Texas Instruments LM185-1.2-MD8

Overview

LM185-1.2-MD8 from Texas Instruments is a micropower 2-terminal band-gap voltage reference diode delivering 1.223 V to 1.247 V reverse breakdown voltage at 10 µA, with 1 Ω typical dynamic impedance and ±50 ppm/°C temperature coefficient across −55°C to +125°C. It operates over 10 µA–20 mA current range and supports radiation-hardened applications up to 100 krad(Si).

For engineers reviewing the LM185-1.2-MD8 datasheet, LM185-1.2-MD8 pinout, LM185-1.2-MD8 application, or LM185-1.2-MD8 equivalent, key selection criteria include low-drift micropower reference stability in space-grade analog circuits, capacitive loading tolerance, and post-irradiation voltage shift compliance under MIL-STD-883 Group A/B testing.

Technical Context

The LM185-1.2-MD8 implements a band-gap reference architecture using only transistors and resistors-enabling low noise, excellent long-term stability, and immunity to process-induced drift. Its on-chip trimming achieves tight initial voltage tolerance without laser adjustment.

It features exceptional capacitive loading tolerance (no external compensation required) and maintains regulation across supply variations due to wide 10 µA–20 mA operating current range. Radiation qualification includes low-dose-rate testing at 10 mrad/s and post-100 krad(Si) electrical verification per MIL-STD-883 Method 1019.

Key Specifications

Pinout & Package

LM185-1.2-MD8 is supplied in an 8-pin metal DIP (MD8) package per TI's legacy military packaging standard. The device is a 2-terminal device: Pin 1 is cathode (+VREF), Pin 8 is anode (V−); all other pins are internally unconnected (NC) and must remain floating or grounded per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM185-1.2-MD8, LM385B-1.2/NOPB offers lower cost and wider availability but lacks radiation hardening and extended temperature validation; REF102CP delivers tighter TC and better long-term drift but triples operating current and requires 3-terminal layout-making LM185-1.2-MD8 optimal for radiation-tolerant, micropower, 2-terminal reference needs.

Availability

LM185-1.2-MD8 is available at Aetrix Electronics and suitable for spacecraft power monitoring, avionics cold-junction compensation, and military thermometer calibration requiring stable component supply across extended product lifecycles.

Supply support for LM185-1.2-MD8 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, embedded processing, and high-reliability components for aerospace, defense, and industrial markets.

The LM185 family was designed specifically for precision, radiation-tolerant voltage referencing in mission-critical analog signal chains-prioritizing long-term stability, micropower operation, and MIL-STD-883 compliance over cost or integration density.

FAQ

What is the maximum reverse current rating for LM185-1.2-MD8?

The absolute maximum reverse current for LM185-1.2-MD8 is 30 mA per TI's SNVS384B datasheet. Exceeding this value risks permanent junction damage. For reliable operation, the recommended reverse current range remains 10 µA to 20 mA-where the device achieves specified voltage accuracy, low dynamic impedance, and minimal temperature coefficient deviation. LM185-1.2-MD8 must never be operated continuously above 30 mA.

Does LM185-1.2-MD8 require an external capacitor for stability?

No, LM185-1.2-MD8 does not require an external capacitor for stability. Its internal design provides inherent immunity to capacitive loading-TI confirms stable operation with output capacitances up to and exceeding 1 µF. This eliminates the need for series isolation resistors or external compensation networks commonly required by older reference diodes. LM185-1.2-MD8 maintains regulation integrity even when directly driving ADC reference inputs or op-amp feedback nodes with large bypass caps.

Is LM185-1.2-MD8 pin-compatible with LM385-1.2 variants?

No, LM185-1.2-MD8 is not pin-compatible with LM385-1.2 variants. LM185-1.2-MD8 uses an 8-pin MDIP package with only Pins 1 and 8 active (cathode/anode); LM385-1.2 typically uses 3-pin TO-92 or SOIC-8 packages with separate adjust, cathode, and anode terminals. Their pinouts, terminal counts, and biasing methods differ fundamentally-requiring PCB redesign for substitution. LM185-1.2-MD8 is a true 2-terminal device; LM385-1.2 is a 3-terminal shunt regulator.

What is the post-irradiation voltage shift specification for LM185-1.2-MD8?

Per TI's SNVS384B datasheet, LM185-1.2-MD8 exhibits a maximum post-100 krad(Si) reverse breakdown voltage shift of ±3% at IR = 10 µA and ±2.5% at IR = 20 mA. These values represent change from the pre-irradiation baseline reading and are verified under MIL-STD-883 Method 1019 low-dose-rate conditions (10 mrad/s). LM185-1.2-MD8 retains full functionality and parameter compliance within these bounds after irradiation exposure.

Can LM185-1.2-MD8 be used as a forward-biased voltage source?

Yes, LM185-1.2-MD8 can operate in forward bias with IF = 2 mA, delivering VF = −1.0 V to −0.4 V per datasheet specifications. However, forward conduction is not its intended function-the device is optimized as a reverse-biased band-gap reference. Forward-mode use sacrifices voltage accuracy, temperature stability, and long-term reliability. For robust forward-voltage applications, dedicated low-VF diodes or regulators should be selected instead of LM185-1.2-MD8.