BC41B143A-ds-003Pc CSR, BC41B143A-ds-003Pc Datasheet - Page 49

• Manufacturer Part Number: BC41B143A-ds-003Pc
• Description: Blue Core ROM Plug-n-Go
• Manufacturer: CSR

Device Terminal Descriptions
10.3
Crystal Oscillator (XTAL_IN, XTAL_OUT)
This section describes the crystal mode. See section 10.2 for the description of the external reference clock mode.
10.3.1 XTAL Mode
BlueCore4-ROM Plug-n-Go contains a crystal driver circuit. This operates with an external crystal and capacitors to
form a Pierce oscillator.
g
m
-
C
C
C
int
trim
trim
C
C
t2
t1
Figure 10.5: Crystal Driver Circuit
Figure 10.6 shows an electrical equivalent circuit for a crystal. The crystal appears inductive near its resonant
frequency. It forms a resonant circuit with its load capacitors.
Figure 10.6: Crystal Equivalent Circuit
The resonant frequency may be trimmed with the crystal load capacitance. BlueCore4-ROM Plug-n-Go contains
variable internal capacitors to provide a fine trim.
Advance Information
BC41B143A-ds-003Pc
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© Cambridge Silicon Radio Limited 2005