LTC2923 - Power Supply Tracking Controller

The LTC2923 provides a simple solution to power supply tracking and sequencing requirements. By selecting a few resistors, the supplies can be configured to ramp-up and ramp-down together or with voltage offsets, time delays or different ramp rates.

By introducing currents into the feedback nodes of two independent switching regulators, the LTC2923 causes their outputs to track without inserting any pass element losses. Because the currents are controlled in an openloop manner, the LTC2923 does not affect the transient response or stability of the supplies. Furthermore, it presents a high impedance when power-up is complete, effectively removing it from the DC/DC circuit.

For systems that require a third supply, one supply can be controlled with a series FET. This optional series FET can also control a supply that does not allow direct access to its feedback resistors (e.g., a power module) or a supply whose output cannot be forced to ground (e.g., a 3-terminal linear regulator). When the FET is used, an electronic circuit breaker provides protection from short-circuit conditions.

Features
  • Flexible Power Supply Tracking
  • Tracks Both Up and Down
  • Power Supply Sequencing
  • Supply Stability is Not Affected
  • Controls Two Supplies Without Series FETs
  • Controls a Third Supply With a Series FET
  • Adjustable Ramp Rates
  • Electronic Circuit Breaker
  • Available in 10-Lead MS and 12-Lead (4mm × 3mm) DFN Packages
Typical Application

Applications
  • VCORE and VI/O Supply Tracking
  • Microprocessor, DSP and FPGA Supplies
  • Servers
  • Communication Systems
Packaging

Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LTC2923CDE#PBF4x3 DFN-12C$3.60$3.15
LTC2923CDE#TRPBF4x3 DFN-12C$3.21
LTC2923CMS#PBFMS-10C$3.90$2.95
LTC2923CMS#TRPBFMS-10C$3.01
LTC2923IDE#PBF4x3 DFN-12I$4.15$3.60
LTC2923IDE#TRPBF4x3 DFN-12I$3.66
LTC2923IMS#PBFMS-10I$4.50$3.40
LTC2923IMS#TRPBFMS-10I$3.46
Demo Boards
Part NumberDescriptionPrice
DC732ALTC2923CMS10 | Power Supply Tracking and Sequencing Controller$50.00
Datasheet
Design Note
Reliability Data
LT Journal
Related Product
LTC2923 - Power Supply Tracking Controller
LTC2923 Package Drawing LTC2923
DN372 - Power Supply Tracker Can Also Margin Supplies
R413 Reliability Data
April 2010 - Dual 500mA µPower LDO Features Independent 1.8V–20V Inputs and Easy Sequencing in a 4mm × 3mm DFN
Dec 2003 Low Voltage Wizardry Provides the Ultimate Power-On Reset Circuit
Feb 2004 Versatile Power Supply Tracking without MOSFETs
November 2004 - Power Supply Tracking for Linear Regulators
LTC2923 Footprints and Symbols