Linear Technology announces the LTC6804 high voltage battery monitor for hybrid electric and electric vehicles, and other high voltage, stacked-battery systems. An LTC6804 can measure up to 12 series connected battery cells at voltages up to 4.2V with 16 bit resolution and better than 0.04% accuracy. This high precision is maintained over time, temperature and operating conditions by a sub-surface Zener voltage reference similar to references used in precision instrumentation. When stacked in series, the LTC6804 enables the measurement of every battery cell voltage in large high voltage systems. Six operating modes are available to optimize update rate, resolution and the low pass response of the built-in 3rd order noise filter. In the fastest mode, all cells can be measured within 290µsec.