Single Event and Total Dose Hardened, High-Speed, Dual Output PWMs


The IS-1825ASRH, IS-1825BSRH, IS-1825BSEH, ISL71823ASRH, and ISL71823BSRH are single event and total dose hardened pulse width modulators designed to be used in high-frequency switching power supplies in either voltage or current-mode configurations. These devices include a precision voltage reference, a low power start-up circuit, a high-frequency oscillator, a wide-band error amplifier, and a fast current-limit comparator.

The IS-1825xSRH and IS-1825xSEH feature dual, alternating output operating from zero to less than 50% duty cycle, and the ISL71823xSRH features dual in-phase output operating from zero to less than 100% duty cycle. The B versions of the parts test the delay from clock out to PWM output switching after power has been applied to the modulator (tPWM ) (see Figure 2 on page 9). The SEH parts are wafer-by-wafer acceptance tested to 50krad(Si) at a low dose rate of <10mrad(Si)/s.

Constructed with the Rad-hard Silicon Gate (RSG) dielectrically isolated BiCMOS process, these devices are immune to single-event latch-up and have been specifically designed to provide a high level of immunity to single-event transients. All specified parameters are established and tested for 300krad(Si) total dose performance.

The devices are offered in a 16 Ld CDIP or a 20 Ld CDFP and fully specified to across the temperature range of -50°C to +125°C.


  • Electrically screened to DLA SMD# 5962-02511
  • QML qualified per MIL-PRF-38535 requirements
  • EH version is wafer-by-wafer acceptance tested to 50krad(Si) LDR
  • Oscillator frequency: 1MHz (max)
  • High output drive current: 1A peak (typ)
  • Low startup current: 300μA (max)
  • Undervoltage Lockout
  • Start threshold: 8.8V (max)
  • Stop threshold: 7.6V (min)
  • Hysteresis: 300mV (min)
  • Pulse-by-pulse current limiting
  • Programmable leading edge blanking
  • Radiation Hardness
  • High Dose Rate (HDR) (50-300rad(Si)/s): 300krad(Si)
  • Low Lose Rate (LDR) (0.01rad(Si)/s): 50krad(Si)
  • Latch-up immune (dielectrically isolated)
  • SEU immune: LET= 35MeV•cm2/mg


Basic Information
Production Status
Mass Production
High Dose Rate (HDR) krad(Si)
SEL (MeV/mg/cm2)
SEL free
Qualification Level
QML Class Q (military), QML Class V (space)
Temperature Range
-55 to +125

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