MSP430F551X_1 Datasheet, PDF (57/115 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430F551x
MSP430F552x
www.ti.com
SLAS590D – OCTOBER 2009 – REVISED APRIL 2010
Crystal Oscillator, XT2
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)^{(1) (2)}
PARAMETER
I_DVCC.XT2
XT2 oscillator crystal
current consumption
f_XT2,HF0
XT2 oscillator crystal
frequency, mode 0
TEST CONDITIONS
f_OSC = 4 MHz, XT2OFF = 0, XT2BYPASS = 0,
XT2DRIVEx = 0, T_A = 25°C
f_OSC = 12 MHz, XT2OFF = 0, XT2BYPASS = 0,
XT2DRIVEx = 1, T_A = 25°C
f_OSC = 20 MHz, XT2OFF = 0, XT2BYPASS = 0,
XT2DRIVEx = 2, T_A = 25°C
f_OSC = 32 MHz, XT2OFF = 0, XT2BYPASS = 0,
XT2DRIVEx = 3, T_A = 25°C
XT2DRIVEx = 0, XT2BYPASS = 0⁽³⁾
V_CC
3.0 V
MIN TYP
200
260
325
450
4
f_XT2,HF1
XT2 oscillator crystal
frequency, mode 1
XT2DRIVEx = 1, XT2BYPASS = 0⁽³⁾
8
f_XT2,HF2
XT2 oscillator crystal
frequency, mode 2
XT2DRIVEx = 2, XT2BYPASS = 0⁽³⁾
16
f_XT2,HF3
XT2 oscillator crystal
frequency, mode 3
XT2DRIVEx = 3, XT2BYPASS = 0⁽³⁾
24
XT2 oscillator logic-level
f_XT2,HF,SW square-wave input
XT2BYPASS = 1^{(4) (3)}
1.5
frequency, bypass mode
XT2DRIVEx = 0, XT2BYPASS = 0,
f_XT2,HF0 = 6 MHz, C_L,eff = 15 pF
450
OA_HF
Oscillation allowance for
HF crystals⁽⁵⁾
XT2DRIVEx = 1, XT2BYPASS = 0,
f_XT2,HF1 = 12 MHz, C_L,eff = 15 pF
XT2DRIVEx = 2, XT2BYPASS = 0,
f_XT2,HF2 = 20 MHz, C_L,eff = 15 pF
320
200
XT2DRIVEx = 3, XT2BYPASS = 0,
f_XT2,HF3 = 32 MHz, C_L,eff = 15 pF
200
t_START,HF Startup time
f_OSC = 6 MHz, XT2BYPASS = 0, XT2DRIVEx = 0,
T_A = 25°C, C_L,eff = 15 pF
f_OSC = 20 MHz, XT2BYPASS = 0, XT2DRIVEx = 2,
T_A = 25°C, C_L,eff = 15 pF
3.0 V
0.5
0.3
Integrated effective load
C_L,eff
capacitance,
1
HF mode ^{(6) (7)}
Duty cycle
f_Fault,HF
Oscillator fault
frequency ⁽⁸⁾
Measured at ACLK, f_XT2,HF2 = 20 MHz
XT2BYPASS = 1⁽⁹⁾
40
50
30
MAX UNIT
µA
8 MHz
16 MHz
24 MHz
32 MHz
32 MHz
Ω
ms
pF
60 %
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) This represents the maximum frequency that can be input to the device externally. Maximum frequency achievable on the device
operation is based on the frequencies present on ACLK, MCLK, and SMCLK cannot be exceed for a given range of operation.
(4) When XT2BYPASS is set, the XT2 circuit is automatically powered down. Input signal is a digital square wave with parametrics defined
in the Schmitt-trigger Inputs section of this datasheet.
(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) Requires external capacitors at both terminals. Values are specified by crystal manufacturers.
(8) 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.
(9) Measured with logic-level input frequency but also applies to operation with crystals.
Copyright © 2009–2010, Texas Instruments Incorporated
Submit Documentation Feedback
57