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Texas Instruments LM385PWE4-2-5
- Part No.:
- LM385PWE4-2-5
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM385PWE4-2-5.pdf
- Description:
- IC VREF SHUNT 3% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,739
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Product details
Overview
LM385PWE4-2-5 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 capacitive-load tolerance are critical.
For engineers reviewing the LM385PWE4-2-5 datasheet, LM385PWE4-2-5 pinout, LM385PWE4-2-5 application, or LM385PWE4-2-5 equivalent, this page provides verified electrical specifications, TSSOP-8 package terminal mapping, real-world use cases in thermocouple compensation and portable metering, and validated alternative parts for design continuity.
Technical Context
The LM385PWE4-2-5 implements a floating shunt topology using an internal band-gap reference and high-gain amplifier to regulate voltage between cathode and anode. Its frequency-compensated loop ensures stability with any capacitive load, eliminating need for external compensation.
It operates exclusively in shunt mode: cathode accepts current input (20 μA–20 mA), anode connects to system ground, and output voltage appears across the device. No adjustment or external feedback is supported - it is a fixed 2.5 V reference with no programmability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V nominal, 2.425 V to 2.575 V (±1.5% initial tolerance at 25°C) |
| Operating Current Range | 20 μA to 20 mA cathode current - enables ultra-low-power operation down to micropower systems |
| Reference Impedance | ≤1.5 Ω over full temperature range - ensures minimal voltage shift under dynamic load changes |
| Tempco | ±20 ppm/°C average - supports stable performance across 0°C to 70°C industrial range |
| Long-Term Drift | ±20 ppm/khr at 100 μA - guarantees predictable aging behavior in battery-powered deployments |
| Noise (10 Hz–10 kHz) | 120 µV broadband - suitable for precision analog signal conditioning without added filtering |
| Min Cathode Current | 8 μA to 20 μA (full temp range) - defines lowest usable bias for regulation startup and hold |
Pinout & Package
TSSOP-8 package (3.00 mm × 4.40 mm body, 0.65 mm pitch), 1.2 mm max height, RoHS-compliant, moisture sensitivity level 1 (260°C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 2) | Shunt Current/Voltage Input | Current sink node - must be driven with ≥8 μA (min) to establish 2.5 V regulation; voltage referenced to ANODE |
| ANODE (Pin 5) | Common Pin | Ground reference terminal - connects directly to system ground; all voltage specs referenced to this node |
| NC (Pins 1, 3, 4, 6, 7, 8) | No Internal Connection | Unused terminals - must remain unconnected; no internal circuitry or parasitic coupling |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive-Load Tolerance | Fully compensated internal loop - stable with unlimited capacitance on cathode, simplifying layout and eliminating external compensation components |
| Floating Shunt Architecture | Enables both high-side and low-side reference configurations - e.g., positive or negative regulation, current-sense biasing |
| Micropower Operation | 20 μA minimum operating current - extends battery life in portable meters and IoT sensors to near shelf-life duration |
| Low Dynamic Impedance | ≤1.5 Ω over 0°C–70°C - minimizes output voltage variation during transient current steps in ADC reference or DAC bias applications |
| Band-Gap Core Stability | Low-noise (120 µV), long-term drift ≤±20 ppm/khr - ensures metrology-grade repeatability in panel meters and calibration tools |
Applications
| Portable Test Instrumentation | Battery-Operated Sensor Nodes |
|---|---|
Use Scenario: Handheld multimeter requiring stable 2.5 V reference for 16-bit ADC conversion across varying battery voltage (3.0–4.2 V Li-ion). IC Role / Device Role / Timing Role: Two-terminal shunt reference providing regulated 2.5 V reference rail independent of supply sag. Use Value: Enables consistent measurement accuracy over full battery discharge cycle without active regulation or trimming. |
Use Scenario: Wireless temperature sensor node powered by coin cell, transmitting data every 60 s. IC Role / Device Role / Timing Role: Micropower voltage reference for RTD or thermistor bridge excitation and ADC reference. Use Value: Draws only 20 μA continuously - contributes <0.5% of total system quiescent current, preserving multi-year battery life. |
| Thermocouple Cold-Junction Compensation | 4–20 mA Current-Loop Transmitters |
Use Scenario: Industrial transmitter measuring Type K thermocouple output, requiring accurate 0°C reference for cold-junction compensation. IC Role / Device Role / Timing Role: Precision 2.5 V reference feeding op-amp circuit that generates PT1000 excitation and offset correction. Use Value: ±20 ppm/°C tempco ensures <±0.1°C error contribution over 0–70°C ambient range. |
Use Scenario: Loop-powered 4–20 mA transmitter where reference stability directly impacts span accuracy and zero point. IC Role / Device Role / Timing Role: Shunt reference establishing precise 2.5 V for DAC output scaling and current sense resistor biasing. Use Value: ≤1.5 Ω impedance prevents gain error drift under varying loop compliance voltage (12–36 V). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385BPWR-2-5 | Same TSSOP-8 package, identical electrical specs, but rated for LM385B-2.5 grade (±0.5% initial tolerance option available) | Supports higher-precision designs requiring tighter initial accuracy; same thermal and noise performance | Select when ±0.5% initial tolerance is required; otherwise LM385PWE4-2-5 meets standard 1.5% spec at lower cost |
| TLVH431ACDBVR | Adjustable shunt reference (2.5 V setpoint via resistors), 0.5% initial tolerance, 0.5 Ω typical impedance, SOT-23-5 | Requires two external resistors for 2.5 V setting; smaller footprint but adds component count and layout sensitivity | Choose for space-constrained designs where adjustable topology is acceptable and resistor matching can be controlled |
Compared with LM385BPWR-2-5, the LM385PWE4-2-5 offers identical pinout and baseline performance at standard tolerance; compared with TLVH431ACDBVR, it eliminates external resistor dependency and layout-induced errors while maintaining TSSOP-8 compatibility - ideal for drop-in replacement in existing 2.5 V shunt reference layouts.
Availability
LM385PWE4-2-5 is available at Aetrix Electronics and suitable for portable test instrumentation, battery-operated sensor nodes, and 4–20 mA current-loop transmitters requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LM385PWE4-2-5 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, designing and manufacturing analog and embedded processing chips for industrial, automotive, and consumer applications.
The LM385 series was developed specifically for micropower, two-terminal shunt voltage reference applications in portable and battery-critical systems - prioritizing low operating current, capacitive-load immunity, and long-term stability over programmability or wide temp range.
FAQ
What is the operating temperature range for the LM385PWE4-2-5?
The LM385PWE4-2-5 is specified for operation from 0°C to 70°C ambient temperature. This industrial-grade range aligns with the LM385-2.5 family designation and is confirmed in Section 6.3 (Recommended Operating Conditions) of the SLVS023L datasheet. Operation outside this range may result in degraded voltage accuracy or increased tempco beyond ±20 ppm/°C.
Does the LM385PWE4-2-5 require external capacitors for stability?
No, the LM385PWE4-2-5 does not require external capacitors for stability. Its internally frequency-compensated loop is designed to remain stable with any capacitive load on the cathode pin - including direct connection to large bulk capacitors or ADC reference inputs - eliminating risk of oscillation and simplifying PCB layout.
What is the minimum cathode current needed for regulation in the LM385PWE4-2-5?
The LM385PWE4-2-5 requires a minimum cathode current of 8 μA to 20 μA across its full operating temperature range (0°C to 70°C), as specified in the Electrical Characteristics table. At 25°C, regulation begins reliably at 20 μA; at extremes of the range, up to 20 μA may be needed to maintain 2.5 V output within tolerance.
Can the LM385PWE4-2-5 be used in negative voltage reference configurations?
Yes, the LM385PWE4-2-5 supports negative reference configurations due to its floating shunt architecture. By connecting the ANODE to a negative rail (e.g., –2.5 V) and sourcing current into the CATHODE from ground, it establishes a stable +2.5 V reference relative to the negative rail - enabling bipolar supply systems and level-shifting applications.
Is the LM385PWE4-2-5 pin-compatible with other LM385 variants in TSSOP-8?
Yes, the LM385PWE4-2-5 shares identical TSSOP-8 pinout and footprint with LM385PWR-2-5 and LM385BPWR-2-5. All three use Pins 2 (CATHODE) and 5 (ANODE) for functional connections, with Pins 1, 3, 4, 6, 7, and 8 as NC - enabling direct PCB-level substitution where electrical specs meet design requirements.
LM385PWE4-2-5 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
LM385PWE4-2-5 FAQ
1.How can I place an order for LM385PWE4-2-5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385PWE4-2-5 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 LM385PWE4-2-5 reliable?
The price and inventory of LM385PWE4-2-5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM385PWE4-2-5 is usually 5 days.
3.What payment methods are accepted for LM385PWE4-2-5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385PWE4-2-5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385PWE4-2-5?
LM385PWE4-2-5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385PWE4-2-5 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 LM385PWE4-2-5?
For technical support, including LM385PWE4-2-5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385PWE4-2-5 requirements.
6.How does Aetrix verify that LM385PWE4-2-5 is sourced from the original manufacturer or authorized distributors?
All LM385PWE4-2-5 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 LM385PWE4-2-5 meets industry standards.
7.What is the process for return or replacement of LM385PWE4-2-5?
All LM385PWE4-2-5 units undergo pre-shipment inspection (PSI). If there is an issue with LM385PWE4-2-5, 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 LM385PWE4-2-5 part is unused and in its original packaging.
Return procedure for LM385PWE4-2-5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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