MSP430F2274-EP_14 Datasheet, PDF (34/81 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430F2274-EP
SLAS614D – SEPTEMBER 2008 – REVISED MAY 2011
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Crystal Oscillator (LFXT1) High Frequency Modes – Electrical Characteristics^{(1) (2)}
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
f_LFXT1,
HF0
f_LFXT1,
HF1
PARAMETER
TEST CONDITIONS
LFXT1 oscillator crystal frequency,
HF mode 0
XTS = 1, LFXT1Sx = 0
LFXT1 oscillator lcrystal frequency,
HF mode 1
XTS = 1, LFXT1Sx = 1
f_LFXT1,
HF2
LFXT1 oscillator crystal frequency,
HF mode 2
XTS = 1, LFXT1Sx = 2
T_A
–55°C to 125°C
V_CC
1.8 V to 3.6 V
MIN TYP MAX UNIT
0.4
1 MHz
–55°C to 125°C 1.8 V to 3.6 V
1
1.8 V to 3.6 V
2
–55°C to 125°C 2.2 V to 3.6 V
2
3 V to 3.6 V
2
4 MHz
10
12 MHz
16
f_LFXT1,
HF,logic
LFXT1 oscillator logic-level
square-wave input frequency,
HF mode
XTS = 1, LFXT1Sx = 3
1.8 V to 3.6 V 0.4
–55°C to 125°C 2.2 V to 3.6 V 0.4
3 V to 3.6 V
0.4
10
12 MHz
16
OA_HF
Oscillation allowance for HF
crystals
(see Figure 18 and Figure 19)
C_L,eff
Integrated effective load
capacitance,
HF mode⁽³⁾
XTS = 0, LFXT1Sx = 0;
f_LFXT1,HF = 1 MHz,
C_L,eff = 15 pF
XTS = 0, LFXT1Sx = 1
f_LFXT1,HF = 4 MHz,
C_L,eff = 15 pF
XTS = 0, LFXT1Sx = 2
f_LFXT1,HF = 16 MHz,
C_L,eff = 15 pF
XTS = 1⁽⁴⁾
–55°C to 125°C
–55°C to 125°C
2700
800
Ω
300
1
pF
Duty
Cycle
f_Fault,HF
HF mode
XTS = 1, Measured at
P1.4/ACLK,
f_LFXT1,HF = 10 MHz
XTS = 1, Measured at
P1.4/ACLK,
f_LFXT1,HF = 16 MHz
Oscillator fault frequency, HF mode
(5)
XTS = 1, LFXT1Sx = 3⁽⁶⁾
–55°C to 125°C
–55°C to 125°C
–55°C to 125°C
2.2 V/3 V
2.2 V/3 V
40 50 60
%
40 50 60
30
300 kHz
(1) To improve EMI on the LFXT1 oscillator the following guidelines should be observed:
(a) Keep as short of a trace as possible between the device and the crystal.
(b) Design a good ground plane around the oscillator pins.
(c) Prevent crosstalk from other clock or data lines into oscillator pins XIN and XOUT.
(d) Avoid running PCB traces underneath or adjacent to the XIN and XOUT pins.
(e) Use assembly materials and praxis to avoid any parasitic load on the oscillator XIN and XOUT pins.
(f) If conformal coating is used, ensure that it does not induce capacitive/resistive leakage between the oscillator pins.
(g) Do not route the XOUT line to the JTAG header to support the serial programming adapter as shown in other documentation. This
signal is no longer required for the serial programming adapter.
(2) Use of the LFXT1 Crystal Oscillator with T_A > 105°C is not guaranteed. It is recommended that an external digital clock source or the
internal DCO is used to provide clocking.
(3) 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.
(4) Requires external capacitors at both terminals. Values are specified by crystal manufacturers.
(5) 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.
(6) Measured with logic-level input frequency, but also applies to operation with crystals
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