LM324QT - Quad Low Power Op Amp, 1.3MHz | STMicroelectronics
Référence : LM324QT ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $0.55 | $0,55 |
| 10 | $0.5 | $5,00 |
| 100 | $0.42 | $42,00 |
| 500 | $0.36 | $180,00 |
| 1 000 | $0.31 | $310,00 |
LM324QT Présentation
An operational amplifier (op amp) is a high-gain voltage amplifier with differential inputs and a single-ended output. It is the fundamental building block of analog signal conditioning, used in filters, comparators, integrators, and many other circuits. The LM324QT belongs to the LM324 family, a classic industry-standard quad op amp known for its low power consumption and wide supply range, which includes the ability to operate from a single supply down to 3V.
Key features include a wide gain bandwidth of 1.3 MHz, a large voltage gain of 100 dB, and a very low supply current per amplifier of 375 uA. The input common-mode voltage range includes ground, allowing single-supply operation with ground-referenced inputs. The device also features low input bias current and internal frequency compensation, simplifying design and reducing external component count.
The LM324QT uses a bipolar process technology, providing robust performance over a wide temperature range. The QFN package offers excellent thermal performance and a small footprint, making it suitable for compact designs. The device is designed for low-power operation, making it ideal for battery-powered equipment where power efficiency is critical.
Typical applications include sensor signal conditioning, active filters, DC gain blocks, and transducer amplifiers. The wide supply voltage range and low power consumption make it suitable for automotive, industrial, and consumer electronics. The QFN package is particularly well-suited for portable devices where board space is at a premium.
When designing with the LM324QT, ensure proper decoupling of the power supply pins with a 0.1 uF ceramic capacitor placed close to the device. The input common-mode range includes ground, but for best performance, keep inputs within the specified range. The output can swing close to the rails, but avoid driving loads that require rail-to-rail output swing without proper design considerations.
Alternatives de remplacement direct pour LM324QT — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
LM224QT
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
LM2902QT
✅ Remplacement direct ⚠️ Spécifications non vérifiées📋 Alternative de référence (hors catalogue)
LM324QT Valeurs maximales et caractéristiques électriques
| Amplifier Type | General Purpose |
| Number of Circuits | 4 |
| Gain Bandwidth Product | 1.3 MHz |
| Slew Rate | 0.4 V/us |
| Open Loop Gain | 100 dB |
| Supply Current Per Amplifier | 375 uA |
| Supply Voltage Range | 3 V to 30 V (single supply) or +/-1.5 V to +/-15 V |
| Input Common-Mode Range | Includes ground (negative rail) |
| Boîtier / Format | 16-VFQFN Exposed Pad (3x3 mm) |
| Type de montage | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Technology | Bipolar |
| Frequency Compensation | Internal |
Configuration des broches de LM324QT
| Broche 1 | OUT1 — Output of amplifier 1 |
| Broche 2 | IN1- — Inverting input, amplifier 1 |
| Broche 3 | IN1+ — Non-inverting input, amplifier 1 |
| Broche 4 | VCC — Positive supply |
| Broche 5 | IN2+ — Non-inverting input, amplifier 2 |
| Broche 6 | IN2- — Inverting input, amplifier 2 |
| Broche 7 | OUT2 — Output of amplifier 2 |
| Broche 8 | OUT3 — Output of amplifier 3 |
| Broche 9 | IN3- — Inverting input, amplifier 3 |
| Broche 10 | IN3+ — Non-inverting input, amplifier 3 |
| Broche 11 | GND/VEE — Ground or negative supply |
| Broche 12 | IN4+ — Non-inverting input, amplifier 4 |
| Broche 13 | IN4- — Inverting input, amplifier 4 |
| Broche 14 | OUT4 — Output of amplifier 4 |
Applications typiques
LM324QT convient pour 6 applications: Sensor Signal Conditioning, Active Filter Design, Battery-Powered Portable Devices, DC Gain Blocks and Comparator-Level Functions, Industrial Process Control Front Ends, Automotive Auxiliary Analog Functions.
Sensor Signal Conditioning
The LM324QT fits sensor front ends because its input common-mode range includes ground, allowing single-supply ground-referenced sensors such as thermistors and bridge transducers to be read directly. With only 375 uA supply current per amplifier, four channels consume about 1.5 mA total, preserving battery runtime in portable instruments. Signals are typically amplified with gain set by two external resistors; the 1.3 MHz bandwidth supports sensor outputs well below 100 kHz. Placing the QFN device close to the sensor and decoupling with 0.1 uF ceramics keeps noise pickup low.
Recommandé
Active Filter Design
Multiple Sallen-Key or multiple-feedback filter stages can be built on one LM324QT since four independent amplifiers share the 3x3 mm QFN package, reducing board area and BOM lines. The 1.3 MHz gain bandwidth supports low-pass and band-pass filters with corner frequencies up to tens of kilohertz at moderate Q; designers should verify gain-bandwidth margin per stage. Internal frequency compensation removes external capacitor networks, and the wide 3 V to 30 V single-supply range allows filters to run directly from industrial rails.
Recommandé
Battery-Powered Portable Devices
The LM324QT is a natural fit for battery-operated equipment: 375 uA per amplifier keeps the whole quad near 1.5 mA, and single-supply operation down to 3 V allows direct use of a Li-ion stack or three AA cells. The 3x3 mm QFN conserves board space in wearables and handheld meters. Because the output swings close to the rails but not fully, designers should budget headroom near the positive rail to preserve dynamic range as the battery discharges.
Recommandé
DC Gain Blocks and Comparator-Level Functions
The 100 dB large-signal voltage gain makes the LM324QT effective for precision DC gain stages such as current-shunt amplification and setpoint error amplifiers in power supplies. The 3 V to 30 V supply range covers 24 V industrial buses, and ground-sensing inputs simplify level shifting from low-side shunts. Note the 0.4 V/us slew rate limits fast transient response, so the part suits slow feedback loops rather than fast protection comparators; add hysteresis and filtering around each stage.
Recommandé
Industrial Process Control Front Ends
In factory instrumentation, the LM324QT amplifies 4-20 mA loop signals and thermocouple mV outputs on a single 24 V rail, exploiting the 30 V maximum supply and ground-inclusive input range. Four channels let one device handle multi-sensor inputs such as pressure, temperature, and flow in one compact footprint. The bipolar process tolerates industrial temperature conditions, and the QFN exposed pad sinks heat from higher-output-current stages; designers should verify output swing against load resistance per the datasheet graphs.
Recommandé
Automotive Auxiliary Analog Functions
For non-critical automotive analog functions such as seat-position sensor buffering, lighting level sense, and dashboard signal conditioning, the LM2902QT drop-in sibling with wider temperature range is often selected on the same 16-QFN footprint. The LM324QT itself serves 12 V battery-rail designs within its 30 V rating, with ground-referenced inputs reading potentiometer and resistive sensors directly. Engineers should confirm temperature grade against the module qualification spec before finalizing the BOM.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LM324QT — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | LM224QT | LM2902QT |
|---|---|---|---|
| Package | 16-QFN (3x3 mm) exposed pad | 16-QFN (3x3 mm) - same | 16-QFN (3x3 mm) - same |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Number of Circuits | 4 | 4 | 4 |
| Gain Bandwidth Product | 1.3 MHz | 1.3 MHz | 1.2 MHz |
| Slew Rate | 0.4 V/us | 0.4 V/us | 0.4 V/us |
| Supply Current per Amplifier | 375 uA | 375 uA | 375 uA |
| Open Loop Gain | 100 dB | 100 dB | 100 dB |
Principaux différenciateurs
- Industry-standard LM324 quad core in the smallest family package (vs LM324N (DIP-14) / LM324DR (SOIC-14))
- Extended temperature grade availability in the same footprint (vs LM224QT)
- Automotive temperature option as true drop-in (vs LM2902QT)
Notes de conception
Decouple the VCC pin (pin 4) with a 0.1 uF ceramic capacitor placed within 2-3 mm of the pin, plus a 2.2-10 uF bulk capacitor near the supply entry. The total supply current of roughly 1.5 mA is small, but four amplifiers switching loads simultaneously can create supply glitches that couple into precision stages. Use a ground or negative-supply connection on pin 11 and ensure the exposed pad is soldered to a grounded copper area for thermal and electrical performance.
The LM324QT output does not swing rail-to-rail. The output typically saturates about 1.5 V below VCC at moderate loads, so a 5 V rail yields only about a 3.5 V usable output swing. Designing gain stages expecting full-swing output is the most common failure mode. Also, at light output currents the class-AB output stage introduces crossover distortion; adding a small pull-down resistor (e.g., 2-10 kOhm to ground) on the output improves linearity for AC signals.
Keep input traces short and guard high-impedance input nodes with ground ring to limit leakage, since input bias currents, while low, can create offsets with large source resistances. The 3x3 mm QFN land pattern requires a center exposed-pad via array (3x3 recommended) tied to ground for heat spreading. Maintain at least 0.2 mm solder mask expansion per IPC-recommended QFN patterns and inspect for solder bridging on 0.5 mm pitch pads.
Informations de conformité
Compliance details not present in the provided verified data; consult ST product page for RoHS/REACH declarations. The LM2902QT sibling carries automotive temperature ratings but LM324QT AEC-Q100 qualification is not stated in the provided data.
