Texas Instruments LP87521SRNFRQ1

Overview

LP87521SRNFRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive buck converter IC with four integrated high-efficiency DC/DC cores configured as a single 4-phase output delivering up to 10 A at 0.6–3.36 V, 2 MHz switching frequency, and I²C programmability for infotainment and ADAS power rails.

For engineers reviewing the LP87521SRNFRQ1 datasheet, LP87521SRNFRQ1 pinout, LP87521SRNFRQ1 application, or LP87521SRNFRQ1 equivalent, key selection criteria include its 4-phase fixed topology, remote differential sensing capability, programmable PGOOD thresholds, and support for spread-spectrum and external clock synchronization in safety-critical automotive systems.

Technical Context

The LP87521SRNFRQ1 implements a fixed 4-phase interleaved buck architecture with per-phase R_DS(on) of 29–65 mΩ (HS) and 17–35 mΩ (LS), automatic PWM-to-PFM mode transition at 200 mA, and phase-add/shed thresholds at 1 A, 2 A, and 3 A for dynamic efficiency optimization across 0–10 A load range.

It supports remote differential voltage sensing on all four feedback channels (FB_B0–FB_B3), configurable GPIOs (EN1–EN3), interrupt masking via I²C, and thermal warning (115–135°C) plus shutdown (140–160°C) with 20°C hysteresis - all operating from 2.8–5.5 V input across –40°C to +125°C ambient.

Key Specifications

Pinout & Package

VQFN-HR (RNF) 26-pin package, 4.50 mm × 4.00 mm body size, exposed thermal pad (AGND-connected).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-phase buck converter applications.

Compared with LP87522SRNFRQ1 and TPS65917B1RSLRQ1, the LP87521SRNFRQ1 provides highest single-rail current density (10 A in 4.5×4.0 mm) and lowest phase-interleaving jitter (300 ps p-p), making it optimal for space-constrained, high-transient automotive core supplies where rail consolidation is preferred.

Availability

LP87521SRNFRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, ADAS radar, and digital instrument cluster applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for LP87521SRNFRQ1 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

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and automotive-grade power management solutions.

The LP8752x-Q1 product line delivers highly integrated, AEC-Q100-compliant multi-phase buck converters optimized for next-generation automotive processor power domains including infotainment, ADAS, and digital cockpit systems.

FAQ

What is the maximum output current capability of the LP87521SRNFRQ1?

The LP87521SRNFRQ1 delivers up to 10 A total output current in its fixed 4-phase configuration when input voltage is ≥3 V. Below 3 V input, the maximum current is derated to 7.2 A. This rating assumes proper thermal design with the exposed thermal pad soldered to a sufficient copper area, and accounts for both forward current limit (14 A peak shared across phases) and thermal limits (140°C junction). The LP87521SRNFRQ1 does not support reconfiguration to other phase counts - its 4-phase topology is hardwired.

Does the LP87521SRNFRQ1 support remote voltage sensing?

Yes, the LP87521SRNFRQ1 supports true remote differential voltage sensing on all four buck channels via dedicated FB_B0–FB_B3 pins. Each feedback pair can be connected directly at the point-of-load to compensate for IR drop across PCB traces or connectors. This ensures ±2% DC output accuracy (≥1 V) and tight regulation under dynamic load conditions, which is essential for powering sensitive automotive processors. The LP87521SRNFRQ1 implements this without requiring external op-amps or resistive dividers.

Can the LP87521SRNFRQ1 be synchronized to an external clock source?

Yes, the LP87521SRNFRQ1 accepts an external clock on the CLKIN pin, supporting nominal frequencies from 1 MHz to 24 MHz with ±30% tolerance. When enabled, the internal PLL locks to the external reference, allowing deterministic phase alignment across multiple LP87521SRNFRQ1 devices or with system clocks - critical for EMI reduction and timing-critical applications like radar or camera synchronization. Clock detection includes 20 µs debounce and 600 µs lock delay.

How does the LP87521SRNFRQ1 handle thermal protection?

The LP87521SRNFRQ1 features dual thermal safeguards: a programmable die temperature warning flag (115–135°C, configurable hysteresis) and hardware thermal shutdown (140–160°C, 20°C hysteresis). Both trigger independently of I²C communication and assert nINT or disable outputs immediately. The device also reports temperature via I²C register reads. These protections operate continuously in all modes - PWM, PFM, or shutdown - ensuring robust operation in sealed automotive enclosures where airflow is limited.

Is the LP87521SRNFRQ1 pin-compatible with other LP8752x-Q1 variants?

Yes, all LP8752x-Q1 devices - including LP87521SRNFRQ1, LP87522SRNFRQ1, LP87523SRNFRQ1, LP87524SRNFRQ1, and LP87525SRNFRQ1 - share identical VQFN-HR 26-pin packaging, pinout, and I²C register map. However, their internal phase configurations differ (e.g., LP87521SRNFRQ1 is fixed 4-phase, LP87522SRNFRQ1 is 3+1-phase), so firmware and layout must match the selected variant's topology. No PCB redesign is needed for substitution within the family, but configuration registers must be updated accordingly.