lines (A0, A1, A2) and provides eight mutually exclusive active-LOW output lines (O0-O7). The device also includes three enable inputs: two active-LOW (E1, E2) and one active-HIGH (E3), which allow for easy parallel expansion to higher decoder configurations.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| DC Supply Voltage (VCC) | 0.5 to 6.5 | V |
| DC Input Voltage (VI) | -0.5 to VCC + 0.5 | V |
| DC Output Voltage (VO) | -0.5 to VCC + 0.5 | V |
| DC Input Diode Current (IIK) | -20 | mA |
| DC Output Diode Current (IOK) | -50 | mA |
| DC Output Sink/Source Current (IO) | -50 | mA |
| Propagation Delay (tPHL, tPLH) | 5.0 to 13.0 | ns |
| Input Capacitance (CIN) | 4.5 | pF |
| Power Dissipation Capacitance (CPD) | 60 | pF |
| Storage Temperature Range (TSTG) | -65 to 150 | °C |
Key Features
- Demultiplexing capability
- Multiple input enables for easy expansion (allowing parallel expansion to 1-of-24 or 1-of-32 decoders)
- Active LOW mutually exclusive outputs
- Outputs source/sink 24 mA
- TTL compatible inputs for the MC74ACT138 variant
- Pb-free packages available
Applications
The MC74AC138DTR2 is ideal for high-speed bipolar memory chip select address decoding. It can be used in various applications such as:
- Memory chip select decoding
- Demultiplexing applications
- Expanding decoder configurations (e.g., 1-of-24 or 1-of-32 decoders)
- High-speed digital logic circuits
Q & A
- What is the primary function of the MC74AC138DTR2?
The MC74AC138DTR2 is a high-speed 1-of-8 decoder/demultiplexer. - How many input lines and output lines does the MC74AC138DTR2 have?
The device has three binary weighted input lines (A0, A1, A2) and eight mutually exclusive active-LOW output lines (O0-O7). - What are the enable inputs on the MC74AC138DTR2?
The device features two active-LOW enable inputs (E1, E2) and one active-HIGH enable input (E3). - Can the MC74AC138DTR2 be expanded to higher decoder configurations?
Yes, it can be expanded to a 1-of-24 or 1-of-32 decoder using multiple devices and an inverter. - What is the maximum output current of the MC74AC138DTR2?
The outputs can source/sink up to 24 mA. - Is the MC74AC138DTR2 available in Pb-free packages?
Yes, Pb-free packages are available. - What is the propagation delay range of the MC74AC138DTR2?
The propagation delay ranges from 5.0 to 13.0 ns. - What is the storage temperature range for the MC74AC138DTR2?
The storage temperature range is -65 to 150 °C. - Can the MC74AC138DTR2 be used as a demultiplexer?
Yes, it can be used as an 8-output demultiplexer by using one of the active LOW enable inputs as the data input and the other enable inputs as strobes. - What types of packages are available for the MC74AC138DTR2?
The device is available in SOIC-16 and TSSOP-16 packages.
