LTC2978
Octal Digital Power Supply
Manager with EEPROM
FEATURES
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DESCRIPTION
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. Programmable fault dependencies and responses
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
across a current sense resistor. Power supply sequencing,
precision point-of-load voltage adjustment and margining
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.
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 and 7420359.
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I
2
C/SMBus Serial Interface
PMBus Compliant Command Set
Configuration EEPROM with CRC
Black Box Fault Logging to Internal EEPROM
Differential Input, 16-Bit
ΔΣ
ADC with Less Than
±0.25% of Total Unadjusted Error
Eight Voltage Servos Precisely Adjust Output
Voltages Using Eight 10-Bit DACs with Soft-Connect
Monitors Eight Output Voltages and One Input
Voltage and Internal Die Temperature
8-Channel Sequencer
Programmable Watchdog Timer
Eight UV/OV V
OUT
and One V
IN
Supervisor
Supports Multi-Channel Fault Management
Operates Autonomously without Additional Software
LTC2978 Can Be Powered from 3.3V or 4.5V to 15V
Available in 64-pin 9mm × 9mm QFN package
APPLICATIONS
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Computers
Network Servers
Industrial Test and Measurement
High Reliability Systems
Medical Imaging
Video
TYPICAL APPLICATION
Octal Power Supply Controller with PMBus Interface
4.5V < V
IBUS
< 15V
V
PWR
3.3V**
TO INTERMEDIATE
BUS CONVERTER ENABLE
PMBus
INTERFACE
V
DD33
V
IN_EN
SDA
SCL
ALERTB
CONTROL0
WRITE-PROTECT
TO/FROM OTHER
LTC2978s
WP
FAULTB00
SHARE_CLK
GND
2978 TA01a
Typical ADC Total Unadjusted
Error vs Temperature
0.035
0.030
0.025
ERROR (%)
0.020
0.015
0.010
0.005
0
–50 –35 –20 –5 10 25 40 55 70 85 100
TEMPERATURE (°C)
2978 TA01b
V
IN
V
IN_SNS
V
DACP0
V
SENSEP0
LTC2978*
V
DACM0
V
SENSEM0
V
OUT_EN0
PWRGD
WDI/RESETB
ASEL0
ASEL1
TO µP RESETB INPUT
WATCHDOG
TIMER INTERRUPT
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF EIGHT CHANNELS SHOWN
**LTC2978 MAY BE POWERED FROM EITHER AN
EXTERNAL 3.3V SUPPLY OR THE INTERMEDIATE BUS
LOAD
R10
SGND
RUN/SS
GND
R30
R20
V
OUT
DIGITALLY
MANAGED
POWER
SUPPLY
ADC V
IN
= 1.8V
V
FB
2978fc
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
