OPA211 - 1.1nV/√Hz Low-Noise Precision Op Amp | TI
MPN: OPA211 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.88 | $8.88 |
| 10 | $7.99 | $79.90 |
| 100 | $6.5 | $650.00 |
| 500 | $5.6 | $2,800.00 |
| 1,000 | $4.95 | $4,950.00 |
Drop-in alternatives for OPA211 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
OPA1611AIDR
✅ Drop-In📋 Reference alternative (not in catalog)
OPA2211AIDR
✅ Drop-In📋 Reference alternative (not in catalog)
OPA211IDGKR
✅ Drop-In📋 Reference alternative (not in catalog)
OPA211AIDGKR
✅ Drop-In📋 Reference alternative (not in catalog)
AD797ARZ
✅ Drop-In📋 Reference alternative (not in catalog)
LT1128CS8
✅ Drop-In📋 Reference alternative (not in catalog)
OPA211 Maximum Ratings & Electrical Characteristics
| Number of Channels | 1 |
| Supply Voltage Range | ±2.25 V to ±18 V |
| Input Voltage Noise Density | 1.1 nV/√Hz |
| Quiescent Current | 3.6 mA |
| Gain-Bandwidth Product | 80 MHz |
| Slew Rate | 20 V/µs |
| Offset Voltage | 50 µV (typical) |
| Input Bias Current | 60 nA |
| Output Type | Rail-to-Rail |
| Operating Temperature Range | -40°C to +125°C |
| Package Options | SOIC-8, VSSOP-8, SON-8 (3 mm × 3 mm) |
| Unity-Gain Stable | Yes |
| RoHS Status | Compliant |
| MSL Level | [DATA_NEEDED: MSL Level] |
| Thermal Resistance (θJA) | [DATA_NEEDED: Thermal Resistance] |
OPA211 Pin Configuration
| Pin 1 | OUT — Output |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — No connect |
| Pin 6 | V+ — Positive supply |
| Pin 7 | NC — No connect |
| Pin 8 | NC — No connect |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
OPA211 is suitable for 6 applications: Low-Noise Audio Preamplifier, Precision Instrumentation Amplifier, Active Filter, Data Acquisition System, Medical Imaging, Test and Measurement Equipment.
Low-Noise Audio Preamplifier
The OPA211's 1.1 nV/√Hz noise density and 80 MHz bandwidth make it ideal for high-fidelity audio preamplifiers. It preserves signal integrity with minimal added noise, ensuring clean amplification of microphone or phono signals. The rail-to-rail output maximizes dynamic range, and the low quiescent current is beneficial for portable audio devices. When used in a non-inverting configuration with a gain of 10, the OPA211 maintains a signal-to-noise ratio above 120 dB, making it a top choice for audiophile-grade equipment.
Recommended
Precision Instrumentation Amplifier
In precision instrumentation, the OPA211's low offset voltage (50 µV) and low noise are critical for accurate measurement. It can be used in a three-op-amp instrumentation amplifier configuration to amplify small sensor signals with high common-mode rejection. The high gain-bandwidth product ensures stability at high gains, and the wide supply range accommodates various sensor excitations. For a bridge sensor with 10 mV full-scale output, the OPA211 provides a noise floor of less than 1 µV, enabling 16-bit resolution in data acquisition systems.
Recommended
Active Filter
The OPA211's high bandwidth and low noise make it suitable for active filters in communication and audio systems. It can implement Butterworth or Chebyshev filters with cutoff frequencies up to several megahertz. The low distortion and high slew rate ensure that filtered signals retain their shape without ringing. In a 4th-order low-pass filter with a cutoff of 1 MHz, the OPA211 achieves a passband ripple of less than 0.1 dB, making it ideal for anti-aliasing filters in ADC front-ends.
Recommended
Data Acquisition System
In data acquisition systems, the OPA211 can drive high-resolution ADCs with its low output impedance and high slew rate. It can be used as a buffer or gain stage before an ADC, ensuring that the signal is accurately sampled. The low noise and high bandwidth prevent aliasing and preserve signal fidelity. For a 24-bit ADC like the ADS8887, the OPA211's noise performance is essential to achieve the full dynamic range, providing a signal-to-noise ratio of over 100 dB.
Recommended
Medical Imaging
The OPA211 is used in medical imaging equipment such as ultrasound and MRI systems, where low noise and high precision are paramount. It amplifies weak signals from transducers with minimal added noise, improving image quality. The wide temperature range ensures reliable operation in clinical environments. In an ultrasound receiver, the OPA211 provides a noise figure of less than 2 dB, enabling detection of small echoes and enhancing diagnostic capability.
Recommended
Test and Measurement Equipment
In test and measurement, the OPA211's accuracy and stability are essential for oscilloscopes, spectrum analyzers, and signal generators. It can be used in front-end amplifiers, filters, and buffer stages. The low offset drift ensures consistent measurements over temperature. For a digital multimeter, the OPA211 provides a stable gain stage with less than 0.01% error, ensuring precise voltage and current readings.
Recommended
Recommended Products Summary
Engineering reference data for OPA211 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA1611AIDR | OPA2211AIDR | AD797ARZ |
|---|---|---|---|---|
| Package | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Input Voltage Noise Density | 1.1 nV/√Hz | 1.0 nV/√Hz | 1.1 nV/√Hz | 0.9 nV/√Hz |
| Quiescent Current | 3.6 mA | 3.6 mA | 3.6 mA (per channel) | 8 mA |
| Gain-Bandwidth Product | 80 MHz | 80 MHz | 80 MHz | 8 MHz |
| Slew Rate | 20 V/µs | 20 V/µs | 20 V/µs | 20 V/µs |
| Offset Voltage | 50 µV | 50 µV | 50 µV | 25 µV |
| Supply Voltage Range | ±2.25 V to ±18 V | ±2.25 V to ±18 V | ±2.25 V to ±18 V | ±5 V to ±15 V |
Key Differentiators
- Ultra-low noise density of 1.1 nV/√Hz (vs AD797ARZ)
- High gain-bandwidth product of 80 MHz (vs LT1128CS8)
- Wide supply voltage range (vs AD797ARZ)
Design Notes
Use 0.1-µF ceramic capacitors close to the V+ and V- pins to filter high-frequency noise. For best performance, add a 10-µF tantalum capacitor in parallel for low-frequency decoupling. According to the TI datasheet, this is essential for applications with noisy power supplies.
Keep the feedback network components close to the inverting input to minimize parasitic capacitance. Use a ground plane to reduce noise pickup. For the SON-8 package, ensure proper thermal pad soldering to improve heat dissipation.
Avoid exceeding the input common-mode voltage range, which can cause output phase reversal. Also, ensure the output load does not exceed the specified output current capability. For high-frequency applications, consider the effect of input capacitance on stability.
Compliance Information
RoHS compliant per TI product page. AEC-Q100 qualification not specified for standard OPA211; OPA211AIDGKR is automotive grade.
