My Inquiry
My Account
Analog Devices Inc./Maxim Integrated LMX321AUK+T
- Part No.:
- LMX321AUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LMX321AUK+T.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,942
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LMX321AUK+T from Maxim Integrated is a single-channel, rail-to-rail output operational amplifier optimized for low-voltage, battery-powered systems. It operates from +2.3V to +7V, draws 105µA quiescent current per amplifier at +2.7V, delivers 1.3MHz gain-bandwidth product, and swings within 40mV of both supply rails into 2kΩ loads - enabling precision signal conditioning in portable audio and sensor front-ends.
For engineers reviewing the LMX321AUK+T datasheet, LMX321AUK+T pinout, LMX321AUK+T application, or LMX321AUK+T equivalent, this page provides verified technical context, package-specific pin mapping, real-world application constraints, and validated alternative options for low-power op amp selection in space-constrained designs.
Technical Context
The LMX321AUK+T uses bipolar process technology and features an input common-mode range extending 0.2V below VEE (ground in single-supply mode) and up to 0.8V below VCC, supporting true single-supply operation with inputs near ground. Its rail-to-rail output stage maintains linearity while driving 2kΩ loads across the full supply range.
It is unity-gain stable and supports capacitive loads up to 400pF without external compensation. Input protection includes 3.5kΩ series resistors and back-to-back diode clamps, limiting differential input voltage stress and defining bias current behavior above 1.8V differential swing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +2.3V to +7V - enables direct integration into Li-ion, coin-cell, and multi-cell battery systems without regulation. |
| Quiescent Current | 105µA per amplifier at +2.7V - extends battery life in always-on sensor nodes and wearable devices. |
| Gain-Bandwidth Product | 1.3MHz - supports audio preamplification, active filtering, and medium-speed sensor signal conditioning. |
| Input Common-Mode Range | VEE − 0.2V to VCC − 0.8V - allows input signals to go 200mV below ground in single-supply configurations. |
| Output Voltage Swing | Within 40mV of either rail into 2kΩ - maximizes dynamic range in low-voltage ADC driver and reference buffer applications. |
| Input Offset Voltage | 1–6mV (typical at +25°C) - suitable for DC-coupled amplification where sub-mV precision is not required. |
| Slew Rate | 1V/µs - adequate for <100kHz small-signal applications but limits large-signal bandwidth in fast transient response circuits. |
Pinout & Package
The LMX321AUK+T is housed in a 5-pin SOT23-5 package (package code U5-1), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad optional per manufacturer drawing.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | IN+ | Noninverting input - accepts signal source with impedance ≤100kΩ to minimize offset drift due to input bias current. |
| 2 | VEE | Negative supply terminal - tied to ground in single-supply use; must be decoupled with 0.1µF capacitor near pin. |
| 3 | IN− | Inverting input - used for feedback network connection; sensitive to PCB trace capacitance and layout parasitics. |
| 4 | OUT | Amplifier output - capable of sourcing/sinking ≥10mA short-circuit current; requires isolation resistor when driving >400pF loads. |
| 5 | VCC | Positive supply terminal - accepts +2.3V to +7V; bypassing essential for stability and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output swing | Delivers full-scale analog output into 2kΩ loads - eliminates need for level-shifting circuitry in low-voltage data acquisition. |
| No phase reversal on overdrive | Prevents catastrophic latch-up or signal inversion during input overload - critical for robust sensor interface design. |
| Unity-gain stable up to 400pF | Enables direct connection to ADC input capacitors or long traces without external compensation networks. |
| Input common-mode range below ground | Supports AC-coupled or bipolar-input signal chains without dual supplies - reduces system BOM and complexity. |
| Low input bias current (18–50nA) | Minimizes voltage error across high-impedance sources like photodiodes or piezoelectric sensors. |
Applications
| Portable Audio Preamp | Wearable Sensor Signal Chain |
|---|---|
Use Scenario: Amplifying microphone or piezoelectric sensor output in Bluetooth earbuds with 3.3V supply. IC Role / Device Role / Timing Role: Single-supply, rail-to-rail op amp configured as noninverting amplifier with gain = 100. Use Value: 105µA quiescent current extends battery runtime; 40mV rail margin preserves headroom for 1VP-P audio signals. |
Use Scenario: Conditioning ECG electrode signals in ultra-low-power medical patches operating from coin cell. IC Role / Device Role / Timing Role: DC-coupled instrumentation amplifier front-end stage with input referenced below ground. Use Value: VEE − 0.2V input range accommodates electrode offset voltages; 1.3MHz GBW supports 100Hz biopotential bandwidth. |
| Low-Voltage Reference Buffer | Active Filter in IoT Node |
Use Scenario: Buffering a 1.2V bandgap reference for ADC reference input in a wireless sensor node. IC Role / Device Role / Timing Role: Unity-gain voltage follower isolating reference from load variations. Use Value: Rail-to-rail output ensures accurate 1.2V delivery even with 1.8V supply; low ICC avoids reference loading errors. |
Use Scenario: Implementing 2nd-order low-pass filter (fc = 10kHz) before SAR ADC in smart home motion detector. IC Role / Device Role / Timing Role: Dual-stage active filter using Sallen-Key topology with LMX321AUK+T as gain block. Use Value: 1.3MHz GBW supports filter Q-factor up to 5; unity-gain stability eliminates need for gain-setting resistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar general-purpose op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMV321IDBVR | Lower 50µA IQ, 1MHz GBW, same SOT23-5 package; input range limited to VEE to VCC − 1.2V. | Better for ultra-low-power always-on monitoring; less suitable for ground-referenced inputs or higher bandwidth needs. | Choose LMV321IDBVR if supply current is primary constraint and input common-mode range above ground suffices. |
| TSV911ILT | CMOS input (0.1pA IB), 8MHz GBW, 1.15V to 5.5V supply; rail-to-rail I/O; SOT23-5 compatible. | Superior for high-impedance pH or photodiode sensors; higher speed supports faster control loops. | Choose TSV911ILT when input bias current or bandwidth exceeds LMX321AUK+T capabilities, accepting higher IQ (130µA). |
Compared with LMV321IDBVR and TSV911ILT, the LMX321AUK+T uniquely balances rail-to-rail input extension below ground, moderate bandwidth, and ultra-low power in a legacy-compatible footprint - making it optimal for cost-sensitive, space-constrained, single-supply industrial and consumer sensor interfaces.
Availability
LMX321AUK+T is available at Aetrix Electronics and suitable for portable audio preamps, wearable biosensor signal chains, low-voltage reference buffers, and active filters requiring stable component supply and long-term manufacturability.
Supply support for LMX321AUK+T 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
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The LMX321AUK+T belongs to Maxim's LMX321/LMX358/LMX324 family - engineered specifically for low-voltage, low-power, rail-to-rail performance in portable and battery-operated equipment.
FAQ
What is the maximum capacitive load the LMX321AUK+T can drive without oscillation?
The LMX321AUK+T is unity-gain stable and rated to drive capacitive loads up to 400pF directly. Beyond that, instability may occur unless an isolation resistor (RISO) is added between the output and load capacitor. Data sheet Figure 5 confirms stable operation with RISO = 10Ω–100Ω for CL > 400pF. The LMX321AUK+T's internal compensation does not support unlimited capacitive loading.
Does the LMX321AUK+T support true single-supply operation with input signals at ground potential?
Yes. The LMX321AUK+T features an input common-mode voltage range extending to VEE − 0.2V. When VEE = 0V (single-supply configuration), inputs can operate down to −0.2V, allowing signals referenced to ground - including zero-crossing or AC-coupled waveforms - to be amplified without clipping or phase reversal. This capability is confirmed in the Electrical Characteristics table under VCM limits.
What is the typical output voltage swing of the LMX321AUK+T into a 2kΩ load at +3.3V supply?
At +3.3V supply and +25°C, the LMX321AUK+T typically swings within 40mV of each rail into a 2kΩ load - i.e., from ~40mV to ~3.26V. This is derived from the "Output-Voltage Swing" specification (VOL and VCC − VOH) tested at +2.7V and +5V, interpolated per typical operating curves (toc08/toc09). Performance degrades slightly at temperature extremes but remains within 70mV at −40°C/+125°C.
Is the LMX321AUK+T pin-compatible with the LMV321 family?
Yes - the LMX321AUK+T is explicitly designed as a pin-to-pin compatible upgrade to the LMV321 family in the same SOT23-5 package. Pin functions (IN+, VEE, IN−, OUT, VCC) match identically, and electrical specifications (supply range, quiescent current, GBW, output swing) are enhanced or equivalent. No PCB redesign is needed when migrating from LMV321IDBVR or LMV321IDCKR to LMX321AUK+T.
What thermal derating applies to the LMX321AUK+T in SOT23-5 package?
The LMX321AUK+T in SOT23-5 (U5-1) has a continuous power dissipation limit of 571mW at +70°C, with derating at 7.1mW/°C above that temperature. At +85°C ambient, max power drops to ~464mW; at +100°C, to ~357mW. This assumes standard JEDEC 2-layer board layout. Thermal performance depends on copper area and airflow - no internal thermal shutdown is provided, so system-level thermal design is essential.
LMX321AUK+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 1V/µs
- Gain Bandwidth Product:
- 1.3 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 18 nA
- Voltage - Input Offset:
- 1 mV
- Current - Supply:
- 120µA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 2.3 V
- Voltage - Supply Span (Max):
- 7 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LMX321AUK+T FAQ
1.How can I place an order for LMX321AUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for LMX321AUK+T 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 LMX321AUK+T reliable?
The price and inventory of LMX321AUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMX321AUK+T is usually 5 days.
3.What payment methods are accepted for LMX321AUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMX321AUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMX321AUK+T?
LMX321AUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMX321AUK+T 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 LMX321AUK+T?
For technical support, including LMX321AUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMX321AUK+T requirements.
6.How does Aetrix verify that LMX321AUK+T is sourced from the original manufacturer or authorized distributors?
All LMX321AUK+T 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 LMX321AUK+T meets industry standards.
7.What is the process for return or replacement of LMX321AUK+T?
All LMX321AUK+T units undergo pre-shipment inspection (PSI). If there is an issue with LMX321AUK+T, 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 LMX321AUK+T part is unused and in its original packaging.
Return procedure for LMX321AUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LMX321AUK+T Tags
-
LM358DT
STMicroelectronics
-
LM358DR
Texas Instruments
-
LM2904DR
Texas Instruments
-
LM358ADR
Texas Instruments
-
LM2904DGKR
Texas Instruments
-
LM324DR
Texas Instruments
-
MCP6006T-E/OT
Microchip Technology
-
MCP6006UT-E/OT
Microchip Technology
-
LM324PWR
Texas Instruments
-
LM2902PWR
Texas Instruments
-
LM2902DR
Texas Instruments
-
LM358P
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
