OPA828IDR - 45MHz JFET Op Amp, 4nV/√Hz | TI | Precision Amplifier
MPN: OPA828IDR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.8 | $2.80 |
| 10 | $2.52 | $25.20 |
| 100 | $2.2 | $220.00 |
| 500 | $1.95 | $975.00 |
| 1,000 | $1.75 | $1,750.00 |
OPA828IDR Overview
A JFET-input operational amplifier is a type of precision amplifier whose input stage uses junction field-effect transistors, providing extremely low input bias current (picoampere range) and high input impedance. Within the signal-chain hierarchy, op amps sit between sensors and data converters, serving as the general-purpose analog building block for amplification, filtering, buffering, and transimpedance conversion.
Key features include 50 uV input offset voltage, 0.45 uV/C offset drift, 1 pA typical input bias current, and only 60 nVRMS of noise from 0.1 Hz to 10 Hz. These DC precision specifications make the OPA828 suitable for applications where both speed and accuracy are demanded simultaneously - a rare combination. MUX-friendly inputs allow multiplexed signal chains without settling artifacts or charge-injection damage.
Architecturally, the OPA828 pairs a JFET input stage with a rail-to-rail output stage, combining classic precision topology with modern output swing. The RRO output maximizes dynamic range in low-voltage systems while the 36 V supply rating supports traditional ±15 V industrial analog rails without redesign.
Typical applications include photodiode transimpedance amplifiers (TIA), high-fidelity audio front ends, precision ADC and DAC buffer stages, and active filters in test and measurement instrumentation. The wide 36 V supply range is particularly valuable for industrial designs retaining legacy ±15 V rails.
For design, ensure supply decoupling with 0.1 uF ceramic capacitors placed within 3 mm of each supply pin. When replacing an OPA627, verify compensation and bias-current paths, as community feedback shows some legacy TIA circuits require adjustment despite pin compatibility.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for OPA828IDR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with OPA828IDR (same form factor and footprint) — differing in Slew Rate, Gain Bandwidth Product, Input Bias Current, Package, Supply Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
OPA827AIDR
✅ Drop-In📋 Reference alternative (not in catalog)
OPA827IDR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
OPA627AIDR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD8610ARZ
✅ Drop-In📋 Reference alternative (not in catalog)
OPA828IDR Maximum Ratings & Electrical Characteristics
| Amplifier Type | JFET-input operational amplifier |
| Number of Channels | 1 |
| Gain Bandwidth Product | 45 MHz |
| Slew Rate | 150 V/us |
| Input Voltage Noise Density | 4 nV/√Hz at 1 kHz |
| Input Voltage Noise (0.1 Hz to 10 Hz) | 60 nVRMS |
| Input Bias Current | 1 pA (typical) |
| Input Offset Voltage | 50 uV |
| Input Offset Voltage Drift | 0.45 uV/C |
| Supply Voltage Range | ±4 V to ±18 V (36 V total) |
| Output Type | Rail-to-rail output (RRO) |
| Input Type | MUX-friendly JFET inputs |
| Package | 8-SOIC (SO-8) |
| Mounting Type | Surface Mount |
| Predecessor Parts | OPA627, OPA827 |
OPA828IDR Pin Configuration
| Pin 1 | NC — Not connected (per datasheet) |
| Pin 2 | IN- — Inverting input |
| Pin 3 | IN+ — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | OUT — Rail-to-rail output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | NC — Not connected (per datasheet) |
Typical Applications
OPA828IDR is suitable for 6 applications: Photodiode Transimpedance Amplifier, High-Fidelity Audio Front End, Precision ADC/DAC Buffering, Test and Measurement Instrumentation, Industrial ±15 V Analog Signal Chains, Sensor Signal Conditioning and Active Filters.
Photodiode Transimpedance Amplifier
The OPA828IDR's 1 pA typical input bias current and 50 uV offset voltage make it a strong fit for photodiode transimpedance amplifiers, where input current error directly translates to measurement offset at the photodiode's high source impedance. The 45 MHz gain bandwidth supports large feedback resistors with fast photodiode signals, while 4 nV/√Hz voltage noise keeps amplifier voltage noise contribution manageable when referred through high-value feedback resistors. MUX-friendly inputs tolerate multiplexed photodiode arrays without charge-injection damage or long settling artifacts. In practice, the TIA feedback capacitor must be sized against the 45 MHz bandwidth for stability; designers migrating from OPA627 circuits should re-verify compensation, as E2E field reports show swapped parts can oscillate without adjustment.
Recommended
High-Fidelity Audio Front End
In audio signal chains, the OPA828IDR contributes 60 nVRMS of noise from 0.1 Hz to 10 Hz and 4 nV/√Hz broadband noise, keeping the amplifier below the noise floor of most preceding circuitry, while its JFET inputs present negligible loading to phono cartridges, volume potentiometers, and vacuum-tube stage outputs. The ±18 V maximum supply supports headroom for full-scale line-level and headphone-drive stages on conventional ±15 V rails, and the rail-to-rail output maximizes swing on reduced supply designs. Community comparisons against the OPA627 and OPA827 on diyAudio show competitive measured performance; designers prioritizing absolute lowest low-frequency noise may still prefer the OPA827A grade, trading away the OPA828's double bandwidth and 150 V/us slew rate.
Recommended
Precision ADC/DAC Buffering
Driving precision converters demands an amplifier that settles quickly without degrading DC accuracy - exactly the OPA828IDR's combination of 45 MHz bandwidth, 150 V/us slew rate, 50 uV offset, and 0.45 uV/C drift. The rail-to-rail output preserves dynamic range into converter full-scale even on ±5 V or single-supply rails, while the 36 V total rating permits the same buffer design on ±15 V systems. MUX-friendly inputs are specifically valuable in multiplexed data-acquisition front ends, where channel switching imposes charge transients that can damage or disturb non-MUX-tolerant inputs. For switch-capacitor SAR ADC inputs, a small series resistor per TI datasheet guidance isolates the amplifier from converter charge kickback; verify settling to the required ADC resolution within the conversion aperture using the 45 MHz small-signal bandwidth.
Recommended
Test and Measurement Instrumentation
Bench instruments, oscilloscope front ends, and automated test equipment benefit from the OPA828IDR's simultaneous speed and precision: 45 MHz of gain bandwidth supports megahertz-range signal paths, while 1 pA bias current and 50 uV offset preserve DC measurement integrity on high-impedance probes and attenuators. The wide ±4 V to ±18 V supply range lets one amplifier design serve both portable battery-powered instruments and benchtop equipment on ±15 V rails, simplifying platform BOMs. Active filter stages in the instrument's signal path also exploit the 150 V/us slew rate for full-scale high-frequency signals without slew-induced distortion. MUX-friendly inputs permit input-channel multiplexing in data loggers and automated test matrices without dedicated protection circuitry at moderate source impedances.
Recommended
Industrial ±15 V Analog Signal Chains
Many industrial PLCs, motor-control supervisory circuits, and process instrumentation still run on legacy ±15 V analog rails. The OPA828IDR's ±18 V maximum supply rating accepts these rails directly with margin, eliminating the need for local point-of-load regulation when upgrading aging op amp sockets. Its rail-to-rail output stage extracts maximum signal swing from the ±15 V rails, improving measurement resolution into downstream ADCs, and the 36 V total supply rating tolerates industrial supply transients better than lower-voltage precision amplifiers. The 0.45 uV/C offset drift maintains calibration accuracy across factory-floor temperature swings, while the 4 nV/√Hz noise keeps small transducer signals, such as strain-gauge bridge outputs after pre-amplification, cleanly above the amplifier noise floor.
Recommended
Sensor Signal Conditioning and Active Filters
High-impedance sensors - piezoelectric accelerometers, hydrophones, pH electrodes via buffer stages, and infrared detectors - require amplifiers whose input bias current does not swamp the signal. The OPA828IDR's 1 pA bias current and high JFET input impedance preserve accuracy at these source impedances, while 45 MHz bandwidth supports active filter topologies such as multiple-feedback and Sallen-Key designs operating into the hundreds of kilohertz. The 150 V/us slew rate ensures large-signal filter stages do not slew-limit, keeping harmonic distortion low at full-scale outputs. In active filter applications, the wide ±18 V supply range increases filter headroom and reduces distortion for a given output level, and the RRO stage supports low-voltage versions of the same filter design for portable instruments.
Recommended
Recommended Products Summary
Engineering reference data for OPA828IDR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA827AIDR | OPA827IDR | OPA627AIDR | AD8610ARZ |
|---|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Gain Bandwidth | 45 MHz | ~22 MHz | ~22 MHz | ~16 MHz | ~25 MHz |
| Slew Rate | 150 V/us | ~22 V/us | ~22 V/us | ~55 V/us | ~42 V/us |
| Input Voltage Noise | 4 nV/√Hz at 1 kHz | ~3.8 nV/√Hz | ~3.8 nV/√Hz | ~4.5 nV/√Hz | ~6 nV/√Hz |
| Input Bias Current | 1 pA typical | pA class (JFET) | pA class (JFET) | pA class (JFET) | pA class (JFET) |
| Maximum Supply Voltage | 36 V total (±18 V) | ~40 V total | ~40 V total | ~36 V total | ~26 V total (±13 V) |
| Output Stage | Rail-to-rail output (RRO) | Non-RRO | Non-RRO | Non-RRO | Rail-to-rail output |
Key Differentiators
- Double the bandwidth of its predecessor family (vs OPA827AIDR)
- Dramatic cost reduction vs OPA627 (vs OPA627AIDR)
- Rail-to-rail output on 36 V supply (vs OPA827AIDR)
- Wider supply headroom than closest ADI equivalent (vs AD8610ARZ)
Design Notes
Place 0.1 uF ceramic decoupling capacitors within 3 mm of each supply pin (V+ pin 7, V- pin 4), with a shared 2.2-10 uF bulk capacitor per supply rail. The OPA828's 45 MHz bandwidth makes it sensitive to supply inductance; long decoupling traces can create high-frequency instability. Follow the TI datasheet PCB layout guidance and use a solid ground plane under the amplifier area. Keep feedback paths short and avoid routing high-impedance input traces (pins 2, 3) near switching signals to protect the picoampere-class bias-current performance from leakage and capacitive pickup.
Although TI lists the OPA828 as a drop-in replacement for the OPA627, E2E forum reports document cases where swapping the part in legacy photodiode TIA circuits produced no output until compensation was reworked. Before direct substitution, verify the feedback network stability margin with the OPA828's 45 MHz bandwidth (roughly 2x the OPA827), check any compensation capacitor values, and confirm bias-current return paths. Also note the OPA627 SOIC package offered pin-strapping options some legacy boards exploited - compare the pin functions on your specific PCB rather than assuming socket equivalence.
The OPA828IDR accepts ±4 V to ±18 V (36 V total). On ±15 V rails, verify total supply stays below 36 V including transients - industrial rails can drift high during unloaded conditions. For single-supply operation, the rail-to-rail output swings close to the negative rail but the JFET input common-mode range does not include the negative rail; keep input common-mode within the datasheet-specified range above V-. Estimated: a 45 MHz amplifier driving a 10 Vpp load at 500 kHz requires 15.7 V/us slew rate, comfortably inside the 150 V/us rating, confirming ample large-signal margin for typical buffer duties.
Compliance Information
Compliance certificates should be obtained from the TI product folder for the exact orderable part; retrieved web data did not include explicit RoHS/REACH statements.
