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Texas Instruments LM385BDR-1-2
- Part No.:
- LM385BDR-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM385BDR-1-2.pdf
- Description:
- IC VREF SHUNT 1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,126
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Product details
Overview
LM385BDR-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 0°C to 70°C. It serves as a precision shunt reference in portable metering, battery-operated instrumentation, and current-loop transmitters.
For engineers reviewing the LM385BDR-1-2 datasheet, LM385BDR-1-2 pinout, LM385BDR-1-2 application, or LM385BDR-1-2 equivalent, this page delivers verified electrical specs, SOIC-8 package mapping, functional role in shunt regulation, thermal and noise performance data, and validated alternative options for low-power analog reference design.
Technical Context
The LM385BDR-1-2 implements a floating shunt topology with internal band-gap core, high-gain amplifier, and frequency-compensated loop enabling stable operation under capacitive loading up to 10 nF. Its two-terminal architecture allows use in both positive and negative regulation configurations without external bias components.
Regulation initiates only after minimum cathode current (15 μA) is supplied; output voltage remains stable across full operating current range (15 μA–20 mA) and temperature (0°C–70°C), with long-term drift limited to ±20 ppm/khr at 100 μA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.235 V nominal at 25°C; tight tolerance enables direct replacement of 1.2 V references in precision analog signal chains |
| Initial Tolerance | ±2% over temperature; supports cost-sensitive applications where calibration is performed post-assembly |
| Temp Coefficient | ±20 ppm/°C average; ensures ≤2.5 mV drift over 0°C–70°C ambient, critical for portable test equipment |
| Reference Impedance | 1.5 Ω max over full temperature range; maintains regulation stability when driving DAC reference inputs or op-amp feedback networks |
| Operating Current | 15 μA to 20 mA cathode current; accommodates ultra-low-power sleep modes and high-accuracy active measurement phases |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz); suitable for 12-bit ADC references without additional filtering |
| Long-Term Drift | ±20 ppm/khr at 100 μA; guarantees <0.02% output change over 10,000 hours in uncalibrated field deployments |
Pinout & Package
LM385BDR-1-2 is housed in an industry-standard SOIC-8 package (4.90 mm × 3.91 mm body, 1.75 mm max height), RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating. Pin 1 is cathode; pin 2 is anode; pins 3–8 are no-connect terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Shunt current input / voltage reference output node | Current must be sourced into this pin to establish reverse bias; output voltage appears between Cathode and Anode |
| Anode (Pin 2) | Common reference return / ground connection | Typically tied to system ground; forms the reference potential against which cathode voltage is defined |
| Pins 3–8 | No internal connection | Unused; may be left floating or grounded per layout best practices-no electrical function or parasitic impact confirmed |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive load tolerance | Stable with ≥10 nF bypass capacitance on cathode-eliminates need for isolation resistors in noisy environments |
| Micropower operation | 15 μA minimum operating current enables multi-year battery life in handheld meters and IoT sensors |
| Low dynamic impedance | 1.5 Ω max over full temperature range ensures minimal line regulation error in varying supply conditions |
| Low-noise reference core | 60 μV RMS broadband noise supports 12-bit accuracy without external filtering in portable instrumentation |
| On-chip trimming | Factory-trimmed band-gap core achieves ±2% initial tolerance-reduces BOM count vs. discrete resistor networks |
Applications
| Portable Meter References | Portable Test Instruments |
|---|---|
Use Scenario: Handheld multimeters requiring stable 1.2 V reference for ADC scaling and auto-zero circuits. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference establishing precise 1.235 V reference point for analog front-end signal conditioning. Use Value: Enables >3.5-digit accuracy with <0.02% total error over 0°C–50°C operating range and 10-year shelf-life battery compatibility. |
Use Scenario: Battery-powered oscilloscope probes and signal generators needing low-drift reference for DAC output scaling. IC Role / Device Role / Timing Role: Precision shunt reference supplying stable bias to current-output DACs and programmable gain amplifiers. Use Value: Delivers ±20 ppm/°C tempco and 60 μV noise-meeting Class II portable instrument specifications per IEC 61000-4-30. |
| Battery-Operated Systems | Current-Loop Instrumentation |
Use Scenario: Wireless sensor nodes with coin-cell batteries requiring microamp-level quiescent current and stable reference for sensor excitation. IC Role / Device Role / Timing Role: Low-power shunt reference powering bridge sensor interfaces and SAR ADC references during wake-up cycles. Use Value: 15 μA min operating current extends 2032 coin-cell life beyond 5 years in duty-cycled monitoring applications. |
Use Scenario: 4–20 mA transmitter modules in industrial process control where reference stability directly impacts loop accuracy. IC Role / Device Role / Timing Role: Primary voltage reference for current-sense amplifier gain setting and DAC-based loop current generation. Use Value: ±20 ppm/khr long-term drift ensures <0.1% full-scale error accumulation over 5-year maintenance intervals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM385DR-1-2 | ±1% initial tolerance (vs. ±2% for LM385BDR-1-2); same 15 μA–20 mA current range and SOIC-8 package | Preferred where tighter initial accuracy is required without calibration; higher cost due to tighter binning | Select LM385DR-1-2 when system-level calibration is omitted and ±1% absolute accuracy is mandatory at power-on |
| TLVH431ACDBVR | Adjustable 1.24 V reference (2.5 V max); 80 μA typical quiescent current; SOT-23-5 package; requires external resistors for 1.2 V setup | Used where programmability or lower-cost adjustable topology is acceptable; not drop-in compatible | Choose TLVH431ACDBVR only if board redesign permits 3-resistor configuration and higher IQ is tolerable |
Compared with LM385DR-1-2, the LM385BDR-1-2 trades initial accuracy for cost and supply-chain availability; versus TLVH431ACDBVR, it offers true two-terminal simplicity and lower IQ but lacks adjustability-making it optimal for fixed-voltage, space-constrained, ultra-low-power designs.
Availability
LM385BDR-1-2 is available at Aetrix Electronics and suitable for portable meter references, battery-operated instrumentation, and current-loop transmitter designs requiring stable component supply with guaranteed long-term continuity.
Supply support for LM385BDR-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 founded in 1930, specializing in analog and embedded processing technologies with broad industrial, automotive, and consumer product portfolios.
The LM385BDR-1-2 belongs to TI's precision voltage reference product line, engineered specifically for micropower, two-terminal shunt regulation in portable and battery-constrained systems where size, IQ, and long-term stability are critical.
FAQ
What is the minimum cathode current required for regulation in the LM385BDR-1-2?
The LM385BDR-1-2 requires a minimum cathode current of 15 μA to achieve proper regulation across its specified temperature range (0°C to 70°C). This value is confirmed in the Electrical Characteristics table of the SLVS075J datasheet and defines the lower boundary of its 15 μA–20 mA operating current range. Below this threshold, output voltage deviates significantly from 1.235 V.
Does the LM385BDR-1-2 require an external capacitor for stability?
No, the LM385BDR-1-2 does not require an external capacitor for basic stability-it is internally compensated and tolerant of capacitive loading up to at least 10 nF on the cathode node. However, a 0.1 μF ceramic bypass capacitor is recommended per TI layout guidelines to suppress high-frequency noise and improve transient response in sensitive analog circuits using the LM385BDR-1-2.
Is the LM385BDR-1-2 pin-compatible with the LM385-1.2 or LM285-1.2 in SOIC-8 packages?
Yes, the LM385BDR-1-2 shares identical SOIC-8 pinout (D package), terminal functions (cathode on Pin 1, anode on Pin 2, NC on Pins 3–8), and mechanical footprint with LM385DR-1-2 and LM285DR-1-2. All three are physically interchangeable on PCBs designed for SOIC-8 shunt references, though electrical differences (e.g., tempco, tolerance, operating temperature range) must be verified per application requirements.
What is the maximum junction temperature and thermal resistance for the LM385BDR-1-2?
The LM385BDR-1-2 has an absolute maximum junction temperature of 150°C and a junction-to-ambient thermal resistance (RθJA) of 95°C/W in the SOIC-8 (D) package. This value assumes standard JEDEC 2S2P board conditions; actual thermal performance depends on PCB copper area, airflow, and adjacent heat sources-all critical when operating near 20 mA in enclosed battery-powered enclosures using the LM385BDR-1-2.
Can the LM385BDR-1-2 be used in negative voltage reference configurations?
Yes, the LM385BDR-1-2 supports floating shunt operation and can serve as a negative reference by connecting its anode to a negative rail and sourcing current into the cathode-enabling precision -1.235 V generation relative to system ground. This capability is explicitly documented in TI's Feature Description section and validated in application circuits such as thermocouple cold-junction compensators using the LM385BDR-1-2.
LM385BDR-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:
- ±1%
- 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
LM385BDR-1-2 FAQ
1.How can I place an order for LM385BDR-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385BDR-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 LM385BDR-1-2 reliable?
The price and inventory of LM385BDR-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 LM385BDR-1-2 is usually 5 days.
3.What payment methods are accepted for LM385BDR-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385BDR-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385BDR-1-2?
LM385BDR-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385BDR-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 LM385BDR-1-2?
For technical support, including LM385BDR-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385BDR-1-2 requirements.
6.How does Aetrix verify that LM385BDR-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385BDR-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 LM385BDR-1-2 meets industry standards.
7.What is the process for return or replacement of LM385BDR-1-2?
All LM385BDR-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385BDR-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 LM385BDR-1-2 part is unused and in its original packaging.
Return procedure for LM385BDR-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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