Analog Devices Inc. DC1545A-A

Overview

DC1545A-A from Analog Devices (formerly Linear Technology) is an evaluation board for the LT5578 high-linearity upconverting mixer IC, supporting RF output frequencies from 0.4GHz to 2.7GHz. It enables rapid prototyping of LTE, W-CDMA, and WiMAX transmitter stages with verified performance at 740MHz, 900MHz, and 1950MHz using single-ended LO and RF interfaces, 3.3V supply, and 5mm × 5mm QFN24 footprint.

For engineers reviewing the DC1545A-A datasheet, DC1545A-A pinout, DC1545A-A application, or DC1545A-A equivalent, this board provides validated reference design schematics (Figure 1), component values for 70–240MHz IF matching, 450–2600MHz RF tuning, and LO port optimization - critical for minimizing LO-RF leakage, achieving >24dBm OIP3, and maintaining <10.5dB SSB noise figure in wireless infrastructure transmitters.

Technical Context

The DC1545A-A implements the LT5578's internal double-balanced mixer core with integrated LO buffer and on-chip baluns, enabling single-ended LO input and RF output while preserving differential IF interface. Its layout strictly follows recommended RF grounding: exposed pad soldered to low-inductance top-side ground plane with multiple vias to inner layers, symmetrical IF trace routing, and precise placement of 0.1% R1/R2 bias resistors to set 40mA per-side mixer current.

Test circuits support three primary configurations: 740MHz (fIF = 140MHz, low-side LO), 900MHz (fIF = 140MHz, low-side LO), and 1950MHz (fIF = 240MHz, high-side LO), each with documented capacitor/inductor values (C1–C14, L1–L3, TL1–TL3) and impedance-matching networks optimized for >12dB return loss across target bands.

Key Specifications

Availability

DC1545A-A is available at Aetrix Electronics and suitable for LTE basestation development, public safety radio design, and wireless repeater prototyping requiring stable component supply and pre-validated RF performance.

Supply support for DC1545A-A 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 acquired Linear Technology in 2017 and maintains its high-performance RF product portfolio, including mixers, modulators, and demodulators for wireless infrastructure.

The DC1545A-A belongs to Linear Technology's evaluation board family for RF signal chain components, designed specifically to accelerate development of high-linearity transmitter architectures in cellular and broadband wireless systems.

FAQ

What is the primary function of the DC1545A-A evaluation board?

The DC1545A-A evaluation board is a fully assembled and tested platform for the LT5578 upconverting mixer IC. It provides immediate access to all pins, pre-tuned matching networks for IF (70–240MHz), RF (450–2600MHz), and LO ports, and validated layout practices - enabling engineers to characterize conversion gain, OIP3, noise figure, and LO-RF isolation without custom PCB design. The DC1545A-A directly supports LTE, W-CDMA, and WiMAX transmitter development.

Which frequency bands does the DC1545A-A support out-of-the-box?

The DC1545A-A supports three factory-validated configurations: 740MHz (fIF = 140MHz, low-side LO), 900MHz (fIF = 140MHz, low-side LO), and 1950MHz (fIF = 240MHz, high-side LO). Component values for these bands are listed in Figure 1 and Tables 2–5 of the LT5578 datasheet. Additional bands (e.g., 450MHz, 2600MHz) are supported via documented rework of C8, L3, C14, and other matching elements on the DC1545A-A board.

Does the DC1545A-A require external power supplies or signal sources?

Yes - the DC1545A-A requires a clean 3.3V DC supply (≤170mA) applied to the VCC test points, and separate RF signal sources for the IF (differential) and LO (single-ended) inputs. The RF output is single-ended and connects to a 50Ω measurement system. No onboard regulators or clock generators are included; all active circuitry relies on the LT5578's internal biasing and the user-provided stimuli.

How is RF grounding implemented on the DC1545A-A to ensure optimal LT5578 performance?

The DC1545A-A implements RF grounding per LT5578 requirements: the exposed pad (Pin 25) is soldered to a solid top-side ground plane with ≥12 thermal vias (0.3mm diameter) connecting to inner ground layers. All GND pins (1, 2, 5–7, 12–14, 16–21, 23, 24) are tied to this plane. Symmetrical IF trace routing and 0.1% matched R1/R2 resistors minimize LO leakage - critical for achieving the –43dBm LO-RF leakage specified for the DC1545A-A when used with the LT5578.

Can the DC1545A-A be used to evaluate alternative mixers compatible with the LT5578 footprint?

No - the DC1545A-A is specifically designed and validated for the LT5578. While it uses a standard 24-lead 5mm × 5mm QFN package, the matching networks (transformer T1, L1/L2, C1–C14), biasing (R1/R2 = 13.7Ω), and layout (trace lengths, via placement) are optimized for the LT5578's internal architecture, 565mV IF common-mode voltage, and 152mA supply current. Substituting another mixer - even pin-compatible parts like the LT5579 - would require full re-characterization and likely component changes to maintain performance.