Overview
The SN74HC251DBR is a data selector/multiplexer produced by Texas Instruments. It is a 3-state version of the 'HC151 and features full binary decoding to select 1-of-8 data sources. This device is designed to interface directly with system buses and can drive up to 15 LSTTL loads. It operates over a wide voltage range of 2 V to 6 V, making it versatile for various applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit | Conditions |
|---|---|---|---|---|---|
| VCC Supply Voltage | 2 | 5 | 6 | V | |
| VIH High-Level Input Voltage | 1.5 | V | VCC = 2 V | ||
| VOH High-Level Output Voltage | 1.9 | 1.998 | V | IOH = -20 μA, VCC = 2 V | |
| VOL Low-Level Output Voltage | 0.002 | 0.1 | V | IOL = 20 μA, VCC = 2 V | |
| ICC Quiescent Current | 8 | 80 | μA | VI = VCC or 0, IO = 0, VCC = 6 V | |
| tpd Propagation Delay | 58 | 205 | ns | VCC = 2 V, CL = 50 pF | |
| TJ Junction Temperature | 150 | °C |
Key Features
- 3-state version of '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 bus 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.
- Perform parallel-to-serial conversion.
- Complementary outputs provide true and inverted data.
Applications
The SN74HC251DBR is suitable for various digital logic applications, including:
- Bus-organized systems where the 3-state outputs can drive data lines.
- Data selection and multiplexing in digital circuits.
- Parallel-to-serial conversion in communication systems.
- General-purpose logic circuits requiring high-current drive capabilities.
Q & A
- What is the operating voltage range of the SN74HC251DBR?
The operating voltage range is 2 V to 6 V.
- How many data sources can the SN74HC251DBR select?
The device can select 1-of-8 data sources.
- What is the typical propagation delay of the SN74HC251DBR?
The typical propagation delay is 9 ns.
- What is the maximum ICC (quiescent current) of the SN74HC251DBR?
The maximum ICC is 80 μA.
- Can the SN74HC251DBR drive LSTTL loads?
Yes, it can drive up to 15 LSTTL loads.
- What is the junction temperature range of the SN74HC251DBR?
The junction temperature range is up to 150 °C.
- How are the outputs controlled in the SN74HC251DBR?
The outputs are controlled by the output-enable (OE) input.
- What happens to the outputs when OE is high?
The outputs are disabled when OE is high.
- Can the SN74HC251DBR perform parallel-to-serial conversion?
Yes, it can perform parallel-to-serial conversion.
- What type of outputs does the SN74HC251DBR provide?
The device provides complementary outputs that offer true and inverted data.
