Texas Instruments LM5056APMH/NOPB

Overview

LM5056APMH/NOPB from Texas Instruments is a high-voltage system power management IC with PMBus™ interface, designed for real-time telemetry in 10 V to 80 V backplane power systems. It performs simultaneous 12-bit sampling of VIN, IIN, and VAUX at 1 kHz, delivers ±1.75% input power accuracy (LM5056A variant), and supports remote diode temperature sensing - enabling precise monitoring in server backplane and base station power distribution.

For engineers reviewing the LM5056APMH/NOPB datasheet, LM5056APMH/NOPB pinout, LM5056APMH/NOPB application, or LM5056APMH/NOPB equivalent, key selection considerations include its HTSSOP-28 package, dual current-sense range selection (27.0 mV / 54.4 mV via CL pin), SMBus alert (SMBA) output, and hardware-programmable WARN/FAULT thresholds for VIN, IIN, PIN, VOUT, and temperature.

Technical Context

The LM5056APMH/NOPB integrates a 12-bit ADC with round-robin acquisition time of 1 ms across VIN, IIN, VOUT, VAUX, and DIODE inputs, using simultaneous Vin–Iin sampling to compute true real-time and averaged input power. Its analog front-end includes anti-parallel protection diodes between VIN_K–SENSE (±3.0 V) and VIN–VIN_K (±0.3 V), requiring Kelvin-connected sense resistors and strict layout control.

It implements a PMBus-compliant command set over SMBus/I²C, supporting READ_TEMPERATURE_1, OT_WARN_LIMIT, OT_FAULT_LIMIT, and DEVICE_SETUP commands. The device latches its 7-bit SMBus address from ADR0–ADR2 during VDD power-on reset (>3.8 V), and uses an internal 2.97 V reference (±0.1% typical drift over –40°C to 125°C) for all ADC conversions.

Key Specifications

Pinout & Package

LM5056APMH/NOPB is housed in a thermally enhanced 28-pin HTSSOP package with exposed pad (PWP), requiring soldering to PCB ground plane for θJCbot = 2.9°C/W thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage PMBus telemetry applications.

Compared with LM5056PMH/NOPB, the LM5056APMH/NOPB delivers tighter power measurement accuracy for revenue-grade energy metering, while MAX34451ETL+ offers higher resolution and integrated power but demands layout and firmware changes - making LM5056APMH/NOPB optimal for precision retrofit into existing HTSSOP-28 PMBus infrastructure.

Availability

LM5056APMH/NOPB is available at Aetrix Electronics and suitable for server backplane systems, base station power distribution, and industrial telemetry applications requiring stable component supply, long-term lifecycle support, and guaranteed PMBus compliance.

Supply support for LM5056APMH/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 connectivity technologies, with decades of expertise in power management and system monitoring ICs.

The LM5056A belongs to TI's high-voltage PMBus telemetry product line, engineered specifically for intelligent power monitoring in telecom, enterprise computing, and industrial infrastructure where accuracy, reliability, and standards compliance are critical.

FAQ

What is the primary function of the LM5056APMH/NOPB in a power system?

The LM5056APMH/NOPB serves as a high-voltage system power management IC that performs real-time, PMBus-enabled telemetry of input voltage, current, power, output voltage, auxiliary voltage, and temperature. It computes true input power using simultaneous VIN and IIN sampling, supports black-box fault capture, and delivers ±1.75% power accuracy - making it ideal for server backplanes and base station power distribution where precise energy monitoring is required. The LM5056APMH/NOPB integrates all necessary analog front-end circuitry and a compliant SMBus interface in a single HTSSOP-28 package.

How does the LM5056APMH/NOPB achieve ±1.75% input power accuracy?

The LM5056APMH/NOPB achieves ±1.75% input power accuracy through simultaneous sampling of VIN and IIN at 1 kHz using its internal 12-bit ADC, eliminating phase-induced errors common in sequential sampling architectures. This specification is guaranteed over 0°C to 85°C when VIN_K–SENSE = 22 mV and CL = VDD, and relies on the device's 2.97 V internal reference (±0.1% typical drift) and calibrated analog front-end. The LM5056APMH/NOPB also employs hardware averaging (programmable 1 ms to 4 s intervals) to suppress noise without sacrificing transient fidelity - a key enabler of its certified accuracy.

Can the LM5056APMH/NOPB monitor output voltage independently of input voltage?

Yes, the LM5056APMH/NOPB can monitor output voltage independently using its dedicated OUT pin (Pin 1), which functions as an auxiliary high-voltage ADC input rated for 0–80 V. Unlike VIN, which powers the device and serves as the primary telemetry input, OUT provides isolated measurement of downstream rails - such as a regulated 12 V or 5 V bus - without affecting input-side calculations. The LM5056APMH/NOPB reports VOUT with ±1.0% accuracy over 0°C to 85°C and supports programmable WARN/FAULT thresholds for this channel via PMBus commands like VOUT_OV_WARN_LIMIT.

What is the role of the CL pin on the LM5056APMH/NOPB, and how does it affect current sensing?

The CL pin (Pin 22) on the LM5056APMH/NOPB selects the full-scale range of the current sense amplifier: logic-high connects to VDD for 27.0 mV FSR, and logic-low connects to DGND for 54.4 mV FSR. This choice directly determines the LSB size (6.7 µV vs. 13.3 µV) and usable current range for a given sense resistor value. For example, with RS = 10 mΩ, CL = VDD yields 2.7 A full-scale, while CL = DGND yields 5.4 A - enabling optimization of resolution versus dynamic range. The LM5056APMH/NOPB retains this setting after power-up unless changed via the DEVICE_SETUP PMBus command.

Does the LM5056APMH/NOPB require external components for stable operation, and which are mandatory?

Yes, the LM5056APMH/NOPB requires several external components for stable operation: a 1 μF ceramic capacitor on VDD (to AGND), a 1 μF ceramic capacitor on VREF (to AGND), and Kelvin-connected sense resistors with optional 10 nF–1 μF bypass (CS) across VIN_K–SENSE. CVDD and CVREF are mandatory for digital logic stability and ADC reference integrity, respectively. While CVIN and CD are optional (for noisy VIN or remote diode layouts), omitting CVDD or CVREF will cause functional failure. The LM5056APMH/NOPB also requires an external MMBT3904 transistor for remote temperature sensing when that feature is used.