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Texas Instruments LM285DR-1-2
- Part No.:
- LM285DR-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM285DR-1-2.pdf
- Description:
- IC VREF SHUNT 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,229
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Product details
Overview
LM285DR-1-2 from Texas Instruments is a micropower, two-terminal, band-gap voltage reference IC operating over 10 μA to 20 mA reference current, delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient and 1.5 Ω max reference impedance across −40°C to +85°C. It serves as a precision shunt reference in portable metering, battery-operated analog front-ends, and low-power current-loop transmitters.
For engineers reviewing the LM285DR-1-2 datasheet, LM285DR-1-2 pinout, LM285DR-1-2 application, or LM285DR-1-2 equivalent, this page delivers verified electrical specs, SOIC-8 package mapping, functional role in shunt regulation, thermal performance data, and validated alternative options for industrial and portable design contexts.
Technical Context
The LM285DR-1-2 implements a floating shunt topology using an internal band-gap core with on-chip trimming for initial accuracy. Its high-gain amplifier and shunt pass element maintain stable cathode-to-anode voltage without external feedback components.
Internal frequency compensation ensures stability under capacitive loading up to 1 μF, and its low-noise (60 μV RMS, 10 Hz–10 kHz) and long-term drift (±20 ppm/khr) support precision analog signal conditioning in unregulated supply environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Reference Voltage | 1.235 V at 25°C - defines system-level ADC/DAC reference point with tight tolerance |
| Initial Voltage Tolerance | ±2% - enables direct use in cost-sensitive portable instrumentation without calibration |
| Operating Current Range | 10 μA to 20 mA - supports ultra-low-power sleep modes and full-scale analog sensing |
| Tempco (αVZ) | ±20 ppm/°C - ensures <±3 mV drift over −40°C to +85°C for field-deployed equipment |
| Reference Impedance | 1.5 Ω max over full temp range - minimizes load-induced error in ratiometric sensor interfaces |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz) - preserves SNR in 16-bit+ data acquisition systems |
| Long-Term Stability | ±20 ppm/khr - guarantees <±0.5 mV drift over 5-year product lifetime |
Pinout & Package
LM285DR-1-2 is housed in an 8-pin SOIC (Package Drawing D), body size 4.90 mm × 3.91 mm, with 1.75 mm max height and RoHS-compliant NiPdAu lead finish. The device uses a two-terminal shunt configuration; pins 3, 5, 6, and 7 are internally unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Shunt current return path | Connected to system ground or negative rail; completes reference current loop |
| Cathode (Pin 2) | Reference voltage node | Provides regulated 1.235 V output; requires external current source (e.g., resistor or LM334) |
| NC (Pins 3, 5, 6, 7) | No internal connection | Must remain unconnected; no routing or grounding required |
Key Features
| Feature | Design Value |
|---|---|
| Floating shunt architecture | Enables both positive and negative regulation topologies without dedicated ground pin |
| Capacitive load immunity | Stable with ≥1 μF bypass capacitor on cathode-eliminates need for external compensation |
| Low dynamic impedance | 1.5 Ω max across full temperature and current range-reduces load regulation error to <30 μV/mA |
| Micropower operation | 10 μA minimum operating current-extends battery life in portable meters beyond shelf life |
| On-chip trimmed accuracy | ±2% initial tolerance without external calibration-reduces BOM count and test time |
Applications
| Portable Meter References | Portable Test Instruments |
|---|---|
Use Scenario: Handheld multimeters and clamp meters requiring stable, low-drift reference for ADC conversion under varying battery voltage. IC Role / Device Role / Timing Role: Shunt voltage reference establishing precise 1.235 V reference for 16-bit sigma-delta ADCs. Use Value: Enables ±0.1% measurement accuracy over full temperature range and multi-year field deployment without recalibration. | Use Scenario: Battery-powered oscilloscope probes and signal generators needing low-noise, stable reference for DAC output stages. IC Role / Device Role / Timing Role: Low-noise band-gap reference supplying clean 1.235 V to precision DAC buffers. Use Value: Maintains <60 μV RMS noise floor and <±3 mV total drift, preserving signal fidelity in sub-mV resolution applications. |
| Battery-Operated Systems | Current-Loop Instrumentation |
Use Scenario: Remote environmental sensors powered by coin cells or Li-SOCl₂ batteries with 10+ year operational life requirements. IC Role / Device Role / Timing Role: Micropower shunt reference powering ultra-low-current analog front-end circuits. Use Value: Draws only 10 μA minimum-enables continuous operation for >10 years on a single CR2032 cell. | Use Scenario: 4–20 mA transmitter modules in industrial process control where reference stability directly impacts loop accuracy. IC Role / Device Role / Timing Role: Precision shunt reference setting current-sense threshold in HART-compatible transmitters. Use Value: ±20 ppm/°C tempco and ±20 ppm/khr long-term drift ensure <0.1% full-scale error over 15-year plant lifecycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385DR-1-2 | Wider operating temperature range (0°C to +70°C vs. −40°C to +85°C); same 1.235 V nominal, ±2% tolerance, and 1.5 Ω impedance | Not rated for extended industrial or automotive ambient conditions; suitable for commercial-grade portable devices | Select when ambient operating temperature stays within 0–70°C and cost sensitivity outweighs extended temp coverage |
| LM385BDR-1-2 | Tighter initial tolerance (±1% vs. ±2%); identical tempco, noise, and impedance specs; same SOIC-8 package | Preferred for high-accuracy sensor signal chains where factory calibration overhead must be minimized | Choose when system-level accuracy budget demands <±10 mV reference error without post-production trimming |
Compared with LM285DR-1-2, LM385DR-1-2 trades extended temperature capability for commercial-grade cost optimization, while LM385BDR-1-2 delivers higher initial accuracy at identical thermal and noise performance-enabling drop-in replacement where tighter tolerance justifies marginal cost increase.
Availability
LM285DR-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply across long-lifecycle industrial deployments.
Supply support for LM285DR-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 over 90 years of innovation in precision analog ICs.
The LMx85 family was designed specifically for micropower, two-terminal shunt voltage reference applications in portable, battery-constrained, and industrial measurement systems-emphasizing low drift, capacitive-load stability, and long-term reliability.
FAQ
What is the operating temperature range of the LM285DR-1-2?
The LM285DR-1-2 is specified for operation from −40°C to +85°C. This extended industrial temperature range is confirmed in the Electrical Characteristics table (Section 7.3) and Package Option Addendum, making it suitable for outdoor, automotive, and factory-floor applications where ambient extremes are expected. The LM285DR-1-2 maintains all key parameters-including reference voltage, tempco, and impedance-within datasheet limits across this full range.
How does the LM285DR-1-2 differ from the LM385DR-1-2?
The LM285DR-1-2 differs from the LM385DR-1-2 primarily in operating temperature range: LM285DR-1-2 supports −40°C to +85°C, while LM385DR-1-2 is rated for 0°C to +70°C. Both share identical reference voltage (1.235 V), tolerance (±2%), impedance (1.5 Ω max), and noise (60 μV RMS). The LM285DR-1-2 is the preferred choice for extended-temperature applications; LM385DR-1-2 offers cost optimization for commercial environments.
Can the LM285DR-1-2 be used in series with other components to generate higher reference voltages?
No-the LM285DR-1-2 is a fixed 1.235 V shunt reference and cannot be configured for higher output voltages. It lacks adjustment terminals or feedback pins. To achieve higher references, external circuitry such as op-amp-based gain stages or cascaded references (e.g., LM285DR-1-2 feeding an LM336-2.5) must be used. The LM285DR-1-2 itself operates only as a two-terminal, non-adjustable shunt device.
What is the minimum cathode current required for regulation in the LM285DR-1-2?
The LM285DR-1-2 requires a minimum cathode current (IZ(min)) of 10 μA to maintain regulation, as specified in Section 7.5 of the datasheet. Below this threshold, reference voltage deviates significantly from 1.235 V. Designers must ensure the external current source-whether resistor-based or active-delivers ≥10 μA across all operating conditions, including lowest supply voltage and highest temperature.
Is the LM285DR-1-2 compatible with ceramic bypass capacitors?
Yes-the LM285DR-1-2 is explicitly designed for capacitive load immunity and remains stable with ceramic bypass capacitors up to at least 1 μF on the cathode pin, per Layout Guidelines (Section 11.1). A 0.1 μF low-ESR ceramic capacitor is recommended for optimal noise suppression and transient response. No series resistance or external compensation is needed, distinguishing it from older shunt references that require careful capacitor selection.
LM285DR-1-2 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):
- 1.235V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 60µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 10 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM285DR-1-2 FAQ
1.How can I place an order for LM285DR-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM285DR-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 LM285DR-1-2 reliable?
The price and inventory of LM285DR-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 LM285DR-1-2 is usually 5 days.
3.What payment methods are accepted for LM285DR-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM285DR-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM285DR-1-2?
LM285DR-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM285DR-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 LM285DR-1-2?
For technical support, including LM285DR-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM285DR-1-2 requirements.
6.How does Aetrix verify that LM285DR-1-2 is sourced from the original manufacturer or authorized distributors?
All LM285DR-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 LM285DR-1-2 meets industry standards.
7.What is the process for return or replacement of LM285DR-1-2?
All LM285DR-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM285DR-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 LM285DR-1-2 part is unused and in its original packaging.
Return procedure for LM285DR-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM285DR-1-2 Tags
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TL431AIDBZR
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