EM260-DEV Ember, EM260-DEV Datasheet - Page 19

• Manufacturer Part Number: EM260-DEV
• Description: KIT DEV FOR EM260
• Manufacturer: Ember
• Series: InSightr
• Type: 802.15.4/Zigbeer

Specifications of EM260-DEV

• Frequency: 2.4GHz
• For Use With/related Products: EM260
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 636-1005

4.10 Clock Sources
The VDD_PADS POR cell holds the always-powered high-voltage domain in reset until the following conditions
have been met:
Additionally, the digital domain counts 1,024 clock edges on the 24MHz crystal before releasing the reset to
the main digital core.
Table 11 lists the features of the EM260 POR circuitry.
Parameter
VDD_PADS POR release
VDD_PADS POR assert
1.8V POR release
1.8V POR hysteresis
The EM260 integrates two oscillators: a high-frequency 24MHz crystal oscillator and a low-frequency internal
10kHz RC oscillator.
4.10.1 High-Frequency Crystal Oscillator
The integrated high-frequency crystal oscillator requires an external 24MHz crystal with an accuracy of +/-
40ppm. Based upon the application Bill of Materials and current consumption requirements, the external
crystal can cover a range of ESR requirements. For a lower ESR, the cost of the crystal increases but the
overall current consumption decreases. Likewise, for higher ESR, the cost decreases but the current consump-
tion increases. Therefore, the designer can choose a crystal to fit the needs of the application.
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
The high-voltage Pads Supply VDD_PADS voltage rises above a threshold.
The internal RC clock starts and generates three clock pulses.
The 1.8V POR cell holds the main digital core in reset until the regulator output voltage rises above a
threshold.
Table 12. High-Frequency Crystal Specifications
Test Conditions
Initial, temperature, and aging
Load capacitance of 10pF
Load capacitance of 18pF
Table 11. POR Specifications
Min.
0.5
0.08
1.0
1.35
Min.
40
- 40
Typ.
1.2
0.6
1.5
0.1
Typ.
24
1.4
0.7
1.65
0.12
Max.
120-1003-000D
Max.
60
- 120
+ 40
100
60
1
EM260
Unit
V
V
V
V
Unit
MHz
%
dBc/H
z
ppm
Ω
Ω
ms
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