Overview
The SN74HC138PWR is a 3-line to 8-line decoder/demultiplexer integrated circuit produced by Texas Instruments. This device is specifically designed for high-performance memory-decoding and data-routing applications, offering very short propagation delay times. It is particularly useful in minimizing the effects of system decoding in high-speed memory systems.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC (Supply Voltage) | 2 | - | 6 | V |
| VIH (High-Level Input Voltage) at VCC = 2 V | 1.5 | - | - | V |
| VIH (High-Level Input Voltage) at VCC = 4.5 V | 3.15 | - | - | V |
| VIH (High-Level Input Voltage) at VCC = 6 V | 4.2 | - | - | V |
| VIL (Low-Level Input Voltage) at VCC = 2 V | 0.5 | - | - | V |
| VIL (Low-Level Input Voltage) at VCC = 4.5 V | 1.35 | - | - | V |
| VIL (Low-Level Input Voltage) at VCC = 6 V | 1.8 | - | - | V |
| TA (Operating Free-Air Temperature) | -40 | - | 125 | °C |
| tpd (Propagation Delay Time) at VCC = 2 V | 66 | - | 155 | ns |
| tpd (Propagation Delay Time) at VCC = 4.5 V | 18 | - | 31 | ns |
| tpd (Propagation Delay Time) at VCC = 6 V | 15 | - | 26 | ns |
| ICC (Quiescent Current) at VCC = 2 V to 6 V | - | - | 80 | µA |
Key Features
- Targeted specifically for high-speed memory decoders and data-transmission systems.
- Wide operating voltage range (2 V to 6 V).
- Outputs can drive up to 10 LSTTL loads.
- Low power consumption, with a maximum ICC of 80 µA.
- Typical propagation delay time (tpd) of 15 ns at VCC = 6 V.
- ±4-mA output drive at 5 V.
- Low input current of 1-µA maximum.
- Active low outputs (selected output is low).
- Incorporates three enable inputs to simplify cascading or data reception.
Applications
The SN74HC138PWR is designed for use in high-performance memory-decoding and data-routing applications. It is particularly useful in:
- High-speed memory systems to minimize system decoding delays.
- Data-routing applications requiring fast enable circuits.
- Cascaded decoder configurations for more complex decoding tasks.
Q & A
- What is the primary function of the SN74HC138PWR?
The SN74HC138PWR is a 3-line to 8-line decoder/demultiplexer, designed for high-speed memory-decoding and data-routing applications.
- What is the operating voltage range of the SN74HC138PWR?
The operating voltage range is from 2 V to 6 V.
- What is the typical propagation delay time of the SN74HC138PWR?
The typical propagation delay time is 15 ns at VCC = 6 V.
- How many LSTTL loads can the outputs of the SN74HC138PWR drive?
The outputs can drive up to 10 LSTTL loads.
- What is the maximum quiescent current (ICC) of the SN74HC138PWR?
The maximum quiescent current is 80 µA.
- What are the input voltage levels for the SN74HC138PWR?
The high-level input voltage (VIH) ranges from 1.5 V to 4.2 V, and the low-level input voltage (VIL) ranges from 0.5 V to 1.8 V, depending on the VCC voltage.
- What is the operating temperature range of the SN74HC138PWR?
The operating temperature range is from -40°C to 125°C.
- How many enable inputs does the SN74HC138PWR have?
The device incorporates three enable inputs.
- What type of outputs does the SN74HC138PWR have?
The outputs are active low, meaning the selected output is low.
- What is the package type of the SN74HC138PWR?
The device is available in a 16-pin TSSOP (Thin Shrink Small Outline Package) package.
