LTC2974CUP-PBF Datasheet, PDF (1/98 Pages) Linear Technology – 4-Channel PMBus Power System Manager

LTC2974
4-Channel PMBus Power System Manager
Featuring Accurate Output Current Measurement
FEATURES
DESCRIPTION
n _{Sequence, Trim, Margin and Supervise Four Power}
Supplies
n _{Manage Faults, Monitor Telemetry and Create Fault Logs}
n _{PMBus Compliant Command Set}
n _{Supported by LTpowerPlay}^TM _GUI
n _{Margin or Trim Supplies to 0.25% Accuracy}
n _{Fast OV/UV Supervisors Per Channel}
n _{Fast Output Current 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 _{External Temperature and Input Voltage Supervisors}
n _{Accurate Monitoring of Four Output Voltages, Four}
Output Currents, Four External Temperatures, 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 _{Available in 64-Lead 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^®2974 is a 4-channel Power System Manager used
to sequence, trim (servo), margin, supervise, manage
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 over and under
current, voltage and temperature threshold limits for four
power supply output channels as well as over and under
voltage threshold limits for a single power supply input
channel. 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 four output
voltages, four output currents, four external temperatures,
one input voltage and die temperature. Output power is
also calculated. A programmable watchdog timer moni-
tors 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, Linear Technology, the Linear logo, and PolyPhase 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.
TYPICAL APPLICATION
4-Channel PMBus Power System Manager
4.5V < V_IBUS < 15V**
OV
PMBus
INTERFACE
TO/FROM
OTHER
DEVICES
V_PWR**
AUXFAULTB
V_DD33**
V_{IN_SNS}
I_SENSEP0
I_SENSEM0
V_DAC0
V_SENSEP0
SDA
SCL
LTC2974*
ALERTB
CONTROL0
FAULTB0
FAULTB1
SHARE_CLK
V_SENSEM0
V_{OUT_EN0}
T_SENSE0
ASEL0
PWRGD
ASEL1
WP _GND WDI/RESETB
V_IN
I^–
I^{+ DC/DC}
CONVERTER
TG
SW
R30
BG
R20
LOAD
V_FB
R10
SGND
MMBT3906
RUN/SS
GND
TO µP
RESETB
INPUT
WATCHDOG
0.1µF
TIMER INTERRUPT
2974 TA01
*SOME DETAILS OMITTED FOR CLARITY
ONLY ONE OF FOUR CHANNELS SHOWN
**LTC2974 MAY BE POWERED FROM
3.3V OR 4.5V TO 14V
For more information www.linear.com/LTC2974
ADC Total Unadjusted Error
vs Temperature
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
–0.01
–0.02
THREE TYPICAL PARTS
–0.03
–50 –25 0 25 50
TEMPERATURE (°C)
75 100
2974 TA01b
2974fa
1