HCTS191MS
Rad-Hard Synchronous 4-Bit Up/Down Counter
Typical Diagram

Key Features
- 3 Micron Radiation Hardened CMOS SOS
- Total Dose 200K RAD (Si)
- SEP Effective LET No Upsets: >100 MEV-cm2/mg
- Single Event Upset (SEU) Immunity < 2 x 10-9 Errors/Bit- Day (Typ)
- Dose Rate Survivability: >1 x 1012 RAD (Si)/s
- Dose Rate Upset: >1010 RAD (Si)/s 20ns Pulse
- Cosmic Ray Upset Immunity 2 x 10-9 Errors/Bit Day
- Latch-Up Free Under Any Conditions
- Fanout (Over Temperature Range)
- Standard Outputs - 10 LSTTL Loads
- Military Temperature Range: -55oC to +125oC
- Significant Power Reduction Compared to LSTTL ICs
- DC Operating Voltage Range: 4.5V to 5.5V
- LSTTL Input Compatibility
- VIL = 0.8V Max
- VIH = VCC/2 Min
- Input Current Levels Ii ≤ 5µA @ VOL, VOH
Description
The Intersil HCTS191MS is a Radiation Hardened asynchronously presettable 4 bit binary up/down synchronous counter. Presetting the counter to the number on the preset data inputs (P0 - P3) is accomplished by a low asynchronous parallel load input (PL). Counting occurs when PL is high, Count Enable (CE) is low, and the Up/Down (U/D) input is either low for up-counting or high for down-counting. The counter is incremented or decremented synchronously with the low-to-high transition of the clock. When an overflow or underflow of the counter occurs, the Terminal Count output (TC), which is low during counting, goes high and remains high for one clock cycle. This output can be used for look-ahead carry in high speed cascading. The TC output also initiates the Ripple Clock output (RC) which, normally high, goes low and remains low for the low-level portion of the clock pulse. These counter can be cascaded using the Ripple Carry output.
The HCTS191MS utilizes advanced CMOS/SOS technology to achieve high-speed operation. This device is a member of radiation hardened, high-speed, CMOS/SOS Logic Family. The HCTS191MS is supplied in a 16 lead Ceramic flatpack (K suffix) or a SBDIP Package (D suffix).

