msm62x42b Oki Semiconductor, msm62x42b Datasheet - Page 17

• Manufacturer Part Number: msm62x42b
• Description: Real Time Clock Ic With Built-in Crystal
• Manufacturer: Oki Semiconductor

¡ Semiconductor
APPLICATION NOTE
Power Supply
Pattern Layout
The oscillation circuit of 32.768kHz consists of high impedance in the oscillation stage to
realize the minimum current consumption. In addition, it is a feature that the time when the
oscillation waveform passes the threshold vicinity is long. For this reason, the power supply
anti-noise by the same method as an analog IC must be considered. As an actual example,
set a tantalum capacitor (4.7 F) and a ceramic capacitor (0.01 F) near this IC. In case that an
another IC, for instance, RAM for backup, exists in battery backup circuit, set a bypass
capacitor close to it.
Maximum value of allowable power supply noise should be 300mV.
Set the current Time
HOLD bit
STOP bit
TEST bit
REST bit
24/12 bit
STOP bit
REST bit
24/12 bit
Start Operation
Power On
Start
¨
¨
¨
¨
¨
¨
¨
¨
*2
*1
0
0
0
0
1
1
*1=*2(=1 or 0)
V
All registers and STD,P
output=undefined
DD
= 0 to V
DD
= 5V
MSM62X42B
57