LTC2978A Datasheet, PDF (1/80 Pages) Linear Technology – 8-Channel PMBus Power System Manager Featuring Accurate Output Voltage Measurement

LTC2978A
Features
8-Channel PMBus Power
System Manager Featuring Accurate
Output Voltage Measurement
Description
n _{Sequence,Trim, Margin and Supervise Eight Power Supplies}
n _{Manage Faults, Monitor Telemetry and Create Fault Logs}
n _{PMBus Compliant Command Set}
n _{Supported by LTpowerPlay™ GUI}
n _{Margin or Trim Supplies to 0.25% Accuracy}
n _{Fast OV/UV Supervisors per Channel}
n _{Coordinate Sequencing and Fault Management}
Across Multiple Chips
n _{Automatic Fault Logging to Internal EEPROM}
n _{Operate Autonomously without Additional Software}
n _{Internal Temperature and Input Voltage Supervisors}
n _{Accurate Monitoring of Eight Output Voltages, Input}
Voltage and Internal Die Temperature
n _I²_{C/SMBus Serial Interface}
n _{Can Be Powered from 3.3V, or 4.5V to 15V}
n _{Programmable Watchdog Timer}
n _{100% Compatible with the LTC2978}
n _{Available in 64-pin 9mm × 9mm QFN Package}
Applications
n _{Computers and Network Servers}
n _{Industrial Test and Measurement}
n _{High Reliability Systems}
n _{Medical Imaging}
n _Video
The LTC^®2978A is an 8-channel Power System Manager
used to sequence, trim (servo), margin, supervise, man-
age faults, provide telemetry and create fault logs. PMBus
commands support power supply sequencing, precision
point-of-load voltage adjustment and margining. DACs use
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
fault responses can disable the power supplies with optional
retry after a fault is detected. Faults that disable a power
supply can automatically trigger black box EEPROM storage
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 chan-
nels can be configured to measure the voltage across a
current sense resistor. A programmable watchdog timer
monitors microprocessor activity for a stalled condition and
resets the microprocessor if necessary. A single wire bus
synchronizes power supplies across multiple LTC power
system management devices. Configuration EEPROM sup-
ports autonomous operation without additional software.
L, LT, LTC, LTM, PolyPhase, Linear Technology and the Linear logo are registered trademarks and
LTpowerPlay ia 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.
Typical Application
4.5V < V_IBUS < 15V**
3.3V**
TO INTERMEDIATE
BUS CONVERTER ENABLE
PMBus
INTERFACE
WRITE-PROTECT
TO/FROM OTHER
LTC2978s
8-Channel PMBus Power System Manager
V_PWR
V_DD33
V_{IN_EN}
V_{IN_SNS}
V_DACP0
V_SENSEP0
SDA ^LTC2978A*
SCL
ALERTB
CONTROL0
V_DACM0
V_SENSEM0
V_{OUT_EN0}
WP
PWRGD
WDI/RESETB
FAULTB00
ASEL0
SHARE_CLK
ASEL1
GND
2978a TA01a
V_IN
LOAD
R30
R20
R10
TO µP RESETB INPUT
WATCHDOG
TIMER INTERRUPT
V_OUT
DIGITALLY
MANAGED
POWER
SUPPLY
V_FB
SGND
RUN/SS
GND
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF EIGHT CHANNELS SHOWN
**LTC2978A MAY BE POWERED FROM EITHER AN
EXTERNAL 3.3V SUPPLY OR THE INTERMEDIATE BUS
Typical ADC Total Unadjusted
Error vs Temperature
0.035
ADC V_IN = 1.8V
0.030
0.025
0.020
0.015
0.010
0.005
0
–50 –35 –20 –5 10 25 40 55 70 85 100
TEMPERATURE (°C)
2978a TA01b
For more information www.linear.com/LTC2978A
2978af
1