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Texas Instruments LM385DR-1-2
- Part No.:
- LM385DR-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385DR-1-2.pdf
- Description:
- IC VREF SHUNT 2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:128
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Product details
Overview
LM385DR-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 test instruments, battery-operated systems, and current-loop instrumentation.
For engineers reviewing the LM385DR-1-2 datasheet, LM385DR-1-2 pinout, LM385DR-1-2 application, or LM385DR-1-2 equivalent, key selection criteria include its 15 μA minimum operating current, 1.235 V initial tolerance (±1.2% at 25°C), low-noise performance (60 μV RMS, 10 Hz–10 kHz), and SOIC-8 package compatibility with standard surface-mount assembly processes.
Technical Context
The LM385DR-1-2 implements a floating shunt topology using an internal band-gap core with on-chip trimming for tight initial voltage accuracy. Its high-gain amplifier and shunt pass element maintain regulation without external components, requiring only a minimum 15 μA cathode current to activate.
Internal frequency compensation ensures stable operation under capacitive loading up to 10 nF, eliminating need for external compensation. The device operates exclusively in fixed-voltage reference mode - no adjustment or programming capability is provided.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Reference Voltage | 1.235 V at 25°C - defines precise bias point for analog signal conditioning and ADC/DAC reference rails |
| Initial Voltage Tolerance | ±1.2% (1.223 V to 1.247 V) - enables single-supply 12-bit system accuracy without calibration |
| Operating Current Range | 15 μA to 20 mA - supports ultra-low-power sensor nodes and high-current regulator feedback paths |
| Temperature Coefficient | ±20 ppm/°C - ensures ≤0.25 mV drift over 0°C to 70°C ambient, critical for portable meter stability |
| Reference Impedance | 1.5 Ω max over full temperature range - minimizes load-induced error in precision current-sense applications |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz) - preserves SNR in low-level signal amplification stages |
| Long-Term Stability | ±20 ppm/khr - supports >10-year calibration intervals in panel meter designs |
Pinout & Package
LM385DR-1-2 is housed in an SOIC-8 package (4.90 mm × 3.91 mm body, 1.75 mm max height), with pins 1 and 2 used for connection and pins 3–8 internally unconnected (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Shunt current return path | Connected to system ground or negative rail; completes current loop for regulation |
| Cathode (Pin 2) | Reference voltage output / current input | Sourced current enters here; regulated 1.235 V appears between Cathode and Anode |
| Pins 3–8 | No internal connection | Electrically isolated; may be left floating or tied to ground for mechanical stability |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive load immunity | Stable with ≥10 nF bypass capacitor - eliminates need for series isolation resistor in noisy environments |
| Micropower operation | 15 μA minimum cathode current - extends battery life in portable meters beyond shelf-life limits |
| Low dynamic impedance | 1.5 Ω max over 0°C–70°C - maintains <0.1% output error under varying load currents |
| Band-gap core architecture | 60 μV RMS noise (10 Hz–10 kHz) - avoids post-regulation filtering in precision data acquisition |
| On-chip trimming | ±1.2% initial tolerance - reduces BOM count by eliminating external calibration potentiometers |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeters and calibrators requiring stable reference over variable battery voltage and temperature. IC Role / Device Role / Timing Role: Shunt voltage reference providing 1.235 V基准 for ADC front-end and display driver biasing. Use Value: ±20 ppm/°C drift ensures <0.5 LSB error in 16-bit measurements across 0°C–50°C operating range. | Use Scenario: Wireless sensor nodes powered by coin-cell batteries with multi-year operational life requirements. IC Role / Device Role / Timing Role: Micropower reference enabling ultra-low-quiescent LDOs and wake-up comparators. Use Value: 15 μA minimum current allows continuous monitoring while consuming <1% of CR2032 capacity per year. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter modules where reference stability directly impacts loop accuracy and HART communication integrity. IC Role / Device Role / Timing Role: Precision shunt reference setting DAC output scale and current-sense amplifier gain. Use Value: 1.5 Ω max impedance prevents load-dependent gain shift during 4–20 mA span calibration. | Use Scenario: Industrial panel meters exposed to wide ambient temperatures and long-term storage before commissioning. IC Role / Device Role / Timing Role: Primary voltage reference for analog-to-digital conversion and LED bar-graph scaling. Use Value: ±20 ppm/khr long-term stability supports factory calibration validity for ≥5 years without field recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385BDR-1-2 | Tighter initial tolerance (±0.5% vs ±1.2%), same SOIC-8 package and 0°C–70°C range | Better suited for 14+ bit measurement systems requiring higher baseline accuracy | Select when initial accuracy outweighs cost sensitivity; identical layout and drive circuitry |
| TLVH431IDBVR | Adjustable 1.24 V reference (2.5 V max), 80 μA min cathode current, SOT-23-5 package | Requires external resistors for 1.235 V setting; higher noise (120 μV RMS) | Choose for space-constrained designs where adjustable output justifies added complexity and reduced accuracy |
Compared with LM385BDR-1-2, LM385DR-1-2 trades ±0.5% initial accuracy for lower unit cost while retaining identical thermal drift, noise, and package compatibility; versus TLVH431IDBVR, it delivers fixed 1.235 V with lower noise and simpler implementation but occupies larger board area.
Availability
LM385DR-1-2 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply across industrial production lifecycles.
Supply support for LM385DR-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 leadership in precision analog ICs since 1951.
The LM385 series was designed specifically for micropower, two-terminal shunt voltage reference applications in portable, battery-sensitive, and industrial measurement systems - prioritizing low drift, low noise, and capacitive-load robustness.
FAQ
What is the minimum operating current required for stable regulation of the LM385DR-1-2?
The LM385DR-1-2 requires a minimum cathode current of 15 μA to achieve proper regulation and specified voltage accuracy. Below this threshold, output voltage deviates significantly from 1.235 V, and temperature stability degrades. This value is confirmed in the Electrical Characteristics table of the SLVS075J datasheet under IZ(min) for LM385-1.2 devices at 25°C.
Does the LM385DR-1-2 require an external capacitor for stability?
No, the LM385DR-1-2 does not require an external capacitor for basic stability due to internal frequency compensation optimized for capacitive loading up to 10 nF. However, a 0.1 μF ceramic bypass capacitor on the cathode node is recommended per TI layout guidelines to suppress broadband noise and improve transient response in sensitive analog circuits.
Can the LM385DR-1-2 be used in negative-voltage reference configurations?
Yes, the LM385DR-1-2 supports floating shunt operation and can serve as a negative reference by connecting its anode to a negative rail and cathode to a more-negative potential. Its two-terminal architecture allows bidirectional current flow, enabling both positive and negative regulation topologies - a key advantage over three-terminal references.
What is the maximum junction temperature rating for the LM385DR-1-2 in SOIC-8 package?
The absolute maximum junction temperature for the LM385DR-1-2 is 150°C, as specified in Section 7.1 of the SLVS075J datasheet. With an SOIC-8 package thermal resistance (RθJA) of 95°C/W, sustained power dissipation above ~150 mW requires careful PCB thermal design or derating to avoid exceeding this limit under worst-case ambient conditions.
Is the LM385DR-1-2 RoHS compliant and lead-free?
Yes, the LM385DR-1-2 is RoHS compliant and lead-free, with "Green (RoHS & no Sb/Br)" eco plan and "NIPDAU" (nickel-palladium-gold) lead finish, as documented in TI's PACKAGE OPTION ADDENDUM dated 6-Feb-2020. It meets JEDEC MSL Level-1 moisture sensitivity classification and is qualified for lead-free reflow soldering at 260°C peak temperature.
LM385DR-1-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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-SOIC
LM385DR-1-2 FAQ
1.How can I place an order for LM385DR-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385DR-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 LM385DR-1-2 reliable?
The price and inventory of LM385DR-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 LM385DR-1-2 is usually 5 days.
3.What payment methods are accepted for LM385DR-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385DR-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385DR-1-2?
LM385DR-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385DR-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 LM385DR-1-2?
For technical support, including LM385DR-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385DR-1-2 requirements.
6.How does Aetrix verify that LM385DR-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385DR-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 LM385DR-1-2 meets industry standards.
7.What is the process for return or replacement of LM385DR-1-2?
All LM385DR-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385DR-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 LM385DR-1-2 part is unused and in its original packaging.
Return procedure for LM385DR-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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