Analog Devices Inc. LT1580IT#06PBF

Overview

LT1580IT#06PBF from Analog Devices (formerly Linear Technology) is a 7A fixed-output 2.5V low-dropout linear regulator with dual-supply architecture, remote sense capability, 1mV load regulation (100mA–7A), and 540mV dropout at full load - designed specifically for Pentium® and PowerPC™ microprocessor core supplies on motherboards using available 3.3V/5V rails.

For engineers reviewing the LT1580IT#06PBF datasheet, LT1580IT#06PBF pinout, LT1580IT#06PBF application, or LT1580IT#06PBF equivalent, key selection criteria include dual-input voltage requirements (VCONTROL ≥ VOUT + 1.0V, VPOWER ≥ VOUT + 0.1V), Kelvin-sense accuracy, thermal derating above 12W, and compatibility with low-ESR tantalum/aluminum output capacitors ≥150µF.

Technical Context

The LT1580IT#06PBF implements a two-rail NPN-based LDO architecture where VCONTROL powers the control circuitry and drives the output transistor base, while VPOWER supplies the collector current path - enabling 100mV dropout at light loads and 540mV at 7A by saturating the pass transistor. This eliminates supply sequencing issues: output remains off until both rails are valid.

It features a dedicated SENSE pin for true Kelvin sensing at the load, an exposed-tab TO-220-7 package with isolated GND pin, and ADJ pin brought out on the fixed 2.5V variant to support transient-response-enhancing bypass capacitance (0.1–1µF).

Key Specifications

Pinout & Package

LT1580IT#06PBF uses a 7-lead plastic TO-220 package (T7) with exposed metal tab (thermal and electrical connection to GND). Pin 1 is SENSE, Pin 2 is ADJ, Pin 3 is VOUT, Pin 4 is VCONTROL, Pin 5 is GND, Pin 6 is VPOWER, Pin 7 is NC. The tab serves as primary thermal path and functional GND return.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3085EDE#PBF and TPS7A8300RGRT, the LT1580IT#06PBF uniquely delivers 7A output with sub-1V dropout via dual-rail architecture and true Kelvin sensing - making it irreplaceable for legacy Pentium®/PowerPC™ core supplies requiring guaranteed 1mV load regulation and sequencing immunity.

Availability

LT1580IT#06PBF is available at Aetrix Electronics and suitable for microprocessor core supplies, high-current industrial logic, post-regulation of switching supplies, and portable Pentium® systems requiring stable component supply with long-term lifecycle assurance.

Supply support for LT1580IT#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 industrial and computing applications.

The LT1580 product line was designed specifically for next-generation microprocessor core voltage regulation - addressing tight load regulation, fast transient response, and dual-rail efficiency needs in desktop and embedded computing platforms.

FAQ

What is the minimum required voltage difference between VCONTROL and VOUT for LT1580IT#06PBF to regulate properly?

The LT1580IT#06PBF requires VCONTROL ≥ VOUT + 1.00V at 100mA load and up to VOUT + 1.30V at 7A load (–40°C to 125°C). For reliable 2.5V operation, a 5V VCONTROL rail is recommended - ensuring margin across temperature and load. Below this threshold, regulation degrades and current limiting may activate.

Can LT1580IT#06PBF operate from a single input supply, and what is the impact on dropout performance?

Yes, LT1580IT#06PBF can operate with VCONTROL and VPOWER tied together (single-supply mode), but dropout is then determined solely by the minimum VCONTROL specification - resulting in higher effective dropout (comparable to LT1584). Dual-supply operation is required to achieve the rated 540mV dropout at 7A.

Why does LT1580IT#06PBF include an ADJ pin on a fixed 2.5V device, and how should it be used?

The ADJ pin on LT1580IT#06PBF is brought out to allow a bypass capacitor (0.1–1µF) to ground, which improves transient response and ripple rejection. It is not used for output adjustment. This feature is unique to the fixed-voltage LT1580 variants and enables optimization for specific PCB output capacitance profiles.

What output capacitor types and minimum values ensure stability for LT1580IT#06PBF?

LT1580IT#06PBF requires ≥150µF aluminum electrolytic or ≥22µF tantalum output capacitance for stability. Low-ESR types (<1Ω) are strongly preferred. Ceramic capacitors alone are insufficient; hybrid networks (bulk tantalum + high-frequency ceramics near the load) are recommended for microprocessor applications to handle fast load transients.

How does the SENSE pin function in LT1580IT#06PBF, and what happens if it is not used?

In LT1580IT#06PBF, the SENSE pin provides Kelvin feedback from the load to the internal reference amplifier. If unused (tied to VOUT), regulation occurs at the regulator output - introducing error from PCB trace resistance (e.g., 7mV error per 1mΩ at 7A). Using SENSE restores <1mV load regulation accuracy at the actual load point.