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Texas Instruments LM385D-2-5
- Part No.:
- LM385D-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385D-2-5.pdf
- Description:
- IC VREF SHUNT 3% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,085
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Product details
Overview
LM385D-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. It serves as a stable reference in portable test instruments, battery-operated systems, and current-loop instrumentation where low power and capacitive-load tolerance are critical.
For engineers reviewing the LM385D-2-5 datasheet, LM385D-2-5 pinout, LM385D-2-5 application, or LM385D-2-5 equivalent, this page provides verified technical context, real-world use cases, validated alternatives, and supply-chain support for industrial and embedded design cycles requiring long-term stability and micropower operation.
Technical Context
The LM385D-2-5 implements a floating shunt topology using an internal band-gap reference and high-gain amplifier to regulate voltage between cathode and anode. Its design enables stable operation with any capacitive load without external compensation.
It operates exclusively in shunt mode: current must be sourced into the cathode (pin 8), while the anode (pin 4) connects to system ground. Regulation requires ≥20 μA minimum cathode current across 0°C to 70°C ambient temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, ±3% initial tolerance - ensures predictable biasing in precision analog circuits without trimming. |
| Cathode Current Range | 20 μA to 20 mA - supports ultra-low-power sensor interfaces and high-current reference buffering in same device. |
| Reference Impedance | ≤1.5 Ω over full temperature range - minimizes output voltage shift under dynamic load changes. |
| Tempco | ±20 ppm/°C average - maintains <±1.5 mV drift across 0°C–70°C for stable ADC/DAC reference applications. |
| Noise (10 Hz–10 kHz) | 120 µV broadband - suitable for high-resolution measurement front-ends without added filtering. |
| Long-Term Drift | ±20 ppm/khr - enables multi-year calibration stability in portable meters and panel instruments. |
Pinout & Package
LM385D-2-5 uses an 8-pin SOIC (D) package measuring 4.90 mm × 3.90 mm, with 1.75 mm max height and JEDEC MS-012 AA compliance. Pins 1, 2, 3, 5, 6, and 7 are no-connect (NC); only pins 4 (ANODE) and 8 (CATHODE) are functional.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ANODE (Pin 4) | Common reference node | Typically connected to system ground; forms return path for cathode current and defines reference potential. |
| CATHODE (Pin 8) | Shunt current/voltage input | Current must be sourced here to establish 2.5 V across ANODE–CATHODE; voltage regulation occurs only when IZ ≥ 20 μA. |
| Pins 1, 2, 3, 5, 6, 7 | No internal connection | Electrically isolated; no routing or grounding required - simplifies PCB layout and avoids parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive-load immunity | Stable with unlimited capacitance on cathode - eliminates need for series resistance or external compensation in battery-powered designs. |
| Micropower operation | 20 μA minimum operating current - extends shelf-life-aligned battery life in portable meters and remote sensors. |
| Floating shunt architecture | Enables both high-side and low-side reference configurations - supports negative rail sensing and current-loop transmitters. |
| Low dynamic impedance | ≤1.5 Ω over 0°C–70°C - maintains regulation accuracy despite varying load currents in analog signal chains. |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeters and calibrators requiring stable, low-drift reference during intermittent use over years. IC Role / Device Role / Timing Role: Shunt voltage reference establishing 2.5 V基准 for ADC conversion and display scaling. Use Value: ±20 ppm/°C tempco and ±20 ppm/khr long-term drift ensure calibration validity between annual service intervals. |
Use Scenario: Wireless sensor nodes powered by coin cells or primary batteries with multi-year deployment goals. IC Role / Device Role / Timing Role: Micropower reference for analog front-end conditioning prior to RF transmission. Use Value: 20 μA minimum cathode current allows direct biasing from high-value resistors, minimizing quiescent drain. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter modules converting sensor outputs in industrial process control cabinets. IC Role / Device Role / Timing Role: Precision shunt reference setting loop current threshold and span calibration points. Use Value: ≤1.5 Ω reference impedance prevents gain error under varying loop supply voltages and cable lengths. |
Use Scenario: DIN-rail mounted digital panel meters used in HVAC, power monitoring, and energy management. IC Role / Device Role / Timing Role: Stable 2.5 V reference for microcontroller ADC and display driver voltage scaling. Use Value: Tolerance of capacitive loading allows direct integration with LCD bias networks without instability risk. |
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 | Same electrical specs; TO-92 (3-pin) package with ANODE/CATHODE/NC pinout; no NC pins on SOIC footprint. | Preferred for through-hole prototyping or space-constrained boards where SOIC thermal mass is unnecessary. | Select when manual assembly, lower cost per unit, or simplified thermal management is prioritized over surface-mount density. |
| LM385PWR-2-5 | Same electrical specs; TSSOP-8 package (3.00 mm × 4.40 mm); identical pin numbering but smaller footprint and finer pitch. | Suitable for high-density PCBs where SOIC real estate is constrained but 0.65 mm pitch assembly capability exists. | Select when board area is premium and reflow process supports fine-pitch TSSOP; verify solder mask definition per IPC-7351. |
Compared with LM385D-2-5, LM385LP-2-5 offers mechanical simplicity and lower cost in through-hole builds, while LM385PWR-2-5 delivers 35% smaller footprint at the expense of tighter assembly tolerances - all three share identical regulation performance and temperature behavior.
Availability
LM385D-2-5 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply across extended production lifecycles.
Supply support for LM385D-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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision voltage references and low-power analog ICs.
The LM385 family was designed specifically for micropower, two-terminal shunt reference applications in portable, battery-sensitive, and industrial measurement systems - emphasizing long-term stability, wide current range, and capacitive-load robustness.
FAQ
What is the operating temperature range for LM385D-2-5?
The LM385D-2-5 is specified for operation from 0°C to 70°C ambient temperature. This range applies to all electrical characteristics including reference voltage tolerance, temperature coefficient, and reference impedance. Operation outside this range may result in uncharacterized performance or reliability degradation.
How much current must be supplied to the cathode of LM385D-2-5 to ensure regulation?
The LM385D-2-5 requires a minimum cathode current (IZ(MIN)) of 20 μA to achieve proper regulation at 25°C, and up to 20 mA maximum. The device remains functional across this full 20 μA–20 mA range, with reference impedance and noise performance optimized within it.
Can LM385D-2-5 be used in negative-voltage reference applications?
Yes - the LM385D-2-5's floating shunt architecture allows it to function as a negative reference. Connect the cathode to the negative rail and the anode to the circuit's most-negative point; regulation occurs across the terminals regardless of absolute potential, provided cathode current is properly sourced.
Does LM385D-2-5 require an external capacitor for stability?
No - the LM385D-2-5 features internal frequency compensation and is stable with unlimited capacitive loading on the cathode. A 0.1-μF ceramic bypass capacitor is optional for noise reduction but not required for loop stability in any configuration.
What is the reference impedance of LM385D-2-5 at 25°C and full temperature range?
At 25°C, the LM385D-2-5 exhibits a typical reference impedance of 0.4–1.0 Ω (measured at 100 μA), with a maximum of 1.5 Ω across the full 0°C–70°C operating range. This low, tightly bounded impedance ensures minimal voltage shift under dynamic load conditions.
LM385D-2-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- 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
LM385D-2-5 FAQ
1.How can I place an order for LM385D-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385D-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 LM385D-2-5 reliable?
The price and inventory of LM385D-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 LM385D-2-5 is usually 5 days.
3.What payment methods are accepted for LM385D-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385D-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385D-2-5?
LM385D-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385D-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 LM385D-2-5?
For technical support, including LM385D-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385D-2-5 requirements.
6.How does Aetrix verify that LM385D-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385D-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 LM385D-2-5 meets industry standards.
7.What is the process for return or replacement of LM385D-2-5?
All LM385D-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385D-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 LM385D-2-5 part is unused and in its original packaging.
Return procedure for LM385D-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385D-2-5 Tags
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