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Texas Instruments LM385BLPR-1-2
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- Part No.:
- LM385BLPR-1-2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
LM385BLPR-1-2.pdf
- Description:
- IC VREF SHUNT 1% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,742
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Product details
Overview
LM385BLPR-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), used in portable test instruments and battery-operated analog signal conditioning.
For engineers reviewing the LM385BLPR-1-2 datasheet, LM385BLPR-1-2 pinout, LM385BLPR-1-2 application, or LM385BLPR-1-2 equivalent, key selection criteria include initial voltage tolerance (1.223–1.247 V at 25°C), long-term stability (±20 ppm/khr), low-noise operation (60 μV broadband), capacitive load tolerance, and TO-92 package compatibility with legacy shunt reference layouts.
Technical Context
The LM385BLPR-1-2 implements a floating shunt topology with internal band-gap core, high-gain amplifier, and frequency-compensated loop enabling stable regulation under capacitive loading up to 1 μF without external compensation. Its design supports both positive and negative regulation configurations.
It operates exclusively in fixed-voltage reference mode with no adjustability; regulation initiates only after minimum cathode current (15 μA) is supplied, and it maintains tight output voltage control via on-chip trimming-achieving 1% initial tolerance and ±20 ppm/°C average temperature coefficient over 0°C to 70°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.235 V nominal at 25°C; 1.223–1.247 V min/max ensures precision analog biasing in portable meters. |
| Initial Tolerance | ±1% (1.223–1.247 V); enables single-point calibration in field-deployed instrumentation. |
| Temp Coefficient | ±20 ppm/°C over 0°C–70°C; guarantees <±1.5 mV drift across industrial ambient range. |
| Ref Impedance | 1.5 Ω max over full temp range; minimizes load-induced error in high-impedance ADC reference paths. |
| Operating Current | 15 μA to 20 mA cathode current; supports ultra-low-power sleep modes and high-current transient response. |
| Broadband Noise | 60 μV RMS (10 Hz–10 kHz); preserves SNR in 16-bit+ data acquisition front-ends. |
| Long-Term Drift | ±20 ppm/khr; ensures <±0.5 mV shift over 5-year deployment in unattended sensors. |
Pinout & Package
LM385BLPR-1-2 uses TO-92 (LP) package: 3-pin through-hole, 4.30 mm × 4.30 mm body, formed leads, Pb-free (SN) finish, RoHS compliant, MSL N/A.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Shunt current return path | Connected to system ground or negative rail; completes current loop for reference regulation. |
| Cathode (Pin 2) | Voltage reference output node | Delivers stable 1.235 V; requires external current source (e.g., resistor or LM334) to sustain ≥15 μA. |
| NC (Pin 3) | No internal connection | Unused terminal; must remain unconnected or tied to ground per layout best practice to reduce noise pickup. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive Load Tolerance | Stable with ≥1 µF ceramic bypass; eliminates need for external compensation in portable meter PCBs. |
| Low Power Operation | 15 µA minimum cathode current enables >10-year battery life in coin-cell-powered sensors. |
| Band-Gap Core Architecture | Delivers low-noise (60 µV), low-drift (±20 ppm/°C), and long-term stability (±20 ppm/khr) simultaneously. |
| Interchangeability | Pins-and-function compatible with LM285-1.2 and LM385-1.2; allows drop-in upgrade to tighter tolerance. |
| ESD Robustness | ±2000 V HBM rating; withstands handling in non-EPA environments during manual assembly. |
Applications
| Portable Test Instruments | Battery-Operated Systems |
|---|---|
Use Scenario: Handheld multimeters requiring stable 1.2 V reference for autoranging ADCs and display drivers. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference providing precise, low-drift bias for measurement front-end. Use Value: Enables 4½-digit accuracy with <±0.01% linearity error over 0–40°C ambient, extending calibration intervals. | Use Scenario: Wireless sensor nodes powered by CR2032 batteries needing ultra-low-quiescent reference for analog sensing. IC Role / Device Role / Timing Role: Micropower shunt reference supplying regulated voltage to op-amps and ADCs during wake-up bursts. Use Value: Draws only 15 µA minimum current, contributing <0.1% to total system standby power-extending battery life to 7+ years. |
| Current-Loop Instrumentation | Panel Meters |
Use Scenario: 4–20 mA transmitter modules where reference stability directly impacts loop accuracy and zero/span drift. IC Role / Device Role / Timing Role: Precision voltage reference setting DAC full-scale and current-sense amplifier gain. Use Value: ±20 ppm/°C tempco limits loop error to <±0.05% FS over industrial temperature range (−20°C to +60°C). | Use Scenario: DIN-rail mounted panel meters with analog bar-graph displays and microcontroller-based scaling. IC Role / Device Role / Timing Role: Fixed 1.235 V reference for analog-to-digital conversion of scaled process signals (e.g., 0–10 V inputs). Use Value: 1.5 Ω max impedance prevents loading errors when driving multiple parallel ADC inputs in multi-channel designs. |
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 | SOIC-8 package; same electrical specs but higher thermal resistance (95°C/W vs TO-92's ~140°C/W); no NC pin. | Suitable for automated SMT assembly; less suited for high-temperature through-hole boards or hand-soldered prototypes. | Select when board space permits SMT and reflow compatibility is required; verify thermal derating above 50°C ambient. |
| TLVH431ACDBVR | Adjustable 3-terminal shunt regulator; 1.24 V nominal; 2% initial tolerance; 0.3 Ω typical impedance; wider 1–100 mA current range. | Requires external resistors for 1.235 V setting; better for designs needing programmable reference or higher current drive. | Choose if future firmware updates may require reference voltage adjustment or if >20 mA load current is anticipated. |
Compared with LM385BDR-1-2, LM385BLPR-1-2 offers lower cost and simpler through-hole layout but higher thermal resistance; versus TLVH431ACDBVR, it delivers tighter initial tolerance and lower noise without external components-ideal for fixed, low-power, high-precision roles.
Availability
LM385BLPR-1-2 is available at Aetrix Electronics and suitable for portable test instruments, battery-operated systems, and current-loop instrumentation requiring stable component supply with long-lifecycle support and RoHS-compliant sourcing.
Supply support for LM385BLPR-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 leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision analog ICs.
The LM385B series was designed specifically for micropower, high-stability shunt voltage references in portable and battery-constrained applications-emphasizing low drift, low noise, and capacitive-load immunity.
FAQ
What is the operating temperature range for LM385BLPR-1-2?
The LM385BLPR-1-2 is specified for 0°C to 70°C free-air operating temperature. This range reflects its LM385B-grade qualification-tighter than LM285-1.2 (−40°C to 85°C) but optimized for commercial portable equipment where ambient extremes are limited. The device maintains ±20 ppm/°C tempco and 1.223–1.247 V output tolerance across this full range. Exceeding 70°C risks parametric shift beyond datasheet limits.
How do I calculate the required current-limiting resistor for LM385BLPR-1-2?
To bias LM385BLPR-1-2, use R = (VSUPPLY − 1.235 V) ÷ IZ(MIN), where IZ(MIN) = 15 μA. For example, with 5 V supply: R ≤ (5 − 1.235) ÷ 0.000015 ≈ 251 kΩ. Select standard value ≤240 kΩ to ensure ≥15 μA under worst-case VSUPPLY tolerance and tempco. Always verify cathode current stays within 15 μA–20 mA per LM385BLPR-1-2 datasheet Section 7.3.
Is LM385BLPR-1-2 pin-compatible with LM285-1.2?
Yes-LM385BLPR-1-2 shares identical TO-92 (LP) pinout (Anode–Cathode–NC) and mechanical footprint with LM285-1.2 LP variants. Both require the same PCB land pattern and mounting. However, LM385BLPR-1-2 offers improved 1% initial tolerance (vs 2% for LM285-1.2) and tighter ±20 ppm/°C tempco, making it a direct performance upgrade without layout changes.
Does LM385BLPR-1-2 require an output capacitor?
No external capacitor is required for stability-LM385BLPR-1-2 is internally compensated and tolerant of ≥1 µF ceramic bypass capacitance on the cathode. TI recommends a 0.1 µF low-ESR ceramic capacitor (CL) directly at the cathode pin to suppress broadband noise (60 µV) and improve transient response. Larger values (up to 1 µF) are acceptable and often used in portable meters to reduce ripple-induced measurement error.
What is the maximum cathode current rating for LM385BLPR-1-2?
The absolute maximum cathode current for LM385BLPR-1-2 is 30 mA (per Section 7.1 Absolute Maximum Ratings). However, the recommended operating range is 15 μA to 20 mA. Operating continuously above 20 mA increases self-heating, degrading tempco and long-term stability. At 30 mA, junction temperature rise exceeds safe limits unless ambient is <25°C and PCB copper area is maximized-TI does not guarantee parametric performance beyond 20 mA.
LM385BLPR-1-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- TO-92-3
LM385BLPR-1-2 FAQ
1.How can I place an order for LM385BLPR-1-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM385BLPR-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 LM385BLPR-1-2 reliable?
The price and inventory of LM385BLPR-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 LM385BLPR-1-2 is usually 5 days.
3.What payment methods are accepted for LM385BLPR-1-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM385BLPR-1-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM385BLPR-1-2?
LM385BLPR-1-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM385BLPR-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 LM385BLPR-1-2?
For technical support, including LM385BLPR-1-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM385BLPR-1-2 requirements.
6.How does Aetrix verify that LM385BLPR-1-2 is sourced from the original manufacturer or authorized distributors?
All LM385BLPR-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 LM385BLPR-1-2 meets industry standards.
7.What is the process for return or replacement of LM385BLPR-1-2?
All LM385BLPR-1-2 units undergo pre-shipment inspection (PSI). If there is an issue with LM385BLPR-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 LM385BLPR-1-2 part is unused and in its original packaging.
Return procedure for LM385BLPR-1-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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