Datasheet

MSP430F6638, MSP430F6637, MSP430F6636
MSP430F6635, MSP430F6634, MSP430F6633
MSP430F6632, MSP430F6631, MSP430F6630
SLAS566D –JUNE 2010–REVISED AUGUST 2013 www.ti.com
Crystal Oscillator, XT2
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
(1) (2)
PARAMETER TEST CONDITIONS V
CC
MIN TYP MAX UNIT
f
OSC
= 4 MHz, XT2OFF = 0,
XT2BYPASS = 0, XT2DRIVEx = 0, 200
T
A
= 25°C
f
OSC
= 12 MHz, XT2OFF = 0,
XT2BYPASS = 0, XT2DRIVEx = 1, 260
T
A
= 25°C
XT2 oscillator crystal current
I
DVCC,XT2
3 V µA
consumption
f
OSC
= 20 MHz, XT2OFF = 0,
XT2BYPASS = 0, XT2DRIVEx = 2, 325
T
A
= 25°C
f
OSC
= 32 MHz, XT2OFF = 0,
XT2BYPASS = 0, XT2DRIVEx = 3, 450
T
A
= 25°C
XT2 oscillator crystal frequency,
f
XT2,HF0
XT2DRIVEx = 0, XT2BYPASS = 0
(3)
4 8 MHz
mode 0
XT2 oscillator crystal frequency,
f
XT2,HF1
XT2DRIVEx = 1, XT2BYPASS = 0
(3)
8 16 MHz
mode 1
XT2 oscillator crystal frequency,
f
XT2,HF2
XT2DRIVEx = 2, XT2BYPASS = 0
(3)
16 24 MHz
mode 2
XT2 oscillator crystal frequency,
f
XT2,HF3
XT2DRIVEx = 3, XT2BYPASS = 0
(3)
24 32 MHz
mode 3
XT2 oscillator logic-level square-
f
XT2,HF,SW
XT2BYPASS = 1
(4) (3)
0.7 32 MHz
wave input frequency
XT2DRIVEx = 0, XT2BYPASS = 0,
450
f
XT2,HF0
= 6 MHz, C
L,eff
= 15 pF
XT2DRIVEx = 1, XT2BYPASS = 0,
320
f
XT2,HF1
= 12 MHz, C
L,eff
= 15 pF
Oscillation allowance for
OA
HF
Ω
HF crystals
(5)
XT2DRIVEx = 2, XT2BYPASS = 0,
200
f
XT2,HF2
= 20 MHz, C
L,eff
= 15 pF
XT2DRIVEx = 3, XT2BYPASS = 0,
200
f
XT2,HF3
= 32 MHz, C
L,eff
= 15 pF
f
OSC
= 6 MHz
XT2BYPASS = 0, XT2DRIVEx = 0, 0.5
T
A
= 25°C, C
L,eff
= 15 pF
t
START,HF
Startup time 3 V ms
f
OSC
= 20 MHz
XT2BYPASS = 0, XT2DRIVEx = 3, 0.3
T
A
= 25°C, C
L,eff
= 15 pF
Integrated effective load
C
L,eff
1 pF
capacitance, HF mode
(6) (1)
Duty cycle Measured at ACLK, f
XT2,HF2
= 20 MHz 40 50 60 %
f
Fault,HF
Oscillator fault frequency
(7)
XT2BYPASS = 1
(8)
30 300 kHz
(1) Requires external capacitors at both terminals. Values are specified by crystal manufacturers.
(2) To improve EMI on the XT2 oscillator the following guidelines should be observed.
(a) Keep the traces between the device and the crystal as short as possible.
(b) Design a good ground plane around the oscillator pins.
(c) Prevent crosstalk from other clock or data lines into oscillator pins XT2IN and XT2OUT.
(d) Avoid running PCB traces underneath or adjacent to the XT2IN and XT2OUT pins.
(e) Use assembly materials and praxis to avoid any parasitic load on the oscillator XT2IN and XT2OUT pins.
(f) If conformal coating is used, ensure that it does not induce capacitive/resistive leakage between the oscillator pins.
(3) Maximum frequency of operation of the entire device cannot be exceeded.
(4) When XT2BYPASS is set, the XT2 circuit is automatically powered down.
(5) Oscillation allowance is based on a safety factor of 5 for recommended crystals.
(6) Includes parasitic bond and package capacitance (approximately 2 pF per pin).
Since the PCB adds additional capacitance, it is recommended to verify the correct load by measuring the ACLK frequency. For a
correct setup, the effective load capacitance should always match the specification of the used crystal.
(7) Frequencies below the MIN specification set the fault flag. Frequencies above the MAX specification do not set the fault flag.
Frequencies in between might set the flag.
(8) Measured with logic-level input frequency but also applies to operation with crystals.
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