LTC2977
8-Channel PMBus Power
System Manager Featuring Accurate
Output Voltage Measurement
FeaTures
DescripTion
The LTC®2977 is an 8-channel Power System Manager
used to sequence, trim (servo), margin, supervise, man-
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Sequence, Trim, Margin and Supervise Eight Power
Supplies
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Manage Faults, Monitor Telemetry and Create Fault Logs age faults, provide telemetry and create fault logs. PMBus
PMBus Compliant Command Set
Supported by LTpowerPlay™ GUI
Margin or Trim Supplies to 0.25% Accuracy
Fast OV/UV Supervisors Per Channel
Coordinate Sequencing and Fault Management
Across Multiple Chips
commands support power supply sequencing, precision
point-of-loadvoltageadjustmentandmargining.DACsuse
a proprietary soft-connect algorithm to minimize supply
disturbances. Supervisory functions include overvoltage
and undervoltage threshold limits for eight power supply
output channels and one power supply input channel, as
well as over and under temperature limits. Programmable
faultresponsescandisablethepowersupplieswithoptional
retry after a fault is detected. Faults that disable a power
supplycanautomaticallytriggerblackboxEEPROMstorage
of fault status and associated telemetry. An internal 16-bit
ADC monitors eight output voltages, one input voltage,
and die temperature. In addition, odd numbered channels
can be configured to measure the voltage across a current
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Automatic Fault Logging to Internal EEPROM
Operate Autonomously without Additional Software
Internal Temperature and Input Voltage Supervisors
Accurate Monitoring of Eight Output Voltages, Input
Voltage and Internal Die Temperature
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I C/SMBus Serial Interface
Can Be Powered from 3.3V, or 4.5V to 15V
Programmable Watchdog Timer
100% Pin-Compatible Upgrade to the LTC2978/LTC2978A sense resistor. A programmable watchdog timer moni-
Available in 64-pin 9mm × 9mm QFN Package
tors microprocessor activity for a stalled condition and
resets the microprocessor if necessary. A single wire bus
synchronizes power supplies across multiple LTC power
systemmanagementdevices.ConfigurationEEPROMsup-
ports autonomous operation without additional software.
L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks
and LTpowerPlay is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents including 7382303, 7420359 and
7940091.
applicaTions
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Computers and Network Servers
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Industrial Test and Measurement
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High Reliability Systems
Medical Imaging
Video
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Typical applicaTion
8-Channel PMBus Power System Manager
Typical ADC Total Unadjusted
Error vs Temperature
V
4.5V < V
IBUS
< 15V**
IN
0.25
V
V
V
IN_SNS
V
PWR
OUT
DIGITALLY
V
= 1.8V
SENSEP0
3.3V**
0.20 THREE TYPICAL PARTS
V
DD33
DACP0
MANAGED
POWER
V
R30
SENSEP0
0.15
0.10
TO INTERMEDIATE
V
IN_EN
BUS CONVERTER ENABLE
R20
R10
SUPPLY
LTC2977*
V
SDA
LOAD
FB
0.05
SCL
V
PMBus
INTERFACE
DACM0
0
ALERTB
V
SENSEM0
SGND
–0.05
–0.10
–0.15
–0.20
–0.25
CONTROL0
V
RUN/SS
OUT_EN0
GND
WRITE-PROTECT
WP
PWRGD
TO µP RESETB INPUT
WDI/RESETB
ASEL0
WATCHDOG
TIMER INTERRUPT
FAULTB00
TO/FROM OTHER
LTC POWER SUPPLY MANAGERS
SHARE_CLK
ASEL1
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF EIGHT CHANNELS SHOWN
GND
–50
–10
30 50 70 90 110
–30
10
2977 TA01a
TEMPERATURE (°C)
**MAY BE POWERED FROM EITHER AN
EXTERNAL 3.3V SUPPLY OR THE INTERMEDIATE BUS
2977 TA01b
2977f
1
For more information www.linear.com/LTC2977