OPA404KU - Quad 6.4MHz Precision Difet Op-Amp | Texas Instruments
MPN: OPA404KU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
Drop-in alternatives for OPA404KU β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
OPA404KUG4
β Drop-Inπ Reference alternative (not in catalog)
OPA404KUE4
β Drop-Inπ Reference alternative (not in catalog)
OPA404KU/1K
β Drop-Inβ In Stock
$20.3 / Unit
View Datasheet βOPA404KU Maximum Ratings & Electrical Characteristics
| Amplifier Type | Precision operational amplifier (Difet) |
| Number of Channels | 4 |
| Bandwidth | 6.4 MHz |
| Slew Rate | 35 V/us |
| Input Offset Voltage (max) | +/-750 uV |
| Input Bias Current (max) | +/-4 pA |
| Settling Time to 0.01% | Low settling, 0.01% class |
| Supply Voltage Range | +/-5 V to +/-18 V (10 V to 36 V total) |
| Total Supply Voltage (max) | 36 V |
| Total Supply Voltage (min) | 10 V |
| Package | 16-SOIC |
| Pins | 16 |
| Mounting Type | Surface Mount |
| Pinout | Standard quad op-amp pinout |
| Category | Standard (General Purpose) Amplifier |
OPA404KU Pin Configuration
| Pin 1 | 1OUT β Amplifier 1 output |
| Pin 2 | 1IN- β Amplifier 1 inverting input |
| Pin 3 | 1IN+ β Amplifier 1 non-inverting input |
| Pin 4 | V- β Negative supply |
| Pin 5 | 2IN+ β Amplifier 2 non-inverting input |
| Pin 6 | 2IN- β Amplifier 2 inverting input |
| Pin 7 | 2OUT β Amplifier 2 output |
| Pin 8 | 3OUT β Amplifier 3 output |
| Pin 9 | 3IN- β Amplifier 3 inverting input |
| Pin 10 | 3IN+ β Amplifier 3 non-inverting input |
| Pin 11 | V+ β Positive supply |
| Pin 12 | 4IN+ β Amplifier 4 non-inverting input |
| Pin 13 | 4IN- β Amplifier 4 inverting input |
| Pin 14 | 4OUT β Amplifier 4 output |
| Pin 15 | NC β Not connected (per datasheet) |
| Pin 16 | NC β Not connected (per datasheet) |
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
OPA404KU is suitable for 6 applications: Data Acquisition Front Ends, Photodiode Transimpedance Amplifiers, Precision Active Filters and Integrators, Test and Measurement Instrumentation, Industrial Signal Processing, Professional Audio Signal Chains.
Data Acquisition Front Ends
The OPA404KU's combination of 6.4 MHz bandwidth, 35 V/us slew rate, and +/-750 uV maximum offset voltage makes it a strong fit for multi-channel data acquisition front ends. Four matched amplifiers in one 16-SOIC package reduce board area and guarantee tight channel-to-channel matching, which matters when digitizing several sensor channels against one ADC. The +/-4 pA maximum bias current limits loading on high-impedance sensor sources, preserving DC accuracy ahead of the converter. Placed as a gain/anti-alias stage between the signal conditioning network and a precision ADC such as the CS5532-ASZ or CS5534-ASZ, the Difet inputs avoid the bias-current errors typical of bipolar op-amps, while the wide bandwidth ensures fast settling to 0.01% so the converter samples an accurate value.
Recommended
Photodiode Transimpedance Amplifiers
Photodiode transimpedance amplifiers demand picoampere-level input currents so that the photodiode signal, not the amplifier's bias error, dominates the output. The OPA404KU's +/-4 pA maximum bias current from its Difet input stage directly addresses this requirement, while the 6.4 MHz gain-bandwidth supports fast optical pulse detection and 35 V/us slew rate handles sharp photocurrent edges without slew limiting. Because four amplifiers share one package, multi-element photodiode arrays can be served from a single 16-SOIC, improving thermal tracking between channels. Designers should employ guard rings driven at the input potential and high-value feedback resistors (10 MOhm and above) with careful PCB cleanliness, since board leakage can exceed the amplifier's own input current if layout is not controlled.
Recommended
Precision Active Filters and Integrators
Active filters and integrators are sensitive to amplifier offset drift and bias current through the summing node. The OPA404KU's +/-750 uV maximum offset and +/-4 pA maximum bias current keep integration droop and filter DC error small, while 6.4 MHz bandwidth supports filter corner frequencies well into the hundreds of kilohertz with adequate loop gain margin. The 35 V/us slew rate prevents slew-induced distortion on large-signal filter outputs, and the 0.01% settling class ensures accurate transient response in pulsed measurement chains. Using the quad package, a complete four-pole multiple-feedback or Sallen-Key filter cascade can be built from one 16-SOIC device, simplifying matching of pole pairs and reducing component count in instrumentation signal chains.
Recommended
Test and Measurement Instrumentation
Bench instruments, signal conditioners, and automated test equipment require amplifiers that combine speed with DC precision. The OPA404KU delivers both: 6.4 MHz bandwidth and 35 V/us slew rate for fast signal paths, plus +/-750 uV offset and +/-4 pA bias current for measurement accuracy. Its operation from +/-5V to +/-18V supplies matches the +/-15V analog rails conventional in instrumentation backplanes, and the standard quad pinout lets it upgrade legacy designs that used general-purpose quad op-amps. In scope front ends or multi-channel sensor scanners, four matched channels in one package improve thermal tracking and reduce channel-to-channel gain variation, while the Difet inputs preserve accuracy when switching high-impedance sources through multiplexers.
Recommended
Industrial Signal Processing
Industrial automation and process-control systems frequently need multiple precision amplifiers per board for sensor conditioning, 4-20 mA loop interfaces, and actuator monitoring. The OPA404KU's quad configuration consolidates four channels in a single 16-SOIC, cutting board area and inventory, while its 36 V maximum total supply accommodates industrial analog rail environments. Low input bias current (+/-4 pA max) suits high-impedance industrial sensors such as piezoelectric vibration probes, and the wide 6.4 MHz bandwidth provides headroom for fast fault-detection paths. Matching with precision instrumentation amplifiers like the INA101KU or INA117KU for isolated/high-common-mode measurement allows the OPA404KU to handle post-gain filtering and buffering stages with consistent precision across all four channels.
Recommended
Professional Audio Signal Chains
High-performance audio equipment benefits from the OPA404KU's low bias current, wide 6.4 MHz bandwidth, and 35 V/us slew rate, which together ensure low distortion at audio frequencies with generous loop-gain margin for linear gain stages. The quad package provides four channels in one 16-SOIC, ideal for stereo balanced signal paths (four amplifiers for two differential channels) in mixers, preamplifiers, and studio processing gear. Operation from +/-18V supplies supports high-signal-headroom professional audio rails. Because Difet inputs draw only picoamperes, input bias resistor noise contributions are minimized in high-impedance microphone and instrument inputs, and the standard quad pinout allows drop-in upgrades of boards originally populated with lower-precision general-purpose quad op-amps.
Recommended
Recommended Products Summary
Engineering reference data for OPA404KU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA404KUG4 | OPA404KUE4 | OPA404KU/1K |
|---|---|---|---|---|
| Package | 16-SOIC | 16-SOIC - same | 16-SOIC - same | 16-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Number of Channels | 4 | 4 | 4 | 4 |
| Bandwidth | 6.4 MHz | 6.4 MHz | 6.4 MHz | 6.4 MHz |
| Slew Rate | 35 V/us | 35 V/us | 35 V/us | 35 V/us |
| Input Offset Voltage (max) | +/-750 uV | +/-750 uV | +/-750 uV | +/-750 uV |
| Input Bias Current (max) | +/-4 pA | +/-4 pA | +/-4 pA | +/-4 pA |
| Supply Range | +/-5 V to +/-18 V | +/-5 V to +/-18 V | +/-5 V to +/-18 V | +/-5 V to +/-18 V |
| Packaging | Tube | Tube | Tube | Tape & Reel (1000) |
Key Differentiators
- Difet inputs combine picoampere bias with high speed (vs OPA404KUG4)
- Four matched high-speed precision channels in one package (vs OPA404KU/1K)
- Standard quad pinout enables legacy upgrades (vs OPA404KUE4)
Design Notes
With a maximum input bias current of only +/-4 pA, board leakage can dominate the input error budget. Drive guard rings around the inverting input nodes at the source potential, clean flux residue thoroughly after reflow, and avoid routing high-potential traces near FET input pins. For transimpedance designs with feedback resistors of 10 MOhm or higher, elevate the guard trace and consider PTFE standoffs or cut slots on the PCB for the highest-impedance nodes.
The OPA404KU operates from +/-5V to +/-18V dual supplies (10 V to 36 V total). Use 0.1 uF ceramic decoupling capacitors at both V+ (pin 11) and V- (pin 4), placed within a few millimeters of the pins, plus a bulk 10 uF capacitor per rail. Because the part draws four amplifiers from the shared supply pins, ensure the local decoupling handles the transient current of all four channels switching simultaneously, especially in filter or comparator-like duty cycles.
The 6.4 MHz bandwidth means the OPA404KU will amplify fast edges that lower-bandwidth quad op-amps ignore. Verify stability with capacitive loads (cable capacitance on outputs can exceed the safe region); use an isolation resistor or a BUF634 buffer when driving long cables. In transimpedance applications, calculate the feedback capacitor from the diode capacitance and feedback resistor to set adequate phase margin at the noise-gain crossover.
The OPA404KU is a dual-supply precision amplifier, not a single-supply rail-to-rail device: input and output common-mode ranges do not include the negative rail, so designs that must sense near 0 V on a single supply need a different topology or a negative rail. Additionally, standard quad pinout compatibility with TL074-class parts is mechanical; verify offset, bias current, and supply requirements before substituting in either direction.
Compliance Information
Compliance status not stated in the provided web data. The G4 suffix variant (OPA404KUG4) conventionally denotes TI green/RoHS ordering, but the provided data does not explicitly confirm compliance values - consult the TI product page for current certification data.
