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Texas Instruments LM385M3X-1.2
- Part No.:
- LM385M3X-1.2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM385M3X-1.2.pdf
- Description:
- IC VREF SHNT -2.43%/+2.02% SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:3,444
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Product details
Overview
LM385M3X-1.2 from Texas Instruments is a micropower 2-terminal band-gap voltage reference diode delivering a precise 1.235 V output with ±1% initial tolerance, 1 Ω dynamic impedance, and 30 ppm/°C temperature coefficient over 0°C to 70°C. It operates from 10 μA to 20 mA reverse current and enables ultra-low-power analog circuitry such as battery-powered thermometers and portable meters.
For engineers reviewing the LM385M3X-1.2 datasheet, LM385M3X-1.2 pinout, LM385M3X-1.2 application, or LM385M3X-1.2 equivalent, this page provides verified specifications, SOT-23 package details, real-world use cases in precision current sources and cold-junction compensation, and validated alternative parts for design continuity.
Technical Context
The LM385M3X-1.2 uses a band-gap reference architecture with on-chip trimming to achieve tight voltage tolerance without external components. Its 2-terminal configuration simplifies integration into bias networks and current-source topologies where minimal quiescent current is critical.
Designed for operation across 0°C to 70°C, it features low noise (60 μVrms, 10 Hz–10 kHz), excellent long-term stability (20 ppm/1000 hr), and robust capacitive loading immunity-enabling direct connection to ADC reference inputs or op-amp feedback nodes without stability concerns.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.235 V nominal; stable output used as precision bias point for analog signal chains and sensor excitation. |
| Initial Tolerance | ±1% at 25°C; eliminates need for post-assembly calibration in cost-sensitive portable instrumentation. |
| Operating Current | 10 μA to 20 mA reverse current range; supports micropower designs (e.g., 1.5 V battery operation) and higher-current regulator references. |
| Dynamic Impedance | 1 Ω at 100 μA; ensures minimal voltage shift under load transients, critical for high-resolution ADC reference accuracy. |
| Temp. Coefficient | 30 ppm/°C (X-suffix); guarantees ≤0.9 mV drift over full 0°C–70°C range, suitable for industrial-grade thermometer front-ends. |
| Long-Term Stability | 20 ppm/1000 hr; maintains calibration integrity in field-deployed devices without periodic recalibration. |
Pinout & Package
SOT-23 (DBZ) 3-pin plastic package, 1.12 mm max height, RoHS-compliant, tape-and-reel packaging (3000 pcs/reel). Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Die Attach Pad (DAP), electrically connected to Pin 2 per TI mechanical drawing DBZ0003A.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connected to system ground or low-impedance return path; defines reference node polarity in 2-terminal configuration. |
| Pin 2 | Cathode | Output terminal delivering regulated 1.235 V; must be decoupled with ≥10 nF capacitor for optimal noise and transient performance. |
| Pin 3 | Die Attach Pad (DAP) | Internally bonded to cathode; recommended to connect to Pin 2 or PCB ground plane to improve thermal dissipation and reduce thermal drift. |
Key Features
| Feature | Design Value |
|---|---|
| Micropower Operation | Functional down to 10 μA reverse current-enables 9 V battery life >10 years in standby metering applications. |
| Capacitive Loading Immunity | Stable with ≥10 μF output capacitance-eliminates need for isolation resistors in noisy supply environments. |
| Low Wideband Noise | 60 μVrms (10 Hz–10 kHz)-preserves SNR in 16-bit+ data acquisition systems without additional filtering. |
| Hermetic Alternative Available | TO-92 (LP) and TO (NDU) packages exist for LM385-1.2-N variants-supports military/aerospace requirements where plastic SOT-23 is insufficient. |
| Trimmed Voltage Accuracy | On-die laser trimming achieves ±1% initial tolerance-reduces BOM count by removing external calibration potentiometers. |
Applications
| Portable Thermometer | Precision Current Source |
|---|---|
Use Scenario: Centigrade thermometer measuring 0°C–100°C using thermistor or RTD with 1.5 V coin-cell supply. IC Role / Device Role / Timing Role: 2-terminal voltage reference establishing 1.235 V bias for ratiometric sensing and ADC reference. Use Value: Enables sub-0.1°C resolution with <50 μA total circuit current, extending battery life beyond shelf life. |
Use Scenario: Programmable 1 μA–1 mA current source for sensor excitation or DAC output buffering. IC Role / Device Role / Timing Role: Stable voltage reference setting current through precision resistor (e.g., 1.235 kΩ for 1 mA). Use Value: Delivers ±0.5% current accuracy over temperature without active regulation or trimming. |
| Micropower Cold-Junction Compensator | Low-Voltage ADC Reference |
Use Scenario: Thermocouple interface compensating for cold-junction temperature in handheld test equipment. IC Role / Device Role / Timing Role: Reference generating Kelvin-proportional voltage (1.8 μV/K) via resistor network. Use Value: Achieves ±1°C compensation accuracy from 0°F–50°F with <100 μA supply current. |
Use Scenario: 12-bit SAR ADC reference in space-constrained IoT sensor node powered by single Li-ion cell. IC Role / Device Role / Timing Role: Low-noise, low-drift reference input replacing larger 2.5 V ICs to save board area and power. Use Value: Maintains ENOB >11.5 bits over 0°C–70°C with no external decoupling beyond 10 nF ceramic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385M3-1.2/NOPB | Same SOT-23 package, identical electrical specs, but rated for same 0°C–70°C range and ±1% tolerance; differs only in reel quantity (1000 vs. 3000 pcs). | No functional difference; suitable for lower-volume prototyping or when smaller reels align with production planning. | Select LM385M3-1.2/NOPB if reel size or inventory turnover favors 1000-unit batches. |
| LM385BXZ-1.2/NOPB | TO-92 (LP) package, same 0°C–70°C rating and ±1% tolerance, but higher thermal resistance (440°C/W vs. 283°C/W) and manual assembly compatibility. | Better suited for through-hole prototyping, repair, or legacy board upgrades where SMT rework is impractical. | Choose LM385BXZ-1.2/NOPB when hand-soldering, thermal derating margin >100°C/W is acceptable, or TO-92 footprint exists. |
Compared with LM385M3-1.2/NOPB, LM385M3X-1.2 offers identical performance in a larger reel optimized for high-volume SMT lines; versus LM385BXZ-1.2/NOPB, it trades manual assembly convenience for superior thermal performance and automated placement efficiency.
Availability
LM385M3X-1.2 is available at Aetrix Electronics and suitable for portable instrumentation, precision current sources, cold-junction compensation circuits, and low-voltage ADC reference designs requiring stable component supply and long-lifecycle support.
Supply support for LM385M3X-1.2 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision reference design and high-reliability manufacturing.
The LM385 series was developed to deliver micropower, high-accuracy voltage references for battery-operated and space-constrained applications-emphasizing low drift, wide operating current range, and ease of use in 2-terminal configurations.
FAQ
What is the operating temperature range of the LM385M3X-1.2?
The LM385M3X-1.2 is specified for operation from 0°C to +70°C. This commercial-grade range matches its intended use in consumer and industrial portable electronics-not aerospace or extended-temperature automotive applications. The LM185-1.2-N and LM285-1.2-N variants cover wider ranges, but LM385M3X-1.2 strictly adheres to 0°C–70°C per TI's SNVS742E datasheet and PACKAGE OPTION ADDENDUM.
Does the LM385M3X-1.2 require an external capacitor for stability?
No, the LM385M3X-1.2 does not require an external capacitor for basic stability-it is explicitly designed to be tolerant of capacitive loading up to ≥10 μF. However, a 10 nF ceramic capacitor placed directly at the cathode (Pin 2) is recommended to suppress wideband noise and improve transient response in precision ADC or op-amp reference applications.
What is the function of Pin 3 on the LM385M3X-1.2 SOT-23 package?
Pin 3 is the Die Attach Pad (DAP), internally connected to the cathode (Pin 2). Per TI mechanical drawing DBZ0003A, it should be connected to Pin 2 or to the PCB ground plane to enhance thermal conduction and reduce temperature-induced voltage drift-especially critical in high-accuracy, low-drift applications like thermometer front-ends.
Can the LM385M3X-1.2 be used as a 1.2 V reference?
No-the LM385M3X-1.2 is a 1.235 V nominal reference, not 1.2 V. Its guaranteed output is 1.223 V (min) to 1.247 V (max) at 25°C with ±1% tolerance. Using it as a "1.2 V" reference introduces systematic error exceeding ±1.2%; for true 1.2 V operation, consider purpose-built 1.2 V references like TLV431 or MAX6012.
Is the LM385M3X-1.2 RoHS compliant and lead-free?
Yes, the LM385M3X-1.2/NOPB variant is RoHS compliant and lead-free, with "Green (RoHS & no Sb/Br)" eco plan and "SN" (matte tin) lead finish per TI's PACKAGE OPTION ADDENDUM. The "NOPB" suffix explicitly denotes lead-free packaging, and JEDEC MSL Level-1 rating confirms suitability for standard Pb-free reflow processes.
LM385M3X-1.2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 1.235V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- -2.43%, +2.02%
- Temperature Coefficient:
- 150ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 60µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 10 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
LM385M3X-1.2 FAQ
1.How can I place an order for LM385M3X-1.2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385M3X-1.2 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 LM385M3X-1.2 reliable?
The price and inventory of LM385M3X-1.2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385M3X-1.2 is usually 5 days.
3.What payment methods are accepted for LM385M3X-1.2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385M3X-1.2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385M3X-1.2?
LM385M3X-1.2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385M3X-1.2 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 LM385M3X-1.2?
For technical support, including LM385M3X-1.2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385M3X-1.2 requirements.
6.How does Aetrix verify that LM385M3X-1.2 is sourced from the original manufacturer or authorized distributors?
All LM385M3X-1.2 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 LM385M3X-1.2 meets industry standards.
7.What is the process for return or replacement of LM385M3X-1.2?
All LM385M3X-1.2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385M3X-1.2, 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 LM385M3X-1.2 part is unused and in its original packaging.
Return procedure for LM385M3X-1.2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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