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Texas Instruments LM385PW-1-2
- Part No.:
- LM385PW-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM385PW-1-2.pdf
- Description:
- IC VREF SHUNT 2% 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,369
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Product details
Overview
LM385PW-1-2 from Texas Instruments is a micropower, two-terminal, band-gap voltage reference IC operating over 15 μA to 20 mA cathode current, delivering 1.235 V nominal output with ±20 ppm/°C temperature coefficient and 1.5 Ω max reference impedance across full temperature range (0°C to 70°C). It serves as a precision shunt reference in portable metering and battery-operated analog signal chains.
For engineers reviewing the LM385PW-1-2 datasheet, LM385PW-1-2 pinout, LM385PW-1-2 application, or LM385PW-1-2 equivalent, this page delivers verified specifications, TSSOP-8 package details, real-world use cases, and validated alternative options for low-power voltage reference design.
Technical Context
The LM385PW-1-2 functions as a floating shunt reference, regulating voltage between cathode and anode via internal band-gap core and high-gain amplifier. Regulation initiates only after minimum cathode current (15 μA) powers the internal circuitry, with internal frequency compensation ensuring stability under capacitive loading up to 0.1 μF.
Its two-terminal architecture enables both positive and negative regulation topologies. The device exhibits low broadband noise (60 μV RMS, 10 Hz–10 kHz) and long-term drift of ±20 ppm/khr at 100 μA, making it suitable for applications demanding stable reference voltage without external biasing circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Reference Voltage | 1.235 V at 25°C - defines precise DC offset point for ADCs, comparators, and regulator feedback loops |
| Initial Voltage Tolerance | ±2% - ensures reference accuracy without post-manufacture trimming in cost-sensitive designs |
| Operating Cathode Current | 15 μA to 20 mA - supports ultra-low-power sleep modes and high-current transient response in same device |
| Temperature Coefficient | ±20 ppm/°C - guarantees ≤2.5 mV drift over 0°C to 70°C ambient range |
| Reference Impedance | 1.5 Ω max over full temperature range - minimizes load-induced error in precision current-sense and DAC reference applications |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz) - preserves signal integrity in high-resolution data acquisition systems |
| Long-Term Stability | ±20 ppm/khr at 100 μA - enables multi-year calibration retention in portable instrumentation |
Pinout & Package
TSSOP-8 package (3.00 mm × 4.40 mm body, 1.2 mm max height), RoHS-compliant, moisture sensitivity level 1, lead finish NiPdAu.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current/voltage input | Current sink node where regulated 1.235 V appears relative to anode; requires external current source |
| Anode (Pin 8) | Common reference node | Typically connected to system ground or negative rail; establishes return path for cathode current |
| NC (Pins 2–7) | No internal connection | Unused pins; must remain unconnected to avoid parasitic coupling or thermal stress |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive load tolerance | Stable with ≥0.1 μF ceramic bypass capacitor on cathode - eliminates need for external compensation in portable designs |
| Low power operation | 15 μA minimum cathode current - extends battery life in handheld meters and IoT sensors beyond shelf life |
| Interchangeability | Pin- and function-compatible with LM285-1.2 and LM385-1.2 - enables drop-in replacement in legacy SOIC-based PCBs using adapter footprints |
| ESD robustness | ±2000 V HBM rating - withstands handling in standard assembly environments without special ESD controls |
Applications
| Portable Meter References | Portable Test Instruments |
|---|---|
Use Scenario: Digital multimeter front-end reference for 3½-digit ADC conversion. IC Role / Device Role / Timing Role: Shunt voltage reference establishing precise 1.235 V full-scale threshold for analog-to-digital conversion. Use Value: Enables ±0.5% measurement accuracy over 0°C–70°C without calibration drift compensation circuitry. | Use Scenario: Handheld oscilloscope vertical amplifier offset calibration. IC Role / Device Role / Timing Role: Stable DC bias reference for op-amp input stage nulling during auto-zero routines. Use Value: Reduces zero-drift error to <10 μV/°C, maintaining baseline stability during field use. |
| Battery-Operated Systems | Current-Loop Instrumentation |
Use Scenario: Low-power gas sensor signal conditioning in wireless node. IC Role / Device Role / Timing Role: Reference for transimpedance amplifier converting photodiode current to voltage. Use Value: Draws only 15 μA quiescent current while maintaining 0.1% gain accuracy across battery discharge curve (3.6 V → 2.8 V). | Use Scenario: 4–20 mA transmitter loop-powered sensor module. IC Role / Device Role / Timing Role: Precision shunt reference for DAC output scaling and current sense resistor biasing. Use Value: Ensures loop current accuracy remains within ±0.1% over industrial temperature range with no external trim components. |
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-1.2 (TSSOP-8) | ±1% initial tolerance vs. ±2%; identical 15 μA–20 mA operating range and 0°C–70°C temp range | Higher accuracy required in calibration-critical lab equipment where ±1% tolerance reduces system-level trimming effort | Select LM385B-1.2 when tighter initial accuracy justifies minor cost premium and board space allows same TSSOP-8 footprint |
| TLVH431AIDBVR | Adjustable 1.24 V reference (2.5 V max); 80 μA typical quiescent current; 0.5 Ω typical impedance | Used where programmable reference voltage or higher current drive (>100 mA) is needed, e.g., adjustable LDO feedback | Choose TLVH431AIDBVR only if voltage adjustability or >20 mA sink capability is required; not a direct replacement due to different topology and pinout |
Compared with LM385B-1.2, LM385PW-1-2 trades ±1% initial tolerance for lower cost and broader supply-chain availability; versus TLVH431AIDBVR, it offers lower quiescent current and fixed 1.235 V output but lacks adjustability and high-current sinking capability.
Availability
LM385PW-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated systems, and current-loop instrumentation requiring stable component supply across extended production lifecycles.
Supply support for LM385PW-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 specializing in analog and embedded processing technologies, with over 90 years of innovation in precision analog ICs.
The LM385 series belongs to TI's micropower voltage reference product line, designed specifically for battery-constrained and portable instrumentation applications where low quiescent current and long-term stability are critical.
FAQ
What is the minimum cathode current required for LM385PW-1-2 to regulate properly?
The LM385PW-1-2 requires a minimum cathode current of 15 μA to initiate and maintain regulation. Below this threshold, the output voltage deviates significantly from 1.235 V. This value is specified in the Electrical Characteristics table under IZ(min) for LM385-1.2 devices and confirmed in the Recommended Operating Conditions section of the SLVS075J datasheet.
Does LM385PW-1-2 require an external capacitor for stability?
Yes - a 0.1 μF low-ESR ceramic capacitor is recommended on the cathode pin (Pin 1) to ensure stability under all operating conditions. The LM385PW-1-2's internal frequency compensation makes it tolerant of this capacitance, eliminating need for additional series resistance or complex compensation networks.
Can LM385PW-1-2 be used in negative voltage reference configurations?
Yes - the LM385PW-1-2 is a floating two-terminal shunt reference and can be configured for negative regulation by connecting its anode to a negative rail and cathode to ground or a more-positive node. Its functional block diagram and Device Functional Modes section confirm this bidirectional capability.
What is the maximum junction temperature for LM385PW-1-2?
The absolute maximum junction temperature for LM385PW-1-2 is 150°C, per the Absolute Maximum Ratings table in SLVS075J. At its rated 1.235 V output and 20 mA cathode current, power dissipation is 24.7 mW; with RθJA = 149°C/W (TSSOP-8), this yields ~3.7°C rise above ambient - well within safe operating limits.
Is LM385PW-1-2 RoHS compliant and lead-free?
Yes - LM385PW-1-2 is RoHS compliant and lead-free, with "Green (RoHS & no Sb/Br)" eco plan and NiPdAu lead finish, as documented in the PACKAGE OPTION ADDENDUM dated 6-Feb-2020. It meets JEDEC MSL Level-1 rating and is qualified for lead-free reflow soldering at 260°C peak temperature.
LM385PW-1-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 1.235V
- Voltage - Output (Max):
- -
- Current - Output:
- 20 mA
- Tolerance:
- ±2%
- Temperature Coefficient:
- 20ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 60µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 15 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
LM385PW-1-2 FAQ
1.How can I place an order for LM385PW-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385PW-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 LM385PW-1-2 reliable?
The price and inventory of LM385PW-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 LM385PW-1-2 is usually 5 days.
3.What payment methods are accepted for LM385PW-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385PW-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385PW-1-2?
LM385PW-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385PW-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 LM385PW-1-2?
For technical support, including LM385PW-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385PW-1-2 requirements.
6.How does Aetrix verify that LM385PW-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385PW-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 LM385PW-1-2 meets industry standards.
7.What is the process for return or replacement of LM385PW-1-2?
All LM385PW-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385PW-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 LM385PW-1-2 part is unused and in its original packaging.
Return procedure for LM385PW-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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