OPA228P - 33MHz, 3nV/√Hz Precision Amplifier | TI
MPN： OPA228P ✓ 啟用中OPA228P 概覽
An operational amplifier is an analog integrated circuit that amplifies the voltage difference between its inverting and non-inverting inputs. The precision amplifier category belongs to the broader operational-amplifier, analog-amplifier, and semiconductor hierarchies. The OPA228P occupies the low-noise, high-precision portion of that market because its published 3 nV/√Hz noise density supports accurate extraction of small signals, while its 33 MHz bandwidth allows the same device to process higher-frequency signals without requiring separate amplifier stages.
The most important published characteristics are the 33 MHz gain-bandwidth product, 3 nV/√Hz input-noise density, single-amplifier configuration, and 8-pin PDIP package. The -55°C to 125°C operating range supports applications across extended industrial environments. Because it is packaged in a through-hole PDIP rather than a compact surface-mount package, the device is especially practical for laboratory instrumentation, precision measurement equipment, audio and analog test systems, and prototypes where socketed construction or hand assembly remains valuable.
OPA228 and OPA227 devices are identified by Texas Instruments as pin-for-pin replacements for the industry-standard OP27 and OP37 families. This relationship supports legacy-design migration because engineers can focus on verifying offset, bias-current, supply, and stability requirements rather than redesigning the footprint. OPA228P specifically provides a single amplifier in the 8-pin PDIP configuration; dual and quad devices in the broader family serve different channel-count requirements.
OPA228P is most appropriate for precision signal-conditioning paths, low-level sensor amplification, instrumentation amplifiers, audio measurement circuits, and laboratory measurement systems. Engineers should preserve the circuit topology and decoupling practices associated with the original OP27 or OP37 design while confirming that the operating points remain within the OPA228P specifications.
For new layouts, verify input-offset requirements, bias-current behavior, output swing, supply range, noise contribution, and stability with external compensation or load capacitance. The 33 MHz bandwidth means that board layout, source impedance, grounding, and feedback-loop behavior remain important even when the target signal is predominantly low frequency.
This page consolidates the verified manufacturer information, distributor pricing, same-package replacement options, and application-focused engineering guidance. It distinguishes documented OPA228P characteristics from unverified parameters and avoids presenting assumed electrical limits as manufacturer specifications.
直接替換替代品，適用於 OPA228P — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： OPA228P （相同外形與佔位） — 差異在於 Gain-Bandwidth Product, Product Type.
OPA227P
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →OP27P
✅ 直接替換📋 參考替代品（不在目錄中）
OP37P
✅ 直接替換📋 參考替代品（不在目錄中）
OPA228P 最大額定值與電氣特性
| Product Type | High-precision, low-noise operational amplifier |
| Amplifier Configuration | 1 circuit |
| Gain-Bandwidth Product | 33 MHz |
| Input Noise Density | 3 nV/√Hz |
| 封裝 | PDIP-8 |
| 腳位數 | 8 pins |
| 工作溫度範圍 | -55°C to 125°C |
| 安裝類型 | Through-hole |
| RoHS 狀態 | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | unknown |
OPA228P pdip-8 腳位配置指南
OPA228P（pdip-8 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： OPA228P.
請參閱 資料表 以查看完整腳位配置。
典型應用
OPA228P 適用於 6 應用s: Precision Instrumentation, Low-Level Sensor Signal Conditioning, Laboratory Audio Measurement, Industrial Process Measurement, Legacy OP27 and OP37 Upgrade, Precision Test and Measurement.
Precision Instrumentation
OPA228P fits precision instrumentation because it combines 3 nV/√Hz input-noise density with 33 MHz gain-bandwidth performance in a single 8-pin PDIP device. It can condition small differential signals ahead of an ADC or measurement instrument while preserving DC accuracy and wider-band signal content. According to the Texas Instruments OPA228 product page, the amplifier is intended for applications requiring both AC and precision DC performance. Designers should still verify offset voltage, bias current, common-mode range, and output swing for the selected gain, and should use short, guarded signal paths to prevent board leakage from dominating a high-impedance measurement.
推薦
Low-Level Sensor Signal Conditioning
OPA228P is appropriate for low-level sensor conditioning where the useful signal is small and the measurement system needs both low noise and usable bandwidth. Its published 3 nV/√Hz noise density limits the amplifier's input-referred noise contribution, while 33 MHz bandwidth prevents the op amp from limiting higher-frequency sensor information unnecessarily. The Texas Instruments OPA228 family information supports precision DC and AC operation. For bridge, strain-gauge, or high-impedance sensors, verify input bias current, input offset voltage, common-mode range, guarding, and leakage paths because those errors can dominate even when the OPA228P itself operates within specification.
推薦
Laboratory Audio Measurement
OPA228P suits laboratory audio measurement circuits that need low input noise without sacrificing wideband response. Its 3 nV/√Hz noise density is relevant when evaluating low-level audio signals, and the 33 MHz gain-bandwidth product provides substantially more bandwidth than many precision measurement tasks require. According to the Texas Instruments product page, OPA228P is a high-precision, low-noise amplifier intended for accurate AC and DC performance. Use low-value, low-noise feedback resistors where possible, maintain symmetric layouts, and confirm stability at the selected closed-loop gain because the available bandwidth can reveal phase-margin issues in copied legacy circuits.
推薦
Industrial Process Measurement
OPA228P can support industrial process-measurement front ends when the sensor signal is low level and the equipment must operate across an extended temperature range. The verified OPA228P listing specifies -55°C to 125°C operation, while its 3 nV/√Hz noise density and 33 MHz bandwidth provide a useful combination for conditioning both slow process variables and higher-frequency ripple or transient components. The Texas Instruments product description identifies OPA228 as a precision low-noise amplifier. Actual industrial suitability still depends on supply range, input common-mode limits, output swing, electromagnetic interference, and whether the selected grade has the required production certifications.
推薦
Legacy OP27 and OP37 Upgrade
OPA228P is especially relevant to legacy OP27 and OP37 socketed designs because Texas Instruments identifies the OPAx227 and OPAx228 families as pin-for-pin replacements with substantial improvements. OPA228P provides a documented 33 MHz gain-bandwidth product and 3 nV/√Hz noise density in an 8-pin PDIP package, allowing an existing board to be evaluated as a modern precision-amplifier upgrade without assuming an immediate footprint change. According to the TI product family information, pin compatibility is available, but engineers must still compare offset, bias current, supply voltage, input range, output swing, noise, and compensation before approving a production substitution.
推薦
Precision Test and Measurement
OPA228P supports precision test and measurement systems that need to amplify weak signals while retaining accurate DC behavior. Its 3 nV/√Hz input-noise density helps reduce the amplifier's contribution to the measurement floor, and the 33 MHz bandwidth allows the same channel to handle faster signals without requiring a separate wideband stage. According to the Texas Instruments OPA228 product page, the device is suitable for high-precision AC and DC performance. Test engineers should account for resistor thermal noise, source impedance, leakage, offset drift, and probe grounding, and should verify that the selected feedback network remains stable over the complete measurement bandwidth.
推薦
推薦產品摘要
工程參考資料，適用於 OPA228P — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | OPA227P | OP27P | OP37P |
|---|---|---|---|---|
| Package | PDIP-8 | PDIP-8 | PDIP-8 | PDIP-8 |
| Brand | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Amplifier Configuration | 1 circuit | 1 circuit | 1 circuit | 1 circuit |
| Mounting Style | Through-hole | Through-hole | Through-hole | Through-hole |
主要差異化特點
- Wideband precision performance (對比OP27P)
- Low input-noise density (對比OP37P)
- Extended temperature capability (對比OPA227P)
設計說明
Preserve the original OP27 or OP37 feedback topology until stability has been rechecked with OPA228P's 33 MHz bandwidth. Higher available bandwidth can expose excessive phase margin at the intended closed-loop gain, especially with capacitive sensor cables or isolated probe networks. Keep the non-inverting input path short, use symmetrical resistor placement around the amplifier, and place input-referencing components close to their pins. Confirm that the selected gain-bandwidth product, output-voltage swing, and phase margin remain adequate before production release.
For low-level measurements, treat the PCB as part of the input circuit. Use a guarded or driven shield around high-impedance inputs, avoid flux residue and contamination near the input pins, and provide a low-leakage cleaning process. The verified OPA228P noise density is 3 nV/√Hz, but that advantage cannot be realized if PCB leakage, breadboard contamination, or socket contact resistance creates a larger error. In the 8-pin PDIP implementation, prefer a clean, quality socket if the design must remain field-replaceable.
Do not treat an 8-pin PDIP package as proof of automatic interchangeability. Before substituting OPA227P, OP27P, or OP37P, compare supply voltage, input offset voltage, input bias current, common-mode input range, output swing, slew rate, noise, bandwidth, and compensation requirements from the manufacturer datasheets. TI identifies OPAx227 and OPAx228 as pin-for-pin replacements for industry-standard OP27 and OP37 designs, but electrical operating points must still remain valid at the temperature, supply, gain, and load used in the target circuit.
合規資訊
The supplied verified data does not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. No compliance status has been inferred from the manufacturer or distributor listings.
