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Texas Instruments OPA391DCKR
- Part No.:
- OPA391DCKR
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
OPA391DCKR.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT SC70-5
- Quantity:
- Payment:
- Shipping:
Inventory:14,926
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Product details
Overview
OPA391DCKR from Texas Instruments is a single-channel, precision rail-to-rail input/output operational amplifier optimized for ultra-low-power, high-impedance sensor signal conditioning. It delivers 1MHz gain-bandwidth, ±45µV max input offset voltage, 24µA quiescent current, and 10fA input bias current - enabling accurate amplification in battery-powered medical sensors (e.g., blood glucose monitors) and industrial transmitters.
For engineers reviewing the OPA391DCKR datasheet, OPA391DCKR pinout, OPA391DCKR application, or OPA391DCKR equivalent, this page provides verified specifications, SC-70 package details, real-world use cases in electrochemical sensing and process analytics, and validated alternative options for low-voltage, low-IQ precision amplification.
Technical Context
The OPA391DCKR employs TI's proprietary e-trim™ technology to achieve ultra-low offset (±45µV max) and drift (±1.2µV/°C) without auto-zero or chopper switching - eliminating switching artifacts and enabling clean DC-coupled operation. Its CMOS input stage supports rail-to-rail common-mode range (±100mV beyond rails) and 1TΩ || 1pF input impedance.
It features a robust output stage tolerant of ≥100pF capacitive load, 1V/µs slew rate, and 60mA output drive capability - allowing direct interface with ADC drivers, active filters, and low-impedance loads without external isolation resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain bandwidth product | 1 MHz - enables stable unity-gain operation and supports bandwidth-critical sensor front ends up to ~800 kHz. |
| Input offset voltage (max) | ±45 µV - ensures ≤0.001% error in 4.5V full-scale ratiometric bridge measurements. |
| Quiescent current | 24 µA - allows continuous operation for >10 years on a CR2032 coin cell in wearable patches. |
| Input bias current (max) | 10 fA - minimizes voltage error across >1 GΩ source impedances (e.g., pH electrodes, photodiodes). |
| Supply voltage range | 1.7 V to 5.5 V - supports direct connection to Li-ion, 2×AA, or 3.3V/5V system rails without regulation. |
| Input common-mode range | ±100 mV beyond rails - permits true rail-to-rail input operation even at 1.7V supply. |
| Slew rate | 1 V/µs - settles 4-V steps in <8 µs, suitable for fast step-response requirements in flow transmitters. |
Pinout & Package
OPA391DCKR is packaged in a 5-pin SC-70 (DCK) surface-mount package, measuring 2.0 mm × 1.25 mm × 0.9 mm (typ), with wettable flanks for automated optical inspection (AOI).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| +IN (Pin 1) | Noninverting input | High-impedance node (1 TΩ || 1 pF); accepts signals from ±100 mV beyond supply rails. |
| V− (Pin 2) | Negative power supply | Reference for dual-supply operation or ground in single-supply configurations. |
| −IN (Pin 3) | Inverting input | Differential input node; no internal ESD diodes to rails - supports unrestricted differential voltage. |
| OUT (Pin 4) | Amplifier output | Rail-to-rail capable; drives ≥60 mA and remains stable with ≥100 pF capacitive load. |
| V+ (Pin 5) | Positive power supply | Accepts 1.7–5.5 V; powers internal e-trim circuitry and output stage. |
Key Features
| Feature | Design Value |
|---|---|
| e-trim™ offset calibration | Eliminates need for external trimming or auto-zero circuitry; achieves ±45 µV max offset without switching noise. |
| EMI/RFI filtered inputs | Rejects >80 dB of RF interference at 900 MHz (EMIRR IN+ = 120 dB), critical for analog security cameras in noisy environments. |
| Rail-to-rail output swing | Drives within 3 mV of rails (no load), maximizing dynamic range into 12-bit+ SAR ADCs. |
| High capacitive load drive | Stable with ≥100 pF directly on output - avoids series isolation resistors in filter or cable-drive applications. |
| Ultra-low temperature drift | ±1.2 µV/°C max drift ensures <0.15 µV error over 0–70°C ambient - essential for uncalibrated medical sensor patches. |
Applications
| Blood Glucose Monitor | Gas Detector |
|---|---|
Use Scenario: Amplifies low-current amperometric signal from enzyme-coated electrode exposed to blood sample. IC Role / Device Role / Timing Role: Precision transimpedance amplifier with ultra-low input bias current (10 fA) and sub-50 µV offset to resolve pA-level currents. Use Value: Enables detection of glucose concentrations down to 20 mg/dL with <2% error, meeting ISO 15197:2013 accuracy requirements. | Use Scenario: Conditions signal from electrochemical gas sensor (CO, NO₂) in portable handheld detector. IC Role / Device Role / Timing Role: Low-drift, low-IQ buffer and gain stage operating from coin-cell supply. Use Value: Delivers 125°C-rated stability and <1 µV/°C drift compensation, extending field calibration interval to 6 months. |
| Temperature Transmitter | Wearable Fitness Patch |
Use Scenario: Interfaces with RTD or thermistor in 4–20 mA loop-powered industrial transmitter. IC Role / Device Role / Timing Role: High-impedance ratiometric amplifier with rail-to-rail I/O for 3.3V microcontroller ADC interface. Use Value: Maintains ±0.1°C accuracy over –40°C to +85°C using only internal trim - eliminates external calibration components. | Use Scenario: Front-end amplifier for dry-electrode ECG or bioimpedance measurement in ultra-thin patch form factor. IC Role / Device Role / Timing Role: Single-supply, 1.7V-operable op amp in space-constrained SC-70 package. Use Value: Enables 2.4 mm² board area footprint and 24 µA IQ - extends 30mAh battery life to >14 days continuous monitoring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision, low-IQ operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA333AIDBVR | Chopper-stabilized; 17 µV max offset, 17 µA IQ, but introduces 100 nVPP switching noise. | Not recommended for DC-coupled electrochemical sensors due to chopper ripple. | Select OPA333AIDBVR only when ultra-low offset dominates over noise sensitivity. |
| LTC2050CS5#TRMPBF | Zero-drift architecture; 1 µV max offset, 45 µA IQ, 1.5 MHz GBW, SO-5 package. | Higher IQ reduces battery life in wearables; larger SO-5 footprint vs. SC-70. | Choose LTC2050CS5#TRMPBF when sub-5 µV offset is mandatory and supply >3V is available. |
Compared with OPA391DCKR, OPA333AIDBVR offers lower quiescent current but introduces chopper noise unsuitable for amperometric sensing, while LTC2050CS5#TRMPBF delivers superior offset performance at the cost of 88% higher IQ and larger PCB area - making OPA391DCKR optimal for balanced precision, power, and size in portable medical and industrial transmitters.
Availability
OPA391DCKR is available at Aetrix Electronics and suitable for blood glucose monitors, gas detectors, and wearable fitness patches requiring stable component supply, long-term lifecycle support, and guaranteed traceability for regulated medical designs.
Supply support for OPA391DCKR 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision amplifiers and low-power signal chains.
The OPAx391 family was designed specifically for high-impedance, battery-powered sensor interfaces - targeting electrochemical cells, bridge transducers, and photodiode amplifiers where offset, drift, bias current, and quiescent power must be simultaneously minimized.
FAQ
What is the maximum operating temperature range for the OPA391DCKR?
The OPA391DCKR is specified for operation from –40°C to +125°C ambient temperature. This extended range is validated per TI's production test conditions and supports deployment in automotive under-hood modules, industrial process analyzers, and outdoor environmental sensors - all while maintaining ±45 µV max offset and 24 µA quiescent current performance.
Does the OPA391DCKR require external compensation for stability?
No, the OPA391DCKR is unity-gain stable and does not require external compensation. Its internal compensation supports stable operation with ≥100 pF capacitive load on the output - a key advantage over many low-IQ amplifiers that oscillate without series RISO. This simplifies layout in ADC driver and cable-interface applications.
Can the OPA391DCKR operate from a 1.8V supply?
Yes, the OPA391DCKR operates down to 1.7V, making it fully compatible with 1.8V logic and microcontrollers. At 1.8V, it maintains rail-to-rail input/output swing, 1 MHz GBW, and 24 µA quiescent current - enabling direct integration into energy-harvesting and ultra-low-voltage IoT nodes without LDO overhead.
Is the OPA391DCKR pin-compatible with other SC-70 op amps like the OPA348 or TLV2460?
No, the OPA391DCKR uses a non-standard SC-70 pinout: Pin 1 = +IN, Pin 2 = V−, Pin 3 = −IN, Pin 4 = OUT, Pin 5 = V+. This differs from industry-standard SC-70 op amps (e.g., OPA348: Pin 1 = OUT, Pin 2 = −IN, Pin 3 = +IN, Pin 4 = V−, Pin 5 = V+). PCB layout must follow TI's DCK mapping to avoid functional failure.
What packaging and marking information is provided on the OPA391DCKR reel?
The OPA391DCKR ships in tape-and-reel format (3,000 units/reel) with SC-70 (DCK) package. Top-side marking is "391" followed by date code and TI logo. Each unit is 100% tested for offset voltage, quiescent current, and open-loop gain per SBOS925E production data - ensuring compliance with medical and industrial reliability standards.
OPA391DCKR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- e-trim™
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 1V/µs
- Gain Bandwidth Product:
- 1 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 0.01 pA
- Voltage - Input Offset:
- 15 µV
- Current - Supply:
- 24µA
- Current - Output / Channel:
- 60 mA
- Voltage - Supply Span (Min):
- 1.7 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-5
OPA391DCKR FAQ
1.How can I place an order for OPA391DCKR through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA391DCKR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for OPA391DCKR reliable?
The price and inventory of OPA391DCKR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA391DCKR is usually 5 days.
3.What payment methods are accepted for OPA391DCKR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA391DCKR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA391DCKR?
OPA391DCKR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA391DCKR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for OPA391DCKR?
For technical support, including OPA391DCKR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA391DCKR requirements.
6.How does Aetrix verify that OPA391DCKR is sourced from the original manufacturer or authorized distributors?
All OPA391DCKR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that OPA391DCKR meets industry standards.
7.What is the process for return or replacement of OPA391DCKR?
All OPA391DCKR units undergo pre-shipment inspection (PSI). If there is an issue with OPA391DCKR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The OPA391DCKR part is unused and in its original packaging.
Return procedure for OPA391DCKR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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