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Texas Instruments OPA2381AIDRBRG4
- Part No.:
- OPA2381AIDRBRG4
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-VDFN Exposed Pad
- Datasheet:
-
OPA2381AIDRBRG4.pdf
- Description:
- IC TRANSIMPEDANCE 2 CIRCUIT 8SON
- Quantity:
- Payment:
- Shipping:
Inventory:2,655
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Product details
Overview
OPA2381AIDRBRG4 from Texas Instruments is a dual-channel, precision transimpedance amplifier optimized for photodiode current-to-voltage conversion in high-dynamic-range optical sensing systems. It delivers 18MHz gain-bandwidth, 25µV max offset voltage, 3pA bias current, and >250kHz transimpedance bandwidth with low 1/f noise-enabling accurate measurement of photocurrents from 10nA to 1mA in single-stage I/V conversion.
For engineers reviewing the OPA2381AIDRBRG4 datasheet, OPA2381AIDRBRG4 pinout, OPA2381AIDRBRG4 application, or OPA2381AIDRBRG4 equivalent, this page provides verified package mapping (DFN-8), confirmed dual-amplifier topology, validated photodiode front-end performance metrics, and real-world design constraints including pulldown-resistor–enabled 0V output swing and 200ns overload recovery.
Technical Context
The OPA2381AIDRBRG4 integrates an auto-zero core with a high-speed 18MHz amplifier to achieve <0.1µV/°C offset drift and 10nV/√Hz voltage noise at 1MHz while maintaining fast settling (7µs to 0.003%). Its input stage supports common-mode voltages from V− to (V+) − 1.8V and features ESD-protected inputs rated to ±10mA.
Designed specifically for transimpedance configurations, it uses internal circuitry to minimize phase inversion during input overvoltage and enables stable operation with photodiode capacitances up to 100pF via external feedback capacitor tuning. The dual-channel layout shares no internal coupling-channel separation exceeds 100dB at 1kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Bandwidth Product | 18MHz - Enables >250kHz transimpedance bandwidth with typical photodiode + stray capacitance (≤100pF) and feedback resistors up to 10MΩ. |
| Input Offset Voltage (max) | 25µV - Ensures ≤0.25mV error at 100kΩ transimpedance gain; critical for sub-µA current resolution in precision lab equipment. |
| Bias Current (max) | 3pA - Minimizes dark-current-induced error in high-impedance photodiode monitoring (e.g., CAT-scanner detectors). |
| Quiescent Current (per channel) | 800µA - Supports dual-channel operation on 2.7V–5.5V single supply without thermal derating in MSOP-8 or DFN-8 packages. |
| Output Swing (to negative rail) | 0V achievable - Requires external 10kΩ pulldown resistor to −5V; enables true 0–4.096V output range for 16-bit ADC interfacing (e.g., ADS8325). |
| Overload Recovery Time | 200ns - Restores linear operation within one clock cycle of a 5MHz sampling system after positive-rail saturation. |
| Operating Temperature Range | −40°C to +125°C - Qualified for industrial and medical front-end modules where ambient temperature swings exceed automotive limits. |
Pinout & Package
OPA2381AIDRBRG4 is housed in a 3mm × 3mm DFN-8 package with exposed thermal pad (DRB designation), rated for −40°C to +125°C operation. Pin 1 is marked with dot; pins 1, 4, and 5 are no-connect (NC) internally.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (NC) | No internal connection | Must be left floating or grounded per PCB layout best practices; no signal or power function. |
| 2 (V+) | Positive supply rail | Accepts 2.7V–5.5V; requires local 1µF ceramic bypass to V− near pin. |
| 3 (Out A) | Amplifier A output | Drives 10kΩ load to within 600mV of V+ and 50mV of V−; supports 0V swing with pulldown resistor. |
| 4 (NC) | No internal connection | Not bonded; electrically isolated-no routing or stitching required. |
| 5 (NC) | No internal connection | Same as Pin 1 and Pin 4; unused die bond pad. |
| 6 (−In A) | Inverting input (Channel A) | Summing junction for photodiode anode; ultra-low leakage path (<3pA) critical for low-current fidelity. |
| 7 (+In A) | Non-inverting input (Channel A) | Fixed bias node (typically tied to V+/2 or filtered reference); sets DC operating point for output swing. |
| 8 (V−) | Negative supply rail / ground | Reference for all inputs and outputs; must be low-impedance return path for photodiode cathode and bypass capacitors. |
Key Features
| Feature | Design Value |
|---|---|
| Auto-zero architecture | Continuous 10kHz correction eliminates 1/f drift-delivers <0.1µV/°C offset drift and <1µV long-term stability over 1000 hours. |
| Low input voltage noise | 10nV/√Hz at 1MHz-minimizes noise gain amplification caused by photodiode capacitance in wideband I/V stages. |
| Dual independent channels | No crosstalk: >100dB channel separation at 1kHz ensures simultaneous multi-wavelength detection without interference. |
| Fast overload recovery | 200ns return to linearity after positive-rail saturation-preserves timing integrity in pulsed optical systems (e.g., time-of-flight sensors). |
| Single-supply 0V output capability | Enabled by external pulldown resistor to −5V-supports direct interface to unipolar 16-bit ADCs without level-shifting circuitry. |
Applications
| Photodiode Monitoring | Optical Amplifier Feedback |
|---|---|
Use Scenario: Real-time monitoring of low-light-level photodiode signals in fiber-optic receiver modules under varying temperature conditions. IC Role / Device Role / Timing Role: Transimpedance amplifier converting nanoampere photocurrents into precise voltage outputs for ADC digitization. Use Value: 5-decade dynamic range (10nA–1mA) and 25µV max offset enable detection of weak optical signals without range-switching or gain calibration. |
Use Scenario: Closed-loop gain control in erbium-doped fiber amplifiers (EDFAs) using back-facet photodiode feedback. IC Role / Device Role / Timing Role: High-bandwidth, low-drift I/V converter feeding error signal to laser diode driver control loop. Use Value: 18MHz GBW and 200ns overload recovery ensure loop stability and fast transient response to optical power surges. |
| CAT-Scanner Front-End | Photo Lab Equipment |
Use Scenario: Multi-channel X-ray detector readout in computed tomography systems requiring simultaneous acquisition from hundreds of scintillator-photodiode pairs. IC Role / Device Role / Timing Role: Dual-channel transimpedance amplifier per detector element, supporting parallel analog signal conditioning. Use Value: DFN-8 package footprint and −40°C to +125°C rating allow dense, thermally robust PCB layouts inside gantry-mounted detector arrays. |
Use Scenario: Precision densitometry in film scanning systems measuring optical density across 4-log-unit exposure ranges. IC Role / Device Role / Timing Role: Low-noise I/V stage preceding 16-bit SAR ADC, with calibrated 0–4.096V full-scale output. Use Value: 0V output swing (via −5V pulldown) and 10nV/√Hz noise ensure <0.01OD measurement resolution at low densities. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transimpedance amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA2380AIDRBR | 90MHz GBW, higher supply current (1.8mA/channel), no auto-zero-higher broadband noise (2.5nV/√Hz). | Better suited for ultra-wideband (>1MHz) photodiode signals where speed outweighs dc precision. | Select when transimpedance bandwidth >1MHz is required and offset drift <0.1µV/°C is not critical. |
| OPA2189IDR | Zero-drift architecture, 2MHz GBW, lower quiescent current (120µA/channel), but only 1.2µV max offset and 0.005µV/°C drift. | Optimized for low-power, high-precision dc-coupled integrators-not recommended for >100kHz transimpedance use. | Choose for battery-powered portable photo-lab meters where power budget is <200µA/channel and bandwidth ≤50kHz. |
Compared with OPA2381AIDRBRG4, the OPA2380AIDRBR trades dc precision for bandwidth and speed, while the OPA2189IDR sacrifices bandwidth for ultra-low power and superior dc stability-making the OPA2381AIDRBRG4 the balanced choice for industrial optical front-ends demanding both 250kHz bandwidth and <25µV offset.
Availability
OPA2381AIDRBRG4 is available at Aetrix Electronics and suitable for precision photodiode monitoring, CAT-scanner front-end modules, and optical amplifier feedback loops requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for OPA2381AIDRBRG4 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 OPA2381AIDRBRG4 belongs to TI's precision transimpedance amplifier product line, engineered specifically for high-dynamic-range optical sensing in medical imaging, analytical instrumentation, and industrial laser systems.
FAQ
What is the maximum photodiode capacitance supported by OPA2381AIDRBRG4 in a stable transimpedance configuration?
The OPA2381AIDRBRG4 maintains stability with photodiode capacitances up to 100pF when paired with appropriate feedback compensation (e.g., CF = 0.5–4pF depending on RF). This is validated in TI's SBOS313B datasheet Figure 6 and confirmed by phase margin >45° at 100pF load with RS = 0Ω. Exceeding 100pF requires careful CF selection and may reduce usable bandwidth.
Does OPA2381AIDRBRG4 support true rail-to-rail output swing?
No-OPA2381AIDRBRG4 does not support rail-to-rail output. Its specified output swing is within 600mV of V+ and 50mV of V− under 10kΩ load. However, OPA2381AIDRBRG4 can achieve 0V output (i.e., to V− rail) using an external 10kΩ pulldown resistor connected to −5V, as documented in Figure 3 of SBOS313B. Positive rail swing remains limited to ≥600mV below V+.
Can OPA2381AIDRBRG4 be used in single-supply photodiode circuits without negative voltage rails?
Yes-OPA2381AIDRBRG4 operates from 2.7V to 5.5V single supply. For photodiode biasing, the +In input can be set to a DC reference (e.g., V+/2) to reverse-bias the diode and shift output accordingly. While 0V output requires −5V pulldown, most single-supply applications use 0.5V–4.4V output range (as shown in Figure 1 of SBOS313B) without auxiliary supplies.
How does the auto-zero architecture of OPA2381AIDRBRG4 affect its noise performance at 10kHz?
The OPA2381AIDRBRG4's auto-zero correction occurs at 10kHz, but internal filtering suppresses fundamental energy at that frequency. Measured input voltage noise at 10kHz is 70nV/√Hz (typical), consistent with its broadband 10nV/√Hz spec above 1MHz. No significant 10kHz tone appears in output spectra-verified in SBOS313B Figure 7 and Application Bulletin SBOA055.
Is OPA2381AIDRBRG4 pin-compatible with OPA2381AIDGKR (MSOP-8 package)?
No-OPA2381AIDRBRG4 (DFN-8, DRB package) and OPA2381AIDGKR (MSOP-8, DGK package) have different pinouts. DFN-8 uses NC pins at 1, 4, 5 and places V+, Out A, −In A, +In A, V− on pins 2–3–6–7–8; MSOP-8 assigns Out A, −In A, +In A, V−, V+, Out B, −In B, +In B to pins 1–8. PCB layout and footprint are not interchangeable.
OPA2381AIDRBRG4 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:
- 2
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 12V/µs
- Gain Bandwidth Product:
- 18 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 3 pA
- Voltage - Input Offset:
- 7 µV
- Current - Supply:
- 800µA (x2 Channels)
- 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)
OPA2381AIDRBRG4 FAQ
1.How can I place an order for OPA2381AIDRBRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for OPA2381AIDRBRG4 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 OPA2381AIDRBRG4 reliable?
The price and inventory of OPA2381AIDRBRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for OPA2381AIDRBRG4 is usually 5 days.
3.What payment methods are accepted for OPA2381AIDRBRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for OPA2381AIDRBRG4 transactions.
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4.How is shipping managed for OPA2381AIDRBRG4?
OPA2381AIDRBRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your OPA2381AIDRBRG4 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 OPA2381AIDRBRG4?
For technical support, including OPA2381AIDRBRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your OPA2381AIDRBRG4 requirements.
6.How does Aetrix verify that OPA2381AIDRBRG4 is sourced from the original manufacturer or authorized distributors?
All OPA2381AIDRBRG4 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 OPA2381AIDRBRG4 meets industry standards.
7.What is the process for return or replacement of OPA2381AIDRBRG4?
All OPA2381AIDRBRG4 units undergo pre-shipment inspection (PSI). If there is an issue with OPA2381AIDRBRG4, 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 OPA2381AIDRBRG4 part is unused and in its original packaging.
Return procedure for OPA2381AIDRBRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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