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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Reference

Texas Instruments LM185BH

Name: LM185BH
Brand: Texas Instruments
SKU: LM185BH
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM185BH

Manufacturer:: Texas Instruments

Category:: Voltage Reference

Package:: TO-99-8 Metal Can

Datasheet:: LM185BH.pdf

Description:: IC VREF SHUNT ADJ 1% TO99-8

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Product details

Overview

LM185BH from Texas Instruments is a hermetically sealed, adjustable 3-terminal band-gap voltage reference IC rated for −55°C to 125°C operation. It delivers 1.24 V to 5.30 V output with 1% initial tolerance, 1 Ω dynamic impedance, and 30 ppm/°C max temperature coefficient. It operates from 10 μA to 20 mA supply current and is used in precision shunt regulators, battery-powered meters, and high-reliability analog circuitry.

For engineers reviewing the LM185BH datasheet, LM185BH pinout, LM185BH application, or LM185BH equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional and thermal differences.

Technical Context

The LM185BH implements a band-gap reference core using only transistors and resistors-no MOS gates-enabling low noise (50 μVrms at V_REF, 10 Hz–10 kHz), excellent long-term stability (20 ppm over 1000 hours), and immunity to capacitive loading. Its internal trimming ensures tight initial voltage accuracy without external calibration.

It operates as a 2-terminal shunt reference but is packaged in a 3-pin TO-46 metal can with Anode, Cathode, and Adjust terminals. The Adjust pin enables precise external resistor-based output programming across its full 1.24–5.30 V range while maintaining regulation under varying load and line conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Reference Voltage Range	1.24 V to 5.30 V - Programmable via external resistor divider; supports precision 2.5 V, 3.3 V, 5.0 V, and 10 V references.
Initial Tolerance	±1% - Tighter than LM285/LM385 variants; reduces system calibration burden in aerospace and industrial instrumentation.
Dynamic Impedance	1 Ω - Enables stable regulation even with fast transient loads up to 20 mA; critical for ADC reference buffers and low-noise LDO feedback.
Operating Current	10 μA to 20 mA - Micropower capability extends battery life; wide range allows direct replacement of legacy references like TL431 in low-current designs.
Temp Coefficient	30 ppm/°C max - Measured over −55°C to 125°C; suitable for unheated outdoor sensors and avionics where ambient extremes occur.
Long-Term Stability	20 ppm over 1000 hrs - Confirmed at 25°C; supports 10+ year field reliability in medical and test equipment without recalibration.
Output Noise	50 μV_rms (10 Hz–10 kHz) - Low enough for 16-bit SAR ADCs; avoids post-filtering in portable data loggers.

Pinout & Package

LM185BH uses a hermetic TO-46 metal-can package (Package Drawing NDV), 3-pin, with 2.67 mm max height. Designed for high-reliability environments including military, space, and downhole instrumentation.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Pin 1)	Reference ground node	Connected to system ground; serves as return path for cathode current and adjust bias current.
Cathode (Pin 2)	Output voltage terminal	Delivers regulated reference voltage; sinks all load + adjust current; requires heatsinking above 10 mA in high-temp environments.
Adjust (Pin 3)	Voltage programming input	Connects to external resistor divider; sets output voltage per V_OUT = V_REF(1 + R1/R2); draws only 13–35 nA typical.

Key Features

Feature	Design Value
Hermetic TO-46 packaging	Enables operation from −55°C to 125°C with zero moisture ingress; qualified per MIL-PRF-19500/425 for space-grade reliability.
Capacitive-load tolerance	Stable with ≥100 nF output capacitance-eliminates need for isolation resistors in noisy power-supply monitoring circuits.
Low quiescent current	10 μA minimum operating current-supports energy harvesting systems and coin-cell-powered IoT nodes for >5 years.
Noise-immune band-gap core	50 μV_rms broadband noise-meets SNR requirements for 16-bit precision measurement front-ends without additional filtering.
Trimmed initial accuracy	±1% over full temperature range-reduces factory calibration time and cost in automated test equipment (ATE) and sensor modules.

Applications

Precision Shunt Regulator	Battery-Powered Instrumentation
Use Scenario: Generating a stable 5.0 V rail from an unregulated 9 V battery in a handheld multimeter. IC Role / Device Role / Timing Role: Shunt voltage reference providing feedback to a discrete PNP pass transistor regulator stage. Use Value: 1% initial tolerance and 30 ppm/°C drift ensure <±0.5% output variation across −20°C to 60°C operating range-meeting IEC 61010 Class II safety margin.	Use Scenario: Supplying reference voltage to a 16-bit sigma-delta ADC in a portable gas analyzer. IC Role / Device Role / Timing Role: Low-noise, micropower reference source for ADC V_REF input. Use Value: 50 μV_rms noise and 10 μA min current enable >92 dB SNR and >10-year battery life on CR2032 cells.
High-Temperature Sensor Interface	Aerospace Power Monitoring
Use Scenario: Biasing RTD bridge and conditioning amplifier in an engine-mounted oil temperature sensor. IC Role / Device Role / Timing Role: Temperature-stable reference for ratiometric bridge excitation and gain-setting resistors. Use Value: Guaranteed operation to 125°C and 20 ppm/1000 hr stability maintain ±0.1°C measurement accuracy over 5000-hour service life.	Use Scenario: Monitoring 28 V aircraft bus voltage with ±0.5% accuracy across −55°C to 70°C. IC Role / Device Role / Timing Role: Adjustable shunt reference feeding comparator input in a redundant overvoltage protection circuit. Use Value: Hermetic TO-46 package withstands vibration and humidity; 1 Ω dynamic impedance prevents false trips during bus transients.

Precision Shunt Regulator

Battery-Powered Instrumentation

Use Scenario: Generating a stable 5.0 V rail from an unregulated 9 V battery in a handheld multimeter.

IC Role / Device Role / Timing Role: Shunt voltage reference providing feedback to a discrete PNP pass transistor regulator stage.

Use Value: 1% initial tolerance and 30 ppm/°C drift ensure <±0.5% output variation across −20°C to 60°C operating range-meeting IEC 61010 Class II safety margin.

Use Scenario: Supplying reference voltage to a 16-bit sigma-delta ADC in a portable gas analyzer.

IC Role / Device Role / Timing Role: Low-noise, micropower reference source for ADC V_REF input.

Use Value: 50 μV_rms noise and 10 μA min current enable >92 dB SNR and >10-year battery life on CR2032 cells.

High-Temperature Sensor Interface

Aerospace Power Monitoring

Use Scenario: Biasing RTD bridge and conditioning amplifier in an engine-mounted oil temperature sensor.

IC Role / Device Role / Timing Role: Temperature-stable reference for ratiometric bridge excitation and gain-setting resistors.

Use Value: Guaranteed operation to 125°C and 20 ppm/1000 hr stability maintain ±0.1°C measurement accuracy over 5000-hour service life.

Use Scenario: Monitoring 28 V aircraft bus voltage with ±0.5% accuracy across −55°C to 70°C.

IC Role / Device Role / Timing Role: Adjustable shunt reference feeding comparator input in a redundant overvoltage protection circuit.

Use Value: Hermetic TO-46 package withstands vibration and humidity; 1 Ω dynamic impedance prevents false trips during bus transients.

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable shunt reference applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM385BM/NOPB	SOIC-8 package; 0°C to 70°C rating; 2% initial tolerance; higher 150 ppm/°C tempco.	Commercial-grade, surface-mount only; unsuitable for extended temperature or hermetic requirements.	Select when cost and PCB space outweigh environmental ruggedness and precision.
REF5025AIDR	2.5 V fixed-output; SOIC-8; 3 ppm/°C max tempco; 3.5 μVpp noise; 100 μA quiescent current.	Ultra-low-drift, low-noise, fixed-voltage reference; not adjustable; requires external DAC or resistor network for programmability.	Select when absolute stability > adjustability; avoid if 1.24–5.30 V range or micropower (<100 μA) is mandatory.

Compared with LM185BH, LM385BM/NOPB trades hermetic reliability and 1% tolerance for lower cost and SMT compatibility, while REF5025AIDR sacrifices adjustability and micropower operation to achieve sub-ppm/°C drift-making LM185BH the sole choice for ruggedized, programmable, ultra-low-power shunt references.

Availability

LM185BH is available at Aetrix Electronics and suitable for precision shunt regulators, battery-powered instrumentation, high-temperature sensor interfaces, and aerospace power monitoring requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for LM185BH 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and longevity.

The LM185 series was designed specifically for high-reliability, extended-temperature applications-including military, aerospace, and industrial control-where hermetic sealing, tight initial tolerance, and low long-term drift are non-negotiable.

FAQ

What is the maximum operating temperature for LM185BH?

The LM185BH is rated for continuous operation from −55°C to 125°C. Its hermetic TO-46 package and internal band-gap architecture ensure stable regulation across this full military-grade temperature range, with junction temperature limited to 150°C per TI's thermal characterization data. This makes LM185BH suitable for engine compartments, downhole tools, and avionics bays where ambient extremes occur.

Does LM185BH require an external capacitor for stability?

No, LM185BH is explicitly designed to be tolerant of capacitive loading and remains stable with output capacitance ≥100 nF-no series isolation resistor or compensation network is needed. This simplifies layout in noise-sensitive applications such as precision ADC references and eliminates risk of oscillation when driving long traces or filter networks.

Can LM185BH replace LM385BXZ/NOPB in a new design?

LM185BH is not a drop-in replacement for LM385BXZ/NOPB due to fundamental differences: LM185BH uses a hermetic TO-46 package (NDV drawing) with −55°C to 125°C rating and 1% tolerance, while LM385BXZ/NOPB uses a plastic TO-92 package (LP drawing), 0°C to 70°C rating, and 2% tolerance. PCB footprint, thermal management, and environmental qualification must be re-evaluated before substitution.

What is the minimum cathode current required for LM185BH regulation?

The LM185BH requires a minimum cathode current of 10 μA to maintain regulation-verified across −55°C to 125°C. Below this threshold, output voltage deviates from specification. This value is confirmed in TI's Electrical Characteristics table under "Minimum Operating Current" and enables ultra-low-power use in energy-harvesting and wake-up circuits.

How is the output voltage set on LM185BH?

The LM185BH output voltage is set using an external resistor divider between Cathode and Adjust pins: V_OUT = V_REF(1 + R1/R2), where V_REF = 1.24 V nominal. The Adjust pin draws only 13–35 nA, so high-value resistors (e.g., 1 MΩ/100 kΩ) introduce negligible error. Full range is 1.24 V to 5.30 V, and the LM185BH datasheet provides standard configurations for 2.5 V, 3.3 V, 5.0 V, and 10 V outputs.

LM185BH Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Package/Case:: TO-99-8 Metal Can

Series:: -

Packaging:: Bulk

Product Status:: Active

Reference Type:: Shunt

Output Type:: Adjustable

Voltage - Output (Min/Fixed):: 1.24V

Voltage - Output (Max):: 5.3 V

Current - Output:: 20 mA

Tolerance:: ±1%

Temperature Coefficient:: 150ppm/°C

Noise - 0.1Hz to 10Hz:: -

Noise - 10Hz to 10kHz:: 50µVrms

Voltage - Input:: -

Current - Supply:: -

Current - Cathode:: 45 µA

Operating Temperature:: -55°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-99-8

LM185BH FAQ

1.How can I place an order for LM185BH through Aetrix?

Please submit a Request for Quotation (RFQ) for LM185BH 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 LM185BH reliable?

The price and inventory of LM185BH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM185BH is usually 5 days.

3.What payment methods are accepted for LM185BH?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM185BH transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM185BH?

LM185BH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM185BH 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 LM185BH?

For technical support, including LM185BH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM185BH requirements.

6.How does Aetrix verify that LM185BH is sourced from the original manufacturer or authorized distributors?

All LM185BH 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 LM185BH meets industry standards.

7.What is the process for return or replacement of LM185BH?

All LM185BH units undergo pre-shipment inspection (PSI). If there is an issue with LM185BH, 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 LM185BH part is unused and in its original packaging.

Return procedure for LM185BH:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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