+3.3V Rising Edge Data Strobe LVDS 21-Bit Channel Link Transmitter# DS90CR217MTD Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The DS90CR217MTD is a 21-bit Channel Link serializer specifically designed for high-speed digital video and data transmission applications. This component serves as a transmitter in LVDS (Low-Voltage Differential Signaling) systems, converting 21 bits of single-ended LVTTL data into three LVDS data streams and one LVDS clock channel.
Primary applications include:
- Flat Panel Display Interfaces : Driving LCD/OLED panels in automotive displays, medical monitors, and industrial HMI systems
- Digital Video Transmission : High-resolution video signal transmission in surveillance systems and broadcast equipment
- Camera Systems : Interface between image sensors and processing units in automotive vision systems and industrial inspection cameras
- Embedded Systems : High-speed data links between processors and peripheral devices in rugged environments
### Industry Applications
Automotive Industry :
- Infotainment Systems : Connects main processors to center stack displays and instrument clusters
- Advanced Driver Assistance Systems (ADAS) : Transfers camera data to processing units with high noise immunity
- Digital Cockpits : Multiple display interfaces with reduced wiring complexity
Medical Equipment :
- Patient Monitoring : High-reliability display connections in critical care environments
- Diagnostic Imaging : Medical grade displays requiring stable, noise-free signal transmission
Industrial Automation :
- Human-Machine Interfaces (HMI) : Robust display connections in manufacturing environments
- Control Systems : Data transmission between controllers and operator panels
### Practical Advantages and Limitations
Advantages:
- Noise Immunity : LVDS differential signaling provides excellent common-mode noise rejection
- Cable Reduction : Transmits 21 data lines plus clock over only 4 differential pairs
- High Speed : Supports data rates up to 75 MHz, enabling 21-bit color at 1280×1024 resolution
- Low Power : 3.3V operation with typical power consumption of 150mW
- EMI Performance : Reduced electromagnetic interference compared to parallel interfaces
Limitations:
- Fixed Configuration : 21-bit fixed data width limits flexibility for other bit-width applications
- Distance Constraints : Maximum cable length typically 5-10 meters depending on environment
- Paired Component Requirement : Requires matching deserializer (DS90CR218A) for complete solution
- Clock Skew Sensitivity : Requires careful clock distribution management
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Power Supply Decoupling:
- Pitfall : Inadequate decoupling causing signal integrity issues and increased EMI
- Solution : Use 0.1μF ceramic capacitors placed within 5mm of each power pin, plus 10μF bulk capacitor per power rail
Signal Integrity Issues:
- Pitfall : Excessive ringing and overshoot on LVDS outputs
- Solution : Implement proper termination (100Ω differential at receiver end) and controlled impedance routing
Clock Distribution Problems:
- Pitfall : Clock skew between serializer and deserializer causing data corruption
- Solution : Use matched length routing for all LVDS pairs and implement deskew features in receiver
### Compatibility Issues with Other Components
Voltage Level Mismatches:
- Input Compatibility : LVTTL inputs (3.3V) may require level shifting when interfacing with 1.8V or 5V systems
- Output Characteristics : LVDS outputs (350mV swing) require compatible receivers; not directly compatible with RS-485 or other differential standards
Timing Constraints:
- Setup/Hold Times : Strict timing requirements for input data relative to PCLK (typically 2ns setup, 1ns hold)
- Clock Frequency : Maximum 75MHz
