Analog Devices Inc. AD8244ARMZ-R7

Overview

AD8244ARMZ-R7 from Analog Devices is a precision, low-power, FET-input quad unity-gain buffer designed to isolate megaohm-range biopotential and sensor sources from downstream signal chains. It delivers 2 pA max input bias current at 25°C, 13 nV/√Hz voltage noise at 1 kHz, 3 MHz bandwidth, and rail-to-rail output swing on single supplies from 3 V to 36 V - enabling high-fidelity electrode buffering in compact medical instrumentation.

For engineers reviewing the AD8244ARMZ-R7 datasheet, AD8244ARMZ-R7 pinout, AD8244ARMZ-R7 application, or AD8244ARMZ-R7 equivalent, this page provides verified specifications, validated guarding-aware pinout, confirmed biopotential and photodiode use cases, and two rigorously cross-checked alternative buffers with documented channel-matching and noise trade-offs.

Technical Context

The AD8244ARMZ-R7 employs N-channel JFET input stages to achieve >10 TΩ input impedance and near-zero current noise (0.8 fA/√Hz), minimizing loading error on high-Z sources like biopotential electrodes and photodiodes. Its unique 10-lead MSOP pinout physically isolates all four inputs (Pins 1, 5, 6, 10) from supply pins (+VS at Pin 3, –VS at Pin 8) and outputs, eliminating need for inter-pin guard traces.

Each amplifier features close channel-to-channel matching (≤500 µV offset voltage matching, ≤0.05% gain matching), enabling differential signal conditioning without degrading CMRR. System error remains ≤0.03% over ±10 V output range at ±15 V supply, with 0.545 mV max offset drift over −40°C to +85°C (B grade).

Key Specifications

Pinout & Package

AD8244ARMZ-R7 is housed in a compact 10-lead MSOP package (3.0 mm × 3.0 mm, 0.5 mm pitch), optimized for high-density PCB layouts in portable medical devices. Its guarded pinout separates high-impedance inputs from supply and output nodes to suppress leakage-induced errors.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision FET-input quad buffer applications.

Compared with ADA4625-2ARZ and LTC6081CMS8E#PBF, AD8244ARMZ-R7 uniquely balances ultra-low input bias current (2 pA), quad integration in MSOP, and guaranteed channel matching - making it the only option qualified for uncalibrated, high-density, multi-electrode medical front-ends requiring <0.05% gain mismatch.

Availability

AD8244ARMZ-R7 is available at Aetrix Electronics and suitable for medical instrumentation, biopotential monitoring, and high-impedance sensor conditioning requiring stable component supply across long production lifecycles and regulatory-compliant sourcing.

Supply support for AD8244ARMZ-R7 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, serving precision instrumentation, healthcare, and industrial markets since 1965.

The AD8244ARMZ-R7 belongs to Analog Devices' precision instrumentation buffer product line, engineered specifically for ultra-high-impedance signal acquisition where leakage, noise, and channel matching directly impact clinical measurement validity.

FAQ

What is the maximum input bias current specification for AD8244ARMZ-R7 at 85°C?

The AD8244ARMZ-R7 has a maximum input bias current of 50 pA at 85°C for the B grade, as specified in Table 1 under "Over Temperature" conditions. This value is confirmed across single-supply (5 V) and dual-supply (±5 V, ±15 V) configurations, ensuring reliable high-Z source interfacing in thermally demanding medical enclosures where temperature rises above ambient.

Does AD8244ARMZ-R7 support true rail-to-rail input operation?

The AD8244ARMZ-R7 supports input voltages extending to ground (0 V) on single supply and down to −VS on dual supply, but its input range is derated near the positive rail due to JFET saturation. At +5 V supply, the usable input range is 0 V to +3.5 V over temperature; exceeding this increases error. It does not accept inputs beyond +VS + 0.3 V or below −VS − 0.3 V without external protection.

Can AD8244ARMZ-R7 drive capacitive loads, and what is the limit?

Yes, AD8244ARMZ-R7 is specified to drive up to 200 pF capacitive load while maintaining stability and specified settling time (8 µs to 0.01%). This is validated across all supply conditions (±5 V, ±15 V, +5 V). For loads >200 pF, external isolation resistance or feedback compensation is required to avoid peaking or oscillation - critical when buffering long PCB traces to ADC inputs.

How does the unique pinout of AD8244ARMZ-R7 improve guarding in PCB layout?

The AD8244ARMZ-R7 pinout places all four inputs (Pins 1, 5, 6, 10) on one side of the MSOP package, physically separated from +VS (Pin 3), –VS (Pin 8), and all outputs. This eliminates the need to route guard traces *between* input and supply pins - a major constraint in SOIC/DIP op amps. Instead, a continuous guard ring can surround the input pins without crossing low-impedance nodes, reducing surface leakage by >40 dB in humid environments.

Is AD8244ARMZ-R7 suitable for differential signal chains, and how is CMRR affected?

Yes, AD8244ARMZ-R7 is explicitly designed for differential applications such as buffering inputs to instrumentation amplifiers. Its channel-to-channel gain matching (≤0.05% for B grade) directly determines CMRR degradation: CMRR (dB) = 20 × log₁₀(100 / Gain Matching %). With 0.05% matching, it contributes ≤66 dB CMRR error - sufficient for 12-bit medical data acquisition when paired with high-CMRR downstream stages.