CSR1001A04-IQQA-R Datasheet, PDF (20/45 Pages) –

Note:
C_TRIM is the internal trimmable capacitance in Table 3.1.
C_LOAD1 and C_LOAD2 in combination with C_TRIM and any parasitic capacitance provide the load capacitance
required by the crystal.
3.2.1 Crystal Specification
Table 3.1 shows the specification for an external crystal.
Parameter
Min
Typ
Max
Unit
Frequency
-
16
-
MHz
Frequency tolerance (without trimming)
(a)
-
-
±25
ppm
Frequency trim range^(b)
Drive level
Equivalent series resistance
Load capacitance
Pullability
-
±50
-
ppm
-
-
100
µW
-
-
60
Ω
-
9
-
pF
10
-
-
ppm/pF
Table 3.1: Crystal Specification
(a) _{Use integrated load capacitors to trim initial frequency tolerance in production or to trim frequency over temperature, increasing the allowable}
frequency tolerance.
(b) _{Frequency trim range is dependent on crystal load capacitor values and crystal pullability.}
3.2.2 Frequency Trim
CSR1001 QFN contains variable integrated capacitors to allow for fine-tuning of the crystal resonant frequency. This
firmware-programmable feature allows accurate trimming of crystals on a per-device basis on the production line.
The resulting trim value is stored in non-volatile memory.
Production Information
© Cambridge Silicon Radio Limited 2011-2013
Page 19 of 44
CS-216358-DSP5
www.csr.com