EM260-BBRD-128K-USART-R Ember, EM260-BBRD-128K-USART-R Datasheet - Page 20

• Manufacturer Part Number: EM260-BBRD-128K-USART-R
• Description: EM260 BREAKOUT BOARD
• Manufacturer: Ember
• Type: Transceiver, 802.15.4/ZigBeer

Specifications of EM260-BBRD-128K-USART-R

• Frequency: 2.4GHz
• For Use With/related Products: EM260
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 636-1026

4.12 Random Number Generator
120-0260-000J
Table 12 lists the specifications for the high-frequency crystal.
4.11.2 Internal RC Oscillator
The EM260 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 used by the sleep timer.
Timekeeping accuracy depends on temperature fluctuations the chip is exposed to, power supply impedance,
and the calibration interval, but in general it will be better than 150ppm (including crystal error of 40ppm).
Table 13 lists the specifications of the RC oscillator.
The EM260 allows for the generation of random numbers by exposing a randomly generated bit from the RX
ADC. Analog noise current is passed through the RX path, sampled by the receive ADC, and stored in a
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
Parameter
Frequency
Analog trim steps
Frequency variation with supply
Table 12. High-Frequency Crystal Specifications
Table 13. RC Oscillator Specifications
For a voltage drop from 3.6V to
3.1V or 2.6V to 2.1V
Test Conditions
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
Page 20
Min.
- 40
40
Min.
Typ.
0.2
24
Typ.
0.75
10
1
Max.
+ 40
120
100
0.3
0.5
60
60
1
2
1
-
Max.
EM260
1.5
dBc/Hz
Unit
ppm
MHz
mA
mA
mA
ms
ms
Ω
Ω
%
Unit
kHz
kHz
%