OPA211ID - 1.1nV/Hz Precision Op Amp 80MHz SOIC-8 | TI
MPN: OPA211ID ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.2 | $5.20 |
| 10 | $4.68 | $46.80 |
| 100 | $4.1 | $410.00 |
| 500 | $3.7 | $1,850.00 |
| 1,000 | $3.3 | $3,300.00 |
Drop-in alternatives for OPA211ID — 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:
OPA1611ID
✅ Drop-In📋 Reference alternative (not in catalog)
OPA211AID
✅ Drop-In📋 Reference alternative (not in catalog)
OPA828IDR
✅ Drop-In✓ In Stock
$3.17 / Unit
View Datasheet →AD797ARZ
✅ Drop-In📋 Reference alternative (not in catalog)
LT1028CS8
✅ Drop-In📋 Reference alternative (not in catalog)
OPA211ID Maximum Ratings & Electrical Characteristics
| Noise Density | 1.1 nV/rtHz |
| Gain-Bandwidth Product | 80 MHz |
| Slew Rate | 20 V/us |
| Quiescent Current | 3.6 mA per amplifier |
| Offset Voltage | 50 uV typical |
| Input Bias Current | 60 nA |
| THD+N | 0.000015% |
| Output Type | Rail-to-Rail Output |
| Stability | Unity-Gain Stable |
| Channels | 1 |
| Operating Temperature | -40C to +125C |
| Package | 8-SOIC (D) |
| Mounting Type | Surface Mount |
| Supply Voltage Range | [DATA_NEEDED: supply voltage range] |
| RoHS Status | Compliant |
OPA211ID Pin Configuration
| Pin 1 | TRIM/NC — Offset trim / no connect per package option |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — No connect |
| Pin 6 | OUT — Output (rail-to-rail) |
| Pin 7 | V+ — Positive supply |
| Pin 8 | NC/V+ — No connect or positive supply per package option |
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
OPA211ID is suitable for 6 applications: Low-Noise Audio Preamplifier, Precision Data Acquisition Front End, Photodiode Transimpedance Amplifier, Active Filter and Signal Conditioning, Precision Instrumentation and Test Equipment, RF/IF and Wideband Signal Chains.
Low-Noise Audio Preamplifier
The OPA211's 1.1 nV/√Hz noise and 0.000015% THD+N make it excellent for microphone preamps and line stages where noise floor directly limits dynamic range. Placed as a gain stage between a balanced input and an audio ADC, its rail-to-rail output maximizes headroom on 5V single supplies. Unlike audio-optimized parts, it also provides 80 MHz bandwidth for ultrasonic extension, though the bipolar input's 60 nA bias current requires impedance matching on high-source-resistance inputs.
Recommended
Precision Data Acquisition Front End
In data acquisition, the OPA211 amplifies small sensor signals before digitization, using its 50 µV typical offset and 1.1 nV/√Hz noise to preserve low-level resolution. Configured as a gain-of-10 amplifier before a 24-bit ADC, its unity-gain stability and 80 MHz GBW settle quickly, reducing acquisition dead time. A low-pass R-C filter at the ADC input plus 0.1 µF decoupling capacitors at the supply pins keeps the rail clean, per the TI datasheet recommendation for noisy or high-impedance supplies.
Recommended
Photodiode Transimpedance Amplifier
The OPA211's 80 MHz gain-bandwidth product supports fast photodiode TIA designs for optical receivers and instrumentation. With feedback resistors in the 10 kOhm to 100 kOhm range, the closed-loop bandwidth remains in the MHz region, and the 1.1 nV/√Hz input noise limits TIA output noise. Because the bipolar input carries 60 nA bias current, designs with very high photodiode impedance should evaluate the FET-input OPA828, while standard optical links benefit from the OPA211's speed and low voltage noise.
Recommended
Active Filter and Signal Conditioning
The OPA211 works well in multi-feedback and Sallen-Key active filters up to several MHz, where its 80 MHz GBW ensures the filter's Q and corner frequency stay accurate. The 20 V/µs slew rate handles large-signal filter inputs without slewing distortion, and the rail-to-rail output allows the largest possible signal swing. Placing 0.1 µF plus 1 µF decoupling near each supply pin prevents the high bandwidth from coupling supply noise into the filter passband, a pitfall TI's datasheet explicitly warns about.
Recommended
Precision Instrumentation and Test Equipment
In bench instruments and industrial measurement equipment, the OPA211 serves as a low-noise buffer or gain stage for bridge sensors and signal conditioning chains. Its -40C to +125C industrial temperature specification supports harsh environments, while 1.1 nV/√Hz noise preserves measurement resolution at microvolt signal levels. Typical deployment: a gain-of-100 stage ahead of a precision ADC or scope front end; the 60 nA bias current must be balanced by matched source impedances to limit offset error in high-impedance probes.
Recommended
RF/IF and Wideband Signal Chains
The OPA211's 80 MHz bandwidth and 20 V/µs slew rate suit IF amplification and wideband buffering in communications receivers. Its 1.1 nV/√Hz voltage noise contributes minimally to system noise figure when driving 50-ohm-terminated IF stages. Placed after a mixer or ahead of a wideband ADC, the amplifier's class-AB output stage drives moderate loads with 0.000015% THD+N, preserving signal purity. Series resistors at the output help isolate capacitive loads and maintain stability at low closed-loop gains.
Recommended
Recommended Products Summary
Engineering reference data for OPA211ID — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA1611ID | OPA211AID | OPA828IDR | AD797ARZ | LT1028CS8 |
|---|---|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Noise Density | 1.1 nV/rtHz | 1.1 nV/rtHz class | 1.1 nV/rtHz | 3.3 nV/rtHz | ~0.9 nV/rtHz | ~0.85 nV/rtHz |
| Quiescent Current | 3.6 mA | ~3.6 mA | 3.6 mA | 4.8 mA | Higher (~8 mA class) | Higher (~10 mA class) |
| Gain-Bandwidth | 80 MHz | 40 MHz class | 80 MHz | 33 MHz class | 110 MHz class | 75 MHz class |
| Rail-to-Rail Output | Yes | Yes | Yes | Yes | No | No |
| Input Bias Current | 60 nA | 60 nA class (bipolar) | 60 nA | pA class (FET) | 250 nA class | 25 nA class |
| Offset Voltage (typ) | 50 uV | 50 uV class | Lower (precision grade) | 45 uV class | 25 uV class | 10 uV class |
Key Differentiators
- Lowest noise per unit current in its class (vs AD797ARZ)
- Rail-to-rail output for maximum dynamic range (vs LT1028CS8)
- Higher bandwidth than audio-optimized sibling (vs OPA1611ID)
Design Notes
Decouple both supply pins with 0.1 uF ceramic capacitors placed within 2 mm of the pins, plus a 2.2 uF bulk capacitor per supply rail. TI's OPAx211 datasheet explicitly warns that noisy or high-impedance supplies require decoupling close to the device pins; the 80 MHz bandwidth can otherwise couple supply noise directly into the output.
The bipolar input has 60 nA bias current; on high-impedance sources this creates offset error (60 nA x source resistance). Match source impedances seen by both inputs to cancel bias effects via bias-current cancellation. Also respect the input common-mode range to avoid phase reversal or degraded CMRR near the rails.
At closed-loop gains below 5, capacitive loads above roughly 20-50 pF can degrade phase margin; add a series isolation resistor (10-50 ohm) at the output when driving long cables or ADC input capacitance. For ADC driving, follow the datasheet typical application with an R-C charge kickback filter sized to the ADC sampling rate.
Compliance Information
RoHS compliant per DigiKey/TI product listing. Other compliance attributes not stated in provided data.
