Overview
The SN74HCT138NG4 is a 3-line to 8-line decoder/demultiplexer produced by Texas Instruments. This device is designed for high-performance memory-decoding and data-routing applications that require very short propagation delay times. It is particularly useful in high-speed memory systems where it can minimize the effects of system decoding, ensuring that the delay times introduced by the decoders are negligible when used with fast enable circuits and high-speed memories.
Key Specifications
| Parameter | Unit | Min | Max | |
|---|---|---|---|---|
| VCC (Supply voltage) | V | 4.5 | 5 | 5.5 |
| VIH (High-level input voltage) | V | 2 | ||
| VIL (Low-level input voltage) | V | 0.8 | ||
| VOH (High-level output voltage) at IOH = –20 μA | V | 4.4 | 4.499 | |
| VOL (Low-level output voltage) at IOL = 20 μA | V | 0.1 | 0.1 | |
| ICC (Supply current) | μA | 8 | 80 | |
| tpd (Propagation delay time) | ns | 17 | 32 | |
| TA (Operating free-air temperature) | °C | -40 | 85 |
Key Features
- Operating voltage range of 4.5 V to 5.5 V
- Outputs can drive up to 10 LSTTL loads
- Low power consumption, 80-µA max ICC
- Typical propagation delay time (tpd) of 17 ns
- ±4-mA output drive at 5 V
- Low input current of 1 µA max
- Inputs are TTL-Voltage compatible
- Designed specifically for high-speed memory decoders and data transmission systems
- Incorporate three enable inputs to simplify cascading and/or data reception
Applications
- High-performance memory systems
- Data-routing applications
- LED displays
- Servers
- White goods
- Power infrastructure
- Building automation
- Factory automation
Q & A
- What is the operating voltage range of the SN74HCT138NG4?
The operating voltage range is from 4.5 V to 5.5 V.
- How many LSTTL loads can the outputs of the SN74HCT138NG4 drive?
The outputs can drive up to 10 LSTTL loads.
- What is the typical propagation delay time (tpd) of the SN74HCT138NG4?
The typical propagation delay time is 17 ns.
- What is the maximum supply current (ICC) of the SN74HCT138NG4?
The maximum supply current is 80 µA.
- What are the input voltage levels compatible with the SN74HCT138NG4?
The inputs are TTL-Voltage compatible.
- How do the three enable inputs simplify the use of the SN74HCT138NG4?
The three enable inputs simplify cascading and/or data reception by reducing the need for external gates or inverters.
- What are some common applications of the SN74HCT138NG4?
Common applications include high-performance memory systems, data-routing applications, LED displays, servers, white goods, power infrastructure, building automation, and factory automation.
- What is the operating temperature range of the SN74HCT138NG4?
The operating free-air temperature range is from -40°C to 85°C.
- How many output lines can be selected by the SN74HCT138NG4?
The device can select one of eight output lines based on the conditions at the binary-select inputs and the three enable inputs.
- What is the significance of the low power consumption of the SN74HCT138NG4?
The low power consumption of 80-µA max ICC makes it suitable for applications where power efficiency is crucial.
