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Texas Instruments OPA381AIDRBRG4
- Part No.:
- OPA381AIDRBRG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-VDFN Exposed Pad
- Datasheet:
-
OPA381AIDRBRG4.pdf
- Description:
- IC TRANSIMPEDANCE 1 CIRCUIT 8SON
- Quantity:
- Payment:
- Shipping:
Inventory:4,993
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Product details
Overview
OPA381AIDRBRG4 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, and >250kHz transimpedance bandwidth with low 1/f noise-enabling high-fidelity optical signal acquisition in CAT-scan front-ends and photo lab equipment.
For engineers reviewing the OPA381AIDRBRG4 datasheet, OPA381AIDRBRG4 pinout, OPA381AIDRBRG4 application, or OPA381AIDRBRG4 equivalent, key selection criteria include its DFN-8 package thermal performance (θJA = 65°C/W), 0.1µV/°C max offset drift, 10nV/√Hz input voltage noise density at >1MHz, and verified 200ns positive overload recovery time-critical for fast optical power control loops.
Technical Context
The OPA381AIDRBRG4 employs an auto-zero architecture with continuous 18MHz signal-path amplification and 10kHz zero-correction cycles, delivering stable dc precision without aliasing artifacts. Its internal topology integrates high-speed recovery clamping and rail-to-rail output swing extension via external pulldown resistor to −5V.
Designed specifically for inverting transimpedance configurations, it supports photodiode reverse biasing through the noninverting input while maintaining common-mode range from V− to (V+) − 1.8V and enabling 0V output operation when paired with RP = 10kΩ to −5V-verified 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 (e.g., 10–100pF) and feedback resistors up to 10MΩ |
| Input Offset Voltage | 25µV (max) - ensures ≤0.25mV error at 100kΩ transimpedance gain, critical for sub-nA photocurrent resolution |
| Bias Current | 3pA (max) - minimizes dark-current-induced errors in high-impedance photodiode interfaces |
| Input Voltage Noise | 10nV/√Hz (>1MHz) - preserves SNR in wideband optical detection where photodiode capacitance elevates noise gain |
| Quiescent Current | 800µA - supports battery-powered portable optical sensors without compromising precision |
| Supply Range | 2.7V to 5.5V - compatible with single-supply industrial and medical systems using 3.3V or 5V rails |
| Overload Recovery | 200ns (positive rail) - restores linear operation within one clock cycle of a 5MHz optical pulse train |
Pinout & Package
OPA381AIDRBRG4 is housed in a thermally enhanced DFN-8 (3mm × 3mm) package with exposed die pad for improved heat dissipation (θJA = 65°C/W). Pin 1 is marked by a dot; pin 5 is V−, pin 6 is +In, pin 7 is −In, pin 8 is V+; pins 1–4 are NC (no internal connection).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (NC) | No internal connection | Must be left unconnected or tied to ground per layout best practices; no functional role |
| Pin 2 (NC) | No internal connection | Not bonded; avoid routing signals or traces to this terminal |
| Pin 3 (NC) | No internal connection | Reserved for future use; electrically isolated |
| Pin 4 (NC) | No internal connection | Do not connect; floating node with no internal circuitry |
| Pin 5 (V−) | Negative supply rail | Reference for internal biasing; must be connected to system ground or negative supply |
| Pin 6 (+In) | Noninverting input | Used for photodiode biasing or reference voltage setting; high-impedance node (10¹³Ω || 2.5pF) |
| Pin 7 (−In) | Inverting input | Photodiode cathode connection point; summing junction with <1pF differential capacitance |
| Pin 8 (V+) | Positive supply rail | Power input for internal circuitry; requires local 1µF ceramic bypass to V− |
Key Features
| Feature | Design Value |
|---|---|
| Auto-zero architecture | Continuous 10kHz correction eliminates 1/f drift, achieving 0.1µV/°C max offset drift over full temperature range |
| Output swing extension | Supports 0V output with external 10kΩ pulldown resistor to −5V-verified across −40°C to +125°C |
| High-speed overload recovery | 200ns return to linearity after positive rail saturation-enables accurate measurement of burst-mode optical signals |
| Low input bias current | 3pA max enables use with high-value feedback resistors (up to 10MΩ) without significant current-induced offset error |
| Thermal performance | DFN-8 package delivers θJA = 65°C/W-supports sustained operation at 125°C ambient in compact optical modules |
Applications
| CAT-Scanner Front-End | Photodiode Monitoring |
|---|---|
Use Scenario: High-speed X-ray photon detection in computed tomography systems requiring sub-microsecond signal fidelity and multi-decade dynamic range. IC Role / Device Role / Timing Role: Transimpedance amplifier converting picoampere-level photodiode currents into precise voltage outputs synchronized to rotating gantry timing. Use Value: 5-decade dynamic range (10nA–1mA) and 250kHz bandwidth enable simultaneous capture of weak scatter and strong primary beam signals without range switching. | Use Scenario: Real-time ambient light and laser power monitoring in analytical instrumentation with variable-intensity sources. IC Role / Device Role / Timing Role: Precision I/V converter interfacing silicon or InGaAs photodiodes in closed-loop optical power control circuits. Use Value: 3pA bias current and 25µV offset ensure <1% error at 100nA photocurrent-critical for calibration-grade optical meters. |
| Optical Amplifiers | Photo Lab Equipment |
Use Scenario: Gain stabilization and output power sensing in erbium-doped fiber amplifiers (EDFAs) and semiconductor optical amplifiers (SOAs). IC Role / Device Role / Timing Role: Fast-response monitor channel amplifier feeding analog-to-digital converters in feedback control loops. Use Value: 18MHz GBW and 12V/µs slew rate support 100kHz modulation envelope tracking for real-time gain adjustment. | Use Scenario: Densitometry and spectral analysis in film scanners and digital microscopy systems requiring ultra-low-noise analog front-ends. IC Role / Device Role / Timing Role: Low-noise transimpedance stage preceding 16-bit ADCs such as ADS8325 in high-resolution image digitization paths. Use Value: 10nV/√Hz noise density and 0.1µV/°C drift maintain 16-bit ENOB across operating temperature without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transimpedance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA380IDGKR | 90MHz GBW, 2.7V–5.5V supply, higher noise (25nV/√Hz), 50pA bias current | Better suited for ultra-high-bandwidth (>1MHz) photodiode circuits where speed outweighs dc precision | Select when transimpedance bandwidth >1MHz is required and offset drift <0.1µV/°C is not mandatory |
| OPA335AIDBVR | Zero-drift architecture, 10µV VOS (max), 0.03µV/°C drift, but only 2MHz GBW and 1.5V–5.5V supply | Preferred for ultra-low-drift, low-bandwidth (<100kHz) integrator or precision sensor conditioning stages | Choose when long-term stability dominates bandwidth needs-e.g., laboratory-grade photometer calibration |
Compared with OPA381AIDRBRG4, the OPA380IDGKR trades dc precision for 3.5× higher bandwidth but exhibits 2.5× higher voltage noise and 17× higher bias current; the OPA335AIDBVR delivers superior drift performance but lacks the 18MHz GBW needed for >250kHz optical signal capture-making OPA381AIDRBRG4 the optimal balance for medical and industrial photodiode front-ends.
Availability
OPA381AIDRBRG4 is available at Aetrix Electronics and suitable for CAT-scan front-ends, photodiode monitoring systems, and optical amplifier control circuits requiring stable component supply, extended temperature operation (−40°C to +125°C), and traceable DFN-8 packaging.
Supply support for OPA381AIDRBRG4 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 OPA381AIDRBRG4 belongs to TI's precision transimpedance amplifier product line, engineered for high-dynamic-range optical current measurement in medical imaging, analytical instrumentation, and industrial sensing-where low drift, low noise, and fast recovery are non-negotiable.
FAQ
What is the maximum transimpedance bandwidth achievable with OPA381AIDRBRG4 in a typical photodiode interface?
The OPA381AIDRBRG4 achieves >250kHz transimpedance bandwidth in most configurations, validated with photodiode capacitances from 1pF to 100pF and feedback resistors up to 10MΩ. This performance stems directly from its 18MHz gain-bandwidth product and low input capacitance (1pF differential, 2.5pF common-mode), as confirmed in TI's SBOS313B datasheet Figure 6 and transimpedance design equations on page 10.
Does OPA381AIDRBRG4 support true 0V output swing, and what external components are required?
Yes, OPA381AIDRBRG4 supports 0V output swing when used with an external 10kΩ pulldown resistor (RP) connected between VOUT and −5V, as detailed in Figure 3 and Applications section page 9 of the datasheet. This configuration extends the negative output swing from 50mV above V− to 0V while maintaining linearity and accuracy across −40°C to +125°C.
How does the auto-zero architecture of OPA381AIDRBRG4 impact its noise performance at low frequencies?
The OPA381AIDRBRG4's auto-zero architecture eliminates 1/f noise, resulting in flat 10nV/√Hz voltage noise density above 1MHz and only 3µVPP (0.1Hz–10Hz). This enables stable dc-coupled photodiode measurements without low-frequency drift artifacts-verified in Electrical Characteristics Table (page 3) and Typical Characteristics (page 7) of SBOS313B.
What is the thermal resistance (θJA) of the OPA381AIDRBRG4 DFN-8 package, and how does it compare to the MSOP-8 variant?
The OPA381AIDRBRG4 in DFN-8 package has θJA = 65°C/W, significantly lower than the MSOP-8 variant's 150°C/W (per Package/Ordering Information table, page 2). This 57% improvement in thermal efficiency allows higher power dissipation or operation in hotter environments-critical for compact optical modules where board space limits heatsinking.
Can OPA381AIDRBRG4 drive a 16-bit ADC like the ADS8325, and what interface considerations apply?
Yes, OPA381AIDRBRG4 is explicitly optimized for driving 16-bit ADCs including the ADS8325, as stated on page 13 of SBOS313B. Key interface requirements include using RC filtering (100Ω + 1nF) between OPA381AIDRBRG4 output and ADC input to absorb charge injection, and ensuring the OPA381AIDRBRG4's 12V/µs slew rate settles 4V steps within 7µs-meeting ADS8325's 100kSPS timing constraints.
OPA381AIDRBRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-SON (3x3)
OPA381AIDRBRG4 FAQ
1.How can I place an order for OPA381AIDRBRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA381AIDRBRG4 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 OPA381AIDRBRG4 reliable?
The price and inventory of OPA381AIDRBRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA381AIDRBRG4 is usually 5 days.
3.What payment methods are accepted for OPA381AIDRBRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA381AIDRBRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for OPA381AIDRBRG4?
OPA381AIDRBRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA381AIDRBRG4 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 OPA381AIDRBRG4?
For technical support, including OPA381AIDRBRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA381AIDRBRG4 requirements.
6.How does Aetrix verify that OPA381AIDRBRG4 is sourced from the original manufacturer or authorized distributors?
All OPA381AIDRBRG4 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 OPA381AIDRBRG4 meets industry standards.
7.What is the process for return or replacement of OPA381AIDRBRG4?
All OPA381AIDRBRG4 units undergo pre-shipment inspection (PSI). If there is an issue with OPA381AIDRBRG4, 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 OPA381AIDRBRG4 part is unused and in its original packaging.
Return procedure for OPA381AIDRBRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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