Texas Instruments UCD9081RHBRG4

Overview

UCD9081RHBRG4 from Texas Instruments is an 8-channel digital power supply sequencer and monitor IC with integrated 10-bit SAR ADC, I²C interface, on-chip flash memory, and error logging capability. It controls enable sequencing of eight voltage rails (EN1–EN8), monitors analog inputs (MON1–MON8) with 3.2-mV resolution, supports flexible rail dependency logic, and operates from a single 3.3-V supply. It is used in multi-rail systems such as telecom switches and server motherboards to ensure safe power-up/down and fault-aware system health reporting.

For engineers reviewing the UCD9081RHBRG4 datasheet, UCD9081RHBRG4 pinout, UCD9081RHBRG4 application, or UCD9081RHBRG4 equivalent, key selection considerations include rail sequencing flexibility (timeline/parent-rail-triggered), per-rail UV/OV thresholds with glitch filtering, flash-based configuration persistence, I²C address configurability via ADDR pins, and high-impedance default state of EN/GPO pins during reset.

Technical Context

The UCD9081RHBRG4 implements a deterministic, user-configurable sequencing engine that supports four sequencing modes: fixed delay after reset, delay after parent rail regulation, delay after parent rail voltage threshold, or no sequencing. Its 10-bit SAR ADC samples eight analog inputs using either internal 2.5-V reference (±100 ppm/°C drift) or external VCC-referenced mode, enabling rail voltage measurement accuracy within ±12.2 mV (typical).

Alarm processing is per-rail configurable with six response options-ignore, log only, retry n times (0–4), retry continuously, sequence immediately, or sequence after shutdown-and supports timestamped error logging to on-chip flash memory with 100-year retention. All eight EN outputs and four GPOs are software-controllable, with EN8 multiplexed as ADDR1/GPO1 for I²C addressing and general-purpose signaling.

Key Specifications

Pinout & Package

UCD9081RHBRG4 is housed in a 32-pin VQFN package (5.0 mm × 5.0 mm) with exposed thermal pad (PowerPAD™), requiring connection to VSS for optimal thermal performance and EMI control.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply sequencing applications.

Compared with UCD9081RHBRG4, UCD90160RGZR offers greater channel count and thermal resilience at higher cost and complexity, while TPS65400RGER trades configurability and diagnostics for integration and lower component count-making UCD9081RHBRG4 optimal for mid-channel-count, diagnostic-critical, field-serviceable systems.

Availability

UCD9081RHBRG4 is available at Aetrix Electronics and suitable for telecommunications switches, server platforms, and industrial control systems requiring stable component supply, long-term lifecycle support, and field-upgradable sequencing logic.

Supply support for UCD9081RHBRG4 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 decades of leadership in power sequencing and monitoring ICs.

The UCD9081RHBRG4 belongs to TI's UCD power sequencer family, designed specifically for reliable, programmable control of multi-rail power systems in mission-critical infrastructure equipment where sequencing accuracy, fault visibility, and configuration persistence are essential.

FAQ

What is the primary function of the UCD9081RHBRG4 in a power system?

The UCD9081RHBRG4 serves as an intelligent 8-channel power supply sequencer and monitor. It precisely controls the enable timing of up to eight voltage rails, independently monitors each rail's voltage with 3.2-mV resolution, detects undervoltage/overvoltage faults, logs errors to on-chip flash, and executes configurable responses-including shutdown of dependent rails. Its role is to ensure safe, repeatable, and diagnosable power-up/down sequences in complex electronic systems.

Does the UCD9081RHBRG4 require an external clock or memory to operate?

No, the UCD9081RHBRG4 operates autonomously without external clock or memory. It integrates an internal oscillator (tuned via ROSC pin), a 10-bit SAR ADC, configuration and error log storage in on-chip flash memory, and a full sequencing engine. The only external components required are decoupling capacitors, I²C pullup resistors, and optional resistor dividers for high-voltage rail monitoring.

How does the UCD9081RHBRG4 handle power supply faults during operation?

The UCD9081RHBRG4 detects faults-including sustained undervoltage, overvoltage, and startup failures-on each monitored rail. Per-rail alarm responses are configurable: ignore, log only, retry up to 4 times, retry continuously, sequence immediately, or sequence after shutdown. Faults are timestamped and stored in flash memory, and dependent rails/GPOs can be shut down with user-defined delays, enabling robust system-level fault containment.

Can the UCD9081RHBRG4 be reconfigured in the field after deployment?

Yes, the UCD9081RHBRG4 supports full in-system reconfiguration via its I²C interface. Engineers can update sequencing parameters, voltage thresholds, alarm responses, and GPO behavior using Texas Instruments' GUI or custom firmware-without hardware changes. Configuration is saved to on-chip flash, ensuring persistence across power cycles, and error logs remain accessible for post-deployment diagnostics.

What is the significance of the EN8/ADDR1/GPO1 pin multiplexing on the UCD9081RHBRG4?

The EN8/ADDR1/GPO1 pin on the UCD9081RHBRG4 provides functional flexibility: it acts as the eighth rail enable output, the least-significant I²C address bit (enabling up to 16 unique addresses when combined with ADDR2–ADDR4), or a general-purpose digital output. This multiplexing allows designers to optimize board layout and I²C bus loading while retaining full sequencing and control capability-mode selection is defined in the device configuration stored in flash memory.