Analog Devices Inc. LT3092EST

Overview

LT3092EST from Analog Devices (formerly Linear Technology) is a 3-lead SOT-223 packaged, 2-terminal programmable current source IC. It delivers precisely set output currents from 0.5mA to 200mA using only two external resistors, operates with 1.2V to 40V input-to-output differential voltage, features 10µA SET pin reference current with 1% initial accuracy, and supports intrinsically safe applications due to capacitor-free stability and reverse-voltage/reverse-current protection.

For engineers reviewing the LT3092EST datasheet, LT3092EST pinout, LT3092EST application, or LT3092EST equivalent, this page provides verified technical context, real-world design meaning for key specs, validated SOT-223 package mapping, confirmed 3-pin terminal roles, and two rigorously cross-checked alternative parts - all grounded in the official LT3092 datasheet and Analog Devices product documentation.

Technical Context

The LT3092EST implements a precision 10µA internal reference current source feeding the noninverting input of a high-gain power operational amplifier. Its 2-terminal configuration enables floating or ground-referred current sourcing without requiring input or output bypass capacitors - a critical enabler for intrinsic safety compliance and surge-immune sensor interfaces.

Regulation relies on Kelvin-sensed current feedback at the OUT pin, achieving better than 10ppm/V line regulation (0.001%/V typical) and <±2mV offset voltage over –40°C to 125°C. Protection includes reverse-battery tolerance up to ±40V on IN relative to OUT, thermal shutdown with hysteresis, and current limiting at 200mA minimum.

Key Specifications

Pinout & Package

LT3092EST uses the 3-lead plastic SOT-223 package (ST package). The exposed tab is electrically connected to the OUT pin and must be soldered directly to the PCB's OUT net for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3092ETS8#TRPBF, the LT3092EST offers superior thermal performance (24°C/W vs. 57°C/W) enabling full 200mA operation in ambient temperatures up to 85°C, while LM334Z/NOPB lacks both the current drive and integrated protection needed for robust industrial current sourcing.

Availability

LT3092EST is available at Aetrix Electronics and suitable for industrial process control, hazardous-area instrumentation, and precision sensor excitation requiring stable component supply with guaranteed long-term continuity.

Supply support for LT3092EST 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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.

The LT3092EST belongs to ADI's precision current source product line, engineered specifically for applications demanding capacitor-free stability, intrinsic safety compliance, and wide-input-range programmable current delivery in harsh industrial environments.

FAQ

What is the minimum load current required for LT3092EST to maintain regulation?

The LT3092EST requires a minimum load current of 0.5mA to sustain regulation. Below this threshold, the internal error amplifier cannot maintain closed-loop control, resulting in unregulated output. This value is specified in the Electrical Characteristics table under "Minimum Load Current" and is independent of input voltage within the 1.2V–40V differential range. Designers must ensure that ROUT is sized such that IOUT ≥ 0.5mA under all operating conditions.

Can LT3092EST operate without any external capacitors?

Yes, the LT3092EST is explicitly designed for capacitor-free operation - both input and output capacitors are optional. Its architecture achieves stability through high DC and AC output impedance, eliminating reliance on external capacitance for phase margin. This feature is critical for intrinsic safety applications where stored energy must be minimized. However, a capacitor across RSET (CSET) may be added to reduce noise, though it introduces a pole requiring external compensation per the datasheet's Stability section.

How does the LT3092EST achieve reverse-voltage protection?

The LT3092EST incorporates internal reverse-voltage protection that blocks conduction when the IN pin is driven more than –40V relative to OUT. This is implemented via integrated diode structures and bias circuitry that disable internal current paths under reverse polarity. Unlike external diode solutions, this protection adds no forward voltage drop or thermal overhead during normal operation and remains active across the full –40°C to 125°C temperature range without derating.

What is the role of the exposed tab on the LT3092EST SOT-223 package?

The exposed tab on the LT3092EST is electrically connected to the OUT pin and serves dual thermal and electrical functions. It must be soldered directly to the PCB copper area assigned to the OUT net to provide low-thermal-resistance heat dissipation (θJC = 15°C/W) and to maintain low-impedance current return. Failure to connect the tab results in excessive junction temperature rise and potential thermal shutdown at currents above ~100mA, as confirmed by the Absolute Maximum Ratings table and Applications Information section.

Is LT3092EST pin-compatible with other LT3092 variants like LT3092EDD?

No, LT3092EST is not pin-compatible with LT3092EDD or LT3092ETS8. The LT3092EST uses a 3-lead SOT-223 package with IN/OUT/SET on pins 3/2/1 respectively, while LT3092EDD is an 8-lead DFN (with NC pins and different pin numbering) and LT3092ETS8 is an 8-lead TSOT-23 (IN/OUT/SET on pins 7/2/5). Mechanical and electrical pinouts differ fundamentally - PCB layout, thermal pad connection, and routing must be redesigned for each variant.