EM250-DEV Ember, EM250-DEV Datasheet - Page 24

• Manufacturer Part Number: EM250-DEV
• Description: KIT DEV FOR EM250
• Manufacturer: Ember
• Series: InSightr
• Type: 802.15.4/Zigbeer

Specifications of EM250-DEV

• Frequency: 2.4GHz
• For Use With/related Products: EM250
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 636-1002

EM250
24
120-0082-000I
Table 12 lists the specifications for the high-frequency crystal.
Parameter
Frequency
Duty cycle
Phase noise from 1kHz to 100kHz
Accuracy
Crystal ESR
Crystal ESR
Start-up time to stable clock (max. bias)
Start-up time to stable clock (optimum
bias)
Current consumption
Current consumption
Current consumption
4.10.2 Low-Frequency Oscillator
The optional low-frequency crystal source for the EM250 is a 32.768kHz crystal. Table 13 lists the require-
ments for the low-frequency crystal. The low-frequency crystal may be used for applications that require
greater accuracy than can be provided by the internal RC oscillator. The crystal oscillator has been designed
to accept any standard watch crystal with an ESR of 100 kΩ.
Parameter
Frequency
Accuracy
Load capacitance (double this each side to
ground)
Crystal ESR
Start-up time
Current consumption
4.10.3 Internal RC Oscillator
The EM250 has a low-power, low-frequency RC oscillator that runs all the time. Its nominal frequency is
10kHz.
The RC oscillator has a coarse analog trim control, which is first adjusted to get the frequency as close to
10kHz as possible. This raw clock is used by the chip management block. It is also divided down to 1kHz using
a variable divider to allow software to accurately calibrate it. This calibrated clock is available to the sleep
timer.
Table 12. High-Frequency Crystal Specifications
Table 13. Low-Frequency Crystal Specifications
Test Conditions
Initial, temperature, and
aging
Load capacitance of 10pF
Load capacitance of 18pF
Good crystal: 20Ω ESR,
10pF load
Worst-case crystals (60Ω,
18pF or 100Ω, 10pF)
At maximum bias
Test Conditions
Initial, temperature, and
aging
At 25°C, VDD_PADS=3.0V
Min.
40
- 40
Min.
- 100
Typ.
24
0.2
Typ.
32.768
12.5
0.6
- 120
100
60
1
Max.
60
+ 40
2
0.3
0.5
1
Max.
+ 100
100
1
Unit
MHz
%
dBc/Hz
ppm
Ω
Ω
ms
ms
mA
mA
mA
Unit
kHz
ppm
pF
kΩ
S
µA