BC41B143A-ANN-E4 ETC, BC41B143A-ANN-E4 Datasheet - Page 57

• Manufacturer Part Number: BC41B143A-ANN-E4
• Description: Bluecore 4-rom CSP EDR Single Chip Bluetooth v2.0 + EDR System
• Manufacturer: ETC

This formula shows the negative resistance of the BlueCore4-ROM CSP driver as a function of its drive strength.
The value of the driver negative resistance can be easily measured by placing an additional resistance in series
with the crystal. The maximum value of this resistor (oscillation occurs) is the equivalent negative resistance of
the oscillator.
11.3.6 Crystal PS Key Settings
See tables in Section 11.2.5.
11.3.7 Crystal Oscillator Characteristics
Figure 11.7 shows results for BlueCore4-ROM CSP crystal driver at maximum drive level.
Conditions:
BC41B143A-ds-002Pd
1000.0
C
Crystal C
Transconductance setting = 2mA/V
Loop gain = 3
C
100.0
10.0
trim
t1
/C
Figure 11.7: Crystal Load Capacitance and Series Resistance Limits with Crystal Frequency
2.5
= 3.4pF centre value
t2
= 3
o
8 MHz
20 MHz
32 MHz
= 2pF
3.5
4.5
Crystal Load Capacitance and Series Resistance Limits with Crystal Frequency
12 MHz
24 MHz
This material is subject to CSR’s non-disclosure agreement
5.5
© Cambridge Silicon Radio Limited 2005
16 MHz
28 MHz
Production Information
6.5
Load Capacitance (pF)
7.5
8.5
9.5
Device Terminal Descriptions
10.5
11.5
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12.5