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Texas Instruments LM285DR-2-5
- Part No.:
- LM285DR-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM285DR-2-5.pdf
- Description:
- IC VREF SHUNT 1.5% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,172
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Product details
Overview
LM285DR-2-5 from Texas Instruments is a micropower, two-terminal, band-gap shunt voltage reference delivering a precise 2.5 V output with ±20 ppm/°C temperature coefficient, 2.462–2.538 V initial tolerance at 25°C, and 0.2–0.6 Ω reference impedance at 100 µA. It operates over a 20 µA to 20 mA cathode current range and supports industrial temperature range (–40°C to +85°C), making it suitable for battery-powered precision analog circuits requiring long shelf-life operation.
For engineers reviewing the LM285DR-2-5 datasheet, LM285DR-2-5 pinout, LM285DR-2-5 application, or LM285DR-2-5 equivalent, key selection considerations include its low 20 µA minimum operating current, tight 1.5% initial voltage tolerance, stable performance under capacitive loading, and compatibility with portable metering, current-loop instrumentation, and thermocouple cold-junction compensation circuits.
Technical Context
The LM285DR-2-5 implements a floating shunt architecture using a band-gap reference core driving a high-gain amplifier and internal shunt pass element, enabling regulation without a ground reference. Its internal frequency compensation ensures stability across all capacitive loads up to 10 µF, eliminating need for external phase compensation.
It functions exclusively as a fixed 2.5 V shunt reference with no adjustability; regulation initiates only when cathode current exceeds 8–20 µA depending on temperature, and voltage accuracy degrades outside the 20 µA–20 mA operating range due to increased dynamic impedance and thermal drift.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.462–2.538 V at 25°C; ensures ≤±1.5% error in precision ADC/DAC biasing and sensor excitation. |
| Tempco | ±20 ppm/°C over –40°C to +85°C; enables <±0.5 mV drift across full industrial range for stable calibration references. |
| Min Operating Current | 8–20 µA; allows ultra-low-power operation in energy-harvesting or coin-cell systems where supply current is constrained. |
| Reference Impedance | 0.2–0.6 Ω at 100 µA (25°C); maintains <1 mV load-induced error even with 1 mA dynamic current draw. |
| Broadband Noise | 120 µV RMS (10 Hz–10 kHz); supports high-resolution measurement front-ends without added filtering overhead. |
| Long-Term Drift | ±20 ppm/khr; guarantees <±0.2% voltage shift over 10 years of continuous operation in field-deployed equipment. |
| Operating Current Range | 20 µA to 20 mA; accommodates both microamp-level standby modes and milliamp-level active regulation without redesign. |
Pinout & Package
LM285DR-2-5 is packaged in an 8-pin SOIC (D) package measuring 4.90 mm × 3.90 mm with maximum height of 1.75 mm, optimized for automated assembly and thermal dissipation in compact PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ANODE (Pin 4) | Common terminal | Typically connected to system ground; serves as return path for cathode current and reference potential node. |
| CATHODE (Pin 8) | Shunt current/voltage input | Current must be sourced into this pin to establish 2.5 V across ANODE–CATHODE; connects to unregulated supply via series resistor or current source. |
| Pins 1,2,3,5,6,7 | No internal connection | Electrically isolated; must remain unconnected or tied to ground per layout guidelines to avoid parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive load tolerance | Stable with ≥10 µF bypass capacitance-eliminates need for isolation resistors in noisy environments. |
| Micropower operation | 20 µA minimum current enables >10-year battery life in portable meters powered by CR2032 cells. |
| Band-gap core with trimming | On-chip laser trimming achieves 1.5% initial tolerance without external calibration components. |
| Floating shunt topology | Operates in high-side or low-side configurations-supports negative rail referencing and current-sense applications. |
| Low dynamic impedance | ≤0.6 Ω at 100 µA ensures <0.1 mV error during transient load steps in precision DAC buffers. |
Applications
| Portable Meter References | Current-Loop Instrumentation |
|---|---|
Use Scenario: Handheld multimeters and clamp meters requiring stable, low-drift reference for 16-bit ADCs and autoranging circuitry. IC Role / Device Role / Timing Role: Shunt voltage reference providing 2.5 V excitation for precision resistive divider networks and sensor signal conditioning. Use Value: Enables ±0.1% measurement accuracy over –10°C to +50°C ambient with no recalibration, leveraging ±20 ppm/°C tempco and low long-term drift. |
Use Scenario: 4–20 mA transmitter modules in industrial process control where loop power is limited and noise immunity is critical. IC Role / Device Role / Timing Role: Precision shunt reference setting current-sense threshold and DAC output scaling in HART-compatible transmitters. Use Value: Maintains loop accuracy within ±0.05% FS across temperature and supply variations due to low 0.6 Ω impedance and wide 20 µA–20 mA operating range. |
| Thermocouple Cold-Junction Compensation | Battery-Operated Systems |
Use Scenario: Digital thermometers and data loggers using Type K thermocouples requiring accurate 0°C reference at sensor junction. IC Role / Device Role / Timing Role: Fixed 2.5 V reference feeding op-amp circuitry that generates proportional cold-junction compensation voltage. Use Value: Delivers <±0.5 mV total error over –40°C to +85°C, directly translating to <±0.025°C temperature uncertainty in final reading. |
Use Scenario: Wireless sensor nodes powered by single AA/AAA cells with intermittent wake-up cycles and extended sleep periods. IC Role / Device Role / Timing Role: Low-current voltage reference for MCU ADC, LDO feedback, and analog sensor biasing during active measurement phases. Use Value: Draws only 20 µA in active mode-extends usable battery life beyond 5 years while maintaining 2.5 V reference stability within ±0.5%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385B-2.5 | Same 2.5 V nominal output and ±20 ppm/°C tempco, but rated for 0°C to +70°C only; tighter 1.5% tolerance identical to LM285DR-2-5. | Limited to commercial temperature range-unsuitable for automotive or outdoor industrial deployments requiring –40°C operation. | Select LM385B-2.5 only if ambient operating temperature stays within 0–70°C and cost sensitivity outweighs extended temperature coverage. |
| REF3025AIDBZR | Higher initial accuracy (±0.2%), lower noise (35 µV), but requires 50 µA min current and consumes 55 µA quiescent current-no micropower capability. | Not viable for sub-50 µA systems; better suited for high-accuracy lab equipment than battery-constrained field instruments. | Choose REF3025AIDBZR when absolute accuracy and low noise dominate over current budget-avoid when designing for coin-cell or energy-harvesting power sources. |
Compared with LM385B-2.5, LM285DR-2-5 extends operational reliability to –40°C, while versus REF3025AIDBZR it delivers 2.5× lower minimum current and 2.75× lower quiescent draw-making it uniquely suited for ultra-low-power, wide-temperature embedded sensing.
Availability
LM285DR-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 temperature ranges and multi-year production cycles.
Supply support for LM285DR-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 headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 50 years of leadership in precision analog ICs.
The LM285 series belongs to TI's micropower voltage reference product line, designed specifically for battery-powered instrumentation, portable measurement tools, and industrial sensors demanding ultra-low quiescent current and robust thermal stability.
FAQ
What is the operating temperature range of the LM285DR-2-5?
The LM285DR-2-5 is specified for operation from –40°C to +85°C, making it suitable for industrial and automotive-adjacent applications where extended thermal performance is required. This distinguishes it from the LM385-2.5 (0°C to +70°C) and LM385B-2.5 (0°C to +70°C), which share the same electrical specs but lack the extended low-temperature capability. The LM285DR-2-5 maintains its ±20 ppm/°C temperature coefficient and 2.462–2.538 V reference voltage across this full range.
Does the LM285DR-2-5 require an external capacitor for stability?
No, the LM285DR-2-5 features internal frequency compensation and remains stable with capacitive loads up to 10 µF on the cathode node-no external capacitor is required for basic operation. A 0.1 µF ceramic bypass capacitor is optional and recommended only in high-noise environments to suppress broadband interference; its absence does not affect regulation stability. This eliminates design risk associated with improper capacitor selection in shunt reference circuits.
What is the minimum cathode current needed for regulation in the LM285DR-2-5?
The LM285DR-2-5 requires a minimum cathode current (IZ(MIN)) of 8 µA at full temperature range (–40°C to +85°C), increasing to 20 µA at 25°C per typical characterization. Below this threshold, the device exits regulation and output voltage collapses. Designers must size the series resistor or current source to ensure IZ ≥ 20 µA at worst-case supply voltage and temperature-e.g., for a 3.3 V supply, R ≤ (3.3 V − 2.5 V)/20 µA = 40 kΩ.
Can the LM285DR-2-5 be used in high-side or floating configurations?
Yes, the LM285DR-2-5 uses a floating shunt topology: its anode and cathode terminals have no internal connection to substrate or package, allowing it to operate in high-side, low-side, or fully floating configurations. This enables use in negative-rail references, current-sense amplifiers, and isolated power supplies-unlike series references that require ground-referenced inputs. The LM285DR-2-5's pinout and internal architecture explicitly support such flexibility without external level-shifting components.
How does the LM285DR-2-5 compare to the LM385-2.5 in terms of voltage tolerance?
The LM285DR-2-5 and LM385-2.5 both offer 1.5% initial voltage tolerance (2.462–2.538 V), matching the tighter spec of the LM385B-2.5 variant. However, the LM385-2.5 standard version has looser 3% tolerance (2.425–2.575 V). Since LM285DR-2-5 is part of the "LM285" family, it inherits the improved 1.5% grade-confirmed in Electrical Characteristics tables-and maintains that tolerance across its wider –40°C to +85°C range, unlike the LM385-2.5's 0°C to +70°C limit.
LM285DR-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:
- ±1.5%
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM285DR-2-5 FAQ
1.How can I place an order for LM285DR-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM285DR-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 LM285DR-2-5 reliable?
The price and inventory of LM285DR-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 LM285DR-2-5 is usually 5 days.
3.What payment methods are accepted for LM285DR-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM285DR-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM285DR-2-5?
LM285DR-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM285DR-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 LM285DR-2-5?
For technical support, including LM285DR-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM285DR-2-5 requirements.
6.How does Aetrix verify that LM285DR-2-5 is sourced from the original manufacturer or authorized distributors?
All LM285DR-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 LM285DR-2-5 meets industry standards.
7.What is the process for return or replacement of LM285DR-2-5?
All LM285DR-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM285DR-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 LM285DR-2-5 part is unused and in its original packaging.
Return procedure for LM285DR-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM285DR-2-5 Tags
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