LTC2924 Quad Power Supply Sequencer Fea T Descrip T n Fully Sequence and Monitor Four Supplies The LTC 2924 is a power supply sequencer designed for n Six with Minimal External Circuitry use with external N-channel MOSFETs or power supplies n Cascadable for Additional Supplies with shutdown pins. Four power supplies can be fully n Power Off in Reverse Order or Simultaneously sequenced by a single LTC2924 and up to five supplies n Charge Pump Drives External MOSFETs can be sequenced to a sixth master supply. The LTC2924 n Drives Power Supply Shutdown Pins with No Exter- requires a minimum of external components, using only nal Pull-Up Resistors two feedback resistors per sequenced power supply and n 10A Output Current Allows Soft-Starting of Supplies a single resistor to set hysteresis. n Done Indicator for Both Power On and Power Off An internally regulated charge pump provides gate drive n Adjustable Time Delay Between Power Supplies voltages for external logic and sub-logic-level MOSFETs. n Power Good Timer Adding a single capacitor enables an adjustable time delay n Power Supply Voltage Monitoring and Power Se- between power supplies during both Power On and Power quence Error Detection and Reporting Off sequencing. A second capacitor can be added to enable n Available in a 16-Lead Narrow SSOP Package 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 a T reported at the FAULT output. The LTC2924 features pre- n Sequenced Power Supplies for ASICs with Multiple cision input comparators which can provide 1% accuracy I/O and Core Voltages in monitoring power supply voltages. n Latch-Up Prevention in Systems with Multiple Power Multiple LTC2924s may be easily cascaded to sequence Supplies 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. Power-Up Sequence Typical a T 5V 3.3V 3.3V V = 2.64V ON 2V/DIV 3V V = 1.98V SHDN OFF 1V Q2 V = 0.93V ON 1V V = 0.915V OFF 5V/DIV DONE 5V V = 3.97V ON 5V 2V/DIV TMR SHDN V = 2.97V OFF 0.1F ON 5V/DIV Q1 V = 2.79V ON 3V V = 2.73V OFF 2924 TA01b 10ms/DIV 6.04k 100k 1.62k 66.5k V CC OUT1 IN1 Power-Down Sequence OUT2 IN2 5V EARLY OUT3 IN3 5V 3.3V 10k 10k OUT4 IN4 3V 2V/DIV 1V ON LTC2924 1.69k 18.2k 3.09k 20k SYSTEM DONE CONTROLLER DONE FAULT 5V/DIV TMR HYS/CFG Q1-Q4: IRL3714S TMR 2V/DIV ALL RESISTORS 1% PGT GND 49.9k 150nF 150nF ON 5V/DIV 2924 TA01a 2924 TA01c 10ms/DIV 2924fc 1 For more information www.linear.com/LTC2924 ion pplica ions pplica ion uresLTC2924 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW Supply Voltage (V ) ................................ 0.3V to 6.5V CC IN1 1 16 ON Input Voltages IN2 2 15 HYS/CFG ON, IN1-IN4 .................................0.3V to V + 0.3V CC IN3 3 14 TMR PGT, TMR, HYS/CFG ....................0.3V to V + 0.3V CC IN4 4 13 GND Open-Drain Output Voltages OUT1 5 12 PGT FAULT, DONE ...............................0.3V to V + 0.3V CC OUT2 6 11 V CC Output Voltages OUT3 7 10 DONE (OUT1 - OUT4) (Note 5) .............. 0.3V to V + 4.5V OUT4 8 9 FAULT CC Operating Temperature Range GN PACKAGE 16-LEAD PLASTIC SSOP LTC2924C ................................................ 0C to 70C T = 125C, = 130C/W JMAX JA LTC2924I .............................................40C to 85C Storage Temperature Range .................. 65C to 150C Lead Temperature (Soldering, 10 sec) ...................300C o r Der i n F Ma T (