SM1125_06 Datasheet, PDF (12/13 Pages) Nippon Precision Circuits Inc – Multimelody IC for Pagers

SM1125 series
OSCILLATOR FREQUENCY MEASUREMENT
The measurement circuit below shows a SM1125××V with built-in RC oscillator circuit and external RC oscil-
lator components capacitor C_O and resistor R_O.
When ST is switched to V_DD, the oscillator starts and outputs a pulse on MTO. The output pulse is counted
using a frequency counter.
RO
CO
Switch
SM1125 V
OSC
SI
SC
ST
VSS
VDD
MTO
TEST
Frequency Counter
Note that the board mounting and wiring will marginally affect the output frequency, even for equivalent values for R_O and C_O.
SEIKO NPC CORPORATION —12