J-Link ULTRA

The J-Link ULTRA is SEGGER’s ultra-fast debug probe. At up to 4 MB/s download speed, it cuts flash-debug-test cycles for projects with large firmware images. Teams flashing multi-megabyte images dozens of times per day recover hours of cumulative wait time compared to slower debug probes.

USB 2.0 Hi-Speed connectivity ensures maximum throughput between host and probe. The standard 20-pin JTAG/SWD target connector covers debug on virtually every Arm and RISC-V board, and SWO capture adds lightweight trace without any extra hardware.

Why J-Link ULTRA for High-Speed Embedded Development

SWO trace capture at up to 100 MHz enables real-time data streaming for printf-style debug output, event tracing, and performance profiling, without consuming UART pins on your target board.

Multiple RTT (Real Time Transfer) channels deliver high-speed bidirectional data transfer with minimal CPU overhead on the target. This is ideal for streaming sensor data, debug logs, and configuration commands simultaneously during active development.

Redesigned in 2026, the J-Link ULTRA now ships in a compact housing with a footprint smaller than a credit card (73 x 46 x 19 mm, 40 g), with USB Type-C connectivity and integrated mounting holes for fixed bench and rack setups. Earlier generations of this probe shipped as the J-Link ULTRA+, a name you will still see in parts of SEGGER’s documentation; the redesigned model continues the same line as the J-Link ULTRA. As SEGGER’s Erik Loehr, Product Manager J-Link, puts it: “The new design brings the same high-speed performance and advanced functionality users know from J-Link Ultra to a much smaller housing.” It keeps full J-Link software support, GDB Server, J-Link Commander, the included Ozone debugger license, and SystemView real-time analysis, and is compatible with the separately licensed J-Link SDK for custom tooling.

J-Link ULTRA Technical Specifications

When to Choose J-Link ULTRA Over Other J-Link Models

The J-Link family includes models for every stage, from J-Link BASE for individual developers to J-Link PRO for enterprise teams. The ULTRA sits at the top of the speed hierarchy:

• J-Link BASE / BASE Compact: Entry-level debug probe. Good for Cortex-M development on a budget. Lower download speed than ULTRA.
• J-Link PLUS: Fully licensed mid-tier. Adds the J-Flash, Unlimited Flash Breakpoints, and Ozone licenses at the same 1 MB/s speed class as the BASE. Suitable for most professional projects.
• J-Link ULTRA: 4 MB/s download speed, the top of the family (shared with PRO). Choose this when firmware size exceeds 1 MB and you flash frequently. The speed difference is measurable on every build cycle.
• J-Link PRO: Adds Ethernet connectivity and remote debug capability. Same speed class as ULTRA but adds network access for shared lab environments and CI/CD pipelines.
• J-Link WiFi: Wireless debug over WiFi. Useful for testing deployed hardware where USB cables are impractical.

For a detailed comparison, see the J-Link comparison table.

J-Link ULTRA Use Cases

• High-speed firmware development: Large firmware images (2+ MB) on Cortex-A or multi-core Cortex-M systems where download speed directly determines iteration speed
• SWO performance profiling: 100 MHz SWO capture for real-time execution tracing, interrupt latency analysis, and RTOS task profiling
• Multi-core debug: Fast target switching between cores on multi-processor SoCs
• Small-batch production testing: Automated flash + verify workflows where download speed directly determines station throughput

Buy J-Link ULTRA in India: GSAS Authorized SEGGER Partner

GSAS Micro Systems is an authorized SEGGER engineering partner in India. Buy J-Link ULTRA with competitive pricing and short lead times, INR invoicing, 12 months of SEGGER Basic Support included, and local FAE support from our offices in Bengaluru, Hyderabad, Chennai, Pune, Mumbai, and Delhi NCR.

Watch the SEGGER J-Link ULTRA introduction

All J-Link models are available from the GSAS online store or via request for quote for volume pricing. GSAS also provides SEGGER Embedded Studio, Ozone, SystemView, and the full SEGGER embedded software portfolio, a complete development ecosystem from one partner.