OPA404KU/1K - Quad 6.4MHz Precision Difet Op Amp | TI
MPN: OPA404KU/1K β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $25.18 | $25.18 |
| 10 | $23.9 | $239.00 |
| 100 | $22.6 | $2,260.00 |
| 500 | $21.4 | $10,700.00 |
| 1,000 | $20.3 | $20,300.00 |
Drop-in alternatives for OPA404KU/1K 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:
OPA404KU
β Drop-Inβ In Stock
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View Datasheet βOPA404KUE4
β Drop-Inπ Reference alternative (not in catalog)
OPA404KUG4
β Drop-Inπ Reference alternative (not in catalog)
OPA404KU/1KE4
β Drop-Inπ Reference alternative (not in catalog)
AD713JRZ-16
β Drop-Inπ Reference alternative (not in catalog)
OPA404KU/1K Maximum Ratings & Electrical Characteristics
| Amplifier Type | Precision Difet Operational Amplifier |
| Number of Circuits | 4 (quad) |
| Bandwidth | 6.4 MHz |
| Slew Rate | 35 V/us |
| Input Offset Voltage | +/-750 uV max |
| Input Bias Current | +/-4 pA max |
| Settling Time | 0.01% (fast settling) |
| Stability | Unity-gain stable |
| Pin Configuration | Standard quad op amp pinout |
| Package | SOIC (DW), 16 pins |
| Operating Temperature Range | 0C to +70C |
| Mounting Type | Surface Mount |
| Input Stage Technology | Difet (dielectrically-isolated FET) |
| Reel Packaging Designator | /1K = Tape and Reel, 1000 units |
OPA404KU/1K Pin Configuration
| Pin 1 | OUT1 β Amplifier 1 output |
| Pin 2 | -IN1 β Amplifier 1 inverting input |
| Pin 3 | +IN1 β Amplifier 1 non-inverting input |
| Pin 4 | V+ β Positive power supply |
| Pin 5 | +IN2 β Amplifier 2 non-inverting input |
| Pin 6 | -IN2 β Amplifier 2 inverting input |
| Pin 7 | OUT2 β Amplifier 2 output |
| Pin 8 | OUT3 β Amplifier 3 output |
| Pin 9 | -IN3 β Amplifier 3 inverting input |
| Pin 10 | +IN3 β Amplifier 3 non-inverting input |
| Pin 11 | V- β Negative power supply |
| Pin 12 | +IN4 β Amplifier 4 non-inverting input |
| Pin 13 | -IN4 β Amplifier 4 inverting input |
| Pin 14 | OUT4 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/1K is suitable for 6 applications: Precision Instrumentation, Optoelectronics / Photodiode Arrays, Sonar and Ultrasound Systems, Professional Audio Equipment, Medical Equipment, Detector Arrays.
Precision Instrumentation
The OPA404KU/1K fits precision instrumentation front ends because its Difet input stage limits input bias current to +/-4 pA max and offset voltage to +/-750 uV max, minimizing DC error when amplifying signals from high-impedance sources such as bridge sensors and pH probes. The 6.4 MHz bandwidth supports fast multi-channel acquisition without settling-induced errors, and the 0.01% settling specification ensures accurate readings immediately after range or channel switching. In a typical instrument, each of the four channels serves as a buffer or gain stage in the analog front end ahead of a multiplexer and ADC. Because all four amplifiers share one die, channel-to-channel tracking over temperature is better than with discrete singles, reducing differential drift in multi-channel measurements.
Recommended
Optoelectronics / Photodiode Arrays
Photodiode and detector applications demand the OPA404KU/1K's standout parameter: +/-4 pA max input bias current. Bias current flowing through the photodiode's high equivalent impedance creates an offset that mimics photocurrent, degrading low-light sensitivity; at 4 pA this error is negligible even with Gohm-level shunt impedances. The 35 V/us slew rate and 6.4 MHz bandwidth accommodate fast optical pulses found in optical communication and pulsed sensing. In a transimpedance configuration, each quad channel amplifies one diode of a detector array, with the feedback resistor setting transimpedance gain. A small feedback capacitor stabilizes the loop given the amplifier's 6.4 MHz crossover. The quad integration reduces board area and, critically, matches the four channels thermally, keeping gain calibration consistent across the array.
Recommended
Sonar and Ultrasound Systems
Ultrasound and sonar receive chains require amplifiers that combine speed with low noise and accurate settling - exactly the OPA404KU/1K profile with 35 V/us slew rate, 6.4 MHz bandwidth, and 0.01% settling. The high slew rate prevents slew-induced distortion of the high-frequency echo envelope, while the FET input's picoampere bias allows direct interfacing with piezoelectric transducers via high-value coupling networks without loading the signal. In a typical receive path, four OPA404 channels amplify four transducer elements or time-gained channels before detection and digitization. The unity-gain-stable compensation simplifies configuring variable-gain stages. Designers should note the 0C to +70C commercial rating suits indoor diagnostic equipment; extended-temperature industrial sonar needs an alternative grade or part.
Recommended
Professional Audio Equipment
In professional audio, the OPA404KU/1K serves multi-channel mixing consoles, equalizers, and active crossovers where four matched amplifiers in one package reduce board space and channel-to-channel coloration. The Difet input's low bias current permits use of high-value input capacitors and potentiometers without DC pops or offset-induced crackle, while the 6.4 MHz bandwidth provides low distortion well beyond the 20 kHz audio band, ensuring fast slew of transients (35 V/us is far above the ~0.5 V/us needed for full-level 20 kHz sine waves). The standard quad pinout lets engineers upgrade older quad sockets to higher performance levels without PCB revision, a key datasheet-noted advantage. The 0C to +70C range covers studio and installed-sound environments; verify derating for amplifier racks with elevated internal temperatures.
Recommended
Medical Equipment
Medical instrumentation such as patient-monitoring analog front ends and diagnostic scanners benefits from the OPA404KU/1K's combination of picoampere input current and precision DC specifications. Electrode interfaces present high and variable source impedance; the +/-4 pA max bias current keeps electrode polarization and offset errors small, while the +/-750 uV max offset preserves measurement accuracy in buffered lead stages. The 6.4 MHz bandwidth and 35 V/us slew rate also support ultrasound imaging front ends, a datasheet-listed application. In a monitoring design, four channels typically buffer electrode leads or condition sensor outputs before filtering and conversion. Note that any patient-connected design additionally requires isolation and safety compliance beyond the amplifier datasheet; the OPA404 provides the analog performance foundation but not galvanic isolation.
Recommended
Detector Arrays
Detector arrays - including infrared, photomultiplier, and charge-output sensor arrays - require many identical low-bias amplification channels, which is precisely the OPA404KU/1K use case. Each quad package provides four channels with thermally matched, die-level-consistent characteristics, so gain and offset calibration applied to one channel tracks the others, simplifying multi-channel calibration in arrays of dozens to hundreds of elements. The +/-4 pA max bias current preserves signal integrity for high-impedance detector outputs, and 6.4 MHz bandwidth accommodates fast readout clocking. Typical implementation: each detector element feeds a transimpedance or voltage-gain stage built on one OPA404 channel, followed by multiplexed digitization. Designers should budget for the 0C to +70C range or implement temperature calibration for array systems with wider environmental excursions.
Recommended
Recommended Products Summary
Engineering reference data for OPA404KU/1K β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA404KU | OPA404KUE4 | OPA404KUG4 | AD713JRZ-16 |
|---|---|---|---|---|---|
| Package | SOIC-16 (DW) | SOIC-16 (DW) - same | SOIC-16 (DW) - same | SOIC-16 (DW) - same | SOIC-16 - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Number of Circuits | 4 | 4 | 4 | 4 | 4 |
| Bandwidth | 6.4 MHz | 6.4 MHz | 6.4 MHz | 6.4 MHz | [DATA_NEEDED] |
| Slew Rate | 35 V/us | 35 V/us | 35 V/us | 35 V/us | [DATA_NEEDED] |
| Input Offset Voltage (max) | +/-750 uV | +/-750 uV | +/-750 uV | +/-750 uV | [DATA_NEEDED] |
| Input Bias Current (max) | +/-4 pA | +/-4 pA | +/-4 pA | +/-4 pA | [DATA_NEEDED] |
| Operating Temperature | 0C to +70C | 0C to +70C | 0C to +70C | 0C to +70C | [DATA_NEEDED] |
| Packaging | Tape & Reel (/1K, 1000 units) | Tray | [DATA_NEEDED] | [DATA_NEEDED] | Tape & Reel (R designator) |
Key Differentiators
- Difet input with 4 pA max bias current at high speed (vs AD713JRZ-16)
- Package-only substitution available with identical die (vs OPA404KU)
- Trade-off: commercial temperature rating limits range (vs AD713JRZ-16)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 2 mm of the V+ (pin 4) and V- (pin 11) pins, with a bulk 4.7 uF to 10 uF capacitor per supply rail nearby. As a quad device, all four channels share these supply pins, so simultaneous switching of multiple channels can couple through the supply impedance - solid decoupling prevents inter-channel crosstalk. Route sensitive high-impedance input traces (pins 2, 3, 5, 6, 9, 10, 12, 13) short and guard them with a driven guard ring tied to the input common potential to exploit the 4 pA bias current in leak-critical layouts.
The OPA404KU/1K is rated 0C to +70C - do not deploy in outdoor or industrial enclosures that can fall below freezing or exceed 70C; use for extended range requires redesign with a wider-temperature amplifier. Second, the /1K designator means tape-and-reel (1000 units): order tray-packaged OPA404KU for prototypes to avoid reel minimums. Third, although pins 15-16 are NC, do not use them as traces; on legacy Difet quads some socket designs expect them floating, and datasheet NC pins must not be connected to any potential.
With 35 V/us slew rate and 6.4 MHz bandwidth, keep feedback resistors moderate (1k to 10k ohm) so resistor parasitic capacitance does not add a pole near crossover; in transimpedance service, set the feedback capacitor from Cf = sqrt(Cin/(2*pi*Rf*GBW)) as an estimate - for Cin = 20 pF, Rf = 1 Mohm, GBW = 6.4 MHz this yields roughly 1.2 pF. Estimated calculation using stated inputs; verify empirically on your layout. Keep analog ground returns of the four channels star-routed to prevent high-current output stages from modulating a neighboring high-gain channel's input ground.
Compliance Information
Compliance status not stated in provided data. The E4/G4 designator variants of the same die are TI's lead-free/eco grades; confirm current compliance on the TI product page for OPA404.
