MSP430G2955
MSP430G2855
MSP430G2755
www.ti.com
SLAS800 –MARCH 2013
Crystal Oscillator, XT1, Low-Frequency Mode(1)
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
MIN
TYP
MAX UNIT
LFXT1 oscillator crystal
frequency, LF mode 0 or 1
fLFXT1,LF
XTS = 0, LFXT1Sx = 0 or 1
1.8 V to 3.6 V
32768
Hz
LFXT1 oscillator logic level
fLFXT1,LF,logic
square wave input frequency, XTS = 0, XCAPx = 0, LFXT1Sx = 3
LF mode
1.8 V to 3.6 V 10000
32768 50000
Hz
XTS = 0, LFXT1Sx = 0,
fLFXT1,LF = 32768 Hz, CL,eff = 6 pF
500
200
Oscillation allowance for
LF crystals
OALF
kΩ
XTS = 0, LFXT1Sx = 0,
fLFXT1,LF = 32768 Hz, CL,eff = 12 pF
XTS = 0, XCAPx = 0
XTS = 0, XCAPx = 1
XTS = 0, XCAPx = 2
XTS = 0, XCAPx = 3
1
5.5
8.5
11
Integrated effective load
capacitance, LF mode(2)
CL,eff
pF
XTS = 0, Measured at P2.0/ACLK,
fLFXT1,LF = 32768 Hz
Duty cycle, LF mode
2.2 V
2.2 V
30
10
50
70
%
Oscillator fault frequency,
LF mode(3)
fFault,LF
XTS = 0, XCAPx = 0, LFXT1Sx = 3(4)
10000
Hz
(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 or 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) Includes parasitic bond and package capacitance (approximately 2 pF per pin).
Because 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.
(3) 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.
(4) Measured with logic-level input frequency but also applies to operation with crystals.
Internal Very-Low-Power Low-Frequency Oscillator (VLO)
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
VLO frequency
VLO frequency temperature drift
TA
VCC
3 V
MIN
TYP
12
MAX UNIT
20 kHz
%/°C
fVLO
-40°C to 85°C
-40°C to 85°C
25°C
4
dfVLO/dT
3 V
0.5
4
dfVLO/dVCC VLO frequency supply voltage drift
1.8 V to 3.6 V
%/V
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