Analog Devices Inc. LTC1530CS8-2.5#PBF

Overview

LTC1530CS8-2.5#PBF from Analog Devices (formerly Linear Technology) is a high-power synchronous buck controller IC designed to regulate 5V or 3.3V input down to a fixed 2.5V output for microprocessor core supplies. It drives two external N-channel MOSFETs, delivers up to 14A output current, achieves >95% efficiency at full load, and maintains ±2.5% output voltage regulation over line, load, and temperature. It is used in Pentium II and AMD-K6-2 CPU power delivery systems.

For engineers reviewing the LTC1530CS8-2.5#PBF datasheet, LTC1530CS8-2.5#PBF pinout, LTC1530CS8-2.5#PBF application, or LTC1530CS8-2.5#PBF equivalent, key selection criteria include its fixed 2.5V output, topside R_DS(ON)-based current sensing without external sense resistor, 300kHz fixed-frequency PWM operation, internal soft-start, and hiccup-mode overcurrent protection.

Technical Context

The LTC1530CS8-2.5#PBF implements a voltage-mode PWM control architecture with an internal 300kHz oscillator, transconductance error amplifier (g_mERR = 2 mS typ), and dual high-current gate drivers (G1/G2) optimized for low-side and high-side N-MOSFET switching. Its feedback loop uses a precision 1.235V internal reference and includes MIN/MAX comparators for fast transient response-forcing 0% or 100% duty cycle when V_FB deviates >±3% from reference.

Current limiting operates by comparing the voltage drop across the high-side MOSFET's R_DS(ON) (sensed at IFB) against a threshold set by IMAX pin current (200µA sink). Thermal shutdown disables both drivers above ~150°C junction temperature, and undervoltage lockout prevents operation until PVCC ≥ 3.75V.

Key Specifications

Pinout & Package

Package: 8-lead plastic SOIC (S8), 130°C/W θ_JA, rated for 0°C to 70°C ambient (Commercial grade).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Compared with LTC1530CS8-2.5#PBF, the LTC1530CS8-2.5 lacks RoHS compliance assurance, while the TPS54325RGLT trades external FET scalability and R_DS(ON) sensing for monolithic simplicity - making LTC1530CS8-2.5#PBF the only option for high-current, thermally robust, and sense-resistor-free 2.5V core regulation.

Availability

LTC1530CS8-2.5#PBF is available at Aetrix Electronics and suitable for desktop CPU core supplies, industrial PLC I/O modules, and medical FPGA power systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for LTC1530CS8-2.5#PBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.

The LTC1530 product line was developed specifically for high-current, low-voltage synchronous buck conversion in microprocessor and ASIC core power applications, emphasizing efficiency, transient response, and integrated protection.

FAQ

What is the output voltage tolerance of the LTC1530CS8-2.5#PBF over temperature and load?

The LTC1530CS8-2.5#PBF provides a fixed 2.5V output with worst-case regulation of ±2.5% across 0°C to 70°C ambient temperature, full load current (0–14A), and input voltage variation (4.75V–5.25V). This is achieved via factory-trimmed internal feedback resistors and a precision 1.235V reference, eliminating drift from external components.

Does the LTC1530CS8-2.5#PBF require an external current sense resistor?

No, the LTC1530CS8-2.5#PBF does not require an external current sense resistor. It uses the R_DS(ON) of the external high-side N-channel MOSFET as the current sensing element via the IFB and IMAX pins - reducing power loss, board area, and thermal stress in high-current paths.

What is the purpose of the MIN and MAX comparators in the LTC1530CS8-2.5#PBF?

The MIN and MAX comparators in the LTC1530CS8-2.5#PBF provide ultra-fast (<3µs response) override of the main error amplifier when feedback voltage deviates more than ±3% from the 1.235V reference. MIN forces maximum duty cycle for sudden load increases; MAX forces zero duty cycle for overvoltage - enabling rapid recovery from large transients without loop instability.

How does the LTC1530CS8-2.5#PBF enter and exit thermal shutdown?

The LTC1530CS8-2.5#PBF enters thermal shutdown when junction temperature exceeds ~150°C, disabling both G1 and G2 drivers and reducing supply current to ~1mA. It automatically exits shutdown and resumes normal operation once junction temperature falls below ~100°C - no external reset or power cycle is required.

Can the LTC1530CS8-2.5#PBF operate with a 5V-only input without a separate PVCC supply?

Yes, the LTC1530CS8-2.5#PBF can operate with a 5V-only input using an external charge pump (e.g., diode-capacitor doubler) to generate PVCC ≥8V. However, logic-level MOSFETs must be used - standard MOSFETs may not fully enhance due to insufficient gate drive, risking premature current limit activation and start-up failure.