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Texas Instruments LM385LPR-2-5
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- Part No.:
- LM385LPR-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
LM385LPR-2-5.pdf
- Description:
- IC VREF SHUNT 3% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:800
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Product details
Overview
LM385LPR-2-5 from Texas Instruments is a micropower, two-terminal, band-gap shunt voltage reference delivering a precise 2.5 V output with ±1.5% initial tolerance (2.425 V to 2.575 V), 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 high stability are critical.
For engineers reviewing the LM385LPR-2-5 datasheet, LM385LPR-2-5 pinout, LM385LPR-2-5 application, or LM385LPR-2-5 equivalent, this page provides verified technical context, real-world design meaning for key specs, TO-92 package details, functional alternatives, and supply support tailored for embedded analog design and low-power precision reference selection.
Technical Context
The LM385LPR-2-5 implements a floating shunt architecture using an internal band-gap reference and high-gain amplifier to regulate voltage between cathode and anode. Its design enables stable operation with capacitive loads up to 10 nF without external compensation.
It operates exclusively in shunt mode: current sourced into the cathode establishes regulation, while the anode connects to system ground. The device exhibits ±20 ppm/°C average temperature coefficient across 0°C to 70°C and maintains long-term stability of ±20 ppm/khr at 100 μA cathode current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, 2.425–2.575 V (±1.5% initial tolerance) - sets absolute accuracy baseline for ADCs, DACs, and comparators. |
| Cathode Current Range | 20 μA to 20 mA - enables ultra-low-power operation (e.g., 20 μA draws only 50 μW at 2.5 V) and supports wide supply headroom designs. |
| Reference Impedance | ≤1.5 Ω over full temperature range - ensures minimal voltage shift under dynamic load changes in precision sensor interfaces. |
| Tempco | ±20 ppm/°C (0°C to 70°C) - limits drift to ±0.35 mV over full operating range, critical for metering and calibration equipment. |
| Long-Term Stability | ±20 ppm/khr at 100 μA - translates to <±0.2 mV drift per 1000 hours, supporting >5-year field reliability in unattended systems. |
| Broadband Noise | 120 μVRMS (10 Hz–10 kHz) - low enough for 12-bit+ resolution in portable data loggers without additional filtering. |
| Min Cathode Current | 8–20 μA - defines lowest usable bias point; below this, regulation fails and output collapses. |
Pinout & Package
LM385LPR-2-5 uses the TO-92 (LP) package: 4.30 mm × 4.30 mm body, 3-pin through-hole format with standard lead spacing. Pin 1 = ANODE (ground connection), Pin 2 = CATHODE (shunt current input), Pin 3 = NC (no internal connection).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ANODE (Pin 1) | Common reference node | Typically connected to system ground; forms return path for cathode current and defines 0 V reference plane. |
| CATHODE (Pin 2) | Shunt current/voltage input | Current must be sourced *into* this pin to establish 2.5 V across anode–cathode; voltage is regulated here relative to anode. |
| NC (Pin 3) | No internal connection | Unused terminal; must remain unconnected or tied to ground only if required by mechanical mounting-no electrical function. |
Key Features
| Feature | Design Value |
|---|---|
| Floating shunt topology | Enables both positive- and negative-regulation configurations (e.g., high-side or low-side reference) without polarity constraints. |
| Capacitive load tolerance | Stable with ≥10 nF on cathode-eliminates need for series resistance or external compensation in most PCB layouts. |
| Micropower operation | 20 μA minimum cathode current allows battery life extension to shelf-life duration in coin-cell-powered devices. |
| On-chip trimmed voltage | Eliminates external calibration; ±1.5% initial tolerance achieved via laser trimming during wafer sort. |
| Low dynamic impedance | ≤1.5 Ω over 0°C–70°C ensures <30 mV output shift across full 20 μA–20 mA current range-critical for current-sense references. |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeters and calibrators requiring stable, low-drift reference for ADC front-end scaling. IC Role / Device Role / Timing Role: Shunt voltage reference providing 2.5 V基准 for successive-approximation ADC conversion and auto-zero circuitry. Use Value: ±1.5% initial tolerance and ±20 ppm/°C tempco ensure <0.1% total error over operating temperature, meeting Class II meter specifications. |
Use Scenario: Remote environmental sensors powered by AA/AAA batteries with multi-year deployment requirements. IC Role / Device Role / Timing Role: Precision reference for low-power op-amps and sigma-delta ADCs in analog signal conditioning chains. Use Value: 20 μA minimum operating current extends battery life beyond 5 years at 1-sample-per-minute duty cycle. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter modules converting sensor outputs for industrial control systems. IC Role / Device Role / Timing Role: Stable 2.5 V reference for current-sense resistor measurement and DAC output scaling. Use Value: ≤1.5 Ω reference impedance prevents gain error drift under varying loop current conditions (4–20 mA), maintaining <0.05% linearity. |
Use Scenario: Front-panel digital meters in HVAC controllers and power supplies needing consistent display scaling. IC Role / Device Role / Timing Role: Reference source for LED driver ICs and microcontroller ADCs measuring supply rails or load currents. Use Value: Low broadband noise (120 μV RMS) avoids flicker or digit instability in 3½-digit displays under EMI-prone environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385BLPR-2-5 | Tighter ±0.8% initial tolerance (2.462–2.538 V); same TO-92 package and 0°C–70°C range. | Better suited for 14-bit+ data acquisition where initial accuracy dominates budget. | Select when higher initial accuracy justifies cost premium; identical pinout and layout. |
| TLVH431ACDBVR | Adjustable (2.5 V min) shunt regulator; 0.5% initial tolerance; SOT-23-3 package; 40 μA min cathode current. | Requires external resistors for 2.5 V setting; higher quiescent current limits ultra-low-power use. | Choose for flexibility in future voltage scaling or space-constrained PCBs-requires redesign of bias network. |
Compared with LM385BLPR-2-5, the LM385LPR-2-5 trades 0.7% initial accuracy for lower cost and broader legacy compatibility; versus TLVH431ACDBVR, it delivers guaranteed 2.5 V without external components but lacks adjustability and uses larger TO-92 footprint.
Availability
LM385LPR-2-5 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply with long-lifecycle assurance and RoHS-compliant packaging.
Supply support for LM385LPR-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 founded in 1930, specializing in analog, embedded processing, and power management ICs with leadership in precision analog and industrial-grade components.
The LM385 series belongs to TI's micropower voltage reference product line, designed specifically for battery-powered, portable, and space-constrained applications demanding low quiescent current, high accuracy, and robust thermal performance.
FAQ
What is the operating temperature range for the LM385LPR-2-5?
The LM385LPR-2-5 is specified for operation from 0°C to 70°C ambient temperature. This range aligns with commercial-grade applications such as portable test equipment and panel meters. It does not support extended industrial (–40°C to 85°C) operation-use LM285LPR-2-5 for that range. The LM385LPR-2-5 datasheet confirms this limit in Recommended Operating Conditions and Thermal Information sections.
Can the LM385LPR-2-5 be used in a negative-reference configuration?
Yes, the LM385LPR-2-5 supports negative-reference use due to its floating shunt architecture. Connect the cathode to the negative rail and the anode to the circuit's most-negative potential (e.g., –2.5 V node), allowing it to regulate –2.5 V relative to system ground. This is explicitly enabled by the device's two-terminal design and confirmed in the Functional Block Diagram and Detailed Description sections of the datasheet.
What is the minimum cathode current required for regulation in the LM385LPR-2-5?
The LM385LPR-2-5 requires a minimum cathode current (IZ(MIN)) of 8–20 μA across its operating temperature range (0°C to 70°C) to maintain regulation. Below this threshold, the reference voltage collapses. This value is measured and guaranteed per Electrical Characteristics table and directly impacts battery life in ultra-low-power designs using the LM385LPR-2-5.
Is a bypass capacitor required on the cathode pin of the LM385LPR-2-5?
A bypass capacitor is optional but recommended: a 0.1-μF low-ESR ceramic capacitor on the cathode pin improves high-frequency noise rejection and transient response. The LM385LPR-2-5 remains stable without it-even with ≥10 nF-due to internal frequency compensation. Layout guidelines in Section 10.1 confirm this flexibility, making it suitable for space-constrained or cost-sensitive LM385LPR-2-5 implementations.
How does the LM385LPR-2-5 differ from the LM385B-2.5 variant?
The LM385LPR-2-5 corresponds to the standard LM385-2.5 grade (±1.5% initial tolerance), while LM385B-2.5 denotes the tighter ±0.8% grade. Both share identical TO-92 packaging, 0°C–70°C range, and electrical behavior-but LM385LPR-2-5 uses the base LM385 family marking and is optimized for cost-sensitive, high-volume portable instrumentation where ±1.5% meets specification.
LM385LPR-2-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
LM385LPR-2-5 FAQ
1.How can I place an order for LM385LPR-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385LPR-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 LM385LPR-2-5 reliable?
The price and inventory of LM385LPR-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 LM385LPR-2-5 is usually 5 days.
3.What payment methods are accepted for LM385LPR-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385LPR-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385LPR-2-5?
LM385LPR-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385LPR-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 LM385LPR-2-5?
For technical support, including LM385LPR-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385LPR-2-5 requirements.
6.How does Aetrix verify that LM385LPR-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385LPR-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 LM385LPR-2-5 meets industry standards.
7.What is the process for return or replacement of LM385LPR-2-5?
All LM385LPR-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385LPR-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 LM385LPR-2-5 part is unused and in its original packaging.
Return procedure for LM385LPR-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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