LM324DST - Quad Op-Amp, 14-SOIC, Low Power | STMicroelectronics
MPN: LM324DST β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.14 | $0.14 |
| 10 | $0.12 | $1.20 |
| 100 | $0.1 | $10.00 |
| 500 | $0.09 | $45.00 |
| 1,000 | $0.08 | $80.00 |
LM324DST Overview
A quad op-amp is an integrated circuit that houses four separate operational amplifiers on one die. An operational amplifier is a high-gain DC-coupled voltage amplifier with differential inputs and, in this family, a single-ended output; it is the foundational building block of the analog signal-chain hierarchy (op-amp -> amplifier IC -> linear IC -> analog/mixed-signal semiconductor). Quad op-amps like the LM324x family are chosen when multiple amplification stages share a common supply and ground, halving board area versus four single op-amps.
Key features of the LM324DST include four internally compensated amplifiers requiring no external frequency-compensation components, wide single-supply operation, and an output that swings close to the negative rail, which is valuable in single-supply designs. The common-mode input range extends to include the negative supply rail, enabling sensing near ground.
The internal compensation is implemented on-chip, giving unity-gain stability without external capacitors. This makes the part forgiving in general-purpose amplification, active filtering, comparators (non-precision), oscillators, and transducer interface circuits.
Typical applications include industrial signal conditioning, consumer audio preamplification, battery-powered instrumentation, and logic-level level-shifting or buffering where four matched gain blocks are needed on one rail.
Design consideration: the LM324 class-B output stage can exhibit crossover distortion at light loads and near-zero output currents; for precision AC applications consider a rail-to-rail upgrade such as the TL074 (JFET input) after verifying bias-current requirements.
This page synthesizes distributor pricing, verified drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for LM324DST β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LM324DST (same form factor and footprint) β differing in Amplifier Type, Package.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
LM124DT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
LM224DT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
LM324BDR
β Drop-Inπ Reference alternative (not in catalog)
LM324DR2G
β Drop-Inβ In Stock
$0.21 / Unit
View Datasheet βLM324D-T
β Drop-Inπ Reference alternative (not in catalog)
TL074CDT
β Drop-Inπ Reference alternative (not in catalog)
LM324DST Maximum Ratings & Electrical Characteristics
| Amplifier Circuits | 4 |
| Amplifier Type | Standard (General Purpose) |
| Package | 14-SO (SOIC-14) |
| Mounting Type | Surface Mount |
| Output Current (per channel) | 70 mA |
| Input Bias Current | Low (per datasheet) |
| Internal Frequency Compensation | Yes |
| RoHS Status | Compliant |
LM324DST Pin Configuration
| Pin 1 | OUT1 β Output of amplifier 1 |
| Pin 2 | IN1- β Inverting input, amplifier 1 |
| Pin 3 | IN1+ β Non-inverting input, amplifier 1 |
| Pin 4 | VCC β Positive supply |
| Pin 5 | IN2+ β Non-inverting input, amplifier 2 |
| Pin 6 | IN2- β Inverting input, amplifier 2 |
| Pin 7 | OUT2 β Output of amplifier 2 |
| Pin 8 | OUT3 β Output of amplifier 3 |
| Pin 9 | IN3- β Inverting input, amplifier 3 |
| Pin 10 | IN3+ β Non-inverting input, amplifier 3 |
| Pin 11 | GND/VEE β Ground or negative supply |
| Pin 12 | IN4+ β Non-inverting input, amplifier 4 |
| Pin 13 | IN4- β Inverting input, amplifier 4 |
| Pin 14 | OUT4 β Output of amplifier 4 |
Typical Applications
LM324DST is suitable for 6 applications: Industrial Signal Conditioning, Consumer Audio Preamplification, Battery-Powered Portable Instrumentation, Active Filter Networks, Comparator and Level-Detection Circuits, Automotive Body and Sensor Front Ends (LM224 Grade).
Industrial Signal Conditioning
The LM324DST fits industrial signal conditioning because its single-supply operation with input common-mode range extending to ground lets sensors such as thermistors, strain-gauge bridges, and current-shunt monitors interface directly without a negative rail. With four amplifiers in one SOIC-14, a single LM324DST provides gain, offset, filtering, and buffering stages in roughly 9 mm x 4 mm of board area, and the ~70 mA output capability can drive panel meters or LED indicators directly. Placed after a sensor divider with a few hundred kHz of closed-loop bandwidth, it amplifies millivolt-level signals on a 5 V or 24 V single rail; the trade-off is modest DC precision, so calibration or a precision-grade part is needed for sub-1% systems.
Recommended
Consumer Audio Preamplification
In cost-sensitive consumer audio - set-top boxes, karaoke mixers, intercoms, and TV audio boards - the LM324DST supplies four gain stages from one part on a single 5 V or 12 V rail. Its internal compensation ensures unity-gain stability with no external compensation parts, and the low input bias current keeps coupling-capacitor sizing reasonable. A typical use puts the LM324DST between a DAC line output and a power-amp input with gain of 2x-10x per stage; designers should note the class-B output stage's crossover distortion at low output currents, which is usually masked by a higher-load output stage or acceptable in low-fi products. For higher-fidelity lines, a JFET-input TL074 in the same footprint is the upgrade path.
Recommended
Battery-Powered Portable Instrumentation
The LM324DST suits battery-powered instrumentation because its low power consumption preserves battery life, its single-supply architecture eliminates negative-rail charge pumps, and four channels in one SOIC-14 reduce component count in multichannel portable meters. Typical products include handheld multimeters, gas-detector front ends, and wearable health monitors that amplify bridge or electrochemical-sensor outputs on a 3 V to 9 V battery. Because the input common-mode range includes ground, low-side current sensing works without level shifting. The performance consideration is quiescent current drawn by all four amplifiers even when only one channel is used - designers of ultra-low-power products may prefer single-channel micropower op-amps or a modern CMOS quad.
Recommended
Active Filter Networks
Four internally compensated amplifiers make the LM324DST an economical core for Sallen-Key and multiple-feedback active filters in a single package - for example, a four-pole low-pass anti-aliasing filter with two stages per op-amp pair. The unity-gain-stable internal compensation removes external capacitor sizing for stability, and single-supply biasing at mid-rail (using one amplifier as a virtual-ground buffer, a classic LM324 trick) simplifies DC-coupled designs. The bandwidth limit of roughly 1 MHz class gain-bandwidth means these filters are appropriate for audio and control-loop frequencies up to tens of kHz; above that, settling and phase accuracy degrade and a faster quad should be substituted in the same SOIC-14 footprint.
Recommended
Comparator and Level-Detection Circuits
Non-precision comparators, window detectors, and level shifters are a classic LM324DST application: with input common-mode reaching the negative rail, one input can be referenced to ground and the LM324DST will still resolve the comparison on a single 5 V or 12 V supply. Multichannel battery and PSU monitor boards frequently use three amplifiers as comparators and the fourth as a reference buffer. The caveat is speed - the device is not a dedicated comparator, so response times are in the microsecond class and outputs are not logic-threshold-guaranteed; add a pull-up and verify logic-high levels into the receiving gate. Where sub-microsecond trip times are required, use a true quad comparator instead.
Recommended
Automotive Body and Sensor Front Ends (LM224 Grade)
For 12 V automotive boards - sensor conditioning, lamp-fault detection, and simple control loops - the LM324DST's wide single-supply tolerance and quad integration reduce BOM cost, and the same-family LM224/LM124 grades in the identical SOIC-14 footprint provide extended temperature capability where the commercial LM324 grade is insufficient. A typical circuit conditions a resistive sensor output (level, temperature, position) referenced to ground, with spare amplifiers implementing filtering and a buffered threshold. Designers should verify the exact temperature grade and AEC qualification status of the specific suffix in the ST datasheet before automotive release, as the commercial LM324 grade does not carry automotive qualification on its own.
Recommended
Recommended Products Summary
Engineering reference data for LM324DST β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM124DT | LM324BDR | LM324DR2G | LM324D-T | TL074CDT |
|---|---|---|---|---|---|---|
| Package | 14-SO (SOIC-14) | 14-SO (SOIC-14) - same | 14-SO (SOIC-14) - same | 14-SO (SOIC-14) - same | 14-SO (SOIC-14) - same | 14-SO (SOIC-14) - same |
| Brand | STMicroelectronics | STMicroelectronics | Texas Instruments | onsemi | NXP Semiconductors | STMicroelectronics |
| Amplifier Circuits | 4 | 4 | 4 | 4 | 4 | 4 |
| Input Technology | Bipolar, common-mode to negative rail | Bipolar, common-mode to negative rail | Bipolar, improved | Bipolar | Bipolar | JFET |
| Temperature Grade | Commercial (LM324 grade) | Military/extended (LM124) | Wider range than classic LM324 (per TI) | Commercial/industrial | Commercial/industrial | Commercial (0C to 70C) |
| Single-Supply Operation | Yes, input includes ground | Yes | Yes | Yes | Yes | Requires higher headroom, no ground sensing |
| Internal Frequency Compensation | Yes | Yes | Yes | Yes | Yes | Yes (unity-gain stable) |
| Crossover Distortion (AC fidelity) | Present (class-B output) | Present (same family) | Reduced vs classic LM324 | Present | Present | Substantially lower (JFET class-AB) |
Key Differentiators
- Ground-sensing bipolar input on single supply (vs TL074CDT)
- Lower noise and distortion upgrade path on same footprint (vs TL074CDT)
- Temperature grade scalability within the same package (vs LM124DT)
- TI drop-in upgrade availability (vs LM324BDR)
Design Notes
The LM324DST's class-B output stage exhibits crossover distortion when output current crosses zero, visible as small glitches in low-amplitude AC signals driving light loads. Mitigate by increasing load current (a pull-down resistor to VEE of 1-2 kOhm biases the output stage), keeping closed-loop gain low, or substituting a TL074-class part in the same SOIC-14 footprint for audio-critical paths. Also remember the output cannot swing to the positive rail - leave roughly 1.5 V of headroom in gain calculations on single supplies.
Place a 100 nF ceramic decoupling capacitor within 5 mm of the VCC pin (pin 4) to the GND/VEE pin (pin 11), with one bulk capacitor per board. Because all four amplifiers share the die and supply, crosstalk increases when amplifier outputs drive low impedances; keep gain-setting resistors above 10 kOhm where bandwidth allows and route sensitive input traces away from adjacent amplifier outputs. The SOIC-14 land pattern is the universal LM324 footprint, so second sources drop onto the same layout without revision.
When using one amplifier as a mid-rail virtual ground for single-supply AC circuits, buffer the divider with the LM324DST amplifier rather than relying on the resistive divider alone - divider impedance of a few kOhm causes channel-to-channel interaction and DC shifts as other amplifiers draw signal current. Estimated: a 10 kOhm/10 kOhm divider on a 5 V rail has 2.5 kOhm Thevenin impedance; buffering it isolates the reference. Verify input common-mode limits stay within the datasheet range at your supply voltage before finalizing bias points.
Compliance Information
RoHS compliance and lead-free status per distributor listings (DigiKey, LCSC) for the ST LM324 SOIC-14 family. Obtain formal REACH and conflict-minerals declarations from the ST product page.
