1 Features
1• Monitor and Sequence 12 Voltage Rails
– All Rails Sampled Every 400 μs
– 12-bit ADC With 2.5-V, 0.5% Internal VREF
– Sequence Based on Time, Rail and Pin
Dependencies
– Four Programmable Undervoltage and
Overvoltage Thresholds per Monitor
• Nonvolatile Error and Peak-Value Logging per
Monitor (up to 12 Fault Detail Entries)
• Closed-Loop Margining for 10 Rails
– Margin Output Adjusts Rail Voltage to Match
User-Defined Margin Thresholds
• Programmable Watchdog Timer and System
Reset
• Flexible Digital I/O Configuration
• Pin-Selected Rail States
• Multiphase PWM Clock Generator
– Clock Frequencies From 15.259 kHz to
125 MHz
– Capability to Configure Independent Clock
Outputs for Synchronizing Switch-Mode Power
Supplies
• JTAG and I2C/SMBus/PMBus™ Interfaces

2 Applications
• Industrial / ATE
• Telecommunications and Networking Equipment
• Servers and Storage Systems
• Any System Requiring Sequencing and Monitoring
of Multiple Power Rails

3 Description
The UCD90120A is a 12-rail PMBus/I2C addressable
power-supply sequencer and monitor. The device
integrates a 12-bit ADC for monitoring up to 12
power-supply voltage inputs. Twenty-six GPIO pins
can be used for power supply enables, power-on
reset signals, external interrupts, cascading, or other
system functions. Twelve of these pins offer PWM
functionality. Using these pins, the UCD90120A offers
support for margining, and general-purpose PWM
functions.
Specific power states can be achieved using the Pin-
Selected Rail States feature. This feature allows with
the use of up to 3 GPIs to enable and disable any
rail. This is useful for implementing system low-power
modes and the Advanced Configuration and Power
Interface (ACPI) specification that is used for
hardware devices.
The TI Fusion Digital Power™ designer software is
provided for device configuration. This PC-based
graphical user interface (GUI) offers an intuitive
interface for configuring, storing, and monitoring all
system operating parameters.