ADA4661-2ARMZ - 18V Precision RRIO CMOS Op Amp | Analog Devices
MPN: ADA4661-2ARMZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.28 | $228.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.82 | $1,820.00 |
ADA4661-2ARMZ Overview
An operational amplifier (op amp) is a high-gain voltage amplifier with differential inputs and a single-ended output, used in signal conditioning, filtering, and buffering applications. The ADA4661-2 belongs to the precision op amp category, which emphasizes low offset voltage, low noise, and high DC accuracy. As a CMOS amplifier, it offers high input impedance and low input bias current, making it suitable for interfacing with high-impedance sensors and precision analog front ends.
Key features of the ADA4661-2 include rail-to-rail input and output swing, which maximizes dynamic range in low-voltage applications. The device guarantees performance at 3.0 V, 10 V, and 18 V supply voltages, ensuring consistent operation across a wide range of power rails. With a typical offset voltage of 50 µV and a temperature drift of 0.5 µV/°C, it provides excellent DC precision. The amplifier also features a high common-mode rejection ratio (CMRR) of 100 dB and a power supply rejection ratio (PSRR) of 110 dB, minimizing errors from supply variations.
Technically, the ADA4661-2 employs a CMOS input stage with chopper-less auto-zeroing techniques to achieve low offset and drift without the noise penalty of chopper amplifiers. The output stage is designed to drive capacitive loads up to 100 pF while maintaining stability, and it can source or sink 30 mA of output current. The device includes internal ESD protection and is available in both MSOP and LFCSP (3 mm × 3 mm) packages, offering design flexibility.
Typical applications include precision sensor signal conditioning, battery-powered instrumentation, active filters, and data acquisition systems. The low power consumption and wide supply range make it ideal for portable and industrial equipment where power efficiency and accuracy are critical. In sensor interfaces, the high input impedance and low bias current preserve signal integrity from high-impedance sources.
When designing with the ADA4661-2, ensure proper decoupling of the supply pins with 0.1 µF ceramic capacitors placed close to the device. For optimal noise performance, use low-value resistors in the feedback network and keep the input traces short to minimize parasitic capacitance. The rail-to-rail output stage can swing within 10 mV of the rails, but for best linearity, avoid operating at the extreme output limits.
Drop-in alternatives for ADA4661-2ARMZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ADA4661-2ARMZ (same form factor and footprint) — differing in Package, Supply Voltage Range, Supply Current per Amplifier, Input Offset Voltage, Output Current.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADA4661-2ARMZ-R7
✅ Drop-In📋 Reference alternative (not in catalog)
ADA4661-2ARMZ-RL
✅ Drop-In📋 Reference alternative (not in catalog)
ADA4666-2ARMZ
✅ Drop-In📋 Reference alternative (not in catalog)
OP279GRUZ-REEL
✅ Drop-In📋 Reference alternative (not in catalog)
TLV9152IDDFR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
ADA4661-2ARMZ Maximum Ratings & Electrical Characteristics
| Number of Channels | 2 |
| Supply Voltage Range | 3.0 V to 18 V (single), ±1.5 V to ±9 V (dual) |
| Gain Bandwidth Product | 4 MHz |
| Supply Current per Amplifier | 725 µA |
| Input Offset Voltage | 50 µV (typical) |
| Offset Voltage Drift | 0.5 µV/°C |
| Input Bias Current | 1 pA (typical) |
| CMRR | 100 dB (typical) |
| PSRR | 110 dB (typical) |
| Output Current | 30 mA (source/sink) |
| Rail-to-Rail Input/Output | Yes |
| Operating Temperature Range | -40°C to +125°C |
| Package | 8-MSOP |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ADA4661-2ARMZ Pin Configuration
| Pin 1 | OUT A — Output of amplifier A |
| Pin 2 | -IN A — Inverting input of amplifier A |
| Pin 3 | +IN A — Non-inverting input of amplifier A |
| Pin 4 | V- — Negative supply (or ground) |
| Pin 5 | +IN B — Non-inverting input of amplifier B |
| Pin 6 | -IN B — Inverting input of amplifier B |
| Pin 7 | OUT B — Output of amplifier B |
| Pin 8 | V+ — Positive supply |
Typical Applications
ADA4661-2ARMZ is suitable for 6 applications: Precision Sensor Signal Conditioning, Battery-Powered Instrumentation, Active Filters, Data Acquisition Systems, Industrial Process Control, Automotive Electronics.
Precision Sensor Signal Conditioning
The ADA4661-2ARMZ's low offset voltage (50 µV), low input bias current (1 pA), and rail-to-rail input/output make it ideal for conditioning signals from high-impedance sensors such as photodiodes, thermocouples, and strain gauges. Its wide supply range (3 V to 18 V) allows direct interfacing with various ADC reference voltages. The low power consumption (725 µA per amp) is beneficial for battery-powered sensor nodes. In a typical transimpedance amplifier configuration, the low bias current minimizes DC error, and the 4 MHz bandwidth supports fast sensor response. The rail-to-rail output maximizes dynamic range, ensuring accurate signal capture for subsequent digitization.
Recommended
Battery-Powered Instrumentation
With a quiescent current of only 725 µA per amplifier, the ADA4661-2ARMZ is well-suited for portable and battery-powered instruments. Its 3 V to 18 V supply range allows operation from a single lithium-ion cell or multiple alkaline batteries. The rail-to-rail input/output ensures maximum signal swing, which is critical in low-voltage systems. The precision specifications (50 µV offset, 0.5 µV/°C drift) maintain accuracy over temperature, making it reliable for handheld multimeters, portable data loggers, and field transmitters. The 4 MHz bandwidth supports audio and vibration monitoring applications. The MSOP package saves board space, enabling compact designs.
Recommended
Active Filters
The ADA4661-2ARMZ's 4 MHz gain bandwidth product and rail-to-rail output make it suitable for active filter designs in audio and communication systems. Its low offset and drift ensure accurate DC performance in high-pass and low-pass filters. The low power consumption allows multiple filter stages without excessive heat generation. In a multiple feedback low-pass filter, the amplifier's high open-loop gain at low frequencies maintains filter accuracy. The wide supply range supports both 5 V and 12 V systems. The device's stability with capacitive loads up to 100 pF simplifies filter design. For higher-order filters, multiple ADA4661-2 stages can be cascaded, and the MSOP package enables compact PCB layouts.
Recommended
Data Acquisition Systems
In data acquisition systems, the ADA4661-2ARMZ can be used as a buffer or gain stage before an ADC. Its low input bias current (1 pA) minimizes loading on high-impedance sources, preserving signal integrity. The rail-to-rail output allows the amplifier to drive the full input range of the ADC, maximizing resolution. The 4 MHz bandwidth is sufficient for sampling rates up to several hundred kSPS. The low offset and drift ensure accurate DC measurements. The wide supply range allows the amplifier to operate from the same supply as the ADC, simplifying power design. The low power consumption is advantageous in multi-channel systems where many amplifiers are used. The MSOP package is ideal for dense PCB layouts.
Recommended
Industrial Process Control
The ADA4661-2ARMZ's wide supply range (up to 18 V) and extended temperature range (-40°C to +125°C) make it suitable for industrial process control applications. It can interface with 4-20 mA current loops, thermocouples, and RTDs. The low offset and drift ensure accurate measurement over temperature. The rail-to-rail output allows direct connection to ADC inputs in PLCs and distributed control systems. The low power consumption reduces heat in control cabinets. The device's robustness and long-term stability make it reliable for 24/7 operation. In a typical application, the amplifier conditions a sensor signal and drives an ADC, with the 4 MHz bandwidth supporting fast control loops.
Recommended
Automotive Electronics
The ADA4661-2ARMZ is suitable for automotive applications such as battery monitoring, motor control, and sensor interfaces. Its wide supply range (3 V to 18 V) accommodates automotive battery voltages (12 V nominal). The extended temperature range (-40°C to +125°C) meets automotive requirements. The low offset and drift ensure accurate measurement of battery voltage and current. The rail-to-rail output allows direct interface with automotive microcontrollers' ADCs. The low power consumption is beneficial for always-on systems. The device's robustness against ESD and its small MSOP package make it suitable for engine control units and body control modules. For higher reliability, consider the ADA4666-2 for its higher bandwidth.
Recommended
Recommended Products Summary
Engineering reference data for ADA4661-2ARMZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADA4661-2ARMZ-R7 | ADA4661-2ARMZ-RL | ADA4666-2ARMZ | OP279GRUZ-REEL | TLV9152IDDFR |
|---|---|---|---|---|---|---|
| Package | 8-MSOP | 8-MSOP | 8-MSOP | 8-MSOP | 8-MSOP | 8-MSOP |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments |
| Supply Voltage Range | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V | 3 V to 18 V | 3 V to 12 V | 2.7 V to 16 V |
| Gain Bandwidth Product | 4 MHz | 4 MHz | 4 MHz | 10 MHz | 5 MHz | 4.5 MHz |
| Supply Current per Amplifier | 725 µA | 725 µA | 725 µA | 1.2 mA | 2.5 mA | 650 µA |
| Input Offset Voltage | 50 µV | 50 µV | 50 µV | 25 µV | 200 µV | 150 µV |
| Input Bias Current | 1 pA | 1 pA | 1 pA | 1 pA | 100 nA | 1 pA |
| Rail-to-Rail Input/Output | Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Low power consumption with 4 MHz bandwidth (vs ADA4666-2ARMZ)
- Ultra-low input bias current of 1 pA (vs OP279GRUZ-REEL)
- Wide supply voltage range up to 18 V (vs TLV9152IDDFR)
Design Notes
The ADA4661-2ARMZ operates from 3 V to 18 V single supply or ±1.5 V to ±9 V dual supply. Ensure the supply voltage does not exceed the absolute maximum rating of 20 V. Use 0.1 µF ceramic capacitors close to each supply pin to decouple high-frequency noise. For dual supply operation, connect the V- pin to the negative rail and V+ to the positive rail, with proper decoupling on both.
For optimal performance, place the ADA4661-2ARMZ close to the signal source to minimize trace length and parasitic capacitance. Use a solid ground plane under the device to reduce noise. Keep feedback resistors and capacitors close to the inverting input to minimize stray capacitance. For high-impedance inputs, guard traces may be necessary to reduce leakage currents.
Avoid driving capacitive loads greater than 100 pF directly, as this may cause instability. If larger capacitive loads are required, use an isolation resistor in series with the output. Also, ensure the input common-mode voltage does not exceed the supply rails, even though the device is rail-to-rail, to prevent phase reversal. For best noise performance, use metal-film resistors with low excess noise.
Compliance Information
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified. Lead-free finish.
