Analog Devices Inc. ADA4000-2ARMZ

Overview

ADA4000-2ARMZ from Analog Devices is a dual-channel, precision JFET-input operational amplifier optimized for high-impedance signal conditioning and data acquisition. It delivers 5 MHz gain bandwidth, 20 V/µs slew rate, ±4 V to ±18 V supply operation, and 1.70 mV maximum offset voltage - enabling accurate buffering of ADC inputs and DAC outputs in industrial sensor interfaces and power monitoring systems.

For engineers reviewing the ADA4000-2ARMZ datasheet, ADA4000-2ARMZ pinout, ADA4000-2ARMZ application, or ADA4000-2ARMZ equivalent, key selection criteria include low 40 pA max input bias current, rail-to-rail common-mode input (including +V_S), fast 1.2 µs settling to 0.1%, and MSOP-8 packaging for space-constrained analog front-ends.

Technical Context

The ADA4000-2ARMZ employs a JFET input stage delivering ultra-low input bias current (≤40 pA) and high input impedance (103 GΩ||5.5 pF common-mode), making it suitable for photodiode amplification and high-impedance source interfacing. Its unity-gain stability, 60° phase margin at ±15 V, and ability to drive ≥1000 pF capacitive loads without oscillation support robust buffer and filter implementations.

Designed for precision DC-coupled applications, the device features input common-mode voltage range extending to +V_S, enabling high-side sensing in power line monitoring. Offset drift is tightly controlled at 2 µV/°C over −40°C to +125°C, and PSRR exceeds 82 dB across its full ±4 V to ±18 V supply range.

Key Specifications

Pinout & Package

ADA4000-2ARMZ is housed in an 8-lead MSOP (RM-8) package, 3.0 mm × 3.0 mm footprint, 0.85 mm height, with exposed pad for thermal enhancement. Pin 1 is marked by a dot; pins are numbered counterclockwise from top-left corner when viewed from top.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision JFET-input op-amp applications.

Compared with AD823AARMZ and OPA2134PA, ADA4000-2ARMZ uniquely balances ultra-low bias current (≤40 pA), fast settling (≤1.2 µs), and high common-mode input (to +V_S) - making it the optimal choice for high-precision, high-impedance, high-speed industrial signal conditioning where all three attributes are simultaneously required.

Availability

ADA4000-2ARMZ is available at Aetrix Electronics and suitable for industrial sensor interfaces, power line monitoring systems, and precision data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADA4000-2ARMZ 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 digital signal processing semiconductors, headquartered in Norwood, MA.

The ADA4000 family was designed specifically for precision, low-power, high-input-impedance signal conditioning in industrial, test, and measurement applications - emphasizing JFET input performance, wide supply range, and robust capacitive load drive.

FAQ

What is the maximum capacitive load the ADA4000-2ARMZ can drive without instability?

The ADA4000-2ARMZ is stable driving up to 1000 pF in unity-gain configurations, per the datasheet's capacitive load drive section. For loads exceeding this, a snubber network (e.g., 41 Ω + 10 nF) reduces overshoot from 30% to 6% and eliminates ringing. This capability eliminates the need for external isolation resistors in many ADC driver and filter applications, preserving signal fidelity and simplifying layout. The ADA4000-2ARMZ achieves this stability without requiring gain compensation or external components under standard conditions.

Does the ADA4000-2ARMZ support operation from a single +5 V supply?

Yes, the ADA4000-2ARMZ operates from ±4 V to ±18 V dual supplies or equivalently from +8 V to +36 V single supply. At +5 V total supply (i.e., +5 V and ground), the input common-mode range is −1.0 V to +5.0 V and output swing is +3.8 V to −3.0 V (min), as specified in Table 2. This makes ADA4000-2ARMZ compatible with modern low-voltage microcontroller-based systems while retaining precision performance - including 1.70 mV max offset and 40 pA max input bias current - even at reduced supply rails.

How does the ADA4000-2ARMZ handle input overvoltage conditions that exceed the common-mode range?

When input voltage exceeds the common-mode range, the ADA4000-2ARMZ may exhibit temporary phase reversal due to saturation of the JFET input stage - a known behavior in precision JFET op-amps. Recovery is automatic once the input returns within specification. To prevent damage or latch-up, input current must be limited to <10 mA per Absolute Maximum Ratings. A series resistor at the non-inverting input mitigates phase reversal in noninverting configurations, though it adds thermal noise. This behavior is documented in the Applications Information section of the ADA4000-2ARMZ datasheet and applies identically across all variants in the ADA4000 family.

What is the thermal resistance (θ_JA) of the ADA4000-2ARMZ in its MSOP-8 package?

The ADA4000-2ARMZ in the 8-lead MSOP (RM-8) package has a junction-to-ambient thermal resistance (θ_JA) of 141.9°C/W, as specified in Table 4 of the datasheet. This value assumes worst-case PCB mounting - i.e., no thermal vias or copper pour. With proper layout (e.g., thermal pad soldered to internal ground plane), actual θ_JA can improve significantly. The junction-to-case (θ_JC) is 43.7°C/W, indicating efficient heat transfer from die to package bottom. These values enable reliable operation up to +125°C ambient when power dissipation remains below ~120 mW.

Can the ADA4000-2ARMZ replace the ADA4000-2ARZ in existing SOIC-8 designs?

No - ADA4000-2ARMZ uses an 8-lead MSOP (RM-8) package (3.0 mm × 3.0 mm), while ADA4000-2ARZ uses an 8-lead SOIC_N (R-8) package (5.0 mm × 4.0 mm). They are not pin-compatible or footprint-compatible. Direct replacement would require PCB redesign. However, both share identical electrical specifications, temperature range (−40°C to +125°C), and functional behavior. If board space is constrained, ADA4000-2ARMZ offers the same precision performance in a 54% smaller footprint; if legacy compatibility is required, ADA4000-2ARZ remains the SOIC option. The ADA4000-2ARMZ branding code "A1H" further distinguishes it in reel markings.