50
SLAS826F – MARCH 2015 – REVISED MARCH 2017
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Specifications
Copyright © 2015–2017, Texas Instruments Incorporated
Table 5-10. High-Frequency Crystal Oscillator, HFXT (continued)
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
TEST CONDITIONS
V
CC
MIN
TYP
MAX
UNIT
(4)
Does not include programable start-up counter.
(5)
This represents all the parasitic capacitance present at the HFXIN and HFXOUT terminals, respectively, including parasitic bond and
package capacitance. The effective load capacitance, CL,eff can be computed as CIN x COUT / (CIN + COUT), where CIN and COUT
is the total capacitance at the HFXIN and HFXOUT terminals, respectively.
(6)
Requires external capacitors at both terminals to meet the effective load capacitance specified by crystal manufacturers. Recommended
effective load capacitance values supported are 14 pF, 16 pF, and 18 pF. Maximum shunt capacitance of 7 pF. Because the PCB adds
additional capacitance, it must also be considered in the overall capacitance. TI recommends verifying that the recommended effective
load capacitance of the selected crystal is met.
(7)
Frequencies above the MAX specification do not set the fault flag. Frequencies in between the MIN and MAX might set the flag. A static
condition or stuck at fault condition will set the flag.
(8)
Measured with logic-level input frequency but also applies to operation with crystals.
t
START,HFXT
Start-up time
(4)
f
OSC
= 1 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 0,
HFFREQ = 0, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
3.0 V
4
ms
f
OSC
= 4 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 0, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
1.8
f
OSC
= 8 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 1, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
0.7
f
OSC
= 16 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 2, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
0.6
f
OSC
= 24 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 3, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
450
µs
f
OSC
= 32 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 4, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
300
f
OSC
= 40 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 5, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
250
f
OSC
= 48 MHz,
HFXTBYPASS = 0, HFXTDRIVE = 1,
HFFREQ = 6, C
L,eff
= 16 pF,
Typical ESR and C
SHUNT
,
FCNTHF_EN = 0
250
C
HFXIN
Integrated load capacitance at
HFXIN terminal
(5) (6)
2
pF
C
HFXOUT
Integrated load capacitance at
HFXOUT terminal
(5) (6)
2
pF
f
Fault,HFXT
Oscillator fault frequency
(7) (8)
400
700
kHz