STMicroelectronics STUW81300T

Overview

STUW81300T from STMicroelectronics is a wideband RF/microwave fractional/integer-N PLL frequency synthesizer with integrated VCOs, LDOs, and differential reference input. It delivers dual RF outputs (1.925–8.0 GHz and 7.7–16.0 GHz), achieves -131 dBc/Hz phase noise @1 MHz offset at 6 GHz, supports up to 100 MHz PFD frequency, and operates from 3.0–5.4 V supply in a VFQFPN36 package - used in satellite communications transceivers and microwave infrastructure radios.

For engineers reviewing the STUW81300T datasheet, STUW81300T pinout, STUW81300T application, or STUW81300T equivalent, key selection criteria include its dual-band VCO architecture, integrated LDOs eliminating external regulators, fast automatic VCO center-frequency calibration across temperature, and SPI-programmable low-power modes for phase-noise/output-level trade-offs.

Technical Context

The STUW81300T implements a dual-path PLL architecture supporting both fractional-N (with 21-bit sigma-delta modulator) and integer-N modes, enabling precise frequency synthesis across 1.925–16 GHz without external VCOs. Its four internal VCOs are auto-calibrated using a closed-loop algorithm that maintains lock over -40°C to +85°C ambient.

It integrates five dedicated LDOs (4.5 V, VCO, REF, DIG, RF) with bypass-capacitor connections per rail, and features two internally 50-Ω-matched RF output stages: RF1 (VCO/VCO÷2) and RF2 (VCO×2), with fundamental VCO rejection >20 dB at the doubler output.

Key Specifications

Pinout & Package

STUW81300T uses a 36-pin VFQFPN (Very Thin Profile Fine Pitch Quad Flat Package) with 6×6 mm body, 0.5 mm pitch, and exposed thermal pad for enhanced thermal dissipation in RF applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wideband PLL synthesizer applications.

Compared with HMC703LP4E and LMS8001, STUW81300T uniquely combines dual-band RF outputs, full on-die power regulation, and 16 GHz coverage in a single 6×6 mm package - making it the only option for compact, thermally constrained satellite and 5G mmWave front-ends requiring both integration and wideband agility.

Availability

STUW81300T is available at Aetrix Electronics and suitable for 5G fixed wireless access radios, satellite communication terminals, and microwave point-to-multipoint base stations requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for STUW81300T 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, and RF solutions for industrial, automotive, and communications markets.

The STuW81300 belongs to ST's high-frequency RF synthesizer product line, designed specifically for infrastructure-grade wireless systems demanding ultra-low phase noise, wideband agility, and high integration density in thermally demanding environments.

FAQ

What reference clock configurations does STUW81300T support?

STUW81300T supports three reference input modes: differential LVDS/LVPECL (pins REF_CLKP/REF_CLKN, up to 800 MHz), single-ended CMOS (via REF_CLKP only), and integrated crystal oscillator (10–50 MHz fundamental mode). The internal XTAL core includes programmable load capacitance and ESR compensation, enabling direct connection of standard 20–50 ppm AT-cut crystals without external components.

How does the automatic VCO calibration work across temperature?

The STUW81300T performs closed-loop VCO center-frequency calibration using an internal frequency discriminator and digital state machine. It measures VCO frequency against a known reference, adjusts VCTRL via DAC, and stores optimal settings in nonvolatile memory. Calibration completes in <10 ms and remains valid across -40°C to +85°C ambient, with ΔTLOCK ≤75°C for FVCO >6.8 GHz at 4.5 V supply.

Can STUW81300T operate without external VCOs?

Yes - STUW81300T contains four fully integrated SiGe VCO cores covering 1.925–8.0 GHz (RF1 path) and 3.85–16.0 GHz (RF2 path via ×2), eliminating need for external VCOs in most applications. External VCO mode (via EXTVCO_INP/EXTVCO_INN) is optional and intended only for specialized ultra-low-noise or custom-frequency requirements beyond the internal VCO range.

What thermal design considerations apply to the VFQFPN36 package?

The VFQFPN36 package features an exposed thermal pad requiring minimum 4×4 mm soldered copper area on PCB Layer 1, connected to internal ground planes via ≥6 thermal vias (0.3 mm diameter, 0.6 mm pitch). Thermal resistance ΘJA is 33°C/W on JEDEC multilayer board; junction temperature must remain ≤125°C, limiting max continuous power dissipation to ~290 mA × 5.4 V ≈ 1.57 W under worst-case conditions.