TPT485
High-speed RS-485/RS-422 transceiver with 20Mbps data rate, ±18kV ESD protection, 1/8 unit load for up to 256 nodes.
Product Overview
Description
The TPT485 is a robust RS-485/RS-422 transceiver designed for harsh industrial environments.
It supports data rates up to 20Mbps and features ±18kV HBM ESD protection on the bus pins.
With 1/8 unit load receiver input impedance, up to 256 transceivers can be connected on the same bus.
Product Series
TPT
Primary Application
Industrial automation networks
Key Features
- 20Mbps maximum data rate
- ±18kV HBM ESD protection
- 1/8 unit load (256 nodes)
- Wide common-mode range: -7V to +12V
- Fail-safe receiver (open/short/idle bus)
- Thermal shutdown protection
Specifications
| Interface | RS-485/RS-422 |
|---|---|
| Data Rate | 20 Mbps max |
| ESD Protection | ±18kV HBM on bus pins |
| Common Mode Range | -7V to +12V |
| Unit Load | 1/8 (256 nodes max) |
| Supply Voltage | 3.0V to 3.6V or 4.5V to 5.5V |
| Package | SOIC-8, DIP-8 |
Applications
Industrial automation networks
Industrial automation and control
Building automation systems
Industrial automation and control
Security and surveillance
Electronic system design
Metering and instrumentation
Electronic system design
Point-of-sale terminals
Electronic system design
Motor control systems
Motor drive and control systems
FAE Expert Insights
"Based on extensive field experience, this product delivers excellent performance across various operating conditions. The design incorporates proven architecture with robust protection features. Customers consistently report high satisfaction with reliability and ease of integration."
The TPT485 stands out for its reliability and performance in real-world applications.
— Senior FAE Team, BeiLuo
Frequently Asked Questions
How many nodes can be on the bus?
The TPT485 features 1/8 unit load receiver input impedance, allowing up to 256 transceivers on the same bus (standard RS-485 allows 32 unit loads). This is useful for large industrial networks. For even larger networks, use repeaters to extend the bus.
256 nodes max with TPT485. Use repeaters for larger networks or longer distances.
What is the maximum data rate and cable length?
The TPT485 supports data rates up to 20Mbps. Maximum cable length depends on data rate: At 100kbps: up to 1200m, At 1Mbps: up to 100m, At 10Mbps: up to 10m, At 20Mbps: up to 5m. Use twisted-pair cable (Cat5e or better) for best noise immunity. Higher data rates require shorter cables due to signal attenuation and timing constraints.
20Mbps max. Reduce cable length at higher speeds. Use twisted pair cable.
How do I terminate an RS-485 bus properly?
Proper termination is critical for reliable RS-485 operation: Place 120Ω termination resistors at both ends of the bus only, Do not place termination at intermediate nodes, Use resistors matched to cable characteristic impedance (typically 100-120Ω), For long buses or high speeds, termination is essential to prevent reflections. The TPT485 does not include internal termination - external resistors required.
120Ω resistors at both ends only. Match to cable impedance.
What is the common-mode voltage range?
The TPT485 supports a wide common-mode voltage range of -7V to +12V. This means the receiver can correctly interpret differential signals even when both A and B lines are shifted by up to -7V or +12V relative to ground. This wide range is essential for reliable operation in industrial environments with ground potential differences between nodes.
-7V to +12V common-mode range handles most industrial ground differential scenarios.
How do I protect against ESD and surges?
The TPT485 includes ±18kV HBM ESD protection on bus pins, sufficient for most applications. For additional protection in harsh environments: Use TVS diodes (e.g., SMBJ series) on bus lines, Add series resistors (10-47Ω) to limit current, Use isolated transceivers for high-voltage environments, Implement proper PCB layout with guard rings and proper grounding. For outdoor or extreme environments, consider additional surge protection devices.
18kV ESD built-in. Add TVS diodes for extreme environments.