MSP430X241X Datasheet, PDF (52/98 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430x241x, MSP430x261x
MIXED SIGNAL MICROCONTROLLER
SLAS541A -- JUNE 2007 -- REVISED OCTOBER 2007
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted) (continued)
crystal oscillator, XT2 (see Note 5)
PARAMETER
TEST CONDITIONS
VCC
MIN TYP MAX UNIT
f_XT2
XT2 oscillator crystal frequency,
mode 0
XT2Sx = 0
1.8 V to 3.6 V 0.4
1 MHz
f_XT2
XT2 oscillator crystal frequency,
mode 1
XT2Sx = 1
1.8 V to 3.6 V
1
4 MHz
XT2 oscillator crystal frequency,
f_XT2
mode 2
XT2Sx = 2
1.8 V to 3.6 V
2
2.2 V to 3.6 V
2
3 V to 3.6 V
2
10
12 MHz
16
XT2 oscillator logic level
f_XT2
square-wave input frequency
XT2Sx = 3
1.8 V to 3.6 V 0.4
2.2 V to 3.6 V 0.4
3 V to 3.6 V
0.4
10
12 MHz
16
OA
C_L,eff
Oscillation allowance
(see Figure 23 and Figure 24)
Integrated effective load
capacitance, HF mode
(see Note 1)
XT2Sx = 0, f_XT2 = 1 MHz,
C_L,eff = 15 pF
XT2Sx = 1, f_XT2 = 4 MHz,
C_L,eff = 15 pF
XT2Sx = 2, f_XT1,HF = 16 MHz,
C_L,eff = 15 pF
See Note 2
2700
800
Ω
300
1
pF
Duty cycle
Measured at P1.4/SMCLK,
f_XT2 = 10 MHz
Measured at P1.4/SMCLK,
f_XT2 = 16 MHz
2.2 V/3 V
40
50
60
%
40
50
60
f_Fault
Oscillator fault frequency, HF mode
(see Note 4)
XT2Sx = 3, (see Note 3)
2.2 V/3 V
30
300 kHz
NOTES: 1. 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.
2. Requires external capacitors at both terminals. Values are specified by crystal manufacturers.
3. Measured with logic level input frequency but also applies to operation with crystals.
4. Frequencies below the MIN specification will set the fault flag, frequencies above the MAX specification will not set the fault flag.
Frequencies in between might set the flag.
5. To improve EMI on the LFXT1 oscillator the following guidelines should be observed.
-- Keep the trace between the device and the crystal as short as possible.
-- Design a good ground plane around the oscillator pins.
-- Prevent crosstalk from other clock or data lines into oscillator pins XIN and XOUT.
-- Avoid running PCB traces underneath or adjacent to the XIN and XOUT pins.
-- Use assembly materials and praxis to avoid any parasitic load on the oscillator XIN and XOUT pins.
-- If conformal coating is used, ensure that it does not induce capacitive/resistive leakage between the oscillator pins.
-- 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.
52
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265