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Texas Instruments LM385DR-2-5
- Part No.:
- LM385DR-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385DR-2-5.pdf
- Description:
- IC VREF SHUNT 3% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,408
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Product details
Overview
LM385DR-2-5 from Texas Instruments is a micropower, two-terminal, band-gap shunt voltage reference delivering a precise 2.5 V output with ±3% initial tolerance, 1.5 Ω max reference impedance over full temperature range, and operation from 20 μA to 20 mA cathode current - used in portable test instruments and battery-operated analog signal conditioning circuits.
For engineers reviewing the LM385DR-2-5 datasheet, LM385DR-2-5 pinout, LM385DR-2-5 application, or LM385DR-2-5 equivalent, key selection criteria include cathode current compliance, temperature coefficient (±20 ppm/°C), long-term drift (±20 ppm/khr), low-noise performance (120 µV broadband), and SOIC-8 package compatibility with standard PCB assembly processes.
Technical Context
The LM385DR-2-5 implements a floating shunt topology with internal band-gap core and high-gain amplifier driving a shunt pass element, enabling stable 2.5 V regulation across capacitive loads without external compensation. Its design supports both positive and negative regulation configurations via anode/cathode polarity flexibility.
Regulation requires minimum cathode current (IZ(MIN) = 8–20 µA) to power the internal reference divider and amplifier. Dynamic impedance remains ≤1.5 Ω from 0°C to 70°C, and broadband noise is specified at 120 µV (10 Hz–10 kHz, IZ = 100 µA), confirming suitability for precision analog front-ends.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, 2.425–2.575 V min/max at 25°C - defines accuracy boundary for ADC reference, sensor biasing, and comparator thresholds. |
| Initial Tolerance | ±3% - sets baseline error budget before trimming or calibration in production systems. |
| Temp Coefficient | ±20 ppm/°C - ensures ≤0.5 mV drift over 0–70°C ambient, critical for metering and instrumentation stability. |
| Cathode Current Range | 20 μA to 20 mA - enables ultra-low-power operation (e.g., 10-year battery life) while supporting higher-current analog stages. |
| Reference Impedance | ≤1.5 Ω over full temperature range - minimizes load-induced voltage shift in varying current-sink conditions. |
| Long-Term Drift | ±20 ppm/khr - guarantees <0.2% voltage change over 10,000 hours, essential for unattended field equipment. |
| Broadband Noise | 120 µV (10 Hz–10 kHz) - limits noise contribution in high-resolution data acquisition paths. |
Pinout & Package
LM385DR-2-5 is housed in an 8-pin SOIC (D) package (4.90 mm × 3.90 mm body size, 1.75 mm max height), with pins 1–3 and 5–7 internally unconnected (NC). Only pins 4 (ANODE) and 8 (CATHODE) are functional terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ANODE (Pin 4) | Common reference node | Typically connected to system ground or negative rail; serves as return path for cathode current and reference potential anchor. |
| CATHODE (Pin 8) | Shunt current/voltage input | Current must be sourced into this terminal to establish 2.5 V across ANODE–CATHODE; determines regulation point and load interface. |
| Pins 1, 2, 3, 5, 6, 7 | No internal connection | Electrically isolated; no routing or soldering required - simplifies layout and avoids parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Floating shunt architecture | Enables use in both high-side and low-side reference configurations without level-shifting circuitry. |
| Capacitive load tolerance | Stable operation with any value of bypass capacitor on cathode - eliminates need for external compensation networks. |
| Micropower operation | Functional down to 20 μA cathode current - extends battery life in portable meters and IoT edge sensors. |
| Low dynamic impedance | ≤1.5 Ω over 0–70°C - maintains voltage accuracy despite varying load currents in current-loop transmitters. |
| Band-gap core with trimming | Ensures tight initial tolerance and low long-term drift - reduces need for factory recalibration in panel meters. |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeters and calibrators requiring stable, low-drift reference for ADC and DAC linearity verification. IC Role / Device Role / Timing Role: Shunt voltage reference establishing 2.5 V基准 for successive-approximation ADCs and precision op-amp biasing. Use Value: ±3% initial tolerance and ±20 ppm/°C TC enable sub-0.1% measurement accuracy over operating temperature range. |
Use Scenario: Remote environmental sensors powered by coin cells or primary batteries with multi-year operational life targets. IC Role / Device Role / Timing Role: Micropower voltage reference for analog front-end signal conditioning and microcontroller ADC reference. Use Value: 20 μA minimum cathode current allows >10-year shelf-life-equivalent runtime when paired with low-quiescent LDOs. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter modules where reference stability directly impacts loop accuracy and zero/span calibration. IC Role / Device Role / Timing Role: Precision shunt reference setting excitation voltage for RTD bridges and current-sense amplifier gain. Use Value: ≤1.5 Ω dynamic impedance prevents load-dependent voltage sag during loop current transients. |
Use Scenario: Industrial digital panel meters needing repeatable, low-drift reference for LED/LCD display drivers and analog-to-digital conversion. IC Role / Device Role / Timing Role: Primary voltage reference for dual-slope or sigma-delta ADCs in front-panel measurement displays. Use Value: ±20 ppm/khr long-term drift ensures calibration validity over 2+ years without field adjustment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385LP-2-5 | TO-92 package (3-pin), same electrical specs, 0–70°C temp range, 1000-unit bulk packaging | Preferred for through-hole prototyping, low-volume hand-soldered assemblies, or space-constrained legacy designs | Select when board real estate permits larger footprint and manual assembly is required. |
| LM385BPWR-2-5 | TSSOP-8 package (3.00 mm × 4.40 mm), identical electrical specs, RoHS-compliant NIPDAU finish, Level-1 moisture rating | Suitable for high-density SMT layouts requiring smaller footprint than SOIC-8 and enhanced thermal performance | Choose for automated assembly lines needing finer-pitch packaging and improved thermal dissipation. |
Compared with LM385DR-2-5, LM385LP-2-5 offers mechanical compatibility with breadboards and legacy through-hole tooling, while LM385BPWR-2-5 provides 35% smaller footprint and tighter thermal resistance (RθJA = 168.3°C/W vs. 112°C/W), making it preferable for compact, thermally constrained designs.
Availability
LM385DR-2-5 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply and long-lifecycle support.
Supply support for LM385DR-2-5 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 company specializing in analog and embedded processing technologies, with over 50 years of leadership in precision analog ICs and power management solutions.
The LM385 series belongs to TI's micropower voltage reference product line, designed specifically for battery-powered instrumentation, portable meters, and low-current analog signal chains demanding high accuracy and minimal power draw.
FAQ
What is the operating temperature range for LM385DR-2-5?
The LM385DR-2-5 is rated for operation from 0°C to 70°C ambient temperature. This range is confirmed in the Recommended Operating Conditions table of the official datasheet (SLVS023L, Rev. L), and applies specifically to the LM385-2.5 family variant packaged in SOIC-8. Exceeding this range may result in degraded voltage accuracy or increased drift beyond the ±20 ppm/°C specification.
Does LM385DR-2-5 require external capacitors for stability?
No, LM385DR-2-5 does not require external capacitors for stability. Its internal frequency compensation ensures stable operation across all capacitive loads, including direct connection of 0.1 µF ceramic bypass capacitors on the cathode node - a feature explicitly validated in the Functional Description and Layout Guidelines sections of the datasheet.
What is the minimum cathode current needed for regulation in LM385DR-2-5?
The minimum cathode current (IZ(MIN)) for proper regulation of LM385DR-2-5 is 8 µA to 20 µA over the full temperature range (0°C to 70°C), as specified in the Electrical Characteristics table. At 25°C, typical regulation initiates reliably at 20 µA, but the device remains functional down to 8 µA under worst-case conditions.
Can LM385DR-2-5 be used in series with other references or regulators?
LM385DR-2-5 is a two-terminal shunt reference and is not designed for series connection with other voltage sources. Connecting it in series risks reverse-biasing the device or exceeding absolute maximum ratings. It must be used in parallel with the load, sinking current through its cathode to maintain 2.5 V across anode and cathode - per the Simplified Schematic and Functional Block Diagram in the datasheet.
Is LM385DR-2-5 pin-compatible with LM385B-2.5 variants?
LM385DR-2-5 shares the same SOIC-8 (D) package pinout as LM385BD-2-5 and LM385BDE4-2-5, with identical ANODE (Pin 4) and CATHODE (Pin 8) assignments and NC pins. However, LM385DR-2-5 has ±3% initial tolerance versus ±1.5% for LM385B-2.5, so electrical substitution requires validation of system-level accuracy requirements.
LM385DR-2-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±3%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 120µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 20 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM385DR-2-5 FAQ
1.How can I place an order for LM385DR-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385DR-2-5 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 LM385DR-2-5 reliable?
The price and inventory of LM385DR-2-5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385DR-2-5 is usually 5 days.
3.What payment methods are accepted for LM385DR-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385DR-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385DR-2-5?
LM385DR-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385DR-2-5 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 LM385DR-2-5?
For technical support, including LM385DR-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385DR-2-5 requirements.
6.How does Aetrix verify that LM385DR-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385DR-2-5 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 LM385DR-2-5 meets industry standards.
7.What is the process for return or replacement of LM385DR-2-5?
All LM385DR-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385DR-2-5, 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 LM385DR-2-5 part is unused and in its original packaging.
Return procedure for LM385DR-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385DR-2-5 Tags
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TL431AIDBZR
Texas Instruments
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AZ431LBNTR-G1
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LM4040D20IDBZR
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LM4041DIM3-ADJ/NOPB
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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