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Texas Instruments LM385PW-2-5
- Part No.:
- LM385PW-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM385PW-2-5.pdf
- Description:
- IC VREF SHUNT 3% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,246
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Product details
Overview
LM385PW-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 - used in portable test instruments and battery-operated analog signal conditioning circuits.
For engineers reviewing the LM385PW-2-5 datasheet, LM385PW-2-5 pinout, LM385PW-2-5 application, or LM385PW-2-5 equivalent, key selection criteria include its TSSOP-8 package, 0°C to 70°C operating range, low 120 µV broadband noise (10 Hz–10 kHz), and compatibility with capacitive loads up to 10 µF without instability.
Technical Context
The LM385PW-2-5 implements a floating shunt architecture with internal band-gap core and high-gain amplifier driving a shunt pass element, enabling stable 2.5 V regulation across wide current and temperature variations. Its frequency-compensated loop ensures stability with any capacitive load, eliminating need for external compensation.
It operates as a two-terminal device where cathode serves as shunt current/voltage input and anode connects to ground; no adjustment or external feedback is possible. Regulation requires minimum cathode current of 8–20 µA depending on temperature, with dynamic impedance as low as 0.4 Ω at 100 µA (25°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.425 V to 2.575 V at 25°C - defines accuracy window for precision analog circuit biasing and ADC/DAC reference scaling. |
| Initial Tolerance | ±3% - sets baseline error budget before trimming or calibration in portable meter designs. |
| Operating Current Range | 20 μA to 20 mA - enables ultra-low-power operation in battery systems while supporting higher-current sensing applications. |
| Reference Impedance | ≤1.5 Ω over full temperature range - ensures minimal voltage shift under varying load currents in current-loop transmitters. |
| Tempco (αVZ) | ±20 ppm/°C - guarantees <±1.5 mV drift over 0°C–70°C, critical for thermocouple cold-junction compensation. |
| Broadband Noise | 120 µV RMS (10 Hz–10 kHz) - supports low-noise sensor front-ends without requiring additional filtering stages. |
| Long-Term Stability | ±20 ppm/khr - provides predictable aging behavior for multi-year deployments in panel meters and industrial loggers. |
Pinout & Package
TSSOP-8 package (3.00 mm × 4.40 mm body size, 1.2 mm max height), lead finish NiPdAu, moisture sensitivity level 1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 5, 6, 7 | No Internal Connection | Unused pins; must be left floating or tied to ground per layout guidelines - no electrical function or thermal benefit. |
| 4 | Anode | Common terminal, typically connected to system ground - establishes reference return path and defines cathode-to-ground voltage. |
| 8 | Cathode | Shunt current/voltage input - receives regulated current from external resistor or current source to develop stable 2.5 V across device. |
Key Features
| Feature | Design Value |
|---|---|
| Floating shunt topology | Enables use in both positive and negative regulation configurations without polarity constraints. |
| Capacitive-load tolerance | Stable with ≥10 µF bypass capacitance - eliminates need for series resistance or isolation in noisy environments. |
| Low power consumption | 20 μA minimum operating current - extends battery life in portable meters to near shelf-life duration. |
| Band-gap core with on-chip trimming | Delivers tight initial tolerance and low long-term drift - reduces need for field calibration in production test equipment. |
| Low dynamic impedance | 0.4 Ω typical at 100 µA - minimizes output voltage variation during transient load changes in current-sensing circuits. |
Applications
| Portable Test Instrumentation | Battery-Operated Analog Front-Ends |
|---|---|
Use Scenario: Handheld multimeter reference rail generation with 3½-digit resolution and auto-ranging capability. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 2.5 V for ADC reference and op-amp biasing. Use Value: ±3% initial tolerance and ±20 ppm/°C tempco ensure measurement repeatability across 0°C–40°C handheld operating range. |
Use Scenario: Low-power sensor node with microcontroller, analog sensor interface, and RF transceiver. IC Role / Device Role / Timing Role: Precision voltage reference for ratiometric sensor excitation and ADC conversion. Use Value: 20 μA minimum current enables operation from coin-cell batteries for >5 years without replacement. |
| Current-Loop Transmitters (4–20 mA) | Thermocouple Cold-Junction Compensation |
Use Scenario: Industrial 4–20 mA transmitter with HART modulation, powered from loop supply. IC Role / Device Role / Timing Role: Stable 2.5 V reference for DAC output scaling and current-sense amplifier gain setting. Use Value: ≤1.5 Ω reference impedance prevents output voltage droop during 20 mA loop current transients. |
Use Scenario: Digital thermometer using K-type thermocouple with microcontroller-based linearization. IC Role / Device Role / Timing Role: Temperature-stable reference for cold-junction sensor amplifier and offset correction. Use Value: ±20 ppm/°C tempco matches thermocouple Seebeck coefficient drift, reducing cold-junction error to <0.5°C. |
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 | TO-92 package, same electrical specs, 0°C–70°C range, higher thermal resistance (157°C/W). | Suitable for through-hole prototyping or space-constrained PCBs where TSSOP reflow is impractical. | Select when manual assembly, lower cost, or legacy footprint compatibility is prioritized over board area savings. |
| REF3025AIDBZR | 2.5 V series reference, SOT-23-3, 50 ppm/°C tempco, 50 µA quiescent current, ±0.2% initial accuracy. | Requires dedicated supply rail; not shunt-configurable - limits use in current-loop or floating-bias topologies. | Choose when higher accuracy and lower tempco justify added complexity and inability to replace LM385PW-2-5 in existing shunt designs. |
Compared with LM385LP-2-5, the LM385PW-2-5 offers superior thermal performance in surface-mount layouts and smaller PCB footprint; compared with REF3025AIDBZR, it retains shunt flexibility and ultra-low current operation but trades absolute accuracy for topology versatility.
Availability
LM385PW-2-5 is available at Aetrix Electronics and suitable for portable test instrumentation, battery-operated analog front-ends, and current-loop transmitters requiring stable component supply with consistent parametric performance across production batches.
Supply support for LM385PW-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 specializing in analog and embedded processing technologies, with leadership in precision analog ICs and broad industrial portfolio coverage.
The LM385 series was designed as a family of micropower shunt references for portable, battery-sensitive applications - emphasizing low operating current, capacitive-load immunity, and long-term stability in compact packages.
FAQ
What is the operating temperature range for the LM385PW-2-5?
The LM385PW-2-5 is specified for operation from 0°C to 70°C ambient temperature. This range is confirmed in the Recommended Operating Conditions table of the official TI datasheet SLVS023L. Operation outside this range may result in degraded voltage accuracy, increased tempco, or failure to regulate. The LM385PW-2-5 does not support extended industrial or automotive temperature grades.
Can the LM385PW-2-5 be used as a series voltage reference?
No, the LM385PW-2-5 is a two-terminal shunt voltage reference and cannot function as a three-terminal series reference. It requires external current sourcing into its cathode pin and connection of its anode to ground. Attempting to wire it as a series regulator will prevent proper regulation and may damage the device. The LM385PW-2-5 must always be used in shunt configuration.
What is the minimum cathode current required for regulation in the LM385PW-2-5?
The LM385PW-2-5 requires a minimum cathode current (IZ(MIN)) of 8 µA to 20 µA depending on temperature - 8 µA minimum at 25°C, rising to 20 µA across the full 0°C–70°C range. Below this threshold, the device exits regulation and output voltage collapses. This value is explicitly defined in Section 6.5 Electrical Characteristics of the TI datasheet SLVS023L.
Does the LM385PW-2-5 require an external capacitor for stability?
No, the LM385PW-2-5 features internal frequency compensation and is stable with any capacitive load, including bypass capacitors up to 10 µF. TI's datasheet confirms that no external capacitor is required for stability. Adding a 0.1 µF ceramic capacitor at the cathode is optional and recommended only to reduce high-frequency noise in sensitive analog circuits.
How does the reference impedance of the LM385PW-2-5 affect circuit performance?
The LM385PW-2-5 has a maximum reference impedance of 1.5 Ω over its full temperature range. This low impedance means the output voltage shifts less than 30 mV when cathode current changes by 20 mA - critical for maintaining accuracy in current-loop transmitters and ratiometric sensor interfaces. Higher impedance would introduce significant load-dependent errors in precision analog designs.
LM385PW-2-5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Tray
- 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-TSSOP
LM385PW-2-5 FAQ
1.How can I place an order for LM385PW-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385PW-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 LM385PW-2-5 reliable?
The price and inventory of LM385PW-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 LM385PW-2-5 is usually 5 days.
3.What payment methods are accepted for LM385PW-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385PW-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385PW-2-5?
LM385PW-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385PW-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 LM385PW-2-5?
For technical support, including LM385PW-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385PW-2-5 requirements.
6.How does Aetrix verify that LM385PW-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385PW-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 LM385PW-2-5 meets industry standards.
7.What is the process for return or replacement of LM385PW-2-5?
All LM385PW-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385PW-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 LM385PW-2-5 part is unused and in its original packaging.
Return procedure for LM385PW-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM385PW-2-5 Tags
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