Overview
The DS485N/NOPB is a low-power RS-485/RS-422 multipoint transceiver produced by Texas Instruments (formerly National Semiconductor). This device is designed to meet the TIA/EIA RS-485 and RS-422 communication standards. It features a single driver and a single receiver, making it suitable for various industrial and commercial applications. The DS485N/NOPB operates from a single +5V supply and is characterized for operation over an industrial temperature range of 0°C to 70°C.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|
| Supply Voltage (VCC) | 4.75 | 5.0 | 5.25 | V | |
| Quiescent Current (ICC) | DE = VCC, RE* = 0V or VCC | 200 | 200 | 900 | μA |
| Differential Driver Output Voltage (VOD3) | Full Load with Max VCM | 1.5 | 2.0 | 5 | V |
| Driver Transition Time (tr, tf) | 3 | 25 | 40 | ns | |
| Driver Propagation Delay (tPLHD, tPHLD) | 10 | 40 | 65 | ns | |
| Receiver Propagation Delay (tPLHD, tPHLD) | 70 | 200 | 320 | ns | |
| Maximum Data Rate | 2.5 | Mbps | |||
| Common-Mode Input Voltage Range | -7 | 12 | V |
Key Features
- Meets TIA/EIA RS-485 Multipoint Standard and RS-422 communication standards.
- Low quiescent current: 200 μA typical.
- TRI-STATE outputs on driver and receiver.
- Current-limiting and thermal shutdown for driver overload protection.
- Operates from a single +5V supply.
- Half-duplex flow through pinout.
- Allows up to 32 transceivers on the bus.
- Industrial temperature range operation: 0°C to 70°C.
- Pin and functional compatibility with MAX485 and LTC485.
- Failsafe feature ensures a logic-high output if the input is open circuit.
Applications
The DS485N/NOPB is designed for use in RS-485 multipoint applications, including industrial automation, process control systems, and any environment requiring reliable, high-speed data transmission over long distances. It supports data rates up to 2.5 Mbps and can be used in systems that require multiple transceivers on a single bus. Typical applications include multipoint networks, remote sensors, and control systems.
Q & A
- What is the typical quiescent current of the DS485N/NOPB?
The typical quiescent current is 200 μA.
- What is the maximum data rate supported by the DS485N/NOPB?
The maximum data rate is 2.5 Mbps.
- What is the common-mode input voltage range of the DS485N/NOPB?
The common-mode input voltage range is -7V to +12V.
- How many transceivers can be connected to the bus using the DS485N/NOPB?
Up to 32 transceivers can be connected to the bus.
- What type of protection does the DS485N/NOPB have against driver overload?
The device features current-limiting and thermal shutdown protection.
- What is the operating temperature range of the DS485N/NOPB?
The operating temperature range is 0°C to 70°C.
- Is the DS485N/NOPB pin and functionally compatible with other transceivers?
Yes, it is compatible with MAX485 and LTC485.
- What happens to the receiver output if the input is open circuit?
The receiver output will be logic-high if the input is open circuit due to the failsafe feature.
- What is the supply voltage range for the DS485N/NOPB?
The supply voltage range is 4.75V to 5.25V.
- What type of packages is the DS485N/NOPB available in?
The device is available in 8-pin SOIC and PDIP packages.
