LT1012CD - Precision Op Amp, 25µV Offset, 8-SOIC | Texas Instruments
部品番号: LT1012CD ✓ 生産中LT1012CD 概要
A precision operational amplifier (op-amp) is a high-gain DC-coupled electronic voltage amplifier with a differential input and, usually, a single-ended output. Precision op-amps are characterized by low input offset voltage, low input bias current, low noise, and high common-mode rejection ratio (CMRR), making them suitable for amplifying small signals from sensors, transducers, and high-impedance sources. The LT1012 belongs to the broader category of linear integrated circuits and is positioned as a universal precision op-amp that combines the low-bias performance of BIFET/JFET-input amplifiers with the low-offset and low-drift characteristics of precision bipolar designs.
Key features of the LT1012CD include 200 µV maximum input offset voltage, 40 pA maximum input bias current, 0.2 V/µs typical slew rate, and the ability to deliver 5 mA of output current while maintaining a voltage gain of one million. The device operates over a wide supply range (typically ±2 V to ±20 V) and offers extremely high CMRR and PSRR, with practically unmeasurable warm-up drift, making it ideal for precision instrumentation.
The LT1012CD uses Linear Technology's advanced bipolar process technology that achieves sub-picoampere bias currents through active bias-current cancellation, while the precision bandgap-based input stage provides the low offset and low drift. The amplifier is internally compensated, eliminating the need for external compensation components in most applications, simplifying PCB layout and reducing BOM cost.
Typical applications include precision thermocouple amplification, strain-gauge and weigh-scale signal conditioning, medical instrumentation, high-impedance sensor buffers, precision integrators for analog computation, and battery-powered portable instrumentation where the LT1012 achieves precision operation on two Ni-Cad batteries with only 1 mW of power dissipation.
When designing with the LT1012CD, note that its 0.2 V/µs slew rate makes it suitable for DC and low-frequency signals but inadequate for high-speed or wide-bandwidth applications. For those applications, a faster op-amp such as the LT1028 or OP-27 should be considered. Standard 8-SOIC layout conventions apply, with input pins (IN+, IN-) at pins 3 and 2, output at pin 6, and power pins at pins 7 (V+) and 4 (V-).
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that go beyond the manufacturer datasheet to support fast engineering decisions.
ドロップイン代替品: LT1012CD — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: LT1012CD （同一形状・フットプリント） — 相違点: Package, Slew Rate, Amplifier Type, Operating Temperature Range, Number of Channels.
LT1012ACN8
✅ ドロップイン ⚠️ 仕様未検証📋 参考代替品（カタログ未掲載）
OPA227PA
✅ ドロップイン📋 参考代替品（カタログ未掲載）
OPA2277UA
✅ ドロップイン価格はお問い合わせください
データシートを見る →TLE2027CD
✅ ドロップイン ⚠️ 仕様未検証📋 参考代替品（カタログ未掲載）
AD8628ARTZ-REEL7
✅ ドロップイン価格はお問い合わせください
データシートを見る →LT1012CD 最大定格＆電気的特性
| Manufacturer | Texas Instruments (originally Linear Technology) |
| Amplifier Type | Precision Operational Amplifier |
| Number of Circuits | 1 |
| Input Offset Voltage (Vos) | 25 µV typical, 200 µV maximum |
| Input Bias Current (Ib) | 40 pA maximum |
| Slew Rate | 0.2 V/µs typical |
| Voltage Gain (Aol) | 1,000,000 (1M) minimum |
| Output Current | 5 mA (with voltage gain of 1M) |
| Common-Mode Rejection Ratio (CMRR) | Extremely high (per datasheet) |
| Power Supply Rejection Ratio (PSRR) | Extremely high (per datasheet) |
| Supply Voltage Range | ±2 V to ±20 V (typical dual supply) |
| 動作温度範囲 | -40°C to +85°C (commercial grade) |
| パッケージ | 8-SOIC (0.154", 3.90 mm width) |
| 実装タイプ | Surface Mount |
| Compensation | Internally compensated |
| Power Dissipation (Ni-Cad operation) | 1 mW |
LT1012CD ピン構成
| ピン 1 | Offset Null — Offset adjustment pin (typically with 10 kΩ pot to pin 5) |
| ピン 2 | IN- — Inverting input |
| ピン 3 | IN+ — Non-inverting input |
| ピン 4 | V- — Negative power supply |
| ピン 5 | Offset Null — Offset adjustment pin (typically with 10 kΩ pot to pin 1) |
| ピン 6 | Output — Amplifier output |
| ピン 7 | V+ — Positive power supply |
| ピン 8 | NC — Not connected (no internal connection) |
主な用途
LT1012CD の用途: 7 件s: Precision Thermocouple Amplification, Strain-Gauge / Weigh-Scale Signal Conditioning, High-Impedance Sensor Buffers, Precision Integrator for Analog Computation, Battery-Powered Portable Instrumentation, Medical Instrumentation Front-Ends, Reference Voltage Buffering.
Precision Thermocouple Amplification
The LT1012CD's 25 µV typical input offset voltage and 40 pA maximum input bias current make it an excellent front-end for thermocouple amplification where microvolt-level signals must be conditioned without zero-point drift. The amplifier's high common-mode rejection ratio rejects the common-mode noise present in long thermocouple leads in industrial environments, while its low bias current prevents the high-impedance thermocouple junction from developing error voltages across source resistance. Placed as a two-op-amp instrumentation configuration with the LT1012CD providing both gain and reference subtraction, the design delivers accurate temperature readings down to the noise floor of the sensor itself. The 0.2 V/µs slew rate is more than adequate for the slow thermal signals (sub-Hz to a few Hz) typical of process-control thermocouple applications.
おすすめ
Strain-Gauge / Weigh-Scale Signal Conditioning
Weigh scales and load-cell-based force measurement systems rely on strain gauges with output signals in the millivolt range, where the LT1012CD's 200 µV maximum input offset voltage and extremely high common-mode rejection are critical. The amplifier is typically configured as a three-op-amp instrumentation front-end, with the LT1012CD providing the input buffers that present high impedance to the bridge while delivering low impedance to the difference amplifier. The 1M minimum open-loop voltage gain ensures the closed-loop gain accuracy is dominated by external resistor matching rather than op-amp limitations. The 8-SOIC package enables compact PCB designs suitable for embedded weighing instruments, while the -40°C to +85°C commercial operating range supports most industrial and laboratory environments.
おすすめ
High-Impedance Sensor Buffers
Photodiode transimpedance amplifiers, pH electrode buffers, and piezoelectric sensor interfaces all demand op-amps with sub-nanoampere bias current - a requirement the LT1012CD meets with its 40 pA maximum input bias current. Placed as a unity-gain buffer between a high-impedance source and downstream circuitry, the LT1012CD prevents the loading effect that would otherwise attenuate the sensor signal and introduces only negligible DC error from bias current times source resistance. The amplifier's low input offset voltage preserves DC accuracy, and the high CMRR rejects common-mode interference from environmental noise sources such as 50/60 Hz power-line pickup.
おすすめ
Precision Integrator for Analog Computation
The LT1012CD's low input bias current and low input offset voltage make it an excellent integrator for analog computation, sample-and-hold circuits, and active filters. Configured with a feedback capacitor on the inverting input, the LT1012CD integrates input current over time with minimal drift, enabling accurate ramp generation, time-base circuits, and analog computing functions. The 0.2 V/µs slew rate limits the output voltage change rate but is suitable for slow integration applications such as long-duration timers (seconds to minutes). The 8-SOIC package and internal compensation simplify PCB design - no external compensation capacitor is needed.
おすすめ
Battery-Powered Portable Instrumentation
The LT1012CD achieves precision operation on two Ni-Cad batteries with only 1 mW of power dissipation, per the Linear Technology datasheet. This low-power operation, combined with the device's picoampere-level bias current, makes the LT1012CD ideal for portable medical, handheld test, and remote-sensor instrumentation where battery life is critical. The amplifier's high CMRR and PSRR maintain accuracy even as battery voltage drops during discharge, while the low bias current extends battery life by reducing quiescent current draw. The 8-SOIC package's small footprint enables integration into compact handheld enclosures.
おすすめ
Medical Instrumentation Front-Ends
ECG, EEG, and other bio-signal acquisition systems require precision amplification of low-amplitude signals in the presence of high common-mode voltages - a perfect match for the LT1012CD's 25 µV typical offset, 40 pA max bias current, and high CMRR. The amplifier is typically used as the input stage of an instrumentation amplifier configuration, providing the high input impedance required to interface with skin-electrode interfaces without loading the source. The low 1/f noise corner and stable DC performance over time support accurate long-duration bio-signal monitoring. The 8-SOIC package's small footprint enables wearable and bedside monitor designs.
おすすめ
Reference Voltage Buffering
Precision voltage references such as the LT1021, LT1027, or buried-zener references require buffering to deliver usable current to downstream circuitry without disturbing the reference voltage. The LT1012CD's 200 µV maximum input offset voltage and 5 mA output current capability (with voltage gain of 1M) make it an excellent unity-gain buffer for 5 V or 10 V reference outputs. Placed between the reference and the load, the LT1012CD isolates the reference from load variations while adding only tens of microvolts of error. The 8-SOIC package simplifies PCB layout in multi-channel data-acquisition systems.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: LT1012CD — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 | LT1012ACN8 | OPA227PA | OPA2277UA | TLE2027CD | AD8628ARTZ |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (0.154", 3.90 mm) | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Input Offset Voltage (max) | 200 µV | 120 µV (tighter) | 75 µV (better) | 50 µV (better) | 100 µV | 5 µV (much better, chopper) |
| Input Bias Current (max) | 40 pA | 40 pA (same) | 10 nA (higher) | 1 nA (higher) | 40 nA (higher) | 30 pA (similar) |
| Slew Rate | 0.2 V/µs | 0.2 V/µs (same) | 0.8 V/µs (faster) | 0.5 V/µs (faster) | 2.8 V/µs (faster) | 1 V/µs (faster) |
| Open-Loop Gain (min) | 1,000,000 (1M) | 1,000,000 (same) | 160,000 (lower) | 500,000 (lower) | 1,000,000 (same) | 10,000,000 (higher) |
| Supply Voltage Range | ±2 V to ±20 V | ±2 V to ±20 V (same) | ±2.5 V to ±18 V | ±2 V to ±18 V | ±2 V to ±19 V | ±2.5 V to ±6 V (lower) |
| Channels | 1 (single) | 1 (single) | 1 (single) | 1 (single) | 1 (single) | 1 (single) |
| Price (qty 1, USD) | $3.15 | $5.00+ (rarer grade) | $2.50 | $3.20 | $2.10 | $5.50 |
主な差別化要因
- Lower input bias current than most precision bipolar op-amps （vs OPA227PA)
- Picoampere bias with extremely high open-loop gain （vs TLE2027CD)
- Drop-in compatible precision op-amp from same family （vs OPA2277UA)
設計ノート
Standard 8-SOIC op-amp layout practices apply to the LT1012CD. Place a 0.1 µF ceramic bypass capacitor as close as possible to pins 7 (V+) and 4 (V-) to maintain high-frequency PSRR. Keep input traces short and guarded if the source impedance is high, since 40 pA input bias current flowing through 10 kΩ of stray resistance creates 400 µV of error. For thermocouple or strain-gauge applications, use a star-ground configuration at the op-amp's V- pin to avoid ground-loop errors.
Do not assume the offset null pins (1 and 5) are no-connects - they are functional adjustment pins. If left floating they will not damage the device, but they may pick up noise that appears at the output. Either tie them to V- through 10 kΩ resistors or use a 10 kΩ potentiometer between pins 1 and 5 with the wiper to V- for trimming. Also note that the LT1012CD's 0.2 V/µs slew rate limits it to small-signal bandwidth; do not use it in audio or video-frequency applications where higher slew rate is required.
The LT1012CD's low power dissipation (1 mW on Ni-Cad batteries per datasheet) makes it suitable for battery-powered designs, but at higher supply voltages (±15 V) the quiescent current draw increases. Estimated: at ±15 V supply, typical quiescent current is approximately 370 µA, drawing 11 mW. For ultra-low-power applications below 100 µA total supply, consider the OPA2333 or zero-drill chopper alternatives such as AD8628. Always include reverse-polarity protection if the LT1012CD is connected directly to a battery without a regulator.
コンプライアンス情報
RoHS, REACH, lead-free, and halogen-free status not explicitly stated in verified web data; marked as unknown. The LT1012CD is not AEC-Q100 qualified - it targets commercial/industrial precision instrumentation, not automotive. For automotive applications, choose an AEC-Q100-qualified alternative.
