Analog Devices Inc. ADA4625-2ARDZ-RL

Overview

ADA4625-2ARDZ-RL from Analog Devices is a dual-channel, rail-to-rail output (RRO), JFET-input operational amplifier optimized for high-voltage, low-noise, fast-settling precision applications. It delivers 18 MHz gain bandwidth, 48 V/µs slew rate, and 3.3 nV/√Hz voltage noise density at 1 kHz, operating from 5 V to 36 V single supply or ±2.5 V to ±18 V dual supply. It is used in PLL loop filters and photodiode sensor interfaces requiring wide dynamic range and minimal signal corruption.

For engineers reviewing the ADA4625-2ARDZ-RL datasheet, ADA4625-2ARDZ-RL pinout, ADA4625-2ARDZ-RL application, or ADA4625-2ARDZ-RL equivalent, key selection criteria include verified 0.01% settling in 1.2 µs (±18 V), ±15 pA input bias current at 25°C, rail-to-rail output swing into 600 Ω, no phase reversal beyond supply rails by 200 mV, and SOIC-8 EPAD package thermal performance (θ_JA = 52.8°C/W).

Technical Context

The ADA4625-2 employs a dual JFET input stage with extended common-mode range (down to V− − 0.2 V and up to V+ + 0.2 V), eliminating phase inversion even when inputs exceed rails by 200 mV. Its two-stage gain architecture uses virtual cascode topology and high-impedance GM2 node to achieve 150 dB open-loop gain and 75° phase margin at unity gain.

Output stage features complementary NPN/PNP emitter followers with active base clamping, enabling rail-to-rail sourcing/sinking (±46 mA short-circuit current) and stable drive into 1000 pF capacitive loads or 600 Ω resistive loads without external compensation.

Key Specifications

Pinout & Package

The ADA4625-2ARDZ-RL is housed in an 8-lead SOIC package with exposed pad (RD-8-4), offering θ_JA = 52.8°C/W and θ_JC = 5.7°C/W when the EPAD is connected to GND, V+, or V− plane per JEDEC JESD-51 standards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual JFET op amp applications.

Compared with ADA4622-2ARMZ and OPA2140IDR, the ADA4625-2ARDZ-RL uniquely combines 18 MHz bandwidth, 3.3 nV/√Hz noise, ±15 pA bias current, and guaranteed no-phase-reversal behavior - making it the only option qualified for demanding RF PLL filter and high-fidelity photodiode interface designs requiring simultaneous speed, precision, and robustness.

Availability

ADA4625-2ARDZ-RL is available at Aetrix Electronics and suitable for PLL loop filter design, photodiode sensor interfacing, low-noise charge amplification, and DAC output buffering requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for ADA4625-2ARDZ-RL 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, serving industrial, communications, automotive, and healthcare markets since 1965.

The ADA4625-2ARDZ-RL belongs to Analog Devices' precision JFET op amp product line, engineered specifically for high-voltage, low-noise, fast-settling applications such as phase-locked loop filters, photodiode transimpedance amplifiers, and precision sensor signal chains.

FAQ

What is the maximum supply voltage rating for the ADA4625-2ARDZ-RL?

The ADA4625-2ARDZ-RL has an absolute maximum supply voltage rating of 40 V across V+ and V− pins. It operates reliably over a recommended range of 5 V to 36 V single supply or ±2.5 V to ±18 V dual supply. Exceeding 40 V risks permanent damage per the Absolute Maximum Ratings table in the Rev. B datasheet.

Does the ADA4625-2ARDZ-RL require external compensation for unity-gain stability?

No, the ADA4625-2ARDZ-RL is internally compensated and unity-gain stable, with a measured phase margin of 75° at AV = 1. It can be used directly in voltage follower, inverting, or noninverting configurations without added compensation components - confirmed across both ±18 V and 5 V supply conditions.

How does the ADA4625-2ARDZ-RL handle input overvoltage conditions beyond the supply rails?

The ADA4625-2ARDZ-RL guarantees no phase reversal when either input exceeds V− or V+ by up to 200 mV, thanks to auxiliary input transistors (M3/M4) that extend the common-mode range. This behavior is validated in Figure 87 of the datasheet and eliminates latch-up risk in transient overvoltage scenarios.

What is the thermal performance of the ADA4625-2ARDZ-RL in its SOIC-8 EPAD package?

The ADA4625-2ARDZ-RL in RD-8-4 package has θ_JA = 52.8°C/W and θ_JC = 5.7°C/W per JEDEC JESD-51, assuming the exposed pad is soldered to a minimum 1-in² copper pour. Leaving the EPAD floating degrades thermal performance and is not recommended for continuous >3 mA per amplifier operation.

Can the ADA4625-2ARDZ-RL drive a 1000 pF capacitive load without oscillation?

Yes, the ADA4625-2ARDZ-RL is characterized to drive ≥1000 pF capacitive loads stably without external isolation resistance or compensation, as stated in the General Description and verified in Figure 36 (overshoot vs. load capacitance). This capability simplifies layout in DAC buffer and cable-driving applications.