LM324QT - Quad Low Power Op Amp, 1.3MHz | STMicroelectronics
MPN: LM324QT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.29 | $29.00 |
| 500 | $0.24 | $120.00 |
| 1,000 | $0.19 | $190.00 |
Drop-in alternatives for LM324QT — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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Request AlternativesLM324QT Maximum Ratings & Electrical Characteristics
| Amplifier Type | General Purpose |
| Number of Circuits | 4 |
| Package / Case | 16-VFQFN Exposed Pad (3x3 mm) |
| Slew Rate | 0.4 V/µs |
| Gain Bandwidth Product | 1.3 MHz |
| Voltage Gain | 100 dB |
| Supply Current per Amplifier | 375 µA |
| Input Common-Mode Voltage Range | Includes ground |
| Supply Voltage Range | 3V to 30V (single supply), ±1.5V to ±15V (dual supply) |
| Input Bias Current | 20 nA (typical) |
| Operating Temperature Range | 0°C to +70°C |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (TR) |
| RoHS Status | Compliant |
| MSL Level | [DATA_NEEDED: MSL Level] |
LM324QT Pin Configuration
| Pin 1 | 1OUT — Output of amplifier 1 |
| Pin 2 | 1IN- — Inverting input of amplifier 1 |
| Pin 3 | 1IN+ — Non-inverting input of amplifier 1 |
| Pin 4 | VCC — Positive power supply |
| Pin 5 | 2IN+ — Non-inverting input of amplifier 2 |
| Pin 6 | 2IN- — Inverting input of amplifier 2 |
| Pin 7 | 2OUT — Output of amplifier 2 |
| Pin 8 | 3OUT — Output of amplifier 3 |
| Pin 9 | 3IN- — Inverting input of amplifier 3 |
| Pin 10 | 3IN+ — Non-inverting input of amplifier 3 |
| Pin 11 | GND — Ground (negative supply) |
| Pin 12 | 4IN+ — Non-inverting input of amplifier 4 |
| Pin 13 | 4IN- — Inverting input of amplifier 4 |
| Pin 14 | 4OUT — Output of amplifier 4 |
| Pin 15 | NC — No connection |
| Pin 16 | NC — No connection |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
LM324QT is suitable for 6 applications: Sensor Signal Conditioning, Active Filters, DC Gain Blocks, Transducer Amplifiers, Battery-Powered Devices, Industrial Control Systems.
Sensor Signal Conditioning
The LM324QT is ideal for conditioning signals from sensors such as thermocouples, strain gauges, and photodiodes. Its low supply current of 375 µA per amplifier and wide supply range (3V to 30V) make it suitable for battery-powered sensor nodes. The input common-mode range includes ground, allowing direct interface with ground-referenced sensors. With a gain bandwidth of 1.3 MHz, it can amplify signals up to a few hundred kHz, sufficient for most sensor applications. The quad configuration allows multiple sensor channels to be processed in a single IC, reducing board space and cost. For example, in a temperature monitoring system, the LM324QT can amplify the small voltage from a thermocouple and drive an ADC. The low power consumption extends battery life in remote sensors. The QFN package's small footprint is ideal for compact sensor modules.
Recommended
Active Filters
The LM324QT can be used to implement active filters such as low-pass, high-pass, and band-pass filters. With a gain bandwidth product of 1.3 MHz, it can support filter cutoff frequencies up to a few hundred kHz, making it suitable for audio and control applications. The low supply current is beneficial in battery-operated devices. The quad configuration allows multiple filter stages in one package, enabling complex filter designs like Butterworth or Chebyshev. For example, a 4th-order low-pass filter can be built using two LM324QT amplifiers. The input common-mode range includes ground, simplifying single-supply filter designs. The high voltage gain of 100 dB ensures accurate filter response. The QFN package's small size is advantageous for compact filter modules. When designing filters, ensure proper component tolerances to maintain filter accuracy.
Recommended
DC Gain Blocks
The LM324QT is well-suited for DC gain blocks in control systems and instrumentation. Its high voltage gain of 100 dB and low input bias current ensure accurate DC amplification. The wide supply range allows operation from various power rails. The quad configuration enables multiple gain stages in one package, such as in a PID controller where proportional, integral, and derivative gains are implemented. The low supply current is advantageous in portable instruments. The input common-mode range includes ground, allowing direct connection to ground-referenced signals. With a gain bandwidth of 1.3 MHz, it can handle DC and low-frequency AC signals. The QFN package's small footprint is ideal for compact control modules. For precision DC applications, use low-drift external resistors to set gain accurately.
Recommended
Transducer Amplifiers
The LM324QT is commonly used to amplify signals from transducers such as pressure sensors, accelerometers, and microphones. Its low noise and low power consumption make it suitable for portable and battery-powered devices. The input common-mode range includes ground, allowing direct connection to many transducers. With a gain bandwidth of 1.3 MHz, it can amplify signals up to a few hundred kHz, covering most transducer outputs. The quad configuration allows multiple transducer channels to be processed in one IC, reducing component count. For example, in a 3-axis accelerometer system, three amplifiers can be used for X, Y, and Z axes, with the fourth for temperature compensation. The QFN package's small size is ideal for compact sensor modules. The wide supply range (3V to 30V) provides flexibility in system power design.
Recommended
Battery-Powered Devices
The LM324QT is ideal for battery-powered devices due to its low supply current of 375 µA per amplifier. This extends battery life in portable electronics such as handheld meters, remote sensors, and wearable devices. The wide supply voltage range (3V to 30V) allows operation from various battery configurations, including single-cell lithium-ion (3.7V) and multi-cell alkaline (9V). The quad configuration provides four amplifiers in a small QFN package, saving board space. The input common-mode range includes ground, simplifying single-supply designs. With a gain bandwidth of 1.3 MHz, it can handle audio and sensor signals. The low power consumption is critical for always-on applications. For example, in a battery-powered smoke detector, the LM324QT can amplify the sensor signal while consuming minimal power, ensuring long battery life.
Recommended
Industrial Control Systems
The LM324QT is widely used in industrial control systems for signal conditioning, process control, and motor control. Its wide supply range (3V to 30V) allows direct operation from 24V industrial power rails. The high voltage gain of 100 dB ensures accurate signal processing. The quad configuration enables multiple control loops in one IC, reducing cost and board space. The input common-mode range includes ground, simplifying interface with sensors and transducers. With a gain bandwidth of 1.3 MHz, it can handle control signals up to a few hundred kHz. The low supply current is beneficial in power-sensitive industrial applications. The QFN package's small footprint is suitable for compact industrial modules. For harsh environments, consider the LM2902DR (TI) with a wider temperature range of -40°C to +125°C.
Recommended
Recommended Products Summary
Engineering reference data for LM324QT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM324QDRQ1 | LM324DR | LM324N |
|---|---|---|---|---|
| Package | 16-QFN (3x3 mm) | SOIC-14 | SOIC-14 | DIP-14 |
| Brand | STMicroelectronics | Texas Instruments | Texas Instruments | STMicroelectronics |
| Number of Circuits | 4 | 4 | 4 | 4 |
| Gain Bandwidth Product | 1.3 MHz | 1.2 MHz | 1.2 MHz | 1.3 MHz |
| Slew Rate | 0.4 V/µs | 0.5 V/µs | 0.5 V/µs | 0.4 V/µs |
| Supply Current per Amplifier | 375 µA | 350 µA | 350 µA | 375 µA |
| Supply Voltage Range | 3V to 30V | 3V to 30V | 3V to 30V | 3V to 30V |
| Operating Temperature Range | 0°C to +70°C | -40°C to +125°C | 0°C to +70°C | 0°C to +70°C |
Key Differentiators
- Compact QFN package (vs LM324N (DIP-14))
- Low supply current (vs LM2902DR (TI))
- Wide supply voltage range (vs LM358DR (dual))
Design Notes
The LM324QT operates from a single supply of 3V to 30V or dual supplies of ±1.5V to ±15V. Ensure the supply voltage does not exceed the absolute maximum ratings. Use a 0.1 µF ceramic capacitor close to the VCC pin and a 10 µF electrolytic capacitor for bulk decoupling. The low supply current of 375 µA per amplifier makes it suitable for battery-powered designs, but consider the total current draw of all four amplifiers when calculating battery life.
For optimal performance, place the LM324QT on a PCB with a solid ground plane. The exposed pad on the QFN package should be soldered to the ground plane for thermal and electrical performance. Keep input traces short and shielded to minimize noise pickup. Use separate analog and digital ground planes if mixed-signal components are present. Follow the layout guidelines in the ST datasheet for the QFN package to ensure proper soldering and thermal dissipation.
A common pitfall is operating the LM324QT outside its input common-mode voltage range. The input common-mode range includes ground but extends only to VCC - 1.5V. Driving inputs above this range can cause phase reversal or latch-up. Also, avoid capacitive loads greater than 100 pF directly on the output, as this can cause instability. Use a series resistor to isolate capacitive loads. Additionally, ensure the output can swing close to the rails, but not exactly to them, as the LM324 is not a rail-to-rail output op amp.
Compliance Information
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Lead-free per datasheet.
