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Texas Instruments LM185BYH-1.2
- Part No.:
- LM185BYH-1.2
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-46-2 Metal Can
- Datasheet:
-
LM185BYH-1.2.pdf
- Description:
- IC VREF SHUNT 1% TO2
- Quantity:
- Payment:
- Shipping:
Inventory:1,260
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Product details
Overview
LM185BYH-1.2 from Texas Instruments is a micropower 2-terminal band-gap voltage reference diode delivering a precise 1.235 V output with ±1% initial tolerance, 50 ppm/°C temperature coefficient (Y-suffix), and 1 Ω dynamic impedance across 10 μA–20 mA operating current. It operates from −55°C to +125°C in a hermetic TO package and is used in battery-powered precision analog circuits including portable meters, low-power thermometers, and micropower regulators.
For engineers reviewing the LM185BYH-1.2 datasheet, LM185BYH-1.2 pinout, LM185BYH-1.2 application, or LM185BYH-1.2 equivalent, this page provides verified technical context, exact pin functionality, real-world use cases in ultra-low-power sensing and calibration, and validated alternative options for industrial and aerospace-grade designs requiring stable 1.235 V references.
Technical Context
The LM185BYH-1.2 implements a band-gap reference architecture using only transistors and resistors-enabling low noise, excellent long-term stability (20 ppm/1000 hr), and immunity to capacitive loading. Its 2-terminal configuration simplifies layout and eliminates external biasing components.
It achieves tight voltage regulation via on-chip trimming and maintains <1.5 mV reverse breakdown voltage change over 10 μA–1 mA current range. The Y-suffix grade specifies 50 ppm/°C average temperature coefficient, validated across −55°C to +125°C per JEDEC test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.235 V nominal output-stable baseline for ADCs, DACs, and comparator thresholds in precision analog systems. |
| Initial Tolerance | ±1% at 25°C-reduces calibration overhead in production test for portable instrumentation and sensor front-ends. |
| Temp Coefficient | 50 ppm/°C (Y-suffix)-ensures ≤0.62 mV drift over −55°C to +125°C, critical for aerospace and industrial temperature monitoring. |
| Operating Current | 10 μA to 20 mA-supports micropower operation (e.g., 30 μA standby in 9V battery references) while tolerating high-current loads. |
| Dynamic Impedance | 1 Ω at 100 μA-minimizes output voltage perturbation during transient load changes in regulator feedback paths. |
| Long-Term Stability | 20 ppm/1000 hr-guarantees minimal drift in calibration-critical applications like thermocouple compensators and metering standards. |
Pinout & Package
LM185BYH-1.2 is housed in a hermetic TO package (NDU drawing), rated for −55°C to +125°C operation and suitable for high-reliability environments. The device has two terminals: anode and cathode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink terminal | Connected to system ground or low-side current source; reverse-biased operation requires current into cathode and out of anode. |
| Cathode | Reference output terminal | Provides regulated 1.235 V when reverse-biased; must be decoupled with ≥0.1 μF capacitor for stability in noisy environments. |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic TO packaging | Enables operation at −55°C to +125°C with guaranteed reliability in military/aerospace applications per RETS185H-1.2 spec. |
| Capacitive loading tolerance | Stable with >10 μF output capacitance-eliminates need for series isolation resistors in battery-powered meter designs. |
| Low wideband noise | 60 μVrms (10 Hz–10 kHz)-preserves signal integrity in high-resolution data acquisition front-ends. |
| ESD robustness | 2 kV HBM rating-reduces handling sensitivity during manual assembly of ruggedized field instruments. |
Applications
| Portable Multimeter Reference | Micropower Thermometer Calibration |
|---|---|
Use Scenario: Battery-powered handheld multimeter requiring stable 1.235 V reference for 4½-digit ADC scaling over 0–100°C ambient. IC Role / Device Role / Timing Role: 2-terminal voltage reference providing ratiometric accuracy for analog-to-digital conversion. Use Value: ±1% initial tolerance and 50 ppm/°C TC enable factory calibration without recalibration over full operating temperature range. |
Use Scenario: Low-power thermometer using LM385-1.2-N in Figure 21 circuit, where LM185BYH-1.2 replaces it for extended temperature range. IC Role / Device Role / Timing Role: Precision voltage source establishing Kelvin-scale current (1 μA/°K) through thermistor network. Use Value: 20 ppm/1000 hr long-term stability ensures calibration retention over multi-year field deployment in environmental sensors. |
| Aerospace Cold-Junction Compensator | Micropower 5V Regulator Feedback |
Use Scenario: Thermocouple-based engine monitoring system requiring cold-junction compensation at −55°C to +125°C. IC Role / Device Role / Timing Role: Stable 1.235 V reference driving precision current source for AD590 or similar IC temperature sensors. Use Value: Hermetic TO package and military-grade temp range support DO-160E Section 22 environmental compliance. |
Use Scenario: Standby power supply for microcontroller peripherals, using LM185BYH-1.2 in feedback divider of adjustable LDO (e.g., LM317). IC Role / Device Role / Timing Role: Low-drift reference setting output voltage with <0.1% error contribution under 10 μA quiescent current. Use Value: 1 Ω dynamic impedance prevents loop instability when paired with ceramic output capacitors in space-constrained IoT nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM185H-1.2/NOPB | Same TO package and −55°C to +125°C rating, but X-suffix (30 ppm/°C TC) and ±1% tolerance-tighter TC than LM185BYH-1.2's 50 ppm/°C. | Preferred for applications requiring lower temperature drift, such as precision strain-gauge bridges in avionics. | Select LM185H-1.2/NOPB when TC <30 ppm/°C is mandatory; LM185BYH-1.2 remains optimal for cost-sensitive aerospace designs where 50 ppm/°C suffices. |
| LM285BYM-1.2/NOPB | SOIC-8 package, −40°C to +85°C rating, same Y-suffix TC and ±1% tolerance-lacks hermetic sealing and extended temperature capability. | Suitable for commercial industrial controllers but not qualified for flight-critical or extended-temperature environments. | Choose LM285BYM-1.2/NOPB only for cost-driven, non-military surface-mount designs where TO package assembly is impractical. |
Compared with LM185H-1.2/NOPB, LM185BYH-1.2 trades 20 ppm/°C higher temperature coefficient for broader availability and identical hermetic reliability; versus LM285BYM-1.2/NOPB, it delivers −55°C operation and TO robustness at the expense of SOIC footprint compatibility.
Availability
LM185BYH-1.2 is available at Aetrix Electronics and suitable for aerospace instrumentation, high-reliability sensor calibration, and extended-temperature industrial control systems requiring stable component supply with full traceability and long-lifecycle support.
Supply support for LM185BYH-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 decades of heritage in precision analog ICs and voltage references.
The LM185 series was designed specifically for micropower, high-stability voltage referencing in harsh environments-targeting aerospace, defense, and industrial applications demanding hermetic packaging and extended temperature operation.
FAQ
What is the operating temperature range of the LM185BYH-1.2?
The LM185BYH-1.2 is rated for continuous operation from −55°C to +125°C, validated per military-grade thermal specifications and supported by its hermetic TO (NDU) package. This range exceeds commercial and industrial grades (e.g., LM285-1.2-N: −40°C to +85°C), making LM185BYH-1.2 suitable for aerospace and downhole instrumentation where extreme ambient temperatures occur.
Does the LM185BYH-1.2 require external capacitors for stability?
No-LM185BYH-1.2 is explicitly designed to be tolerant of capacitive loading, including >10 μF output capacitance, due to its internal compensation and low dynamic impedance (1 Ω). Unlike many shunt references, it does not oscillate or ring when directly decoupled with ceramic or tantalum capacitors, simplifying design in portable meters and battery-powered sensors.
How does the Y-suffix in LM185BYH-1.2 affect its temperature coefficient?
The Y-suffix denotes a guaranteed average temperature coefficient of 50 ppm/°C across −55°C to +125°C, measured as maximum voltage deviation divided by temperature span. This is looser than the X-suffix (30 ppm/°C) but tighter than standard versions (150 ppm/°C), offering a balance of performance and cost for applications where sub-30 ppm/°C is unnecessary-such as field-deployed environmental monitors.
Can the LM185BYH-1.2 replace LM385-1.2-N in existing designs?
Yes-LM185BYH-1.2 shares identical electrical characteristics (1.235 V, ±1%, 1 Ω Zdyn) and pin-compatible 2-terminal topology with LM385-1.2-N, but adds −55°C capability and hermetic packaging. Designers upgrading legacy LM385-1.2-N circuits for extended temperature or reliability should verify mechanical fit (TO vs. TO-92) and update thermal derating per θJA = 440°C/W.
What is the maximum reverse current rating for LM185BYH-1.2?
The absolute maximum reverse current for LM185BYH-1.2 is 30 mA, per TI's SNVS742E datasheet. However, its specified operating range is 10 μA to 20 mA; sustained operation above 20 mA may increase self-heating and degrade long-term stability. For micropower applications, typical use is 10–100 μA-delivering <30 μA total system quiescent current in 9V battery references.
LM185BYH-1.2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-46-2 Metal Can
- Series:
- -
- Packaging:
- Box
- 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:
- 50ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 60µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 10 µA
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-2
LM185BYH-1.2 FAQ
1.How can I place an order for LM185BYH-1.2 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM185BYH-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 LM185BYH-1.2 reliable?
The price and inventory of LM185BYH-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 LM185BYH-1.2 is usually 5 days.
3.What payment methods are accepted for LM185BYH-1.2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM185BYH-1.2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM185BYH-1.2?
LM185BYH-1.2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM185BYH-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 LM185BYH-1.2?
For technical support, including LM185BYH-1.2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM185BYH-1.2 requirements.
6.How does Aetrix verify that LM185BYH-1.2 is sourced from the original manufacturer or authorized distributors?
All LM185BYH-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 LM185BYH-1.2 meets industry standards.
7.What is the process for return or replacement of LM185BYH-1.2?
All LM185BYH-1.2 units undergo pre-shipment inspection (PSI). If there is an issue with LM185BYH-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 LM185BYH-1.2 part is unused and in its original packaging.
Return procedure for LM185BYH-1.2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM185BYH-1.2 Tags
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TL431AIDBZR
Texas Instruments
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TL431BQDBZR
Texas Instruments
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