5042 series
Power-saving Pull-up Resistor
The INHN pin pull-up resistance R
or R
changes in response to the input level (open, HIGH, or LOW).
PU1
PU2
When INHN is tied LOW level, the pull-up resistance is large (R ), reducing the current consumed by the
PU1
resistance. When INHN is left open circuit (HIGH), the pull-up resistance is small (R ), which increases the
PU2
input susceptibility to external noise. However, the pull-up resistance ties the INHN pin HIGH level to prevent
external noise from unexpectedly stopping the output.
Oscillation Detector Function
The 5042 series also feature an oscillation detector circuit. This circuit functions to disable the outputs until the
oscillator circuit starts and oscillation becomes stable. This alleviates the danger of abnormal oscillator output
at oscillator start-up when power is applied or when INHN is switched.
SEIKO NPC CORPORATION—10