Radiation Hardened Quad Power Supply Sequencer


The ISL70321SEH and ISL73321SEH are radiation hardened and SEE mitigated power supply sequencers designed to drive Point-of-Load (POL) regulators with enable pins. Up to four power supplies can be fully sequenced by a single device or multiple devices can be easily cascaded to sequence an unlimited number of power supplies for dense RF applications.

This power supply sequencer requires only two feedback resistors per power supply and a single resistor to set the rising and falling delay. The device features precision input comparators with an input threshold voltage of 600mV ±1.5% for the highest possible accuracy when monitoring the power supply voltages.

The ISL70321SEH and ISL73321SEH are offered in an 18 Ld 10mmx12mm CDFP package or die form and are fully specified across the military ambient temperature range of -55°C to +125°C.

With minimal external component count, precision voltage monitoring, and SET mitigation, the ISL70321SEH and ISL73321SEH are the ideal choice to control many of today’s highly dense power systems in high reliability applications.


  • Wide operating voltage range, 3V to 13.2V
  • Single resistor sets the rising and falling delay
  • Power-off POLs in reverse order or simultaneously
  • Precision voltage monitoring
  • 600mV ±1.5% threshold voltage over temperature and radiation
  • Full military temperature range operation
  • TA = -55°C to +125°C
  • TJ = -55°C to +150°C
  • Radiation Hardness
  • High Dose Rate (HDR) (50-300rad(Si)/s): 100krad(Si) - ISL70321SEH only
  • Low Lose Rate (LDR) (0.01rad(Si)/s): 75krad(Si) ISL70321SEH and ISL73321SEH
  • SEE Hardness (Review SEE Report for details)
  • No SEB/SEL LETTH, VDD = 14.7V: 86MeV•cm2/mg
  • SET, SEFI free at LET 20MeV•cm2/mg
  • Electrically screened to DLA SMD 5962-17225


Basic Information
Production Status
Mass Production
Low Dose Rate (ELDRS) krad (Si)
SEL (MeV/mg/cm2)
SEL free
Qualification Level
QML Class V (space)
Can Sample
Temperature Range
-55 to +125

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