Texas Instruments LP877021RHBRQ1

Overview

LP877021RHBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive power management IC integrating two high-efficiency buck converters (3.5-A max each), a 5-V boost converter (600-mA max), dual external voltage monitoring inputs, programmable power-good signals, window watchdog with reset output, and comprehensive protection including overtemperature warning/shutdown, OVP/UVLO, short-circuit, and overload detection. It serves as the primary power sequencer and safety monitor in radar and camera ECU designs.

For engineers reviewing the LP877021RHBRQ1 datasheet, LP877021RHBRQ1 pinout, LP877021RHBRQ1 application, or LP877021RHBRQ1 equivalent, this device delivers deterministic power sequencing, real-time diagnostic coverage for ASIL-B–capable systems, I²C-controlled configuration up to 3.4 MHz, and spread-spectrum modulation to reduce EMI in dense automotive PCB layouts.

Technical Context

The LP877021RHBRQ1 implements dual independent buck regulators with auto PWM/PFM mode switching and remote voltage sensing to compensate IR drop at point-of-load, ensuring ±2% DC accuracy across load and temperature. Its integrated 5-V boost supports always-on domains and sensor biasing, while the dedicated analog reference voltage (VREF) and two configurable VMON inputs enable precise external rail monitoring.

Functional safety features include a window watchdog with programmable timeout and reset assertion, dual independent power-good outputs with adjustable delay and polarity, and thermal warning (115–150°C) plus shutdown (140–160°C) thresholds. All diagnostics are accessible and maskable via I²C register interface supporting Standard (100 kHz), Fast (400 kHz), Fast+ (1 MHz), and High-Speed (3.4 MHz) modes.

Key Specifications

Pinout & Package

The LP877021RHBRQ1 is housed in a thermally enhanced 32-pin VQFN package (5.0 mm × 5.0 mm) with exposed thermal pad for efficient heat dissipation in automotive under-hood environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive power management applications.

Compared with TPS653211CQDQ1 and LP87745RJBRQ1, the LP877021RHBRQ1 uniquely balances dual high-current buck regulation, comprehensive safety diagnostics (dual VMON, window watchdog, thermal warning), and compact 5-mm VQFN packaging - making it optimal for ASIL-B radar and camera ECUs where space, safety, and performance intersect.

Availability

LP877021RHBRQ1 is available at Aetrix Electronics and suitable for automotive radar, ADAS camera, and sensor fusion applications requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.

Supply support for LP877021RHBRQ1 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 and embedded processing technologies, with leadership in automotive power management and functional safety solutions.

The LP877021RHBRQ1 belongs to TI's LP877x-Q1 automotive PMIC family, designed specifically for radar, camera, and sensor fusion ECUs requiring high-efficiency dual-buck regulation, integrated safety diagnostics, and AEC-Q100 Grade 1 operation.

FAQ

What is the maximum supported switching frequency of the LP877021RHBRQ1 buck converters?

The LP877021RHBRQ1 buck converters support OTP-programmable switching frequencies of 2 MHz, 3 MHz, or 4 MHz. At 4-MHz operation, the typical minimum input-to-output voltage difference required is 1.0 V for loads above 2 A. This high-frequency capability allows use of smaller 0.47-µH inductors and 22-µF ceramic output capacitors, reducing solution size in space-constrained radar modules. The LP877021RHBRQ1 maintains stable regulation and <5 mV_p-p ripple even at 4 MHz in PWM mode.

Does the LP877021RHBRQ1 support external clock synchronization, and what is the valid input frequency range?

Yes, the LP877021RHBRQ1 supports external clock synchronization via the CLKIN pin (Pin 22), which accepts nominal frequencies from 1 MHz to 24 MHz with ±30% tolerance. Clock detection delay is 1.8 µs for loss and 20 µs for valid signal recognition. Once locked, the internal PLL achieves <300 ps cycle-to-cycle jitter. This feature enables EMI reduction through frequency alignment with other system clocks and eliminates beat frequencies in multi-PMIC designs. The LP877021RHBRQ1 uses the external clock to drive both buck and boost switching stages synchronously.

How does the LP877021RHBRQ1 implement remote voltage sensing, and which pins are used?

The LP877021RHBRQ1 implements remote voltage sensing using dedicated FB_B0 (Pin 2) and FB_B1 (Pin 3) pins, which connect directly to the point-of-load (e.g., SoC VDD pins) rather than the regulator output node. This compensates for IR drop across PCB traces and improves DC output voltage accuracy to ±2% across load, line, and temperature. The LP877021RHBRQ1 does not require separate sense resistors - the feedback path is high-impedance analog input. Remote sensing is active in both PWM and PFM modes and is essential for maintaining tight regulation in high-current radar processor applications.

What diagnostic functions are integrated into the LP877021RHBRQ1, and how are they accessed?

The LP877021RHBRQ1 integrates dual voltage monitoring inputs (VMON1/Pin 30, VMON2/Pin 31), window watchdog (WDI/Pin 7, WD_RESET/Pin 6), programmable power-good outputs (PG0/Pin 29, PG1/Pin 32), thermal warning/shutdown, and overvoltage/undervoltage protection. All diagnostics are configured and monitored via its I²C interface (SCL/Pin 20, SDA/Pin 21) supporting up to 3.4 MHz. Interrupts (nINT/Pin 1) flag active faults, and registers provide real-time status of each monitored parameter. The LP877021RHBRQ1 uses a dedicated internal 1.2-V reference (VREF) to ensure consistent threshold accuracy across all diagnostic blocks.

Is the LP877021RHBRQ1 pin-compatible with other devices in the LP877x-Q1 family?

No, the LP877021RHBRQ1 is not pin-compatible with other LP877x-Q1 variants such as LP87745RJBRQ1 or LP877022RHBRQ1. While sharing the same 32-pin VQFN (RHB) package outline, pin functions differ significantly - for example, LP87745RJBRQ1 repurposes VMON2 and GPO0 for additional buck control, and LP877022RHBRQ1 reassigns EN2/EN3 to different enable logic. The LP877021RHBRQ1 has unique pin mapping optimized for dual-buck + boost + dual VMON architecture. PCB layout must be designed specifically for LP877021RHBRQ1; no mechanical or electrical drop-in replacement exists within the family.