LT1028CP - 75MHz Ultralow-Noise Precision Op Amp | Analog Devices
MPN: LT1028CP ✗ End of LifeLT1028CP Overview
An operational amplifier, or op amp, is an analog integrated circuit that amplifies the voltage difference between its inverting and non-inverting inputs. The LT1028 belongs to the precision op-amp category, combining high open-loop gain, low offset, low noise, and wide bandwidth. It is used where the measured signal is small and errors introduced by the amplifier must remain below the signal being measured.
The LT1028's key features include a 75 MHz gain-bandwidth product, 30 million voltage gain, 10 µV offset voltage, and 0.1 µV/°C offset drift. Analog Devices describes these characteristics as combining ultralow noise with high-speed and precision performance. The result is useful in low-level sensor interfaces, precision filters, audio circuitry, infrared detectors, hydrophone amplifiers, and phase-locked-loop filters.
Its speed makes the LT1028 more demanding than a general-purpose op amp. Short feedback paths, careful grounding, suitable bypass capacitors, and attention to capacitive loading help preserve the intended bandwidth and stability. Designers should also verify the power-supply requirements and compensation network against the manufacturer datasheet before applying it to a new board.
Typical applications include high-end audio amplification, infrared-detector signal conditioning, hydrophone amplification, active filters, and precision measurement front ends. In these circuits, low noise reduces the circuit's input-referred error, while the 75 MHz bandwidth supports signal processing beyond the bandwidth of many precision amplifiers.
The main design consideration is matching the amplifier's speed to the circuit. A high-bandwidth amplifier can amplify high-frequency noise and may require more careful layout than a slow precision op amp. Confirm the package pinout, common-mode range, supply voltage, output swing, and stability requirements against the LT1028 datasheet.
This page consolidates the verified LT1028CP product information, application context, design guidance, and source links. It is intended to support preliminary part selection, while the manufacturer datasheet remains the controlling reference for final engineering and production decisions.
Drop-in alternatives for LT1028CP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
LT1128
✅ Drop-In📋 Reference alternative (not in catalog)
LT1028
✅ Drop-In📋 Reference alternative (not in catalog)
LT1128
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT1028
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT1128
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT1028CP Maximum Ratings & Electrical Characteristics
| Product Type | Ultralow-noise precision high-speed operational amplifier |
| Gain-Bandwidth Product | 75 MHz |
| Voltage Gain | 30 million |
| Input Offset Voltage | 10 µV |
| Input Offset Drift | 0.1 µV/°C |
| Package | PDIP-8 |
| Package Pins | 8 pins |
| Mounting Type | Through-hole |
| Amplifier Category | Precision operational amplifier |
| Noise Class | Ultralow noise |
| RoHS Status | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | unknown |
LT1028CP 8 pins Pin Configuration Guide
Pin configuration for LT1028CP (8 pins package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for LT1028CP.
Refer to the datasheet for full pin configuration.
Typical Applications
LT1028CP is suitable for 7 applications: High-End Audio Signal Path, Infrared Detector Signal Conditioning, Hydrophone Amplifier, Precision Active Filter, PLL and Frequency-Control Loop, Precision Measurement Front End, Low-Level Sensor Interface.
High-End Audio Signal Path
The LT1028CP fits high-end audio front ends where low input-referred noise and precision are more useful than raw bandwidth alone. Its verified 10 µV offset voltage and 0.1 µV/°C drift help reduce DC error in gain stages, while the 75 MHz gain-bandwidth product leaves substantial bandwidth above the audio range. Use it as a low-level preamplifier or intermediate gain stage, and keep the feedback network short. Verify the actual noise density, distortion, output swing, and supply conditions from the manufacturer datasheet before setting the gain.
Recommended
Infrared Detector Signal Conditioning
The LT1028CP is suitable for low-level analog signal conditioning in infrared detectors, where the amplifier must add little noise before downstream filtering or digitization. Its verified 75 MHz gain-bandwidth product allows useful bandwidth for detector transients and modulation content, while the 10 µV offset specification supports low-DC-error operation. Place the amplifier close to the detector output, use a quiet ground plane, and keep feedback traces short to minimize parasitic coupling. Confirm common-mode range, supply voltage, and input bias current in the datasheet.
Recommended
Hydrophone Amplifier
The LT1028CP can serve in a hydrophone or other low-level acoustic signal path when low noise and precision are priorities. Its 75 MHz gain-bandwidth product is considerably faster than typical audio-band amplifiers, allowing the circuit to preserve transient content and support filtering without severe bandwidth limitation. The 10 µV offset and 0.1 µV/°C drift help reduce slowly varying errors in the amplifier chain. Use a low-noise reference supply, short input connections, and an isolated or carefully filtered analog ground to prevent environmental noise from entering the small-signal node.
Recommended
Precision Active Filter
The LT1028CP is suitable for active filters requiring both precision and substantial bandwidth. Its 75 MHz gain-bandwidth product can support filter stages operating above the bandwidth of many conventional precision op amps, while the 10 µV offset limits low-frequency error in integrator and amplifier sections. The key trade-off is increased sensitivity to layout parasitics and capacitive loading at higher frequencies. Follow the datasheet's compensation guidance, terminate unused inputs appropriately, and verify the completed filter's response and stability on target hardware.
Recommended
PLL and Frequency-Control Loop
The LT1028CP can be evaluated for precision active filtering or control loops around phase-locked loops, where loop dynamics and signal-to-noise ratio both matter. Its verified 75 MHz gain-bandwidth product provides a high-speed operating point, while low offset helps reduce DC error in the filter or integrator path. This is not evidence that LT1028CP is a universal PLL replacement; loop stability, phase margin, noise density, and required compensation must be analyzed with the actual filter topology. Keep loop traces short and use a controlled ground return to avoid adding uncontrolled phase delay.
Recommended
Precision Measurement Front End
The LT1028CP is a candidate for low-level measurement front ends when offset and noise must remain small relative to the sensed quantity. Its 10 µV input offset voltage and 0.1 µV/°C drift provide useful precision characteristics, while the 75 MHz gain-bandwidth product can accommodate faster measurement signals than a conventional slow-precision amplifier. Use guarding, shielding, and a quiet reference supply to reduce leakage and environmental effects. Validate input bias current, common-mode range, supply limits, and stability using the exact manufacturer data before production release.
Recommended
Low-Level Sensor Interface
The LT1028CP can amplify weak sensor outputs when the design requires more precision than a general-purpose op amp and more bandwidth than a slow precision type. Its verified 75 MHz gain-bandwidth product allows the signal path to retain bandwidth, and its 10 µV offset specification helps limit amplification of small DC errors. Place the device close to the sensor connection, minimize input-node capacitance, and use a clean analog ground. Confirm the common-mode input range and bias-current behavior because those values are not present in the supplied verified excerpts.
Recommended
Recommended Products Summary
Engineering reference data for LT1028CP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LT1128 | LT1028 | LT1128 | LT1028 | LT1128 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 |
| Product Type | Ultralow-noise precision high-speed operational amplifier | Precision high-speed operational amplifier | Ultralow-noise precision high-speed operational amplifier | Precision high-speed operational amplifier | Ultralow-noise precision high-speed operational amplifier | Precision high-speed operational amplifier |
| Gain-Bandwidth Product | 75 MHz | 20 MHz | 75 MHz | 20 MHz | 75 MHz | 20 MHz |
Key Differentiators
- Higher verified gain-bandwidth product (vs LT1128)
- Ultralow-noise positioning (vs LT1128)
- Precision DC-error characteristics (vs LT1128)
Design Notes
Because the LT1028 family has a 75 MHz gain-bandwidth product, keep the input, feedback, and output paths short and route them over a continuous ground plane. High-frequency parasitic capacitance and inductance can change closed-loop response, add peaking, or reduce stability. Place compensation and gain-setting components close to the relevant pins, and use a low-impedance analog return path.
Follow the manufacturer datasheet for supply voltage, decoupling, input common-mode range, and output swing. The supplied excerpts verify the low-noise and bandwidth characteristics but do not provide the complete power specifications, so do not infer suitable supply rails from the package family. Use local bypass capacitance and verify the supply is quiet enough for the intended noise floor.
Do not assume that a related family member is automatically a drop-in replacement. LT1128 is listed with a 20 MHz gain-bandwidth product versus the verified 75 MHz for LT1028, and the available data does not prove identical pin assignments or operating conditions. Verify the exact suffix, package drawing, pinout, and electrical limits before substitution.
Compliance Information
The supplied web results provide technical and sourcing links but do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-mineral status. Verify these attributes with the current manufacturer product documentation before regulated production use.
