Texas Instruments LM185H-2.5/NOPB

Overview

LM185H-2.5/NOPB from Texas Instruments is a hermetically sealed, 2-terminal adjustable micropower shunt voltage reference delivering a precise 2.5 V output at 100 μA, with 1% initial tolerance, 1 Ω dynamic impedance, and operation across −55°C to 125°C - used in precision analog sensing, battery-powered instrumentation, and high-reliability aerospace power monitoring.

For engineers reviewing the LM185H-2.5/NOPB datasheet, LM185H-2.5/NOPB pinout, LM185H-2.5/NOPB application, or LM185H-2.5/NOPB equivalent, this page delivers verified electrical specs, thermal performance data, TO-can package layout guidance, and validated alternative options for ruggedized reference design.

Technical Context

The LM185H-2.5/NOPB implements a band-gap reference architecture using only transistors and resistors - enabling low noise (50 μV_RMS), excellent long-term stability (20 ppm), and immunity to capacitive loading. Its 2-terminal configuration simplifies PCB layout versus 3-terminal adjustable variants.

It operates as a shunt regulator with reverse-biased terminal configuration: anode grounded, cathode connected to supply via series resistor. Minimum operating current is 6 μA (max), and it sustains regulation up to 30 mA reverse current while maintaining <4 mV voltage change over 1–20 mA load range.

Key Specifications

Pinout & Package

LM185H-2.5/NOPB uses a hermetic TO-46 metal can package (NDU drawing), 2.67 mm max height, with 2 terminals: Anode (pin 1) and Cathode (pin 2). The package is lead-free, RoHS-compliant, and rated for 300°C soldering (10 sec).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM385Z-2.5/NOPB, LM185H-2.5/NOPB provides tighter tolerance, lower TC, and full military-temperature operation in a hermetic package; versus REF3025AIDBZR, it offers superior long-term stability and zero external component count but lacks fixed-output convenience and sub-1% tolerance.

Availability

LM185H-2.5/NOPB is available at Aetrix Electronics and suitable for aerospace power monitoring, downhole instrumentation, portable precision multimeters, and medical infusion pump controllers requiring stable component supply under extended temperature and long-lifecycle conditions.

Supply support for LM185H-2.5/NOPB 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, with decades of heritage in precision reference design and space-qualified product development.

The LM185 series was engineered for high-stability, low-drift voltage references in mission-critical systems - targeting aerospace, defense, oilfield, and industrial applications demanding hermetic packaging and extended temperature operation.

FAQ

What is the maximum reverse current rating for LM185H-2.5/NOPB?

The absolute maximum reverse current for LM185H-2.5/NOPB is 30 mA, as specified in the Absolute Maximum Ratings table. This defines the upper limit before potential device damage occurs. Operating continuously near this limit requires careful thermal design due to junction-to-ambient thermal resistance of 165°C/W in the TO-46 package. For reliable long-term operation, TI recommends staying below 20 mA under worst-case ambient conditions.

Does LM185H-2.5/NOPB require an external capacitor for stability?

No, LM185H-2.5/NOPB does not require an external capacitor for stability. Its internal design is tolerant of capacitive loading - a key feature confirmed in the datasheet - allowing direct connection of ≥1 μF bypass capacitors without oscillation. This simplifies layout in noise-sensitive applications like precision ADC references and eliminates risk of instability caused by PCB parasitics or ceramic capacitor ESR variations.

Can LM185H-2.5/NOPB be used as a 2.5 V series voltage reference?

No, LM185H-2.5/NOPB is a 2-terminal shunt voltage reference and cannot function as a series reference. It must be connected with its anode to ground and cathode to a positive supply through a current-setting resistor. Attempting series-mode connection violates its operational topology and will prevent proper regulation. For series topology, consider fixed-output series references like TLV431 or REF3025.

What is the marking code printed on the LM185H-2.5/NOPB package?

The device marking on LM185H-2.5/NOPB is "LM185H2.5" (as shown in the PACKAGE OPTION ADDENDUM), with possible secondary marking "LM185 H2.5". This 2-line marking appears on the top surface of the TO-46 metal can. The "H" denotes the hermetic TO-46 package variant, and "2.5" specifies the nominal 2.5 V output version - distinct from the adjustable LM185-ADJ family members.

How does the temperature coefficient of LM185H-2.5/NOPB compare to LM285Z-2.5/NOPB?

LM185H-2.5/NOPB has a guaranteed maximum temperature coefficient of 30 ppm/°C (X suffix), while LM285Z-2.5/NOPB is rated at 50 ppm/°C (Y suffix) over −40°C to +85°C. The LM185H-2.5/NOPB achieves tighter TC via on-chip trimming and hermetic packaging that minimizes stress-induced drift - making it preferable for applications requiring stability across −55°C to +125°C where LM285Z-2.5/NOPB is not rated to operate.