TMS320DM6467T_17 Datasheet, PDF (150/352 Pages) Texas Instruments – Digital Media System-on-Chip

TMS320DM6467T
SPRS605C – JULY 2009 – REVISED JUNE 2012
www.ti.com
Table 7-5. Input Requirements for Crystal on the 27 – 35-MHz System Oscillator
PARAMETER
Start-Up Time (from power up until oscillating at stable frequency)
Oscillation Frequency
ESR
27 – 31-MHz
32 – 35-MHz
Parallel Load Capacitance (C1 and C2) [Max]
Frequency Tolerance
Aging
Thermal Stability
Oscillation Mode
Drive Level (Max)
Shunt Capacitance (Max)
MIN
NOM
27
33 or 33.3
± 50
±5
± 50
Fundamental
MAX
4
35
50
40
12 – 20
0.8
5
UNIT
ms
MHz
Ω
Ω
pF
ppm
ppm
ppm
n/a
mW
pF
7.4.1.2 24-MHz Auxiliary Oscillator Clock Input Option 1—Crystal
In this option, a crystal is used as the external clock input to the DM6467T auxiliary oscillator.
The 24-MHz oscillator provides the reference clock for USB and UART peripherals and the internal clock
source for the McASP peripherals. The on-chip oscillator requires an external 24-MHz crystal connected
across the AUX_MXI and AUX_MXO pins, along with two load capacitors, as shown in Figure 7-8. The
external crystal load capacitors must be connected only to the 24-MHz oscillator ground pin (AUX_V_SS).
Do not connect to board ground (V_SS). The AUX_DV_DD18 pin can be connected to the same 1.8 V power
supply as DV_DDR2.
AUX_MXI/
AUX_CLKIN
Crystal
24 MHz
AUX_MXO AUX_V_SS
AUX_DV_DD18 AUX_DV_SS AUX_CV_DD
C1
C2
1.8 V
1.3 V
Figure 7-8. 24-MHz Auxiliary Oscillator
The load capacitors, C1 and C2, should be chosen such that the equation is satisfied (for typical values,
see Table 7-6). C_L in the equation is the load specified by the crystal manufacturer. All discrete
components used to implement the oscillator circuit should be placed as close as possible to the
associated oscillator pins (AUX_MXI and AUX_MXO) and to the AUX_V_SS pin.
CL
=
C1C2
(C1 + C2 )
Table 7-6. Input Requirements for Crystal on the 24-MHz Auxiliary Oscillator
PARAMETER
Start-Up Time (from power up until oscillating at stable
frequency of 24 MHz)
Oscillation Frequency
ESR
MIN
NOM
MAX
4
24
60
UNIT
ms
MHz
Ω
150 Peripheral Information and Electrical Specifications
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