Overview
The SN65HVD78DR is a low-power, half-duplex RS-485 transceiver produced by Texas Instruments. This device is part of the SN65HVD7x family, which is designed for demanding industrial applications. It operates from a single 3.3-V power supply and features robust drivers and receivers in small packages, including SOIC, VSSOP, and VSON. The transceiver is optimized for data transmission rates up to 50 Mbps and is characterized over a wide ambient temperature range from –40°C to 125°C.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| Supply Voltage (VCC) | -0.5 | 5 | V | |
| Voltage at A or B Inputs | -13 | 16.5 | V | |
| Voltage at D, DE, or RE | -0.3 | 5.7 | V | |
| Driver Differential Output Rise or Fall Time | 1 | 3 | 6 | ns |
| Driver Propagation Delay | 0.7 | 1 | µs | |
| Receiver Output Rise or Fall Time | 5 | 10 | ns | |
| Receiver Propagation Delay | 60 | 70 | ns | |
| Supply Current (Quiescent) | 750 | 950 | µA | |
| Junction Temperature (TJ) | 125 | °C |
Key Features
- Small-size VSSOP packages save board space, or SOIC for drop-in compatibility.
- Bus I/O protection: ±15 kV HBM, ±12 kV IEC 61000-4-2 contact discharge, and ±4 kV IEC 61000-4-4 fast transient burst.
- Extended industrial temperature range: –40°C to 125°C.
- Large receiver hysteresis (80 mV) for noise rejection.
- Low unit-loading allows over 200 connected nodes.
- Low power consumption: Low standby supply current (< 2 µA), ICC < 1 mA quiescent during operation.
- 5-V tolerant logic inputs compatible with 3.3-V or 5-V controllers.
- Signaling rate options optimized for 250 kbps, 20 Mbps, and 50 Mbps.
- Glitch-free power-up and power-down bus inputs and outputs.
Applications
- Factory Automation
- Telecommunications Infrastructure
- Motion Control
Q & A
- What is the maximum data transmission rate of the SN65HVD78DR?
The SN65HVD78DR supports data transmission rates up to 50 Mbps.
- What are the operating temperature ranges for the SN65HVD78DR?
The device operates over a temperature range from –40°C to 125°C.
- What types of ESD protection does the SN65HVD78DR offer?
The device offers ±15 kV HBM, ±12 kV IEC 61000-4-2 contact discharge, and ±4 kV IEC 61000-4-4 fast transient burst protection.
- How many nodes can be connected using the SN65HVD78DR?
The device allows for over 200 connected nodes due to its low unit-loading.
- What is the standby current of the SN65HVD78DR when both driver and receiver are disabled?
The standby current is less than 2 µA when both driver and receiver are disabled.
- Is the SN65HVD78DR compatible with 5-V logic inputs?
Yes, the device has 5-V tolerant logic inputs compatible with 3.3-V or 5-V controllers.
- What are the typical package options for the SN65HVD78DR?
The device is available in SOIC, VSSOP, and VSON packages.
- How does the driver enable pin (DE) function in the SN65HVD78DR?
The driver enable pin (DE) is active-high, meaning the driver is enabled when DE is logic high and disabled when DE is logic low or left open.
- What is the receiver hysteresis of the SN65HVD78DR?
The receiver hysteresis is 80 mV, which helps in noise rejection.
- Are the power-up and power-down transitions of the SN65HVD78DR glitch-free?
Yes, the device features glitch-free power-up and power-down bus inputs and outputs.
