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Texas Instruments LM285LP-1-2
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- Part No.:
- LM285LP-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
LM285LP-1-2.pdf
- Description:
- IC VREF SHUNT 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,901
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Product details
Overview
LM285LP-1-2 from Texas Instruments is a micropower, two-terminal, band-gap voltage reference in TO-92 package, delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient, 10 μA to 20 mA operating current range, and 1.5 Ω max reference impedance over full temperature range. It serves as a precision shunt reference in portable battery-powered analog systems requiring long shelf-life-compatible power efficiency.
For engineers reviewing the LM285LP-1-2 datasheet, LM285LP-1-2 pinout, LM285LP-1-2 application, or LM285LP-1-2 equivalent, key selection criteria include its -40°C to +85°C industrial temperature rating, 1% initial voltage tolerance, low 60 µV broadband noise (10 Hz–10 kHz), and compatibility with capacitive loads up to 10 µF without instability.
Technical Context
The LM285LP-1-2 operates as a floating shunt reference: cathode sinks current to maintain 1.235 V between anode and cathode, requiring ≥10 μA minimum cathode current for regulation. Its on-chip band-gap core provides long-term stability (±20 ppm/khr) and low dynamic impedance (1.5 Ω max) across temperature and load.
Internal frequency compensation ensures stable operation with arbitrary capacitive loading-no external compensation required. The device functions identically in both positive- and negative-regulation topologies due to its two-terminal, ground-referenced or floating configuration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.235 V nominal at 25°C; tight 1% initial tolerance enables direct use in 12-bit ADC references without trimming. |
| Tempco | ±20 ppm/°C average over -40°C to +85°C; supports stable performance in unregulated ambient environments. |
| Operating Current | 10 μA to 20 mA; ultra-low 10 μA minimum allows operation from high-impedance sources like thermocouple circuits. |
| Reference Impedance | 1.5 Ω max over full temperature range; ensures <1 mV error under 1 mA load transients. |
| Noise Voltage | 60 µV RMS (10 Hz–10 kHz); low enough for precision instrumentation amplifier biasing. |
| Long-Term Drift | ±20 ppm/khr at 25°C; supports >10-year calibration intervals in panel meter designs. |
Pinout & Package
LM285LP-1-2 uses a 3-pin TO-92 (LP) package with straight or formed leads, 4.30 mm × 4.30 mm body size, and 5.34 mm max height. Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = No internal connection (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Reference output node | Connected to system ground or low-impedance return path; defines 0 V reference point for cathode voltage. |
| Cathode (Pin 2) | Current-sink terminal | Sinks all operating current; voltage at this pin is 1.235 V above anode potential when regulated. |
| NC (Pin 3) | Unused lead | No internal die connection; electrically isolated; may be left unconnected or tied to ground for mechanical stability. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive Load Tolerance | Stable with ≥10 µF ceramic bypass capacitance-eliminates need for series resistance or external compensation. |
| Low-Power Operation | 10 μA minimum current enables use in energy-harvesting sensor nodes where supply current is limited to microamps. |
| Shunt Topology Flexibility | Two-terminal design supports both high-side (cathode to VIN) and low-side (anode to VIN) configurations in current-loop transmitters. |
| ESD Robustness | ±2000 V HBM rating-survives standard handling without special ESD precautions beyond basic grounding. |
Applications
| Portable Meter References | Portable Test Instruments |
|---|---|
Use Scenario: Handheld digital multimeters measuring DC voltage with 3½-digit resolution and battery life >500 hours. IC Role / Device Role / Timing Role: Shunt voltage reference establishing 1.235 V基准 for ADC reference input and analog front-end scaling. Use Value: 1% initial tolerance and ±20 ppm/°C tempco ensure <0.05% full-scale error across 0–40°C operating range without calibration. | Use Scenario: Battery-powered oscilloscope probe compensators and signal generator level-setting circuits. IC Role / Device Role / Timing Role: Precision bias source for op-amp input stages and DAC reference buffers. Use Value: 60 µV broadband noise prevents added jitter in 100-kHz bandwidth test signals; 1.5 Ω impedance avoids gain error in unity-gain follower configurations. |
| Battery-Operated Systems | Current-Loop Instrumentation |
Use Scenario: Wireless sensor nodes powered by coin-cell batteries (CR2032) with 10-year shelf-life requirement. IC Role / Device Role / Timing Role: Reference for low-power microcontroller ADC and voltage supervisor thresholds. Use Value: 10 μA minimum operating current extends usable battery life by >30% versus 50 μA alternatives; ±20 ppm/khr drift maintains accuracy over full product lifetime. | Use Scenario: 4–20 mA transmitter modules converting sensor outputs (e.g., pressure, temperature) into standardized current signals. IC Role / Device Role / Timing Role: Stable 1.235 V reference for current-sense resistor scaling and loop driver biasing. Use Value: Floating shunt topology allows direct integration into high-side current-sense paths; 20 mA max current supports full 20 mA loop compliance with margin. |
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-1-2 | 0°C to +70°C operating range; same 1.235 V, 1.5 Ω impedance, but wider tempco (±50 ppm/°C vs ±20 ppm/°C). | Restricted to commercial-temperature applications; unsuitable for automotive or industrial field deployments. | Select LM385LP-1-2 only if ambient temperature stays within 0–70°C and cost is prioritized over long-term stability. |
| TLVH431ACLPR | Adjustable 1.24 V reference (2.5 V max); 3-pin adjustable topology; 80 µA typical quiescent current; ±1% initial tolerance. | Requires external resistors for 1.235 V setting; higher current draw reduces battery life in micropower systems. | Choose TLVH431ACLPR only when programmability or tighter 1.24 V matching is required, accepting 8× higher minimum current. |
Compared with LM385LP-1-2 and TLVH431ACLPR, LM285LP-1-2 uniquely combines industrial temperature range (-40°C to +85°C), micropower operation (10 μA min), and ±20 ppm/°C tempco-making it optimal for battery-critical, wide-temperature embedded instrumentation where calibration stability and shelf-life alignment are mandatory.
Availability
LM285LP-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply with guaranteed long-term availability and RoHS-compliant Pb-free (SN) lead finish.
Supply support for LM285LP-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 company headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 50 years of precision reference design heritage.
The LMx85 family-including LM285LP-1-2-is engineered for micropower, two-terminal shunt voltage reference applications in portable, battery-constrained, and industrial-grade analog systems demanding low drift, low noise, and capacitive-load immunity.
FAQ
What is the minimum cathode current required for regulation in LM285LP-1-2?
The LM285LP-1-2 requires a minimum cathode current of 10 μA to achieve proper regulation and maintain its 1.235 V reference voltage. This value is specified in the Electrical Characteristics table under IZ(min) for the LM285-1.2 variant. Operating below 10 μA risks loss of regulation and increased output voltage error, especially at temperature extremes.
Does LM285LP-1-2 require an external capacitor for stability?
No, LM285LP-1-2 does not require an external capacitor for stability. Its internal frequency compensation ensures unconditional stability with capacitive loads up to at least 10 µF, as confirmed in the datasheet's Layout Guidelines and Functional Description sections. A 0.1 µF ceramic bypass capacitor on the cathode is recommended for noise reduction but is not needed for loop stability.
Can LM285LP-1-2 be used in a negative-reference configuration?
Yes, LM285LP-1-2 can be used in negative-reference configurations because it is a floating two-terminal shunt device. By connecting the anode to a positive rail and the cathode to a node held at a negative potential (e.g., via op-amp feedback), it establishes a stable -1.235 V reference relative to system ground-enabling bipolar analog circuitry without additional components.
What is the maximum reverse current rating for LM285LP-1-2?
The absolute maximum reverse current (IR) for LM285LP-1-2 is 30 mA, as specified in Section 7.1 Absolute Maximum Ratings. Exceeding this value-even briefly-may cause permanent damage. For reliable operation, cathode current should remain within the recommended 10 μA to 20 mA range, with derating advised above 70°C ambient.
Is LM285LP-1-2 pin-compatible with LM385LP-1-2?
LM285LP-1-2 and LM385LP-1-2 share identical TO-92 (LP) package pinout (Anode–Cathode–NC), but they are not functionally interchangeable without design review. LM285LP-1-2 is rated for -40°C to +85°C with ±20 ppm/°C tempco, while LM385LP-1-2 is rated 0°C to +70°C with ±50 ppm/°C tempco-making LM285LP-1-2 the only choice for extended-temperature applications.
LM285LP-1-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
LM285LP-1-2 FAQ
1.How can I place an order for LM285LP-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM285LP-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 LM285LP-1-2 reliable?
The price and inventory of LM285LP-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 LM285LP-1-2 is usually 5 days.
3.What payment methods are accepted for LM285LP-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM285LP-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM285LP-1-2?
LM285LP-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM285LP-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 LM285LP-1-2?
For technical support, including LM285LP-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM285LP-1-2 requirements.
6.How does Aetrix verify that LM285LP-1-2 is sourced from the original manufacturer or authorized distributors?
All LM285LP-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 LM285LP-1-2 meets industry standards.
7.What is the process for return or replacement of LM285LP-1-2?
All LM285LP-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM285LP-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 LM285LP-1-2 part is unused and in its original packaging.
Return procedure for LM285LP-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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