Overview
The SN74HC251D is a data selector/multiplexer produced by Texas Instruments. This device is part of the 74HC series, known for its high-speed and low-power CMOS logic. The SN74HC251D features full binary decoding to select one of eight data sources and includes strobe-controlled complementary 3-state outputs. This component is designed to interface directly with system buses or drive up to 15 LSTTL loads, making it versatile for various digital circuit applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | 2 | 5 | 6 | V |
| VIH High-Level Input Voltage | 1.5 (VCC = 2V) | - | 3.15 (VCC = 4.5V) | V |
| VOH High-Level Output Voltage | 1.9 (VCC = 2V, IOH = -20μA) | - | 5.9 (VCC = 6V, IOH = -20μA) | V |
| VOL Low-Level Output Voltage | 0.1 (VCC = 2V, IOL = 20μA) | - | 0.4 (VCC = 6V, IOL = 7.8mA) | V |
| ICC Quiescent Current | - | 8 | 80 | μA |
| tpd Propagation Delay | 58 (VCC = 2V, CL = 50pF) | - | 205 (VCC = 2V, CL = 50pF) | ns |
| TJ Junction Temperature | - | - | 150 | °C |
| Tstg Storage Temperature | -65 | - | 150 | °C |
Key Features
- 3-state version of the 'HC151, with strobe-controlled complementary 3-state outputs.
- Wide operating voltage range of 2 V to 6 V.
- High-current 3-state outputs that can interface directly with system buses or drive up to 15 LSTTL loads.
- Low power consumption, with a maximum ICC of 80 μA.
- Typical propagation delay of 9 ns.
- ±6-mA output drive at 5 V.
- Low input current of 1 μA max.
- Ability to perform parallel-to-serial conversion.
- Complementary outputs provide true and inverted data.
Applications
- Bus-organized systems where multiple data sources need to be selected and routed.
- Digital multiplexing and demultiplexing applications.
- Parallel-to-serial conversion circuits.
- General-purpose logic circuits requiring high-speed and low-power operation.
- Embedded systems and microcontroller interfaces.
Q & A
- What is the operating voltage range of the SN74HC251D?
The operating voltage range is from 2 V to 6 V.
- What is the maximum propagation delay of the SN74HC251D?
The maximum propagation delay is approximately 205 ns at VCC = 2 V and CL = 50 pF.
- How many LSTTL loads can the SN74HC251D drive?
The device can drive up to 15 LSTTL loads.
- What is the typical quiescent current of the SN74HC251D?
The typical quiescent current is 8 μA.
- What is the junction temperature range for the SN74HC251D?
The junction temperature range is up to 150°C.
- Can the SN74HC251D perform parallel-to-serial conversion?
Yes, the device can perform parallel-to-serial conversion.
- What type of outputs does the SN74HC251D have?
The device has strobe-controlled complementary 3-state outputs.
- What is the recommended bypass capacitor for the power supply?
A 0.1-μF capacitor is recommended, and it is acceptable to parallel multiple bypass caps to reject different frequencies of noise.
- What are the package options available for the SN74HC251D?
The device is available in various packages including SOIC, SSOP, PDIP, SO, TSSOP, and LCCC.
- What is the storage temperature range for the SN74HC251D?
The storage temperature range is from -65°C to 150°C.
