MSP430F543X_1 Datasheet, PDF (46/90 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430F543x, MSP430F541x
MSP430F543xA, MSP430F541xA
SLAS612 – SEPTEMBER 2008.......................................................................................................................................................................................... www.ti.com
Crystal Oscillator, XT1, Low-Frequency Mode⁽¹⁾
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
ΔI_DVCC.LF
Differential XT1 oscillator crystal
current consumption from lowest
drive setting, LF mode
f_XT1,LF0
f_XT1,LF,SW
XT1 oscillator crystal frequency,
LF mode
XT1 oscillator logic-level
square-wave input frequency,
LF mode
OA_LF
Oscillation allowance for
LF crystals⁽⁴⁾
C_L,eff
Integrated effective load
capacitance, LF mode⁽⁵⁾
Duty cycle LF mode
f_Fault,LF
Oscillator fault frequency,
LF mode⁽⁷⁾
t_START,LF Startup time, LF mode
TEST CONDITIONS
f_OSC = 32768 Hz, XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 1,
T_A = 25°C
f_OSC = 32768 Hz, XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 2,
T_A = 25°C
f_OSC = 32768 Hz, XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 3,
T_A = 25°C
XTS = 0, XT1BYPASS = 0
XTS = 0, XT1BYPASS = 1⁽²⁾⁽³⁾
XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 0,
f_XT1,LF = 32768 Hz, C_L,eff = 6 pF
XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 1,
f_XT1,LF = 32768 Hz, C_L,eff = 12 pF
XTS = 0, XCAPx = 0⁽⁶⁾
XTS = 0, XCAPx = 1
XTS = 0, XCAPx = 2
XTS = 0, XCAPx = 3
XTS = 0, Measured at ACLK,
f_XT1,LF = 32768 Hz
XTS = 0⁽⁸⁾
f_OSC = 32768 Hz, XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 0,
T_A = 25°C,
C_L,eff = 12 pF
f_OSC = 32768 Hz, XTS = 0,
XT1BYPASS = 0, XT1DRIVEx = 3,
T_A = 25°C,
C_L,eff = 12 pF
V_CC
3.0 V
3.0 V
MIN TYP MAX UNIT
0.075
0.170
µA
0.290
32768
Hz
10 32.768
50 kHz
210
kΩ
300
2
5.5
8.5
12.0
30
pF
70 %
10
10000 Hz
1000
ms
500
(1) To improve EMI on the XT1 oscillator, the following guidelines should be observed.
a. Keep the trace 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 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.
(2) When XT1BYPASS is set, XT1 circuits are automatically powered down.
(3) Maximum frequency of operation of the entire device cannot be exceeded.
(4) Oscillation allowance is based on a safety factor of 5 for recommended crystals. The oscillation allowance is a function of the
XT1DRIVEx settings and the effective load. In general, comparable oscillator allowance can be achieved based on the following
guidelines, but should be evaluated based on the actual crystal selected for the application:
a. For XT1DRIVEx = 0, C_L,eff ≤ 6 pF.
b. For XT1DRIVEx = 1, 6 pF ≤ C_L,eff ≤ 9 pF.
c. For XT1DRIVEx = 2, 6 pF ≤ C_L,eff ≤ 10 pF.
d. For XT1DRIVEx = 3, C_L,eff ≥ 6 pF.
(5) 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.
(6) Requires external capacitors at both terminals. Values are specified by crystal manufacturers.
(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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