PT7C4372A Datasheet, PDF(27/30 Page) Pericom Semiconductor Corporation

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

PT7C4372A Datasheet, PDF (27/30 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

◁

PT7C4372A/4372C

Real-time Clock Module (I2C Bus)

||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

Configuration of Oscillating Circuit and Timing Trimming

Recommended Layout for Crystal

OSCIN

OSCOUT

Note: The crystal, traces and crystal input pins

should be isolated from RF generating signals.

Considerations in Mounting Components Surrounding Oscillating Circuit

1) Mount the crystal oscillators in the closest possible position to the IC.

2) Avoid laying any signal or power line close to the oscillation circuit (particularly in the area marked with ââAââ in the

above figure).

3) Apply the highest possible insulation resistance between the OSCOUT pin and the PCB.

4) Avoid using any long parallel line to wire the OSCIN and OSCOUT pin.

5) Take extreme care not to cause condensation, which leads to various problems such as oscillation halt.

Built-in Capacitors Specifications and Recommended External Capacitors

Parameter

Symbol

Typ

Unit

Build-in capacitors

OSCIN to GND

OSCOUT to GND

Recommended External capacitors OSCIN to GND

for crystal CL=12.5pF

OSCOUT to GND

Note: The frequency of crystal can be optimized by external capacitor C1 and C2, for frequency=32.768kHz, C1 and C2 should

meet the equation as below:

Cpar + [(C1+CG)*(C2+CD)]/ [(C1+CG)+(C2+CD)] =CL

Cpar is all parasitical capacitor between X1 and X2.

CL is crystalâs load capacitance.

Crystal Specifications

Parameter

Symbol

Min

Typ

Max

Unit

Nominal Frequency

32.768

kHz

Series Resistance

ESR

kï

Load Capacitance

12.5

12-07-0001

PT0150-8 07/04/12

▷