Linear Technology Corp. (LTC, Milpitas, CA) announced the new LTC1921, which provides a complete precision, dual -48V, battery voltage and fuse-monitoring solution for high-reliability telecommunications equipment in less than 20mm².
Three separate alarm outputs drive three optocouplers or green LEDs. Should either of the -48V supplies have an under-voltage (-38.5V, ±1Vmax) or over-voltage (-70V, ±1.5Vmax) failure condition, the LTC1921 turns off one or more of the LEDs/optos to indicate the fault to a diagnostic system. During an under-voltage condition, the LED/opto is held off until the supply recovers to -43V (±0.5Vmax). In addition, if the voltage across either fuse exceeds 2.5V, the LTC1921 will turn off a third LED/opto. The LTC1921 is designed to withstand +100Vdc faults and 10µs transients up to ±200V.
The LTC1921 is available in either an MSOP or SOIC eight-lead package specified for -40 to +85 degrees C operation, and costs from $2.50 each in 1,000-piece quantities.
