LTC2978
Octal Digital Power Supply
Manager with EEPROM
FEATURES
DESCRIPTION
2
The LTC®2978 is an octal, digital power-supply monitor,
supervisor, sequencer, and margin controller. Eight output
channels can be managed per user defined configura-
tion settings. Supervisory functions include fault OV/UV
threshold limits for eight output channels and one input
channel.Programmablefaultdependenciesandresponses
allow the power supplies to be disabled with optional retry
after a fault has been detected. Serial bus telemetry allows
eight output voltages, one input voltage, die temperature
and fault status to be monitored. In addition, odd num-
bered channels can be configured to measure the voltage
acrossacurrentsenseresistor. Powersupplysequencing,
precisionpoint-of-loadvoltageadjustmentandmargining
are supported with PMBus commands. A programmable
watchdog timer monitors microprocessor activity for a
stalled condition and resets the microprocessor if neces-
sary. The 1-wire synchronization bus supports power
supply sequencing across multiple LTC digital power
devices. User programmable parameters can be stored
in EEPROM. Faults and telemetry data can be logged to
EEPROM for diagnostic analysis.
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I C/SMBus Serial Interface
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PMBus Compliant Command Set
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Configuration EEPROM with CRC
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Black Box Fault Logging to Internal EEPROM
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Differential Input, 16-Bit ΔΣ ADC with Less Than
±±.2ꢀ5 of Total Unadjusted Error
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Eight Voltage Servos Precisely Adjust Output
Voltages Using Eight 1±-Bit DACs with Soft-Connect
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Monitors Eight Output Voltages and One Input
Voltage and Internal Die Temperature
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8-Channel Sequencer
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Programmable Watchdog Timer
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Eight UV/OV V
and One V Supervisor
OUT
IN
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Supports Multi-Channel Fault Management
Operates Autonomously without Additional Software
LTC2978 Can Be Powered from 3.3V or 4.ꢀV to 1ꢀV
Available in 64-pin 9mm × 9mm QFN package
APPLICATIONS
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Computers
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Network Servers
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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 73823±3 and 742±3ꢀ9.
Industrial Test and Measurement
High Reliability Systems
Medical Imaging
Video
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TYPICAL APPLICATION
Typical ADC Total Unadjusted
Octal Power Supply Controller with PMBus Interface
Error vs Temperature
0.035
0.030
ADC V = 1.8V
IN
V
4.5V < V
IBUS
< 15V
IN
V
V
V
IN_SNS
V
PWR
OUT
3.3V**
V
DIGITALLY
DD33
DACP0
0.025
MANAGED
POWER
V
R30
SENSEP0
TO INTERMEDIATE
BUS CONVERTER ENABLE
V
IN_EN
R20
R10
0.020
0.015
0.010
0.005
SUPPLY
LTC2978*
V
SDA
LOAD
FB
SCL
V
PMBus
DACM0
INTERFACE
ALERTB
V
SENSEM0
SGND
CONTROL0
WP
V
RUN/SS
OUT_EN0
GND
WRITE-PROTECT
PWRGD
TO µP RESETB INPUT
0
WDI/RESETB
ASEL0
WATCHDOG
–50
–5
25 40 55 70 85 100
–35 –20
10
TIMER INTERRUPT
FAULTB00
TO/FROM OTHER
LTC2978s
TEMPERATURE (°C)
SHARE_CLK
ASEL1
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF EIGHT CHANNELS SHOWN
2978 TA01b
GND
2978 TA01a
**LTC2978 MAY BE POWERED FROM EITHER AN
EXTERNAL 3.3V SUPPLY OR THE INTERMEDIATE BUS
2978fc
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