Overview
The SN74LVC138A, including the SN74LVC138ADGVR variant, is a 3-Line to 8-Line decoder/demultiplexer produced by Texas Instruments. This device is designed for high-performance memory-decoding or data-routing applications, particularly in systems requiring very short propagation delay times. It operates within a supply voltage range of 2.7 V to 3.6 V, making it suitable for use in mixed 3.3-V/5-V system environments. The device features two active-low enable inputs and one active-high enable input, which reduce the need for external gates or inverters when expanding the decoder functionality.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage (VCC) | 2.7 | - | 3.6 | V |
| Input Voltage (VI) | -0.5 | - | 6.5 | V |
| Output Voltage (VO) | -0.5 | - | VCC + 0.5 | V |
| Propagation Delay Time (tpd) | 5.8 | - | - | ns |
| High-Level Output Current (IOH) | -100 | - | -24 | mA |
| Low-Level Output Current (IOL) | 100 | - | 24 | mA |
| Operating Free-Air Temperature (TA) | -55 | - | 125 | °C |
| Storage Temperature Range (Tstg) | -65 | - | 150 | °C |
Key Features
- Operates from 2.7 V to 3.6 V supply voltage.
- Inputs accept voltages up to 5.5 V.
- ESD protection exceeds 2000 V per MIL-STD-883, Method 3015.
- Maximum propagation delay time of 5.8 ns at 3.3 V.
- Typical output ground bounce (VOLP) < 0.8 V and output VOH undershoot > 2 V at VCC = 3.3 V, TA = 25°C.
- Supports defense, aerospace, and medical applications with controlled baseline, one assembly/test site, and one fabrication site.
- Available in military temperature range (-55°C to 125°C).
Applications
The SN74LVC138A is designed for high-performance memory-decoding or data-routing applications. It is particularly useful in high-speed memory systems where fast enable circuits are employed. The device minimizes system decoding delays, making it suitable for applications where short propagation delay times are critical. It can also be used as a translator in mixed 3.3-V/5-V system environments.
Q & A
- What is the primary function of the SN74LVC138A?
The SN74LVC138A is a 3-Line to 8-Line decoder/demultiplexer. - What is the operating voltage range of the SN74LVC138A?
The device operates from 2.7 V to 3.6 V. - What is the maximum propagation delay time of the SN74LVC138A?
The maximum propagation delay time is 5.8 ns at 3.3 V. - Does the SN74LVC138A support mixed voltage systems?
Yes, it can be driven from either 3.3-V or 5-V devices. - What kind of ESD protection does the SN74LVC138A have?
The device has ESD protection that exceeds 2000 V per MIL-STD-883, Method 3015. - What are the typical output ground bounce and VOH undershoot values?
Typical output ground bounce (VOLP) is < 0.8 V, and output VOH undershoot is > 2 V at VCC = 3.3 V, TA = 25°C. - Is the SN74LVC138A suitable for high-speed memory systems?
Yes, it is designed to minimize the effects of system decoding in high-speed memory systems. - Can the SN74LVC138A be used in military and medical applications?
Yes, it supports defense, aerospace, and medical applications with controlled baseline and extended product life cycle. - What are the storage and operating temperature ranges for the SN74LVC138A?
The storage temperature range is -65°C to 150°C, and the operating free-air temperature range is -55°C to 125°C. - How many enable inputs does the SN74LVC138A have?
The device has two active-low enable inputs and one active-high enable input.
