Analog Devices Inc. LT1580CT#06PBF

Overview

LT1580CT#06PBF from Analog Devices (formerly Linear Technology) is a 7A, fixed 2.5V low-dropout linear regulator with dual-supply architecture (VPOWER and VCONTROL), remote SENSE capability, 1mV load regulation (100mA–7A), and 540mV dropout at full load. It serves as a high-current microprocessor core supply on motherboards where both 3.3V/5V rails are available.

For engineers reviewing the LT1580CT#06PBF datasheet, LT1580CT#06PBF pinout, LT1580CT#06PBF application, or LT1580CT#06PBF equivalent, key selection criteria include its 2.5V fixed output accuracy (±0.6% initial), dual-input dropout optimization, Kelvin sensing for <1mV load regulation, and TO-220-7L package thermal performance (θ_JA = 50°C/W).

Technical Context

The LT1580CT#06PBF uses a two-rail architecture: VPOWER supplies the NPN pass transistor collector (output current path), while VCONTROL powers the control circuitry and provides ~1% drive current (e.g., ~70mA at 7A). This enables saturation of the output transistor, reducing dropout by one V_BE versus conventional LDOs.

It features internal ratiometric resistor dividers for fixed 2.5V output, a dedicated SENSE pin for true Kelvin sensing at the load, and an exposed ADJ pin-even on the fixed-voltage variant-to allow external capacitor bypassing (0.1–1µF) for enhanced transient response and ripple rejection (60–80dB).

Key Specifications

Pinout & Package

LT1580CT#06PBF is housed in a 7-lead plastic TO-220 package (T7) with exposed tab (thermal and electrical connection to GND). The package includes dedicated pins for remote sensing and dual-supply operation, enabling precise load regulation and minimized dropout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current, low-dropout regulator applications.

Compared with LTC3085-2.5#PBF and TPS7A8300RGRT, the LT1580CT#06PBF uniquely delivers <1mV load regulation via remote SENSE and achieves 540mV dropout through dual-supply optimization - making it irreplaceable in applications demanding both precision and efficiency at 7A.

Availability

LT1580CT#06PBF is available at Aetrix Electronics and suitable for microprocessor core supplies, post-regulators for switching supplies, and high-current industrial loads requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for LT1580CT#06PBF 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, emphasizing precision, power efficiency, and reliability for demanding applications.

The LT1580 product line was designed specifically for next-generation microprocessor core supplies - addressing the need for high-current, ultra-low-dropout regulation with remote sensing and dual-rail architecture in desktop and industrial computing platforms.

FAQ

What is the maximum dropout voltage of the LT1580CT#06PBF at 7A load?

The LT1580CT#06PBF exhibits a maximum dropout voltage of 540 mV at 7A output current (VPOWER–VOUT), measured at 0°C ≤ T_J ≤ 125°C. This value increases slightly at lower temperatures (up to 0.80 V at –40°C ≤ T_J ≤ 0°C), and is specified under conditions where VCONTROL is ≥1.0V above VOUT. The LT1580CT#06PBF achieves this low dropout via its dual-supply architecture, separating VPOWER (collector drive) and VCONTROL (bias and base drive) paths.

Can the LT1580CT#06PBF operate with only one input supply?

Yes, the LT1580CT#06PBF can operate as a single-supply device by connecting VPOWER and VCONTROL together. In this configuration, dropout is determined solely by the minimum VCONTROL requirement (≥1.0V above VOUT), resulting in higher effective dropout than dual-supply mode. The LT1580CT#06PBF retains all protection features and remote sensing capability, but loses the sub-0.6V dropout advantage - typical dropout rises to ~1.15V at 7A.

Why does the LT1580CT#06PBF have an ADJ pin despite being a fixed 2.5V regulator?

The ADJ pin is brought out on the LT1580CT#06PBF to enable external capacitor bypassing (0.1–1µF to GND), which improves transient response and ripple rejection - a feature absent in legacy fixed-output LDOs. This allows system designers to optimize stability and dynamic performance without modifying internal feedback resistors. The LT1580CT#06PBF's ADJ pin is not used for voltage adjustment but serves as a dedicated noise-filtering node tied to the internal reference divider.

How does remote sensing work on the LT1580CT#06PBF, and what benefit does it provide?

Remote sensing on the LT1580CT#06PBF uses the dedicated SENSE pin connected directly to the load's VDD point, closing the regulation loop at the load instead of at the regulator output. This eliminates voltage errors caused by PCB trace resistance between the LT1580CT#06PBF and the load. As a result, the LT1580CT#06PBF achieves <1mV load regulation over 100mA–7A - critical for CPU core voltage compliance where even millivolt shifts affect timing margins.

What thermal considerations apply to the LT1580CT#06PBF in TO-220-7L package?

The LT1580CT#06PBF in TO-220-7L has separate thermal specifications: θ_JA = 50°C/W (power transistor), θ_JC = 2.7°C/W (junction-to-case), and control-section θ_JC = 0.65°C/W. With 7A at 540mV dropout, power dissipation reaches ~3.8W - requiring a heatsink to keep T_J ≤ 125°C (control section limit). The exposed tab must be thermally and electrically connected to GND for optimal performance. The LT1580CT#06PBF includes thermal shutdown but relies on external heatsinking for continuous operation.