FT4232H datasheet(32/43 Pages) FTDI

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Document No.: FT_000060

FT4232H QUAD HIGH SPEED USB TO MULTIPURPOSE UART/MPSSE IC

Datasheet Version 2.05

Clearance No.: FTDI#78

6.3

Oscillator Configuration

Figure 6.5 Recommended FT4232H Crystal Oscillator Configuration.

Figure 6.5 illustrates how to connect the FT4232H with a 12MHz ± 0.5% crystal. In this case loading

capacitors should to be added between OSCI, OSCO and GND as shown. A value of 27pF is shown as the

capacitor in the example – this will be good for many crystals but it is recommended to select the loading

capacitor value based on the manufacturer’s recommendations wherever possible. It is recommended to use

a parallel cut type crystal.

It is also possible to use a 12 MHz oscillator with the FT4232H. In this case the output of the oscillator would

drive OSCI, and OSCO should be left unconnected. The oscillator must have a CMOS output drive

capability.

Parameter

Description

Minimum

Typical

Maximum

Units

Conditions

OSCI Vin

Input Voltage

2.97

3.30

3.63

FIn

Input Frequency

MHz

+/- 30ppm

Cycle to cycle jitter

< 150

Table 6.1 OSCI Input characteristics

OSCI

OSCO

FT4232H

Crystal

12MHz

27pF

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