Texas Instruments LM25066APSQE/NOPB

Overview

LM25066APSQE/NOPB from Texas Instruments is a PMBus™-compliant system power management and protection IC designed for hot-swap control and real-time telemetry in 2.9 V–17 V input systems. It integrates current/power limiting, undervoltage/overvoltage lockout with hysteresis, remote temperature sensing, and black-box fault capture. It serves as the primary power supervisory controller on server backplane and base station power distribution boards.

For engineers reviewing the LM25066APSQE/NOPB datasheet, LM25066APSQE/NOPB pinout, LM25066APSQE/NOPB application, or LM25066APSQE/NOPB equivalent, key selection criteria include its 24-pin WQFN package, ±1% current measurement accuracy over temperature, 12-bit telemetry resolution, programmable 25-mV/46-mV current limit thresholds, and SMBus timing compliance up to 400 kHz.

Technical Context

The LM25066APSQE/NOPB implements a dual-stage protection architecture: fast current limiting (1.2 µs response) followed by configurable circuit breaker tripping (0.6–1.2 µs), both referenced to the SENSE–VIN differential voltage. Its analog front-end simultaneously samples VIN and IIN to compute true input power with ±2% accuracy across –40°C to +85°C.

Control logic is managed via PMBus commands with register-mapped configuration of UVLO/OVLO thresholds (1.16 V nominal, 23 µA hysteresis current), PGD assertion delay (115 ns), and TIMER-based insertion delay/fault timeout. The device supports three SMBus address bits (ADR0–ADR2), SMBA alert signaling, and black-box telemetry capture triggered by WARN or FAULT events.

Key Specifications

Pinout & Package

LM25066APSQE/NOPB is housed in a 24-pin WQFN package (5.0 mm × 4.0 mm body, 0.5 mm pitch) with an exposed thermal pad soldered to PCB ground for optimal thermal performance (R_θJB = 13.4°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar hot-swap and power telemetry applications.

Compared with LM25066IY/NOPB, LM25066APSQE/NOPB offers VAUX telemetry and simpler EEPROM usage but trades off nonvolatile fault retention; versus TPS2490DRCT, it delivers full digital power management at higher BOM cost and design complexity.

Availability

LM25066APSQE/NOPB is available at Aetrix Electronics and suitable for server backplane systems, telecom base station power distribution, and solid-state circuit breaker designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM25066APSQE/NOPB 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 leader specializing in analog, embedded processing, and power management technologies, with decades of heritage in high-reliability industrial and communications ICs.

The LM25066A product line was engineered specifically for intelligent power distribution in modular computing and telecom infrastructure, combining precision analog sensing with standardized digital control via PMBus.

FAQ

What is the primary function of the LM25066APSQE/NOPB in a power system?

The LM25066APSQE/NOPB serves as a system-level power management and protection IC that combines hot-swap control, real-time telemetry (VIN, IIN, PIN, VOUT, VAUX, temperature), and PMBus-compliant digital interface. It actively limits inrush current, enforces programmable overcurrent/overvoltage/undervoltage thresholds, and captures fault-triggered telemetry snapshots - all within a single 24-pin WQFN package. Its core role is to safeguard downstream loads while providing actionable power data to the system host controller.

How does the LM25066APSQE/NOPB achieve ±1% current measurement accuracy over temperature?

The LM25066APSQE/NOPB achieves ±1% current measurement accuracy over temperature through factory-trimmed analog front-end circuitry, simultaneous sampling of VIN and SENSE signals, and internal calibration routines executed at power-up and during periodic self-checks. Its 12-bit ADC resolves current sense voltage with LSB sizes of 7.32 µV (25-mV range) or 14.64 µV (46-mV range), and error remains bounded across –40°C to +85°C junction temperature per TI's production test specifications.

Can the LM25066APSQE/NOPB be used without an external microcontroller or PMBus host?

Yes - the LM25066APSQE/NOPB operates autonomously as a standalone hot-swap controller even without PMBus communication. Core protection functions (current limiting, UVLO/OVLO, circuit breaker, PGD assertion) are fully functional using only passive components (resistors, capacitors) on pins like UVLO/EN, OVLO, CL, CB, TIMER, and FB. PMBus is optional for telemetry readout, dynamic reconfiguration, and advanced diagnostics - not required for basic power enable/disable and fault response.

What is the purpose of the VAUX pin on the LM25066APSQE/NOPB?

The VAUX pin on the LM25066APSQE/NOPB is an auxiliary analog input supporting 12-bit telemetry of a secondary voltage rail, with a full-scale range of 0 V to 1.16 V. It enables monitoring of auxiliary supplies such as standby regulators, sensor bias voltages, or reference sources - extending the IC's visibility beyond the main power path. This input shares the same ADC and accuracy specs (±1% typical) as VIN and VOUT measurements, and its data is accessible via PMBus READ_VAUX command.

How does the TIMER pin affect startup and fault behavior in the LM25066APSQE/NOPB?

The TIMER pin on the LM25066APSQE/NOPB sets three critical timing parameters via an external capacitor: insertion delay (soft-start duration), fault timeout period (time before GATE disables after overcurrent detection), and retry interval (if RETRY = GND). For example, a 100 nF capacitor yields ~140 ms insertion delay and ~8.3 ms fault timeout. The pin uses internal hysteresis thresholds (0.85 V and 1.7 V) to define timing cycles, ensuring predictable, RC-tunable behavior independent of host software.