Analog Devices Inc. DC821A

Overview

DC821A from Analog Devices (formerly Linear Technology) is a demonstration circuit board built around the LTC5533 dual RF power detector IC, designed for precision RF power measurement in wireless infrastructure and test equipment. It supports 300MHz–11GHz input frequency range, −32dBm to +12dBm input power, and features dual independent channels with shutdown mode (<2µA/channel) and VOS-adjustable output offset.

For engineers reviewing the DC821A datasheet, DC821A pinout, DC821A application, or DC821A equivalent, this page provides verified board-level specifications, functional context, supply chain availability, manufacturer background, and answers to common evaluation questions including RF calibration, VOS adjustment, shutdown sequencing, load capacitance limits, and absolute maximum ratings.

Technical Context

Demonstration Circuit 821 implements the LTC5533 in a fully assembled, SMA-connected layout optimized for RF accuracy. Each channel integrates an on-chip Schottky diode peak detector, temperature-compensated buffer amplifier, and dedicated VOS offset trim input - enabling precise DC output voltage scaling proportional to RF input amplitude.

The board operates from 2.7V–6V supply, delivers 2MHz VOUT bandwidth with 3V/µs slew rate, and maintains ≥45dB channel-to-channel isolation at 2GHz. Shutdown control is active-high, with defined enable/disable voltage thresholds and sub-µA quiescent current per channel.

Key Specifications

Availability

DC821A is available at Aetrix Electronics and suitable for RF power monitoring, cellular base station maintenance, 5G mmWave test instrumentation, and production line RF calibration requiring stable component supply and traceable evaluation hardware.

Supply support for DC821A 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. (ADI) is a global leader in high-performance analog, mixed-signal, and RF integrated circuits, serving communications, industrial, automotive, and healthcare markets.

The DC821A belongs to ADI's Linear Technology Demonstration Circuit series, engineered specifically to accelerate validation of RF signal chain components - emphasizing layout integrity, calibrated measurement paths, and direct interface to standard lab equipment.

FAQ

What is the purpose of the VOS pins on the DC821A?

The VOS pins on the DC821A provide external DC bias adjustment for each LTC5533 channel's output offset voltage. By applying 0V–1V to these pins, users can precisely calibrate the VOUT voltage under zero-RF conditions (typically 110–150mV) to align with system ADC reference levels or eliminate baseline drift. This function is implemented directly via the LTC5533's internal trimming architecture and is fully accessible on the DC821A through test points E3 and E9.

Does the DC821A require external RF termination?

No - the DC821A includes 50Ω RF input terminations at SMA connectors J1 and J2, as confirmed in the Quick Start Guide and typical performance test conditions. The board is designed for direct connection to 50Ω signal sources without additional external matching or termination, ensuring accurate power detection across its 300MHz–11GHz range.

What is the maximum allowable RF input power for the DC821A?

The absolute maximum RF input power for the DC821A is +12dBm, as explicitly stated in the Quick Start Guide caution note. Exceeding this level risks permanent damage to the LTC5533 detectors. This limit applies per channel and is enforced by the on-chip Schottky diodes' thermal and voltage breakdown characteristics - not by external protection circuitry on the demo board.

How is shutdown sequencing handled on the DC821A?

DC821A requires strict power sequencing: VCC must be applied before SHDN. Jumper connections from E1/E6 (VCC) to E4/E8 (SHDN) enable both channels, but the guide warns that SHDN voltage must never exceed VCC. This reflects the LTC5533's specified SHDN enable threshold (≥1.4V) and absolute max rating - improper sequencing may cause latch-up or undefined behavior in the DC821A's LTC5533 ICs.

Can the DC821A be used for pulsed RF measurements?

Yes - the DC821A supports pulsed RF detection due to the LTC5533's 3V/µs slew rate and 2MHz VOUT bandwidth. With 33pF max load capacitance and 2kΩ load resistance, the output settles within 8µs after shutdown enable, making it suitable for burst-mode signals with repetition rates up to ~100kHz. However, pulse width resolution is limited by the 2MHz bandwidth, not the detector's intrinsic response time.