Analog Devices Inc. AD831AP

Overview

AD831AP from Analog Devices is a monolithic doubly balanced RF mixer IC with +24 dBm output-referred third-order intercept (IP3), –10 dBm LO drive requirement, and dual-mode IF output (250 MHz differential current or >200 MHz single-ended voltage). It operates from ±4.5 V to ±5.5 V dual supplies or 9–11 V single supply, supports DC-coupled operation to baseband, and is used in high-performance downconversion, I/Q demodulation, and direct-to-baseband systems.

For engineers reviewing the AD831AP datasheet, AD831AP pinout, AD831AP application, or AD831AP equivalent, this page delivers verified specifications including RF/LO bandwidth (500 MHz), SSB noise figure (10.3 dB at 70 MHz), programmable bias current (45–125 mA), isolation performance (LO-to-RF ≥70 dB), and dual-supply compatibility - all critical for RF front-end design validation and mixer selection.

Technical Context

The AD831AP integrates a Class-A voltage-to-current RF converter, a low-noise limiting LO amplifier, a differential mixer core, and a user-configurable low-noise output amplifier. Its architecture enables true DC-to-500 MHz RF/LO operation with no lower frequency limit and eliminates insertion loss inherent in passive mixers.

Port isolation is achieved via internal differential switching and on-chip bias networks; LO-to-RF isolation exceeds 70 dB at 100 MHz, while RF-to-IF and LO-to-IF reach 45 dB and 30 dB respectively. The BIAS pin allows dynamic quiescent current adjustment between 45 mA and 125 mA, trading IP3 (24 → ~18 dBm) and 1 dB compression (10 → ~7 dBm) for power savings.

Key Specifications

Pinout & Package

AD831AP is housed in a 20-lead Plastic Leaded Chip Carrier (PLCC) package per JEDEC MO-047-AA, with dimensions 0.385" × 0.385" (9.78 mm × 9.78 mm), 1.27 mm pitch, and exposed thermal pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD831AP, AD8361ARUZ performs entirely different signal conditioning (RMS detection), while LT5560EDE#TRPBF offers smaller footprint and lower power but sacrifices 200 MHz bandwidth and dual-supply operation - making AD831AP uniquely suited for wideband, high-linearity, DC-coupled RF systems.

Availability

AD831AP is available at Aetrix Electronics and suitable for HF/VHF receivers, ultrasound Doppler imaging systems, and DMR base station designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD831AP 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with deep expertise in RF, precision instrumentation, and power management.

The AD831 product line was designed specifically for high-dynamic-range RF mixing in communication and medical imaging systems, emphasizing low distortion, DC coupling, and integrated IF amplification to replace multi-component passive mixer + amplifier solutions.

FAQ

What is the maximum RF input frequency supported by the AD831AP?

The AD831AP supports RF input frequencies up to 500 MHz at –10 dBm signal level with IP3 ≥ +20 dBm, as confirmed in the Rev. D datasheet's "RF INPUT" specification table. This bandwidth enables use in HF, VHF, and lower-UHF bands without external preselection filtering.

Can the AD831AP operate with a single 9 V supply?

Yes, the AD831AP supports single-supply operation from 9 V to 11 V. In this mode, the COM pin must be biased to half-supply (4.5 V) using resistive dividers, and the OUT pin requires AC coupling to the load - details are provided in Figure 10 of the AD831 Rev. D datasheet.

How does the BIAS pin affect AD831AP performance?

The BIAS pin on the AD831AP adjusts quiescent current from 125 mA (open circuit) down to 45 mA (tied to VP), reducing power consumption at the cost of lower IP3 (~18 dBm) and 1 dB compression point (~7 dBm). This tradeoff is documented in the "POWER SUPPLIES" section and TPC 12–14 of the AD831 Rev. D datasheet.

What is the noise figure of the AD831AP and under what conditions is it measured?

The AD831AP has a 10.3 dB SSB noise figure at 70 MHz RF input and 10.7 MHz IF with matched source impedance, as specified in the "DISTORTION AND NOISE" table of Rev. D. At 150 MHz RF, the noise figure rises to 14 dB, confirming frequency-dependent degradation consistent with its broadband architecture.

Does the AD831AP require external termination resistors on its differential IF outputs?

No - the AD831AP's IFP and IFN pins are open-collector outputs with internal load resistors (~14 Ω each), enabling direct transformer coupling or capacitor-coupled connection to 50 Ω systems. External termination is optional and used only for custom filtering (e.g., shunt capacitors for low-pass response), as described in Figure 4 and Theory of Operation.