Overview
The SN75ALS1178 is a dual differential driver and receiver integrated circuit designed by Texas Instruments. This component is optimized for bidirectional data communication on multipoint bus transmission lines, adhering to the TIA/EIA-422-B and TIA/EIA-485-A standards. It operates from a single 5V power supply and is characterized for operation from 0°C to 70°C. The SN75ALS1178 features dual 3-state differential line drivers and dual 3-state differential input line receivers, making it suitable for various industrial and automation applications.
Key Specifications
| Parameter | Min | Nom | Max | Unit |
|---|---|---|---|---|
| VCC (Supply Voltage) | 4.75 | 5 | 5.25 | V |
| VID (Differential Input Voltage) | ±12 | V | ||
| VOC (Common-mode Output Voltage) | –7 | 12 | V | |
| VIC (Common-mode Input Voltage) | ±12 | V | ||
| VIH (High-level Input Voltage) | 2 | V | ||
| VIL (Low-level Input Voltage) | 0.8 | V | ||
| IOH (High-level Output Current) | –60 | mA | ||
| IOL (Low-level Output Current) | 60 | mA | ||
| TA (Operating Free-air Temperature) | 0 | 70 | °C | |
| ICC (Supply Current) | 35 | 50 | mA |
Key Features
- Meets or exceeds TIA/EIA-422-B and TIA/EIA-485-A standards.
- Designed for multipoint bus transmission on long bus lines in noisy environments.
- Low supply-current requirement: 50mA maximum.
- Driver positive-and negative-current limiting.
- Driver common-mode output voltage range of –7V to 12V.
- Thermal shutdown protection and driver 3-state outputs with active-high enable.
- Receiver common-mode input voltage range of –12V to 12V.
- Receiver input sensitivity: ±200mV and hysteresis: 50mV typical.
- Receiver high input impedance: 12kΩ minimum.
- Operates from a single 5V supply.
- Fail-safe design ensures receiver outputs are always high when inputs are open.
Applications
- Motor Drives
- Factory Automation
- Building Automation
Q & A
- What are the primary standards that the SN75ALS1178 complies with?
The SN75ALS1178 meets or exceeds the TIA/EIA-422-B and TIA/EIA-485-A standards.
- What is the operating temperature range of the SN75ALS1178?
The SN75ALS1178 operates from 0°C to 70°C.
- What is the supply voltage range for the SN75ALS1178?
The supply voltage range is from 4.75V to 5.25V.
- What is the common-mode output voltage range of the drivers?
The common-mode output voltage range is from –7V to 12V.
- What is the common-mode input voltage range of the receivers?
The common-mode input voltage range is from –12V to 12V.
- What is the input sensitivity of the receivers?
The receiver input sensitivity is ±200mV.
- Does the SN75ALS1178 have thermal shutdown protection?
- What is the maximum supply current for the SN75ALS1178?
The maximum supply current is 50mA.
- What are some typical applications of the SN75ALS1178?
Typical applications include motor drives, factory automation, and building automation.
- How many differential drivers and receivers does the SN75ALS1178 have?
The SN75ALS1178 has dual differential drivers and dual differential receivers.
