The robotics industry faces a persistent engineering challenge: how to route cables through hollow joints while maintaining high-precision position feedback in an extremely compact space. Two Chinese semiconductor companies have recently stepped up with compelling answers. Conntek Microelectronics and Novosense have each launched off-axis magnetic encoder ICs that push the boundaries of compact, high-precision angle sensing.

This article examines both solutions — and explains how OTV Sensing provides complete, ready-to-deploy encoder systems that bridge the gap between these advanced ICs and production-ready hardware.

Conntek KTM5900: 24-Bit TMR Absolute Angle Encoder IC

Conntek Microelectronics has developed the KTM5900, a 24-bit absolute angle magnetic encoder IC based on Tunnel Magnetoresistance (TMR) technology. The device integrates high-precision TMR sensors with dual 16-bit 2M SAR ADCs, creating a high-speed, high-accuracy non-contact magnetic encoder module.

Key Specifications

Architecture & Key Features

The KTM5900 reads differential analog sine/cosine signals from the TMR sensors through its high-speed SAR ADCs, then performs angle calculation via digital circuitry. Standout features include:

• One-button self-calibration: Automatically detects and corrects non-linear errors during normal operation. The process completes in approximately 30 seconds via a single button press or SPI command.
• 256-point correction table: Allows users to store non-linear error corrections to improve absolute accuracy beyond the base specification.
• Automatic linear and nonlinear calibration with Z-signal calibration and absolute position synchronization for multipole applications.
• 8-bit CRC verification on SPI angle transmission and multiple self-diagnosis alarm functions for functional safety.
• Programmable operational amplifier gain and 12-bit multi-pole pair counter supporting up to 4,096 pole pairs.

Off-Axis Advantage

In off-axis configurations, the chip is mounted offset from the encoder ring, leaving the hollow shaft completely free for cable routing. The entire encoder module — chip + FPC + magnetic ring — can achieve an axial thickness of less than 3 mm, providing critical space savings for lightweight, compact robot joints.

For collaborative robot joints operating below 100 rpm, 32-pole or 64-pole pair configurations are recommended for optimal accuracy.

Novosense NSM350x Series: Hall-Effect Dual-Track Vernier Encoder

In July 2026, Novosense announced the NSM350x series — China’s first Hall-effect-based dual-track vernier algorithm magnetic encoder IC. With this launch, Novosense became the first Chinese company to offer both magnetic (Hall) and eddy-current dual-track vernier encoder products.

Key Specifications

Architecture & Key Features

The NSM350x employs a differential Hall detection architecture combined with a dual-track vernier magnet ring. Key features include:

• Integrated self-calibration algorithm: Eliminates errors caused by component mismatch, mechanical structure deviations, installation tolerances, and uneven magnetization of the magnetic ring.
• Dual-track vernier algorithm: Enables high-precision angle measurement by detecting magnetic field changes perpendicular to the chip surface.
• Flexible calibration modes: Choose between simple self-calibration (faster) and uniform self-calibration (higher precision).
• Off-axis installation: Provides greater mechanical design freedom for hollow joints and industrial motion control systems.

The NSM3502 model (2.0mm magnetic gap) is currently available for sample requests. The AEC-Q100 qualification ensures long-term reliability for industrial automation, robotics, and automotive applications.

Comparison at a Glance

OTV Sensing: Complete Encoder Solutions for Any Chip Platform

While advanced encoder ICs are essential, their real-world performance depends critically on the quality of the encoder ring — the magnetic target — and the overall system integration. OTV Sensing specializes in designing and manufacturing precision magnetic encoder targets — multi-pole rings and linear scales — to complete the encoder system.

1. High-Precision Dual-Track Encoder Rings

OTV manufactures precision dual-track magnetic rings fully compatible with both the Conntek KTM5900 and Novosense NSM350x series. Key capabilities:

• Multiple magnetic gap options: 1.28mm, 1.5mm, and 2.0mm — fully covering the NSM350x series
• Flexible pole pair counts: 16, 32, and 64 pole pair designs
• Full customization: ring dimensions, pole configurations, and mounting options to meet specific application requirements
• Precision manufacturing: ring accuracy matched to 22-bit and 24-bit resolution requirements

2. Multi-Platform Support

OTV Sensing provides encoder solutions for both European and Chinese chip platforms — iC-Haus, Infineon, Melexis, RLS, and now Conntek and Novosense — giving customers the flexibility to choose the best IC for their application while relying on a single, proven source for the encoder system.

3. Complete System Integration

• Verified reference designs: Chip + ring + PCB layouts that have been system-level optimized
• Assembly guidance: Precise magnetic circuit design and mounting instructions to ensure specified accuracy in production
• Calibration support: Comprehensive calibration procedures and production test support to accelerate time-to-market

4. One-Stop Delivery

From the magnetic ring to the complete encoder module, OTV Sensing provides end-to-end support that significantly reduces development cycles and simplifies supply chain management.

Application Focus: Hollow-Joint Robotics

Both the KTM5900 and NSM350x series are particularly well-suited for:

• Collaborative robot joints: Hollow shafts must accommodate cables while maintaining high precision
• Humanoid robot joints: Extreme space constraints demand ultra-compact sensing solutions
• Industrial automation: Servo motors, linear motors, and direct-drive motors
• Automotive applications: AEC-Q100 qualification (NSM350x) provides additional reliability assurance

The off-axis mounting capability of both solutions frees the central shaft space entirely for cable routing, while the entire encoder module can achieve an axial thickness under 3mm — a critical advantage for lightweight, compact joint designs.

OTV Sensing specializes in the design and manufacturing of custom magnetic encoder targets — including multi-pole rings and linear scales — and provides complete magnetic encoder solutions for robotics, industrial automation, and automotive applications. With support for both European and Chinese chip platforms, OTV Sensing helps customers accelerate development while ensuring system-level performance and reliability.