STMicroelectronics STW81200-EVB

Overview

STW81200-EVB from STMicroelectronics is a dedicated evaluation board for the STW81200 ultra-low-noise RF fractional/integer-N synthesizer with integrated VCOs and LDOs, supporting 50 MHz–6 GHz output frequency range, <−110 dBc/Hz phase noise at 100 kHz offset (at 2.4 GHz), and PC-based GUI-controlled register programming via USB interface. It enables lab-level characterization of RF synthesis performance in wireless infrastructure and test equipment.

For engineers reviewing the STW81200-EVB datasheet, STW81200-EVB pinout, STW81200-EVB application, or STW81200-EVB equivalent, this page delivers verified hardware setup guidance, GUI operation workflow, loop filter configuration tables, RF output interface details, and real-time register control capabilities - all specific to evaluating the STW81200 RF synthesizer IC under controlled lab conditions.

Technical Context

The STW81200-EVB implements direct USB-to-SPI communication with the STW81200 IC using an FTDI USB-to-serial bridge, enabling full read/write access to all 128+ device registers. Its analog/RF section includes differential RFout1 (0.7–2.7 GHz) and single-ended RFout2P/N (0.05–6 GHz) outputs with on-board 50 Ω termination support.

Hardware controls include HW_PD (power-down), PD_RF1/2 (RF output enable), and OSC_EN (on-board oscillator enable), all active without GUI write commands. The board integrates a 100 MHz CMOS crystal oscillator and supports external reference injection via REFinP/N (LVDS/LVECL/CMOS-compatible), critical for phase noise and spur optimization.

Key Specifications

Availability

STW81200-EVB is available at Aetrix Electronics and suitable for RF synthesizer evaluation, phase noise characterization, wireless infrastructure prototyping, and lab-grade PLL development requiring stable component supply and traceable evaluation hardware.

Supply support for STW81200-EVB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in analog, power, microcontrollers, and RF solutions for industrial, automotive, and communications markets.

The STW81200-EVB belongs to ST's RF Synthesizer Evaluation Platform product line, designed specifically to accelerate validation and tuning of high-performance fractional-N synthesizers in base station, test instrumentation, and radar subsystem design.

FAQ

What power supply configuration is required for accurate STW81200 current measurement?

Accurate RFIC current measurement requires using jumper JP1 with an inline ammeter. First, enable HW_PD and OSC_EN to measure combined STW81200 + oscillator current (~15 mA). Then disable OSC_EN to isolate oscillator current (~10 mA), subtracting it from total to obtain true STW81200 operating current. USB power must be avoided for lab-grade measurements due to shared current paths.

How does the STW81200-EVB support external reference clock injection?

The board provides dedicated REFinP/N terminals compatible with LVDS, LVECL, and CMOS logic standards, allowing injection of low-noise external reference signals. This bypasses the on-board 100 MHz crystal oscillator and directly feeds the STW81200 reference input, which is essential for minimizing close-in phase noise and spurious emissions in high-fidelity RF synthesis applications.

What are the key differences between RFout1 and RFout2 outputs on the STW81200-EVB?

RFout1 is a differential output limited by balun bandwidth (0.7–2.7 GHz), optimized for low-noise spectral purity. RFout2P/N are single-ended outputs covering 50 MHz–6 GHz with full bandwidth, intended for wideband signal routing and spectrum analyzer interfacing. Unused ports must be terminated with 50 Ω coaxial loads to prevent reflections and measurement artifacts.

Can the STW81200-EVB be used with an external VCO?

Yes - the board includes EXT VCO terminals (J4) and onboard jumpers to disconnect internal VCOs. When enabled via GUI VCO settings, the STW81200 operates in external-VCO mode, accepting user-supplied VCO signals across its supported frequency range. Loop filter components remain configurable per VCO gain bands (3–4 GHz, 4–5 GHz, 5–6 GHz) as defined in Table 1 of the data brief.