Linear Technology LTC2924 Quad Supply Sequencer DC818A DC818A Fiche De Données
Codes de produits
DC818A
LTC2924
1
2924fb
Typical applicaTion
FeaTures
DescripTion
Quad Power Supply
Sequencer
The LTC
®
2924 is a power supply sequencer designed for
use with external N-channel MOSFETs or power supplies
with shutdown pins. Four power supplies can be fully
sequenced by a single LTC2924 and up to five supplies
can be sequenced to a sixth master supply. The LTC2924
requires a minimum of external components, using only
two feedback resistors per sequenced power supply and
a single resistor to set hysteresis.
An internally regulated charge pump provides gate drive
An internally regulated charge pump provides gate drive
voltages for external logic and sub-logic-level MOSFETs.
Adding a single capacitor enables an adjustable time delay
between power supplies during both Power On and Power
Off sequencing. A second capacitor can be added to enable
a power good timer for detecting the failure of any power
supply to turn on within the selected time. Errors in power
supply sequencing and the control input are detected and
reported at the FAULT output. The LTC2924 features pre-
cision input comparators which can provide 1% accuracy
in monitoring power supply voltages.
Multiple LTC2924s may be easily cascaded to sequence a
Multiple LTC2924s may be easily cascaded to sequence a
virtually unlimited number of power supplies.
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.
applicaTions
n
Fully Sequence and Monitor Four Supplies
– Six with Minimal External Circuitry
n
Cascadable for Additional Supplies
n
Power Off in Reverse Order or Simultaneously
n
Charge Pump Drives External MOSFETs
n
Drives Power Supply Shutdown Pins with No
External Pull-Up Resistors
n
10µA Output Current Allows Soft-Starting of Supplies
n
Done Indicator for Both Power On and Power Off
n
Adjustable Time Delay Between Power Supplies
n
Power Good Timer
n
Power Supply Voltage Monitoring and Power
Sequence Error Detection and Reporting
n
Available in a 16-Lead Narrow SSOP Package
n
Sequenced Power Supplies for ASICs with Multiple
I/O and Core Voltages
n
Latch-Up Prevention in Systems with Multiple Power
Supplies
Power-Up Sequence
OUT1
OUT2
OUT3
OUT4
ON
DONE
FAULT
TMR
PGT
OUT2
OUT3
OUT4
ON
DONE
FAULT
TMR
PGT
IN1
IN2
IN3
IN4
IN2
IN3
IN4
HYS/CFG
LTC2924
V
CC
GND
150nF
2924 TA01a
SYSTEM
CONTROLLER
150nF
1.69k
6.04k
0.1µF
Q1
Q2
100k
1.62k
66.5k
18.2k
3.09k
Q1-Q4: IRL3714S
ALL RESISTORS 1%
20k
V
ON
= 2.64V
V
OFF
= 1.98V
V
ON
= 0.93V
V
OFF
= 0.915V
V
ON
= 3.97V
V
OFF
= 2.97V
V
ON
= 2.79V
V
OFF
= 2.73V
49.9k
10k 10k
5V
3V
1V
3.3V
SHDN
5V
SHDN
5V EARLY
2V/DIV
2V/DIV
10ms/DIV
2924 TA01b
5V
3V
1V
1V
3.3V
ON
TMR
DONE
5V/DIV
5V/DIV
2V/DIV
2V/DIV
10ms/DIV
2924 TA01c
5V
3V
1V
1V
3.3V
ON
TMR
DONE
5V/DIV
5V/DIV
Power-Down Sequence