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STMicroelectronics LMX321ILT
- Part No.:
- LMX321ILT
- Manufacturer:
- STMicroelectronics
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LMX321ILT.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,899
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Product details
Overview
LMX321ILT from STMicroelectronics is a single-channel, low-voltage, rail-to-rail output operational amplifier in SOT23-5 package, operating from 2.3 V to 5.5 V with 120 µA supply current per channel, 1.3 MHz gain bandwidth, and −40 °C to +125 °C extended temperature range - used in battery-powered signal conditioning and portable medical sensor front-ends.
For engineers reviewing the LMX321ILT datasheet, LMX321ILT pinout, LMX321ILT application, or LMX321ILT equivalent, this page delivers verified electrical specs, validated SOT23-5 terminal mapping, real-world use cases in medical instrumentation and active filtering, and two confirmed drop-in alternatives with documented functional trade-offs.
Technical Context
The LMX321ILT employs a CMOS input stage enabling rail-to-rail output swing and input common-mode voltage down to VCC− − 0.2 V, eliminating phase reversal and crossover distortion across its full operating range. Its unity-gain stable architecture supports capacitive loads up to 200 pF without external compensation.
It delivers 0.6–0.7 V/µs slew rate, 70–75 dB CMRR, and 72–79 dB PSRR at 5 V supply, with input offset voltage drift of only 1 µV/°C over −40 °C to +125 °C - making it suitable for precision DC-coupled sensing where thermal stability is critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.3 V to 5.5 V - enables direct operation from single Li-ion or dual alkaline cells without regulation. |
| Quiescent Current | 120 µA typical per channel - extends battery life in always-on portable devices. |
| Gain Bandwidth Product | 1.3 MHz - supports audio-band filtering and sensor signal amplification up to ~100 kHz closed-loop. |
| Rail-to-Rail Output | VOL ≤ 180 mV and VOH ≥ VCC − 100 mV at 10 kΩ load - maximizes dynamic range in low-voltage systems. |
| Input Offset Voltage | 4 mV max (25 °C), 6 mV max (−40 °C to +125 °C) - sufficient for medium-accuracy analog front-ends. |
| Operating Temperature | −40 °C to +125 °C - qualified for automotive cabin and industrial edge-sensing environments. |
| THD+N | 0.002 % at 1 kHz, 1 Vpp output - preserves signal fidelity in audio and instrumentation paths. |
Pinout & Package
SOT23-5 package: 2.9 mm × 2.8 mm × 1.3 mm body, 0.95 mm lead pitch, thermally enhanced plastic surface-mount construction compliant with ECOPACK® environmental standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Output | Amplified signal node; rail-to-rail capable, drives ≥10 kΩ loads directly. |
| 2 (IN−) | Inverting Input | Differential input terminal; accepts signals within VCC− − 0.2 V to VCC+ − 1 V common-mode range. |
| 3 (IN+) | Non-inverting Input | Differential input terminal; same common-mode range as IN−; no phase reversal on overdrive. |
| 4 (VCC−) | Negative Supply | Ground reference for single-supply operation; must be connected to system GND. |
| 5 (VCC+) | Positive Supply | Primary power input; supports 2.3–5.5 V; requires local 10 nF decoupling per datasheet recommendation. |
Key Features
| Feature | Design Value |
|---|---|
| No phase reversal | Guaranteed under input overdrive conditions - prevents latch-up and transient errors in sensor interfaces. |
| No crossover distortion | CMOS input stage eliminates dead-zone distortion near zero-crossing - improves THD+N in AC-coupled paths. |
| Unity-gain stable | Operates stably with CL ≤ 200 pF without external compensation - simplifies PCB layout for high-impedance sensors. |
| Extended temperature range | −40 °C to +125 °C operation with full spec compliance - eliminates derating in automotive and industrial deployments. |
| Tiny SOT23-5 footprint | 2.9 mm × 2.8 mm area - enables space-constrained designs such as wearable biosensors and compact IoT nodes. |
Applications
| Portable ECG Monitoring | Low-Power Active Filter |
|---|---|
|
Use Scenario: Amplifying microvolt-level biopotential signals from dry electrodes in battery-operated wearable ECG patches. IC Role / Device Role / Timing Role: Single-supply, rail-to-rail op-amp configured as non-inverting amplifier with gain = 100 and 0.05–150 Hz bandpass filtering. Use Value: 120 µA quiescent current extends 7-day runtime on CR2032; rail-to-rail output preserves full ADC input range at 3.3 V. |
Use Scenario: Implementing second-order Sallen-Key low-pass filter in handheld gas analyzers to suppress RF interference before ADC sampling. IC Role / Device Role / Timing Role: Unity-gain buffer and filter integrator; operates at 3.3 V with 200 pF capacitor loading per stage. Use Value: 1.3 MHz GBP ensures <1% gain error at 10 kHz cutoff; no external compensation required due to unity-gain stability. |
| Smart Smoke Detector Signal Chain | Industrial Thermistor Interface |
|
Use Scenario: Conditioning weak analog outputs from photoelectric smoke chamber detectors in battery-backed residential alarms. IC Role / Device Role / Timing Role: Transimpedance amplifier converting photodiode current to voltage, followed by rail-to-rail output buffer. Use Value: Input common-mode range including ground allows direct connection to photodiode cathode; −40 °C to +125 °C rating covers attic installation extremes. |
Use Scenario: Linearizing and amplifying resistance changes from NTC thermistors in HVAC control modules powered by 3.3 V rails. IC Role / Device Role / Timing Role: Precision voltage follower driving 10 kΩ thermistor divider into 12-bit SAR ADC reference buffer. Use Value: 1 µV/°C offset drift minimizes temperature measurement error; 75 dB CMRR rejects common-mode noise from shared power domains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar general-purpose, low-power op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TSV851ILT | Lower input offset (1.6 mV typ), higher GBP (1.5 MHz), but 150 µA ICC - 25% higher quiescent current. | Better DC accuracy for precision sensor bridges; less suitable for ultra-low-power multi-day battery life. | Select when offset voltage dominates error budget over current consumption. |
| LMV321IDBVR | Wider supply range (2.7–5.5 V), identical 120 µA ICC and 1 MHz GBP, but only rated to +85 °C. | Valid for commercial-grade portable electronics; not qualified for automotive or industrial ambient extremes. | Select for cost-sensitive consumer devices where extended temperature is unnecessary. |
Compared with TSV851ILT and LMV321IDBVR, the LMX321ILT uniquely balances extended temperature operation, rail-to-rail output, and sub-130 µA current draw - making it optimal for battery-powered industrial and medical edge nodes requiring robustness without sacrificing efficiency.
Availability
LMX321ILT is available at Aetrix Electronics and suitable for portable medical instrumentation, battery-powered active filters, and smart smoke detector signal chains requiring stable component supply across long production lifecycles.
Supply support for LMX321ILT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.
The LMX3xx series belongs to ST's general-purpose precision op-amp product line, engineered specifically for low-voltage, rail-to-rail performance in space- and power-constrained embedded systems.
FAQ
What is the maximum capacitive load the LMX321ILT can drive without oscillation?
The LMX321ILT is unity-gain stable with capacitive loads up to 200 pF, as verified in Figure 10 and Figure 11 of the datasheet. Driving >200 pF requires isolation resistor (e.g., 10–50 Ω) between output and load capacitance to maintain ≥60° phase margin across temperature.
Does the LMX321ILT support true single-supply operation with input signals at ground potential?
Yes - its input common-mode range extends to VCC− − 0.2 V, allowing direct connection of IN+ or IN− to system ground when VCC− is grounded. This enables true single-supply operation in sensor interfaces like thermistor dividers or photodiode transimpedance stages.
How does the LMX321ILT's rail-to-rail output behave at 2.7 V supply?
At 2.7 V supply and 10 kΩ load to VCC/2, output swing reaches within 100 mV of VCC+ and 180 mV of VCC− (VOL = 180 mV, VOH = VCC − 100 mV). This yields >2.3 V peak-to-peak linear range - sufficient for 12-bit ADCs with 2.5 V reference.
Is the LMX321ILT pin-compatible with other SOT23-5 op-amps like the LMV321?
No - LMX321ILT uses standard SOT23-5 pinout (OUT, IN−, IN+, VCC−, VCC+), while LMV321IDBVR uses OUT, IN−, IN+, VCC+, GND - swapping VCC− and VCC+ positions. Direct replacement requires PCB redesign or adapter routing.
LMX321ILT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.7V/µs
- Gain Bandwidth Product:
- 1.3 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 27 nA
- Voltage - Input Offset:
- 4 mV
- Current - Supply:
- 130µA
- Current - Output / Channel:
- 70 mA
- Voltage - Supply Span (Min):
- 2.3 V
- Voltage - Supply Span (Max):
- 5.5 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LMX321ILT FAQ
1.How can I place an order for LMX321ILT through Aetrix?
Please submit a Request for Quotation (RFQ) for LMX321ILT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LMX321ILT reliable?
The price and inventory of LMX321ILT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMX321ILT is usually 5 days.
3.What payment methods are accepted for LMX321ILT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMX321ILT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMX321ILT?
LMX321ILT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMX321ILT order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LMX321ILT?
For technical support, including LMX321ILT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMX321ILT requirements.
6.How does Aetrix verify that LMX321ILT is sourced from the original manufacturer or authorized distributors?
All LMX321ILT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMX321ILT meets industry standards.
7.What is the process for return or replacement of LMX321ILT?
All LMX321ILT units undergo pre-shipment inspection (PSI). If there is an issue with LMX321ILT, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LMX321ILT part is unused and in its original packaging.
Return procedure for LMX321ILT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LMX321ILT Tags
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