Texas Instruments LM25066APSQX/NOPB

Overview

LM25066APSQX/NOPB from Texas Instruments is a PMBus™-compliant system power management and protection IC for hot-swap control and real-time telemetry. It monitors VIN (2.9–17 V), IIN (±1% accuracy), PIN (±2% accuracy), VOUT, VAUX, and temperature; enforces programmable current limit (25 mV or 46 mV), circuit breaker, UVLO/OVLO with hysteresis, and power-good signaling; and serves in server backplane power distribution.

For engineers reviewing the LM25066APSQX/NOPB datasheet, LM25066APSQX/NOPB pinout, LM25066APSQX/NOPB application, or LM25066APSQX/NOPB equivalent, key selection criteria include its 24-pin WQFN package, SMBus/I²C interface compliance, dual current-limit threshold configuration, true input power measurement via simultaneous VIN/IIN sampling, and black-box fault-triggered telemetry capture.

Technical Context

The LM25066APSQX/NOPB integrates a high-speed hot-swap controller with a 12-bit ADC telemetry engine and PMBus command interpreter. Its analog front end samples VIN, IIN, VOUT, VAUX, and remote diode temperature at 1 kHz, computes real-time and averaged power using synchronized voltage/current acquisition, and supports configurable insertion delay, fault timeout, and retry behavior via external TIMER capacitor and RETRY pin logic.

Protection architecture includes independent UVLO/EN and OVLO pins with 23-µA hysteresis current sources, programmable CL/CB pins setting 25/46-mV current thresholds and 1.8×/3.6× circuit breaker ratios, and GATE drive capable of sourcing –22 µA (normal) or sinking 2 mA (fault) to control external N-channel MOSFETs. The PGD output asserts open-drain low when FB falls below 1.167 V or VIN exits UVLO/OVLO windows.

Key Specifications

Pinout & Package

LM25066APSQX/NOPB uses a 24-pin WQFN package (5.0 mm × 4.0 mm) with exposed thermal pad soldered to PCB ground plane 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 system power management and protection applications.

Compared with LM25066IY/NOPB, LM25066APSQX/NOPB trades auxiliary ADC channels for lower BOM cost and identical core protection and PMBus telemetry; versus TPS2491PWR, it adds full digital observability and true power measurement at the expense of higher integration complexity and unit cost.

Availability

LM25066APSQX/NOPB is available at Aetrix Electronics and suitable for server backplane systems, telecom base station power distribution, solid-state circuit breakers, and industrial rack-mount power supplies requiring stable component supply, long-term lifecycle support, and PMBus-compliant telemetry.

Supply support for LM25066APSQX/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 company specializing in analog, embedded processing, and power management technologies, with leadership in high-reliability industrial and communications ICs.

The LM25066A product line delivers integrated hot-swap control and digital telemetry for high-density computing and telecom infrastructure, designed specifically to replace discrete protection circuits with PMBus-enabled system visibility and control.

FAQ

What is the primary function of the LM25066APSQX/NOPB in a power system?

The LM25066APSQX/NOPB functions as a PMBus-compliant hot-swap controller and system power monitor. It protects downstream circuitry during live insertion, enforces programmable current and power limits, detects faults (UVLO/OVLO/shorts), and provides real-time telemetry of VIN, IIN, PIN, VOUT, VAUX, and temperature - all accessible via SMBus interface. Its core value lies in replacing discrete protection with digital observability.

How does the LM25066APSQX/NOPB achieve ±2% input power measurement accuracy?

The LM25066APSQX/NOPB achieves ±2% input power accuracy by simultaneously sampling VIN and IIN at 1 kHz using synchronized ADC acquisition. This eliminates phase-induced errors common in sequential sampling, enabling true instantaneous power calculation (P = V × I) and accurate averaging over programmable intervals (0.001–4 s). Calibration and temperature compensation further maintain this spec across –40°C to +125°C.

Can the LM25066APSQX/NOPB operate without an external microcontroller?

Yes, the LM25066APSQX/NOPB operates autonomously for protection functions: UVLO/OVLO thresholds, current limiting, circuit breaker activation, and PGD assertion require only passive components (resistors, capacitors). However, SMBus communication, telemetry readback, black-box snapshot retrieval, and register configuration require a host microcontroller or BMC - the IC does not embed firmware or decision logic beyond hardwired analog comparators and timers.

What is the role of the TIMER pin on the LM25066APSQX/NOPB?

The TIMER pin on the LM25066APSQX/NOPB connects to an external capacitor that sets three critical timing parameters: insertion delay (soft-start time before GATE enables), fault timeout period (duration before GATE shuts down during overcurrent), and retry interval (if RETRY = GND). For example, a 100-nF capacitor yields ~140 ms insertion delay and ~8.3 ms fault timeout - enabling single-component timing control without external clocks or counters.

Does the LM25066APSQX/NOPB support remote temperature sensing?

Yes, the LM25066APSQX/NOPB supports remote temperature sensing via its DIODE pin, which interfaces with an external NPN transistor or diode-connected transistor placed near a thermally sensitive component (e.g., power MOSFET). It provides 9-bit resolution and ±2°C to ±10°C accuracy depending on diode matching and layout, enabling thermal-aware power limiting and fault prediction without adding separate temperature sensors.