Analog Devices Inc. LTC5548IUDB

Overview

LTC5548IUDB from Analog Devices is a SiGe double-balanced passive RF mixer with 3 GHz–20 GHz RF bandwidth, 500 MHz–9 GHz IF bandwidth, and 0 dBm LO drive requirement. It delivers 23 dBm IIP3, 14 dBm P1dB, and 9 dB conversion loss, operating from a 3.3 V supply at 132 mA. It is used in microwave backhaul transceivers requiring wideband frequency agility.

For engineers reviewing the LTC5548IUDB datasheet, LTC5548IUDB pinout, LTC5548IUDB application, or LTC5548IUDB equivalent, key selection criteria include its ultra-low LO drive, integrated broadband baluns for RF/IF, flip-chip QFN packaging, and verified performance across 3–20 GHz without external matching networks.

Technical Context

The LTC5548IUDB implements a Ruthroff-style 3-inductor balun on both RF and IF ports to achieve 3–20 GHz RF and 0.5–9 GHz IF bandwidths-enabling true wideband operation without tuning. Its passive mixer core uses MOSFET switching cells driven by an internal LO amplifier that converts single-ended 0 dBm LO input into differential signals.

It operates as a double-balanced topology with 50 Ω single-ended RF, LO, and IF ports; all ports exhibit >15 dB return loss across full bandwidth. The flip-chip 2 mm × 3 mm QFN package employs copper pillars to minimize parasitic degradation of RF performance.

Key Specifications

Pinout & Package

The LTC5548IUDB is housed in a 2 mm × 3 mm, 12-lead QFN package with exposed thermal pad (UDB grade). Pin assignment is validated per Analog Devices' official datasheet and layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with HMC663LC3 and SIM-193H+, the LTC5548IUDB uniquely combines ultra-wide RF/IF bandwidth, lowest LO drive, and monolithic SiGe integration-making it optimal for software-defined, frequency-agile systems where board space and power efficiency are critical.

Availability

LTC5548IUDB is available at Aetrix Electronics and suitable for 5G backhaul infrastructure, radar front-ends, satellite communications terminals, and RF test instrumentation requiring stable component supply and guaranteed long-term availability.

Supply support for LTC5548IUDB 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. is a global leader in high-performance analog, mixed-signal, and RF ICs, serving industrial, communications, automotive, and aerospace markets since 1965.

The LTC5548IUDB belongs to Analog Devices' high-frequency RF mixer product line, designed specifically for wideband, low-LO-power microwave transceivers in next-generation wireless infrastructure and defense electronics.

FAQ

What is the RF frequency range supported by the LTC5548IUDB?

The LTC5548IUDB supports an RF frequency range of 3 GHz to 20 GHz, verified through measurement across the full band. This range covers C-band (4–8 GHz), X-band (8–12 GHz), Ku-band (12–18 GHz), and lower K-band (18–20 GHz), enabling single-mixer solutions for multi-band systems without hardware reconfiguration. Performance remains consistent with <±0.5 dB conversion loss variation and >15 dB port return loss throughout.

Does the LTC5548IUDB require external baluns for RF or IF connections?

No, the LTC5548IUDB does not require external baluns. It integrates Ruthroff-style 3-inductor baluns on both RF and IF ports, enabling direct 50 Ω single-ended interfacing. These on-die baluns provide amplitude and phase balance within ±0.3 dB and ±5° across 3–20 GHz (RF) and 0.5–9 GHz (IF), eliminating discrete balun components and associated layout sensitivity in the LTC5548IUDB design.

What LO drive level is required for optimal performance of the LTC5548IUDB?

The LTC5548IUDB requires only 0 dBm LO drive for optimal performance, confirmed by measurement data in the official Analog Devices datasheet. This low drive level is enabled by an internal active LO buffer that converts the single-ended input to differential signals for the passive mixer core. Using higher LO power does not improve linearity or conversion loss and may increase DC current draw unnecessarily in the LTC5548IUDB.

How is thermal management handled in the LTC5548IUDB package?

The LTC5548IUDB uses a 2 mm × 3 mm 12-lead QFN package with an exposed EPAD that serves as the primary thermal and ground reference. For proper thermal management, the EPAD must be soldered to a minimum 100 mm² copper pour connected to internal ground planes via ≥4 thermal vias. At 132 mA and 3.3 V, the LTC5548IUDB dissipates 436 mW; this layout achieves <25°C junction-to-ambient rise under typical 4-layer PCB conditions.

Can the LTC5548IUDB be used for both upconversion and downconversion?

Yes, the LTC5548IUDB is a bidirectional double-balanced passive mixer and functions identically for both upconversion and downconversion. Its symmetric architecture and matched 50 Ω ports allow RF and IF roles to be interchanged-verified by measurement data showing identical conversion loss, IIP3, and noise figure whether used as upconverter (IF→RF) or downconverter (RF→IF). System-level isolation and filtering determine functional direction in the LTC5548IUDB implementation.