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Texas Instruments OPA381AIDGKT
- Part No.:
- OPA381AIDGKT
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
OPA381AIDGKT.pdf
- Description:
- IC TRANSIMPEDANCE 1 CIRC 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:617
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Product details
Overview
OPA381AIDGKT from Texas Instruments is a precision single-channel transimpedance amplifier optimized for photodiode current-to-voltage conversion, featuring 18MHz gain-bandwidth product, 25µV (max) offset voltage, 3pA bias current, 10nV/√Hz input voltage noise at >1MHz, and >250kHz transimpedance bandwidth in typical configurations-used in optical front-ends requiring high dynamic range and long-term stability.
For engineers reviewing the OPA381AIDGKT datasheet, OPA381AIDGKT pinout, OPA381AIDGKT application, or OPA381AIDGKT equivalent, this page delivers verified specifications, MSOP-8 package details, photodiode monitoring design context, and validated alternative options for I/V conversion in medical imaging, analytical instrumentation, and fiber-optic power control loops.
Technical Context
The OPA381AIDGKT employs an auto-zero architecture with time-continuous 18MHz signal-path amplifier, zero-corrected every 100µs, delivering <0.1µV/°C offset drift and eliminating 1/f noise without introducing 10kHz correction artifacts. Its internal high-speed overload recovery clamp enables 200ns return to linear operation after positive-rail saturation.
Designed exclusively for inverting transimpedance configurations, it accepts photodiode current at the inverting input while holding the noninverting input at a fixed bias voltage; input common-mode range extends from V− to (V+) −1.8V, and output swing reaches within 50mV of V− (or 0V with external −5V pulldown resistor), supporting single-supply 2.7V–5.5V operation across −40°C to +125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth Product | 18MHz - enables >250kHz transimpedance bandwidth with typical photodiode capacitance and feedback resistors up to 10MΩ. |
| Input Offset Voltage (max) | 25µV - ensures ≤0.25% full-scale error in 10V-output I/V stages using 1MΩ RF, critical for sub-nA current resolution. |
| Bias Current (typ) | 3pA - minimizes dark-current-induced offset in high-impedance photodiode circuits, preserving accuracy at low light levels. |
| Input Voltage Noise Density | 10nV/√Hz above 1MHz - low high-frequency noise prevents amplification of photodiode capacitance-induced noise gain. |
| Quiescent Current | 800µA - enables battery-powered portable optical sensors while maintaining precision performance. |
| Supply Voltage Range | 2.7V to 5.5V - supports direct interfacing with 3.3V and 5V logic/system rails without level-shifting. |
| Operating Temperature | −40°C to +125°C - qualified for industrial and medical equipment deployed in uncontrolled thermal environments. |
Pinout & Package
OPA381AIDGKT is packaged in an MSOP-8 (DGK) thermally enhanced surface-mount package with exposed die pad, measuring 3.0mm × 3.0mm × 1.0mm. Pin 1 is marked with a dot; pin numbering follows standard MSOP convention (counterclockwise from top-left corner when viewed from top).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | V+ | Positive supply rail connection; bypass with 1µF ceramic capacitor near pin for stability. |
| 2 | Out | Amplifier output; capable of swinging to within 50mV of V− (or 0V with external −5V pulldown resistor). |
| 3 | −In | Inverting input; summing node for photodiode anode connection in transimpedance configuration. |
| 4 | +In | Noninverting input; used as fixed DC bias point (e.g., 0.5V) to set output baseline and reverse-bias photodiode. |
| 5 | V− | Negative supply rail (typically ground); must be low-impedance for optimal PSRR and noise rejection. |
| 6 | NC | No internal connection; electrically isolated - no routing or soldering required. |
| 7 | NC | No internal connection; electrically isolated - no routing or soldering required. |
| 8 | NC | No internal connection; electrically isolated - no routing or soldering required. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-zero architecture | Zero-correction every 100µs eliminates 1/f noise and drift without injecting 10kHz artifacts into signal path. |
| Fast overload recovery | 200ns return to linear operation after positive-rail saturation - maintains loop integrity in burst-mode optical sensing. |
| Extended output swing | 0V output achievable with optional −5V pulldown resistor - enables true single-supply 0–4.096V ADC interfacing. |
| Low input bias current | 3pA typ ensures <10nA measurement error in 10GΩ-equivalent transimpedance stages, preserving dynamic range. |
| High transimpedance bandwidth | >250kHz usable bandwidth with 100pF photodiode capacitance and 1MΩ RF - supports fast pulse detection in CAT-scan detectors. |
Applications
| Photodiode Monitoring | Optical Amplifier Control |
|---|---|
Use Scenario: Real-time monitoring of low-light-level photodiode current in spectrophotometers and fluorescence readers. IC Role / Device Role / Timing Role: Transimpedance amplifier converting 10nA–1mA photocurrent into 0.01–10V analog output with <0.1µV/°C drift. Use Value: Enables 5-decade dynamic range measurement in a single stage, eliminating need for programmable-gain or log-amp alternatives. |
Use Scenario: Closed-loop gain stabilization in erbium-doped fiber amplifiers (EDFAs) using back-facet photodiode feedback. IC Role / Device Role / Timing Role: High-bandwidth I/V converter feeding error signal to laser diode driver for sub-µs response to optical power fluctuations. Use Value: 18MHz GBW and 200ns overload recovery ensure stable control under transient optical load changes. |
| CAT-Scanner Front-End | Photo Lab Equipment |
Use Scenario: X-ray detector signal conditioning in computed tomography systems requiring radiation-hardened analog front-end. IC Role / Device Role / Timing Role: Precision transimpedance stage for scintillator-photodiode pairs, operating over −40°C to +125°C with minimal calibration drift. Use Value: Long-term stability and 25µV max VOS reduce recalibration frequency in medical-grade imaging hardware. |
Use Scenario: Densitometry and colorimetry in film development analyzers requiring accurate low-current photodiode readout. IC Role / Device Role / Timing Role: Low-noise I/V converter driving 16-bit ADCs (e.g., ADS8325) with integrated anti-aliasing filtering. Use Value: 10nV/√Hz noise density and 12-bit+ ENOB support high-fidelity digitization of optical density gradients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transimpedance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA380IDGKT | 90MHz GBW, higher noise (12nV/√Hz), 50pA bias current - trades precision for bandwidth. | Better suited for ultra-fast photodiode signals (>1MHz transimpedance BW) where offset and drift are secondary. | Select OPA380IDGKT only when >250kHz transimpedance bandwidth is mandatory and 25µV VOS tolerance is relaxed. |
| OPA335AIDBVR | 10µV max VOS, zero-drift, but only 2MHz GBW and 500pA bias current - optimized for dc/low-frequency precision. | Ideal for static or slowly varying photocurrents (e.g., environmental light sensing) where bandwidth <10kHz suffices. | Choose OPA335AIDBVR when ultra-low offset dominates requirements and transimpedance bandwidth ≤50kHz is acceptable. |
Compared with OPA381AIDGKT, OPA380IDGKT offers 3.5× higher bandwidth at the cost of 17× higher bias current and reduced dc precision, while OPA335AIDBVR delivers 2.5× lower offset voltage but sacrifices >8× bandwidth-making OPA381AIDGKT the balanced choice for wide-dynamic-range, medium-speed optical sensing.
Availability
OPA381AIDGKT is available at Aetrix Electronics and suitable for photodiode monitoring, CAT-scan front-ends, and optical amplifier control requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for OPA381AIDGKT 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 op amps and signal-chain solutions.
The OPA381AIDGKT belongs to TI's precision transimpedance amplifier product line, engineered specifically for high-dynamic-range, low-drift optical current measurement in medical, analytical, and industrial instrumentation.
FAQ
What is the maximum transimpedance bandwidth achievable with OPA381AIDGKT?
The OPA381AIDGKT achieves >250kHz transimpedance bandwidth in typical configurations using standard photodiode capacitances (e.g., 100pF) and feedback resistors up to 10MΩ. This is enabled by its 18MHz gain-bandwidth product and optimized internal compensation - confirmed in TI SBOS313B Figure 6 and Table 1.
Does OPA381AIDGKT support true 0V output swing on a single supply?
Yes - OPA381AIDGKT can deliver 0V output with a single +5V supply when a 10kΩ pulldown resistor connects the output to −5V, as documented in Figure 3 and Section "Achieving Output Swing to Ground" of SBOS313B. This extends the linear output range to 0V–4.4V without sacrificing accuracy.
What is the input bias current specification for OPA381AIDGKT over temperature?
The OPA381AIDGKT has a typical input bias current of 3pA at +25°C, with ±50pA maximum over −40°C to +125°C (per Electrical Characteristics table, IB column). This ultra-low bias current is critical for preserving signal integrity in high-impedance photodiode circuits.
Can OPA381AIDGKT drive a 16-bit ADC like the ADS8325 directly?
Yes - the OPA381AIDGKT is explicitly optimized for driving 16-bit ADCs such as the ADS8325, as stated in Section "DRIVING 16-BIT ANALOG-TO-DIGITAL CONVERTERS (ADC)" of SBOS313B. Its low output impedance, fast settling (7µs to 0.0015%), and low noise ensure full-resolution digitization without external buffering.
Is OPA381AIDGKT pin-compatible with OPA2381AIDGKT?
No - OPA381AIDGKT is a single-channel device in MSOP-8 with NC pins at positions 6–8, whereas OPA2381AIDGKT is dual-channel with active pins at all eight positions (Out A, −In A, +In A, V−, V+, −In B, +In B, Out B). Their pinouts are fundamentally incompatible; PCB layout must be redesigned for channel count change.
OPA381AIDGKT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Transimpedance
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 12V/µs
- Gain Bandwidth Product:
- 18 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 3 pA
- Voltage - Input Offset:
- 7 µV
- Current - Supply:
- 800µA
- Current - Output / Channel:
- 10 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
OPA381AIDGKT FAQ
1.How can I place an order for OPA381AIDGKT through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA381AIDGKT 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 OPA381AIDGKT reliable?
The price and inventory of OPA381AIDGKT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA381AIDGKT is usually 5 days.
3.What payment methods are accepted for OPA381AIDGKT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA381AIDGKT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA381AIDGKT?
OPA381AIDGKT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA381AIDGKT 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 OPA381AIDGKT?
For technical support, including OPA381AIDGKT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA381AIDGKT requirements.
6.How does Aetrix verify that OPA381AIDGKT is sourced from the original manufacturer or authorized distributors?
All OPA381AIDGKT 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 OPA381AIDGKT meets industry standards.
7.What is the process for return or replacement of OPA381AIDGKT?
All OPA381AIDGKT units undergo pre-shipment inspection (PSI). If there is an issue with OPA381AIDGKT, 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 OPA381AIDGKT part is unused and in its original packaging.
Return procedure for OPA381AIDGKT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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