LTC2928 Datasheet, PDF (1/32 Pages) Linear Technology – Multichannel Power Supply Sequencer and Supervisor

FEATURES
■ _{Easily Configure Power Management}
without Software
■ _{Controls Up to Four Supplies per Device}
■ _{Cascades for Additional Supplies}
■ _{Staged Supply Sequencing with}
Adjustable Time Positions
■ _{Fault Event Reporting with Diagnostics}
■ _{Selectable System Shutdown on Fault}
■ _{1.5% Undervoltage Monitor Accuracy}
■ _{Overvoltage and/or Fault Indication}
■ _{Configurable Undervoltage and}
Overvoltage Thresholds
■ _{Charge Pumped Enable Pins Drive N-Channel}
MOSFETs
■ _{Operates from 2.9V to 16.5V}
■ _{5mm × 7mm 38-lead QFN and}
36-lead SSOP Packages
U
APPLICATIO S
■ _{Network/Telecom Infrastructure}
■ _{Sequencing for Multiple I/O and Core Voltages}
■ _{Power Management}
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All
other trademarks are the property of their respective owners. Protected by U.S. Patents
including 4843302, 6949965.
LTC2928
Multichannel Power Supply
Sequencer and Supervisor
DESCRIPTIO
The LTC^®2928 is a four channel cascadable power
supply sequencer and high accuracy supervisor. Sequenc-
ing thresholds, order and timing are configured with just a
few external components, negating the need for PC board
layout or software changes during system development.
Multiple LTC2928s may be easily connected to sequence
an unlimited number of power supplies.
Sequence outputs control supply enable pins or
N-channel pass gates. Precision input comparators with
individual outputs monitor power supply voltages to 1.5%
accuracy. Supervisory functions include undervoltage
and overvoltage monitoring and reporting as well as μP
reset generation. RST may be forced high to complement
margin testing.
Application faults, whether internally or externally gener-
ated, can shutdown all controlled supplies. The type and
source of faults are reported for diagnosis. Individual
channel controls are available to independently exercise
enable outputs and supervisory functions.
A high voltage input allows the LTC2928 to be powered
from voltages as high as 16.5V. A buffered reference
output permits single negative power supply sequencing
and monitoring operations.
TYPICAL APPLICATIO
LTM4600
12V
V_IN
V_OUT
RUN
LTC1628
V_IN
V_OUT
RUN
10k
LTC3414
V_IN
V_OUT
RUN
AUSTIN LYNX
V_IN
V_OUT
Si7894ADP
AXA010AY93
100
0.1 F
ON
95.3k
24.3k
9.53k
1.5k
3.4k
1F
HV_CC EN2 EN1 EN4 EN3
ON
RT1
RT2
RT3
RT4
DONE
V_CC
GND MS1 VSEL
V1
V2
V3
LTC2928
V4
RST
OV
FLT
RTMR PTMR STMR
0.047 F
3300pF
ALL RESISTORS 1%
3.3V
1.2V
2.5V
1.8V
12.1k
36.5k
23.2k
51.1k
SYSTEM
RESET
FAULT
10k 10k 10k 10k
2928 TA06
Sequencing Up and Down
3.3V
2.5V
1.8V
1.2V
1V/DIV
ON
DONE
START
SEQUENCE _{SEQUENCE UP START}
UP _{COMPLETE SEQUENCE}
DOWN
SEQUENCE
DOWN
COMPLETE
2928 TA07
2928f
1