LM324DG4 - Quad 1.2MHz Op Amp | Texas Instruments
MPN： LM324DG4 ✓ 啟用中LM324DG4 概覽
An operational amplifier is an active semiconductor device that amplifies the voltage difference between its differential inputs while using negative feedback to define closed-loop gain and bandwidth. The LM324 belongs to the operational-amplifier hierarchy, where it is also classified as a quad general-purpose amplifier, analog amplifier IC, and signal-conditioning semiconductor. This category makes the LM324 suitable for buffer, amplifier, comparator, differential, and current-to-voltage conversion circuits.
The LM324DG4 combines four amplifiers in one 14-SOIC package, reducing component count and board area compared with four single-amplifier packages. Its 1.2 MHz gain-bandwidth product supports general-purpose signal amplification rather than high-speed precision work. The common-mode input range includes ground, which allows single-supply sensing of signals near the lower supply rail. A typical low supply-current drain of 0.8 mA per amplifier also supports power-conscious designs.
The LM324 architecture is suited to low- and moderate-frequency closed-loop applications where economy, ease of use, and supply flexibility matter. Because the device includes internal bias compensation, external nulling components are not required for normal operation. The common-mode range includes ground but does not extend to the positive supply rail, so input and output headroom must be checked when signals approach either rail.
Typical applications include sensor-signal conditioning, transducer amplification, current-to-voltage conversion, audio preamplification, low-frequency active filters, and general industrial control interfaces. In each case, the amplifier operates inside a negative-feedback network, and the closed-loop bandwidth and output swing must satisfy the signal amplitude and accuracy requirements.
A key design consideration is rail-to-rail compatibility. The LM324 can operate from one supply or two supplies, but its output cannot swing fully to the positive rail and input signals must remain inside its common-mode range. Decoupling near the supply pins, stable feedback-component selection, and output-loading checks remain necessary even though the circuit is commonly used with basic resistor networks.
This page combines the verified LM324DG4 device identity, package information, functional characteristics, source links, and engineering guidance with application-oriented selection criteria. It also distinguishes electrically meaningful alternatives from simple reel or tape packaging codes and highlights where compatibility checks are required before substitution.
直接替換替代品，適用於 LM324DG4 — 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： LM324DG4 （相同外形與佔位） — 差異在於 Amplifier Type, Package, Gain Bandwidth Product, Input Offset Voltage, Number of Amplifiers.
LM324DR
✅ 直接替換聯絡詢價
查看資料表 →LM324ADR2G
✅ 直接替換聯絡詢價
查看資料表 →LM324M
✅ 直接替換聯絡詢價
查看資料表 →LM324BAIDR
✅ 直接替換聯絡詢價
查看資料表 →LM324BAIDR
✅ 直接替換聯絡詢價
查看資料表 →LM324DG4 最大額定值與電氣特性
| Amplifier Type | General-purpose operational amplifier |
| Number of Amplifier Circuits | 4 circuits |
| Unity-Gain Bandwidth | 1.2 MHz |
| 封裝 | 14-SOIC |
| Package Width | 3.90 mm |
| 工作溫度範圍 | 0 °C to 70 °C |
| Typical Supply Current Drain | 0.8 mA per amplifier |
| Common-Mode Input Range | Includes ground |
| 安裝方式 | Surface mount |
| RoHS 狀態 | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | not_applicable |
LM324DG4 腳位配置
| 腳位 1 | OUT1 — Amplifier 1 output |
| 腳位 2 | IN1- — Amplifier 1 inverting input |
| 腳位 3 | IN1+ — Amplifier 1 non-inverting input |
| 腳位 4 | V+ — Positive supply voltage |
| 腳位 5 | IN2+ — Amplifier 2 non-inverting input |
| 腳位 6 | IN2- — Amplifier 2 inverting input |
| 腳位 7 | OUT2 — Amplifier 2 output |
| 腳位 8 | OUT3 — Amplifier 3 output |
| 腳位 9 | IN3- — Amplifier 3 inverting input |
| 腳位 10 | IN3+ — Amplifier 3 non-inverting input |
| 腳位 11 | V- — Negative supply voltage |
| 腳位 12 | IN4+ — Amplifier 4 non-inverting input |
| 腳位 13 | IN4- — Amplifier 4 inverting input |
| 腳位 14 | OUT4 — Amplifier 4 output |
典型應用
LM324DG4 適用於 6 應用s: Industrial Sensor Signal Conditioning, Transducer and Bridge Measurement, Audio Preamplifier and Mixer, Current-to-Voltage Conversion, Active Filtering and Control Loops, Data Acquisition Front End.
Industrial Sensor Signal Conditioning
The LM324DG4 is well suited to conditioning resistive, capacitive, and low-level voltage sensors in industrial control systems. Its four independent amplifier sections allow a single 14-SOIC package to implement buffering, gain stages, and active filtering, while the 1.2 MHz unity-gain bandwidth supports signals well beyond ordinary slow process-control loops. The common-mode input range includes ground, which is useful when the sensor output is referenced to the lower supply rail. Designers should verify the sensor excitation range against the input common-mode limits and keep feedback resistors practical for the device's input-bias-current and noise characteristics.
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Transducer and Bridge Measurement
The LM324DG4 can amplify low-level bridge or transducer signals without requiring a separate amplifier for every channel. Its four-channel arrangement provides enough amplification, impedance conversion, and active filtering for a multi-sensor acquisition front end, with the 1.2 MHz bandwidth allowing moderate-bandwidth filtering after amplification. Because the common-mode range includes ground, the device is practical for sensors whose outputs remain close to 0 V. The bridge excitation, signal polarity, output range, and permissible input offset error should be evaluated together so that the amplifier does not consume the available measurement span.
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Audio Preamplifier and Mixer
The LM324DG4 can implement the gain and mixing stages of a general-purpose audio preamplifier when the signal bandwidth and noise requirements remain modest. Its 1.2 MHz unity-gain bandwidth is substantially above the audio band, while four amplifiers provide useful flexibility for input stages, summing paths, and active filters in one package. The common-mode input range including ground simplifies single-supply biasing of source-coupled signals. Input bias-current return paths, resistor thermal noise, output-loading capability, and rail-to-rail headroom must be checked for quiet, low-impedance source implementations.
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Current-to-Voltage Conversion
The LM324DG4 is appropriate for converting a small sensor current into a measurable voltage when the required bandwidth is no greater than its 1.2 MHz unity-gain capability. Four channels allow multiple current outputs to be monitored without requiring four separate packages, and the common-mode range that includes ground is helpful for unipolar current sensing. The transimpedance network should use a feedback resistor and compensation capacitor selected to stabilize the intended closed-loop bandwidth. Additional design checks include input-bias-current offset, input and feedback-capacitor parasitics, output swing, and the sensor's allowable compliance voltage.
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Active Filtering and Control Loops
The LM324DG4 can form the active-filter and controller blocks of low-frequency industrial equipment because four amplifiers share one package without requiring individual biasing. Its 1.2 MHz unity-gain bandwidth supports closed-loop gains and filter poles well above typical process-control bandwidths, while the common-mode range including ground simplifies zero-centered or single-supply filter designs. Stable feedback-component ratios, practical resistor values, and output-load limits remain important. For higher-Q filters, faster settling requirements, or tighter DC accuracy, the complete data-sheet limits should be compared with the control-system error budget.
推薦
Data Acquisition Front End
The LM324DG4 provides four buffered channels for analog inputs in a compact data-acquisition front end. It can drive moderate input impedances into external analog-to-digital converters, combine with local RC filtering to control aliasing, and perform gain or offset conditioning close to the sensor connector. The 1.2 MHz bandwidth permits useful anti-alias filter bandwidth, but the selected ADC's acquisition time and settling behavior determine the actual usable channel rate. Layout should keep the amplifier feedback loops compact, preserve a quiet ground reference, and place bypass capacitance near the supply pins to reduce coupling between adjacent channels.
推薦
推薦產品摘要
工程參考資料，適用於 LM324DG4 — 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 | LM324DR | LM324ADR | LM324M | LM324B | LM324BA |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 14-SOIC | 14-SOIC - same | 14-SOIC - same | 14-SOIC - same | 14-SOIC - same | 14-SOIC - same |
| Amplifier Circuits | 4 circuits | 4 circuits | 4 circuits | 4 circuits | 4 circuits | 4 circuits |
| Unity-Gain Bandwidth | 1.2 MHz | 1.2 MHz | 1.2 MHz | 1.2 MHz | 1.2 MHz | 1.2 MHz |
| Common-Mode Input Range | Includes ground | Includes ground | Includes ground | Includes ground | Includes ground | Includes ground |
主要差異化特點
- Four general-purpose amplifiers integrated into one 14-SOIC package (對比LM324DR)
- B-version alternatives provide a documented 36 V upper supply limit (對比LM324B)
- BA alternative offers tighter offset-voltage grading (對比LM324BA)
設計說明
Treat the LM324 as a non-rail-to-rail amplifier even though it can operate from a single supply. Confirm that every input remains inside the common-mode range and that the required output stays within the load-dependent output swing. Ground-referenced sensor signals are generally straightforward because the common-mode range includes ground, but signals that approach the positive supply require attenuation, biasing, or a rail-to-rail amplifier instead.
Place the supply bypass capacitor close to pins 4 and 11, with a short return path to the ground reference. Keep each inverting-input feedback loop compact because parasitic capacitance in a high-gain feedback node can reduce phase margin. Avoid routing sensitive input and output nets beneath digital switching paths, and provide a quiet ground-current strategy so that output currents from one amplifier do not modulate the reference shared by the remaining channels.
Estimated: with a 12 V supply, a 5 V output, and a 1 mA load, the LM324 dissipates approximately 7 mW using the calculation (12 V - 5 V) × 0.001 A. Actual dissipation includes all four channels, load current, bias current, and supply variation. Although the total is modest, verify the maximum load and ambient temperature because output current, input-bias paths, and adjacent-channel loading can increase the thermal design envelope.
Use feedback resistors large enough for acceptable bias-current offset but small enough to avoid excessive Johnson noise and parasitic capacitance. When driving an ADC or sampling network, calculate the settling time from the closed-loop bandwidth and allow additional acquisition margin. For filtering after a multiplexer, include the amplifier's gain-bandwidth product, load capacitance, and channel-switching transients in the settling budget.
合規資訊
The manufacturer product family is active, but no explicit RoHS, REACH, lead-free, halogen-free, or conflict-minerals declaration was identified in the cited device listings. Compliance should be confirmed for the exact orderable suffix and current manufacturer documentation.