Overview
The SN65HVD1781DR is a half-duplex RS-485 transceiver designed and manufactured by Texas Instruments. This device is part of the SN65HVD178x family, which is known for its robust fault protection and wide operating range. The SN65HVD1781DR is engineered to survive overvoltage faults, including direct shorts to power supplies, mis-wiring faults, connector failures, cable crushes, and tool mis-applications. It also offers high levels of protection against electrostatic discharges (ESD) according to the human-body-model specification.
The device combines a differential driver and a differential receiver, operating from a single power supply, and is fully compliant with ANSI TIA/EIA 485-A standards. It is pin-compatible with the industry-standard SN75176 transceiver, making it a drop-in upgrade in most systems.
Key Specifications
| Parameter | Min | Nom | Max | Unit |
|---|---|---|---|---|
| VCC (Supply Voltage) | 3.15 | 5 | 5.5 | V |
| Vi (Input Voltage at any bus terminal) | -7 | 12 | V | |
| Vih (High-level input voltage) | 2 | VCC | V | |
| Vil (Low-level input voltage) | 0 | 0.8 | V | |
| VID (Differential input voltage) | -12 | 12 | V | |
| IO (Output current, driver) | -60 | 60 | mA | |
| IO (Output current, receiver) | -8 | 8 | mA | |
| Rl (Differential load resistance) | 54 | 60 | Ω | |
| CL (Differential load capacitance) | 50 | pF | ||
| Ta (Operating free-air temperature) | -40 | 125 | °C | |
| Tj (Junction temperature) | -40 | 150 | °C | |
| Signaling Rate | 115 kbps | 1 Mbps | 10 Mbps |
Key Features
- Bus-Pin Fault Protection up to ±70 V (SN65HVD1780, SN65HVD1781)
- Operation with 3.3-V to 5-V Supply Range
- ±16-kV HBM Protection on Bus Pins
- Reduced Unit Load for up to 320 Nodes
- Failsafe Receiver for Open-Circuit, Short-Circuit, and Idle-Bus Conditions
- Low Power Consumption:
- Low Standby Supply Current, 1 µA Maximum
- ICC 4-mA Quiescent Current During Operation
- Pin-Compatible With Industry-Standard SN75176
- Signaling Rates of 115 kbps, 1 Mbps, and up to 10 Mbps
Applications
The SN65HVD1781DR is suitable for a variety of applications, including:
- Multipoint applications over long cable runs due to its wide common-mode voltage range
- Industrial automation and control systems where robust fault protection is necessary
- Telecommunications and networking equipment requiring reliable data transmission
- Automotive systems where the device's ability to operate over a wide temperature range is beneficial
- Any system requiring half-duplex RS-485 communication with high reliability and fault tolerance
Q & A
- What is the primary function of the SN65HVD1781DR?
The SN65HVD1781DR is a half-duplex RS-485 transceiver that combines a differential driver and a differential receiver, operating from a single power supply.
- What are the signaling rates supported by the SN65HVD1781DR?
The device supports signaling rates of 115 kbps, 1 Mbps, and up to 10 Mbps.
- What is the operating temperature range of the SN65HVD1781DR?
The device operates over a temperature range from -40°C to 125°C.
- What level of bus-pin fault protection does the SN65HVD1781DR offer?
The device offers bus-pin fault protection up to ±70 V.
- Is the SN65HVD1781DR compatible with other industry-standard transceivers?
Yes, it is pin-compatible with the industry-standard SN75176 transceiver.
- What is the maximum standby supply current of the SN65HVD1781DR?
The maximum standby supply current is less than 1 µA.
- Does the SN65HVD1781DR have built-in ESD protection?
Yes, it has ±16-kV HBM protection on bus pins.
- What is the recommended operating supply voltage range for the SN65HVD1781DR?
The recommended operating supply voltage range is from 3.15 V to 5.5 V.
- How many nodes can the SN65HVD1781DR support?
The device can support up to 320 nodes.
- Is the SN65HVD1781DR suitable for multipoint applications over long cable runs?
Yes, it features a wide common-mode voltage range, making it suitable for such applications.
