Texas Instruments UCD9081RHBTG4

Overview

UCD9081RHBTG4 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 operates from a single 3.3-V supply, provides 3.2-mV voltage measurement resolution per rail, supports independent under/overvoltage thresholding per channel, and enables flexible sequencing based on time, regulation status, or voltage thresholds. It is used in multi-rail systems such as telecom switches and server motherboards to ensure safe power-up/down sequences and detect rail faults.

For engineers reviewing the UCD9081RHBTG4 datasheet, UCD9081RHBTG4 pinout, UCD9081RHBTG4 application, or UCD9081RHBTG4 equivalent, key selection criteria include its 8-channel analog monitoring capability, programmable EN/GPO timing and polarity, internal/external reference selection, flash-based configuration storage, and I²C-configurable alarm response (log-only, retry, sequence, or shutdown).

Technical Context

The UCD9081RHBTG4 implements a deterministic, event-driven 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 MON inputs with 3.2-mV LSB resolution using either an internal 2.5-V ±100 ppm/°C reference or external VCC-derived reference.

Each of the eight ENx outputs and four GPOs (multiplexed with EN8/ADDR1–ADDR4) is configurable for active-high/low polarity and supports independent fault-triggered shutdown with user-defined delay (0–4095 ms). Alarm processing includes ignore, log-only, retry (0–4×), continuous retry, immediate sequence, or sequence-after-shutdown - all stored in nonvolatile flash with timestamped error logging.

Key Specifications

Pinout & Package

UCD9081RHBTG4 is housed in a 32-pin VQFN (RHB) package with 5.00 mm × 5.00 mm body size and exposed thermal pad (PowerPAD™) recommended to be connected to VSS for thermal and EMI performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCD9081RHBTG4, UCD90160RGZT offers greater channel density and precision but requires PCB redesign, while TPS65400RGER integrates power conversion at the expense of configurability and diagnostic depth - making UCD9081RHBTG4 optimal for modular, serviceable, and analytically rigorous multi-rail systems.

Availability

UCD9081RHBTG4 is available at Aetrix Electronics and suitable for telecom switches, server motherboards, and industrial control systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for UCD9081RHBTG4 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 headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The UCD9081RHBTG4 belongs to TI's digital power management product line, engineered specifically for high-reliability, multi-rail sequencing and monitoring in infrastructure equipment where deterministic power control and failure diagnostics are critical.

FAQ

What is the primary function of the UCD9081RHBTG4 in a power system?

The UCD9081RHBTG4 serves as an 8-channel digital power supply sequencer and monitor. It controls the timing and order of voltage rail enablement, continuously monitors rail voltages for under/overvoltage conditions, logs faults with timestamps in on-chip flash, and executes configurable responses (e.g., retry, shutdown, or sequence) - all without external memory or clock sources. Its core value lies in ensuring safe, repeatable, and diagnosable power-up/down behavior in complex electronic systems.

Does the UCD9081RHBTG4 require an external crystal or oscillator?

No, the UCD9081RHBTG4 uses an internal oscillator and does not require an external crystal or clock source. The ROSC pin is used to fine-tune oscillator frequency stability via a 100-kΩ pullup resistor to VCC; this adjustment minimizes drift and ensures accurate ADC sampling and sequencing timing. No external timing components are needed for basic operation.

How many independent voltage rails can the UCD9081RHBTG4 monitor and sequence?

The UCD9081RHBTG4 monitors and sequences exactly eight independent voltage rails via its MON1–MON8 analog inputs and EN1–EN8 digital outputs. Each rail has fully independent configuration for UV/OV thresholds, regulation timeout, glitch rejection window, sequencing trigger condition (time, regulation, or voltage threshold), and alarm response - enabling precise, application-specific control without cross-channel interference.

Can the UCD9081RHBTG4 store its configuration permanently?

Yes, the UCD9081RHBTG4 includes on-chip flash memory that retains user configuration - including sequencing parameters, voltage thresholds, alarm actions, and GPO settings - for over 100 years at 25°C. Configuration is written via I²C using TI's Windows GUI or custom firmware, and automatically loads on power-up or reset, eliminating the need for external EEPROM or boot-time initialization code.

What is the resolution and accuracy of the UCD9081RHBTG4's ADC?

The UCD9081RHBTG4 features a 10-bit SAR ADC with 3.2-mV LSB resolution when using the internal 2.5-V reference. Total unadjusted error is ±12.2 mV (±4.9 LSB) with internal reference and ±14.7 mV with external VCC reference. Accuracy depends on reference choice, source impedance of external resistor dividers, and PCB layout; TI recommends ≤2 kΩ Thevenin impedance at MON pins for full specification compliance.