LM842 - CMOS RRIO Wide-Supply Dual Op-Amp | Texas Instruments
Артикул: LM842 ✓ Активен| Кол-во | Цена за ед. | Итого |
|---|---|---|
| 1 | $2.45 | $2,45 |
| 10 | $2.18 | $21,80 |
| 100 | $1.85 | $185,00 |
| 500 | $1.55 | $775,00 |
| 1.000 | $1.32 | $1.320,00 |
LM842 Обзор
A CMOS operational amplifier (op-amp) is a high-gain DC-coupled analog building block whose differential inputs and single-ended output form the foundation of signal conditioning. The RRIO family extends usable signal swing to within millivolts of either supply rail - critical for modern low-voltage single-supply systems. Within the broader power management and analog hierarchy, op-amps sit alongside voltage regulators, references, and ADCs as core signal-chain components that convert, scale, filter, and buffer analog signals before digitization or further amplification.
Key features of the LM842 include 4.5 MHz unity-gain bandwidth, 1.3 V/us slew rate, 12 nV/sqrt(Hz) input voltage noise density, RRIO swing on both input and output stages, and a 2.7 V to 12 V supply range that accommodates 3.3 V, 5 V, and 12 V rails without level shifting. The CMOS input stage presents pA-level bias current, eliminating the bias-current errors common to bipolar and JFET op-amps in high-impedance sensor interfaces.
The architecture uses a complementary CMOS input differential pair with a rail-sensing output stage, achieving true rail-to-rail output swing at loads up to several mA. The wide supply range and low quiescent current (typically 0.4 mA per channel) make the device attractive for both line-powered and portable equipment.
Typical applications include active filters, transducer amplifiers, battery-powered instrumentation, portable audio buffers, and general-purpose signal conditioning for sensor front ends. Designers should note that the dual-package 8-pin pinout shares the industry-standard SOIC-8/VSSOP-8 dual op-amp footprint, enabling direct drop-in substitution with pin-compatible parts from multiple vendors. This page synthesizes distributor pricing, parametric alternatives, and practical design guidance beyond the manufacturer datasheet.
Аналоги без доработки для LM842 — тот же корпус, pin-to-pin совместимость. Компоненты в других корпусах, требующие переработки PCB, исключены.
Инструмент быстрого сравнения — выберите альтернативные компоненты для сравнения бок о бок:
LMV842MM/NOPB
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LMV842MA/NOPB
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LMV841MA/NOPB
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
OPA2333AIDR
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
MCP6002-E/SN
✅ Прямая замена📋 Справочный аналог (нет в каталоге)
LM842 Максимальные параметры и электрические характеристики
| Number of Channels | 2 (Dual) |
| Amplifier Type | CMOS, RRIO, Wide Supply Range |
| Gain Bandwidth Product (GBW) | 4.5 MHz |
| Slew Rate | 1.3 V/us |
| Input Offset Voltage | 500 uV (max, typical 50 uV) |
| Input Bias Current | 0.3 pA (typical) |
| Input Voltage Noise Density | 12 nV/sqrt(Hz) at 10 kHz |
| Supply Voltage Range | 2.7 V to 12 V |
| Quiescent Current per Channel | 0.4 mA (typical) |
| Input Common-Mode Range | Rail-to-Rail |
| Output Swing | Rail-to-Rail |
| Диапазон рабочих температур | -40 C to +125 C |
| Корпус | 8-pin VSSOP (DGK) or 8-pin SOIC (D) |
| Тип монтажа | Surface Mount |
| Статус RoHS | Compliant |
Конфигурация выводов LM842
| Контакт 1 | OUT_A — Amplifier A output |
| Контакт 2 | IN-_A — Amplifier A inverting input |
| Контакт 3 | IN+_A — Amplifier A non-inverting input |
| Контакт 4 | V- / GND — Negative supply or ground for single-supply operation |
| Контакт 5 | IN+_B — Amplifier B non-inverting input |
| Контакт 6 | IN-_B — Amplifier B inverting input |
| Контакт 7 | OUT_B — Amplifier B output |
| Контакт 8 | V+ — Positive supply |
Типичное применение
LM842 подходит для 6 применениеs: Active Filters and Audio Signal Conditioning, Transducer and Sensor Front-End Amplifiers, Portable Battery-Powered Instrumentation, Industrial Process Control Signal Conditioning, ADC and DAC Buffer Amplifiers, General-Purpose Comparator and Threshold Detector.
Active Filters and Audio Signal Conditioning
The LM842's 4.5 MHz gain-bandwidth product and 1.3 V/us slew rate make it well-suited for active filter topologies in the audio band and beyond, including Sallen-Key low-pass, high-pass, and band-pass stages. Its rail-to-rail input and output swing maximizes dynamic range on 3.3 V or 5 V single-supply rails, while 12 nV/sqrt(Hz) input voltage noise preserves audio signal integrity in portable headphone drivers, line-level preamps, and tone-control circuits. Place 1 nF to 10 nF feedback capacitors in parallel with gain-setting resistors to ensure stability above 100 kHz.
Рекомендуется
Transducer and Sensor Front-End Amplifiers
The LM842 is well-matched to transducer front-end designs requiring low input bias current, moderate bandwidth, and rail-to-rail operation on a single supply. Its 0.3 pA typical input bias current minimizes DC error across high-impedance piezoelectric, photodiode, or pH-electrode sources, while 4.5 MHz GBW supports sample rates up to several hundred kHz. Typical circuits include transimpedance amplifiers for photodiode current-to-voltage conversion, charge amplifiers for piezo elements, and Wheatstone-bridge gain stages for strain gauges and RTD sensors.
Рекомендуется
Portable Battery-Powered Instrumentation
With 0.4 mA quiescent current per channel and 2.7 V to 12 V supply compatibility, the LM842 enables long-runtime portable designs powered from single-cell Li-ion, two-AA, or 9 V batteries. The CMOS input stage draws negligible current from sensor sources, preserving battery capacity for downstream functions. Applications include handheld multimeters, portable medical monitors, wireless sensor node signal conditioning, and battery-backed industrial data loggers where every microamp of quiescent current translates directly into field-runtime hours.
Рекомендуется
Industrial Process Control Signal Conditioning
The LM842's 12 V supply tolerance and -40 C to +125 C operating range make it a strong fit for industrial process control signal chains, including 4-20 mA current-loop transmitters, isolated signal conditioning, and PLC analog input modules. The rail-to-rail output swing maximizes dynamic range on 5 V and 12 V analog rails, while CMOS inputs reduce leakage in high-impedance transducer interfaces. Designers should add TVS diodes and current-limiting resistors at the inputs for surge protection.
Рекомендуется
ADC and DAC Buffer Amplifiers
The LM842 serves as an excellent input buffer or output driver for ADCs and DACs in mixed-signal data acquisition systems. Its 4.5 MHz bandwidth supports sampling rates up to 1 MSPS with adequate settling, while RRIO operation preserves dynamic range on low-voltage rails. As a DAC output buffer, the rail-to-rail output swing and 1.3 V/us slew rate maintain signal integrity for audio reconstruction filters and arbitrary waveform generation. Use a feedback capacitor of 10 pF to 47 pF for unity-gain stability.
Рекомендуется
General-Purpose Comparator and Threshold Detector
Although primarily an op-amp, the LM842 can serve as a low-cost threshold detector or window comparator in non-critical applications, with rail-to-rail input sensing and 1.3 V/us slew rate enabling response times in the low microsecond range. Use it for battery voltage monitoring, over-temperature flags, and digital logic-level translation from analog sensor signals. For faster switching and deterministic timing, pair the LM842 with a dedicated comparator such as the LMV331 or TLV3201.
Рекомендуется
Сводка рекомендуемых товаров
Справочные инженерные данные для LM842 — сравнение, рекомендации по проектированию и информация о соответствии.
Руководство по выбору
Сравнение с аналогами
| Параметр | Этот товар | LMV842MM/NOPB | LMV842MA/NOPB | OPA2333AIDR | MCP6002-E/SN |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Microchip Technology |
| Package | 8-pin VSSOP (DGK) / 8-pin SOIC (D) | 8-pin VSSOP (DGK) - same | 8-pin SOIC (D) - same | 8-pin SOIC (D) - same | 8-pin SOIC (D) - same |
| Channels | 2 (Dual) | 2 (Dual) | 2 (Dual) | 2 (Dual) | 2 (Dual) |
| Supply Voltage Range | 2.7 V to 12 V | 2.7 V to 12 V | 2.7 V to 12 V | 1.8 V to 5.5 V | 1.8 V to 6.0 V |
| Gain Bandwidth Product | 4.5 MHz | 4.5 MHz | 4.5 MHz | 350 kHz | 1 MHz |
| Slew Rate | 1.3 V/us | 1.3 V/us | 1.3 V/us | 0.16 V/us | 0.6 V/us |
| Quiescent Current per Channel | 0.4 mA | 0.4 mA | 0.4 mA | 50 uA | 0.1 mA |
| Input Offset Voltage (max) | 500 uV | 500 uV | 500 uV | 10 uV | 4500 uV |
| Input Voltage Noise Density | 12 nV/sqrt(Hz) | 12 nV/sqrt(Hz) | 12 nV/sqrt(Hz) | 55 nV/sqrt(Hz) | 28 nV/sqrt(Hz) |
| Input/Output Range | Rail-to-Rail / Rail-to-Rail | RRIO | RRIO | RRIO | RRIO |
Ключевые отличия
- 12 V supply tolerance exceeds most CMOS RRIO competitors (против MCP6002-E/SN (1.8 V to 6 V supply))
- Higher bandwidth than typical low-power CMOS RRIO op-amps (против OPA2333AIDR (350 kHz GBW))
- Precision-trimmed low offset with 0.3 pA CMOS bias current (против TL082 JFET-input dual op-amp)
Заметки по проектированию
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of the V+ supply pin and a bulk capacitor (1 uF to 10 uF) on the same node. The CMOS input stage draws negligible supply current for bias, but the output stage can deliver tens of mA transients into capacitive loads - inadequate decoupling causes oscillation. For dual-supply operation, decouple V+ and V- symmetrically.
Route input traces away from noisy digital and switching power traces, especially when amplifying low-level signals below 1 mV. Use a guard ring driven by a low-impedance source (such as the inverting input at unity gain) to surround high-impedance input nodes and minimize leakage on FR4 PCBs. The exposed pad (if present on VSSOP-8) should be soldered to a grounded copper pour for thermal relief and supply bypassing.
Do not assume the LM842 is unity-gain stable into heavy capacitive loads (>1 nF) without compensation - the 4.5 MHz GBW and 1.3 V/us slew rate can produce peaking above 5 dB at capacitive loads above 200 pF. Insert a series resistor (10 ohm to 100 ohm) between the output and the load for cable driving or ADC input buffering. For sensor front-ends, ensure the input common-mode voltage stays within 0.3 V of either rail to avoid input-stage distortion.
Estimated: at 12 V single supply, Vout = 6 V, 1 mA load, the LM842 dissipates approximately 6 mW per channel - well within the VSSOP-8 theta_JA of 220 C/W. Junction temperature rise above ambient is therefore negligible (< 2 C). Even at the maximum rated output current of 50 mA per channel, power dissipation stays below 50 mW per channel, requiring no heatsinking. Ambient derating is required above 85 C to stay within the 125 C maximum junction rating.
Информация о соответствии
RoHS and REACH compliant per TI LMV84x datasheet. Standard LMV842MM/NOPB is not AEC-Q100 qualified - use LMV842Q1 variant for automotive applications. Lead-free and halogen-free packaging confirmed.
