Analog Devices Inc. LT3092MPST

Overview

LT3092MPST from Analog Devices (formerly Linear Technology) is a precision 2-terminal programmable current source IC designed for intrinsically safe and high-impedance applications. It delivers 0.5mA to 200mA output current with 1% initial SET pin current accuracy, <0.001%/V line regulation, and operates across 1.2V–40V input-to-output differential voltage. It requires no input or output capacitors for stability and features reverse-voltage and reverse-current protection.

For engineers reviewing the LT3092MPST datasheet, LT3092MPST pinout, LT3092MPST application, or LT3092MPST equivalent, this device is selected for precision current sourcing in hazardous-area sensor interfaces, remote 4–20mA loop drivers, and fault-tolerant current limiting where capacitor-free operation and wide temperature range (–55°C to 125°C) are critical.

Technical Context

The LT3092MPST implements a Kelvin-sensed, low-noise 10µA reference current source feeding a power operational amplifier, enabling accurate resistor-ratio-based current programming without external feedback. Its architecture provides >100dB AC impedance at the OUT pin and eliminates need for bypass capacitors by design.

It operates in true 2-terminal mode-only IN and OUT carry load current-while the SET pin sources a precision 10µA current referenced to OUT. Internal protection includes thermal shutdown with hysteresis, current limiting (200mA min), and robust ±40V IN-to-SET/OUT absolute maximum rating.

Key Specifications

Pinout & Package

LT3092MPST is packaged in a 3-lead plastic SOT-223 with exposed tab electrically connected to OUT. The tab must be soldered directly to the PCB's OUT net for thermal and electrical integrity. Pin 1 = IN, Pin 2 = OUT (and tab), Pin 3 = SET.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-terminal current source applications.

Compared with LT3092MPST, LT3092EST#TRPBF trades extended cold-temperature operation for lower cost, while LT3092ETS8#TRPBF offers miniaturization at the expense of thermal performance - both retain the core 2-terminal programmability and capacitor-free stability.

Availability

LT3092MPST is available at Aetrix Electronics and suitable for 4–20mA loop transmitters, intrinsically safe sensor interfaces, and remote power supply limiters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LT3092MPST 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

Analog Devices acquired Linear Technology in 2017 and maintains its high-performance analog IC portfolio. The company specializes in precision signal conditioning, power management, and interface solutions for demanding industrial and aerospace applications.

The LT3092MPST belongs to Linear Technology's precision current source product line, engineered specifically for applications demanding capacitor-free stability, intrinsic safety compliance, and operation across extreme ambient temperatures.

FAQ

What is the minimum load current required for LT3092MPST to regulate?

The LT3092MPST requires a minimum load current of 0.5mA to maintain regulation. Below this threshold, the device exits regulation and output current becomes undefined. This value is specified in the Electrical Characteristics table under "Minimum Load Current" and is consistent across the –55°C to 125°C operating range for the MP grade. The LT3092MPST achieves this via internal biasing that ensures sufficient quiescent current flow even at ultra-low output settings.

Does LT3092MPST require input or output capacitors for stability?

No, the LT3092MPST is explicitly designed to operate stably without input or output capacitors - a key feature enabling intrinsic safety compliance. Its architecture provides inherently high DC and AC output impedance (>100dB), eliminating the need for external frequency compensation in most configurations. Capacitors may be added only for noise reduction or specific frequency compensation in complex impedance environments, but they are never mandatory for basic regulation.

How is output current programmed on the LT3092MPST?

Output current on the LT3092MPST is programmed using two external resistors: R_SET connected from SET to OUT, and R_OUT connected from OUT to load. The 10µA precision current sourced from the SET pin develops a voltage across R_SET, which is then applied across R_OUT to generate I_OUT = (10µA × R_SET) / R_OUT. This resistor-ratio method provides inherent temperature tracking when R_SET and R_OUT share the same material and TC.

What protection features does the LT3092MPST include?

The LT3092MPST integrates reverse-voltage protection, reverse-current protection, current limiting (guaranteed ≥200mA), and thermal shutdown with hysteresis. These features are implemented in silicon and do not rely on external components. Reverse-voltage protection prevents damage if IN is driven below OUT; reverse-current protection blocks current flow from OUT to IN during fault conditions; and thermal shutdown activates at ~165°C junction temperature, latching off until cooldown.

Can multiple LT3092MPST devices be paralleled to increase output current?

Yes, multiple LT3092MPST devices can be paralleled to scale output current. Two validated methods exist: (1) Tie all IN pins together and all OUT pins together - simple but less precise sharing; (2) Tie all SET pins together and all IN pins together, then connect each OUT through a small ballast resistor (e.g., 40mΩ) to a common node - achieves >80% current sharing at full load. Both methods preserve the LT3092MPST's capacitor-free operation and protection features.