Texas Instruments UCD9080RHBT

Overview

UCD9080RHBT from Texas Instruments is an 8-channel power-supply sequencer and monitor IC designed for precise control of voltage rail startup, shutdown, and fault response in complex multi-rail systems. It operates from a single 3.3-V supply, provides 3.2-mV analog measurement resolution across eight MON inputs, samples rails every 50 µs at >20-kHz rate, and supports configurable digital outputs (EN1–EN8, GPO1–GPO4) for sequencing and system reset functions - deployed in telecom switches and server power management.

For engineers reviewing the UCD9080RHBT datasheet, UCD9080RHBT pinout, UCD9080RHBT application, or UCD9080RHBT equivalent, key selection considerations include per-rail undervoltage/overvoltage threshold programming, parent-child rail dependency configuration, I²C address latching via ADDR1–ADDR4 pins during reset, and brownout reset timing compliance with VCC drop profiles.

Technical Context

The UCD9080RHBT implements a deterministic sequencing engine that supports three timing modes: fixed delay after reset, delay after parent rail regulation, or delay after parent rail reaches a defined voltage threshold. Its 10-bit SAR ADC uses either internal 2.5-V or external 3.3-V (VCC) reference, with accuracy of ±17.4 mV (internal) or ±6.8 mV (external) across monitored rails.

Rail enable outputs (EN1–EN8) and general-purpose outputs (GPO1–GPO4) are Schmitt-trigger I/Os with programmable polarity and share pins with I²C address selection (ADDR1–ADDR4). All EN/GPO pins default to high-impedance input during device reset and require external biasing to VIT+ (≥1.9 V) for active-low or VIT– (≤0.9 V) for active-high configurations to ensure deterministic startup behavior.

Key Specifications

Pinout & Package

The UCD9080RHBT is housed in a 32-pin QFN package (RHB) with 5-mm × 5-mm body and 0.5-mm pitch; exposed thermal pad requires solder connection to PCB ground plane for thermal performance and EMI reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCD9080RHBT, UCD90120ARGCT adds channel count and EEPROM but increases footprint and cost, while LTC2978IUP#PBF delivers superior measurement accuracy and margining capability at the expense of I²C compatibility and simpler brownout handling - making UCD9080RHBT optimal for cost-sensitive, 8-rail telecom/server designs prioritizing deterministic reset behavior and minimal BOM count.

Availability

UCD9080RHBT is available at Aetrix Electronics and suitable for telecom switches, server motherboards, and networking equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing for industrial deployments.

Supply support for UCD9080RHBT 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The UCD9080RHBT belongs to TI's UCD power management IC family, engineered specifically for high-reliability, multi-rail sequencing and monitoring in infrastructure equipment where deterministic startup, fault logging, and I²C configurability are critical.

FAQ

What is the primary function of the UCD9080RHBT in a power system?

The UCD9080RHBT serves as an 8-channel power-supply sequencer and monitor IC that controls the precise timing of voltage rail enablement, verifies regulation status, detects undervoltage/overvoltage faults with timestamping, and executes configurable shutdown sequences. In practice, the UCD9080RHBT replaces discrete timers, comparators, and logic gates in telecom and server power trees - reducing design complexity while improving reliability through deterministic, software-configurable behavior.

Does the UCD9080RHBT require an external clock or memory to operate?

No, the UCD9080RHBT operates autonomously without external clock or memory components. Its internal oscillator - calibrated via the ROSC pin with a 100-kΩ pullup to VCC - generates timing for 50-µs sampling intervals and sequencer events. Configuration parameters are stored in on-chip nonvolatile memory with 100-year retention, eliminating the need for external EEPROM or battery-backed RAM. This self-contained architecture simplifies BOM and improves robustness in harsh environments where external components may fail.

How does the UCD9080RHBT handle brownout conditions during operation?

The UCD9080RHBT incorporates a dedicated brownout detection circuit that monitors VCC and triggers a full device reset when voltage drops below 1.71 V (V(B_IT–)), with 70–180 mV hysteresis to prevent chatter. Upon detection, all EN and GPO outputs enter high-impedance input mode for ~4–5 ms, then re-execute the configured sequencing routine. This behavior is hardware-enforced and independent of I²C communication - ensuring fail-safe recovery even if the host processor is unresponsive. The UCD9080RHBT's brownout response is validated across temperature and VCC ramp rates per SLVS692E specifications.

Can the UCD9080RHBT monitor voltage rails above 3.3 V?

Yes, the UCD9080RHBT can monitor rails exceeding 3.3 V using external resistor divider networks on MON1–MON8 inputs. The device's analog front end accepts 0–3.3 V, so dividers must scale higher voltages (e.g., 12 V, 5 V) to fit this range while maintaining ≤20-kΩ Thec source impedance to preserve the 20-kHz sampling rate. For example, a 12-V rail would use a 270-kΩ top resistor and 91-kΩ bottom resistor (3.3 V output at MON pin), with optional op-amp buffering if source impedance exceeds limits. Accuracy depends on divider tolerance and reference choice (±6.8 mV with external 3.3-V reference).

What I²C addressing options are supported by the UCD9080RHBT?

The UCD9080RHBT supports 16 unique 7-bit I²C slave addresses (0x60–0x6F) determined by the logic states of ADDR1–ADDR4 pins (EN8/ADDR1/GPO1, ADDR2/GPO2, ADDR3/GPO3, ADDR4/GPO4) sampled during device reset. External pullup/pulldown resistors must be used - no internal biasing is provided. After reset, these pins become configurable GPOs, allowing dynamic reuse without address conflict. The UCD9080RHBT does not support I²C general-call (0x00) or 10-bit addressing, and its standard-mode interface operates from 10 kHz to 100 kHz per SMBus v2.0 timing requirements.