LTC2978 Datasheet, PDF (1/64 Pages) Linear Technology – Octal PMBus Power Supply Monitor and Controller with EEPROM

Features
n _{PMBus Compliant Interface and Command Set}
n _{Configuration EEPROM}
n _{Fault Logging to Internal EEPROM}
n _{Differential Input, 15-Bit ∆Σ ADC with Less Than}
±0.25% of Total Unadjusted Error
n _{Monitors Eight Output Channels and One Input}
Voltage
n _{8-Channel Sequencer}
n _{Programmable Watchdog Timer}
n _{Eight UV/OV Voltage Supervisors}
n _{Eight 10-Bit Voltage-Buffered IDACs with Soft}
Connect
n _{Linear, Voltage Servo Adjusts Supply Voltages by}
Ramping Voltage-Buffered IDAC Outputs Up/Down
n _{Supports Multichannel Fault Management}
n _{On-Chip Digital Temperature Sensor}
n _{Available in 64-Pin 9mm × 9mm QFN Package}
Applications
n _Computers
n _{Network Servers}
LTC2978
Octal PMBus Power Supply
Monitor and Controller
with EEPROM
Description
The LTC^®2978 is an octal, PMBus compliant power sup-
ply monitor, supervisor, sequencer and margin control-
ler. PMBus functions include warning and fault OV/UV
threshold pairs for eight output channels and one input
channel. Programmable fault response allows the power
supplies to be disabled with optional retry after a fault has
been detected. PMBus reads allow eight output voltages
and one input voltage to be monitored. In addition, odd
numbered channels can substitute sense resistor voltage
measurements for output voltage measurements. PMBus
commands support power supply sequencing and precision
point-of-load voltage servo to one of three programmed
values: margin high, margin low and nominal. A program-
mable watchdog timer monitors microprocessor activity
for a stalled condition and resets the micro if necessary.
The 1-wire synchronization bus supports power supply
sequencing across multiple LTC2978 devices. User pro-
grammable parameters can be stored in EEPROM. Voltage
supervisor, voltage monitor and temperature faults can
also be logged to EEPROM.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 7382203 and 7420359.
Typical Application
Octal Power Supply Controller with PMBus Interface
4.5V < V_IBUS < 15V
TO INTERMEDIATE
BUS CONVERTER
ENABLE
PMBus
INTERFACE
WRITE-PROTECT
TO/FROM OTHER
LTC2978s
V_PWR
V_{IN_EN}
V_{IN_SNS}
V_DACP0
V_SENSEP0
SDA ^LTC2978*
SCL
ALERTB
CONTROL0
V_DACM0
V_SENSEM0
V_{OUT_EN0}
WP
PWRGD
WDI/RESETB
FAULTB00
ASEL0
SHARE_CLK
ASEL1
GND
2978 TA01
V_IN
LOAD
V_OUT
DIGITALLY
R20
7.5k
R30
41.2k
MANAGED
POWER
SUPPLY
V_FB
R10
20k
SGND
RUN/SS
GND
TO µP RESETB INPUT
WATCHDOG
TIMER INTERRUPT
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF EIGHT CHANNELS SHOWN
2978fa