Analog Devices Inc. LT5519EUF#PBF

Overview

LT5519EUF#PBF from Analog Devices (formerly Linear Technology) is a high-linearity, upconverting double-balanced mixer IC designed for wireless and cable infrastructure transmitters. It operates across 0.7–1.4GHz RF output, delivers +17.1dBm typical input IP3 at 1GHz, features on-chip 50Ω-matched LO/RF ports and integrated RF output transformer, and supports single-ended LO/RF operation with –5dBm LO drive - enabling compact, low-cost transmitter front-ends in macro base stations.

For engineers reviewing the LT5519EUF#PBF datasheet, LT5519EUF#PBF pinout, LT5519EUF#PBF application, or LT5519EUF#PBF equivalent, key selection criteria include its 13.6dB noise figure, 1µs-scale enable/disable timing, 5V single-supply operation, 16-lead 4mm × 4mm QFN package with exposed ground pad, and verified performance in high-side/low-side LO injection architectures.

Technical Context

The LT5519EUF#PBF integrates a high-speed limiting LO buffer driving a double-balanced bipolar mixer core, with internal 50Ω broadband matching on LO and RF ports. Its IF input uses emitter-coupled differential topology requiring external 100Ω termination to ground per side and DC-blocking capacitors for optimal LO-to-RF isolation.

It employs an on-chip 4:1 RF output transformer to deliver 50Ω single-ended RF output without external matching components, while maintaining wideband return loss >20dB from 700–1400MHz. The enable function controls bias current to achieve <100µA shutdown current, with 2µs turn-on and 6µs turn-off times measured at RF envelope level.

Key Specifications

Pinout & Package

LT5519EUF#PBF is housed in a 16-lead plastic QFN package (4mm × 4mm) with exposed thermal pad (Pin 17) that must be soldered to PCB ground for thermal and RF performance. Pin pitch is 0.65 mm; package conforms to JEDEC MO-220 WGGC outline.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar upconverting mixer applications.

Compared with LT5520IUF#PBF and LT5511EUF#PBF, the LT5519EUF#PBF uniquely combines 700–1400 MHz coverage, +17.1 dBm IIP3, and integrated RF transformer - delivering lowest component count and highest integration for sub-1.5 GHz macro base station and cable CMTS applications.

Availability

LT5519EUF#PBF is available at Aetrix Electronics and suitable for wireless infrastructure transmitters, cable downlink systems, point-to-point microwave radios, and high-linearity test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT5519EUF#PBF 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

Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and RF ICs, serving communications, industrial, automotive, and aerospace markets with precision signal processing solutions.

The LT5519EUF#PBF belongs to Linear Technology's high-linearity RF mixer product line, engineered specifically for wireless infrastructure transmitter front-ends where IP3, noise figure, and integration density directly impact system spectral efficiency and thermal design.

FAQ

What is the recommended LO drive level for LT5519EUF#PBF?

The LT5519EUF#PBF is characterized and optimized for –5 dBm single-ended LO drive at the LO+ pin (with LO– grounded). Driving LO+ with –5 dBm delivers the specified +17.1 dBm IIP3 and –0.6 dB conversion gain. LO input power can range from –10 dBm to 0 dBm, but deviation from –5 dBm degrades linearity or gain per Figure G06–G09 in the datasheet. The LT5519EUF#PBF includes an integrated LO buffer, eliminating need for external amplification in most cases.

Does LT5519EUF#PBF require external matching components on the RF output?

No, the LT5519EUF#PBF integrates a 4:1 on-chip RF output transformer that provides a 50Ω single-ended output impedance across 700–1400 MHz when one RF pin (e.g., RF–) is grounded. External matching is unnecessary for standard 50Ω systems. A 10pF series capacitor may optionally be added below 850 MHz to extend 10dB return loss coverage down to 700 MHz, as shown in Figure F09. The LT5519EUF#PBF's internal matching eliminates baluns, transformers, and discrete LC networks.

How is the IF input configured for optimal performance with LT5519EUF#PBF?

The IF+ and IF– pins of the LT5519EUF#PBF require differential drive with DC blocking capacitors and 100Ω resistors to ground on each pin to establish ~18mA per side bias current. Resistors should be 0.1% tolerance for best LO-to-RF isolation. The LT5519EUF#PBF's IF port is internally biased at 1.77V common-mode; external AC coupling preserves this bias while enabling impedance transformation (e.g., via 4:1 balun) to match 50Ω or 75Ω sources.

What is the thermal management requirement for LT5519EUF#PBF?

The LT5519EUF#PBF has θJA = 37°C/W and a maximum junction temperature of 125°C. Its exposed pad (Pin 17) must be soldered to a solid copper ground plane covering ≥25 mm² to achieve rated thermal performance. Without proper pad soldering, junction temperature rise exceeds specifications under full 70mA supply current. Thermal vias (≥4× 0.3mm diameter) beneath the pad are recommended for high-reliability infrastructure applications. The LT5519EUF#PBF operates continuously from –40°C to +85°C ambient.

Can LT5519EUF#PBF operate with high-side and low-side LO injection?

Yes, the LT5519EUF#PBF supports both high-side and low-side LO injection configurations, as confirmed in Figures G03–G05 and G09–G11. When fLO > fIF, high-side injection yields fRF = fLO + fIF; when fLO < fIF, low-side injection yields fRF = fIF – fLO. Performance metrics including IIP3, conversion gain, and LO leakage remain within spec across both modes. The LT5519EUF#PBF's symmetric mixer core and broadband matching make it agnostic to injection side - a key advantage in flexible IF-staged architectures.