EM357-RTR Ember, EM357-RTR Datasheet - Page 47

• Manufacturer Part Number: EM357-RTR
• Description: IC RF TXRX ZIGBEE 192KB 48QFN
• Manufacturer: Ember

Specifications of EM357-RTR

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 2.1 V ~ 3.6 V
• Current - Receiving: 26mA
• Current - Transmitting: 31mA
• Data Interface: PCB, Surface Mount
• Memory Size: 192kB Flash, 12kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 636-1011-2

6.3.3
A low-frequency RC oscillator (OSCRC) is provided as an internal timing reference. The nominal frequency
coming out of reset is 10 kHz, and Ember software calibrates this clock to 10 kHz. From the tuned 10 kHz
oscillator (OSCRC) Ember software calibrates a fractional-N divider to produce a 1 kHz reference clock, CLK1K.
Table 6-8 contains the specification for the low frequency RC oscillator.
6.3.4
A low-frequency 32.768 kHz crystal oscillator (OSC32K) is provided as an optional timing reference for on-chip
timers. This oscillator is designed for use with an external watch crystal. When using the 32.768 kHz crystal,
you must connect it to GPIO PC6 and PC7, and must configure these two GPIOs for analog input. Alternatively,
when PC7 is configured as a digital input, PC7 can accept an external digital clock input instead of a
32.786 kHz crystal. The digital clock input signal must be a 1 V peak-to-peak sine wave with a DC bias of
0.5 V. Refer to Chapter 7, GPIO for GPIO configuration details. Using the low-frequency oscillator, crystal or
digital clock, is enabled through Ember software.
Parameter
Current consumption at max bias
Crystal with high ESR
Crystal with low ESR
Parameter
Nominal Frequency
Analog trim step size
Supply dependence
Temperature
dependence
Low-Frequency Internal RC Oscillator (OSCRC)
Low-Frequency Crystal Oscillator (OSC32K)
Load capacitance
Crystal capacitance
Crystal power dissipation
Load capacitance
Crystal capacitance
Crystal power dissipation
Table 6-8. Low-Frequency RC Oscillator Specification
Test conditions
After trimming
For a voltage drop from 3.6 V to 3.1 V or 2.6 V to 2.1 V
(without re-calibration)
Frequency variation with temperature for a change
from -40
(without re-calibration)
o
C to +85
Final
6-9
o
C
Test conditions
Min
EM351 / EM357
Typ
Min
9
Max
100
200
Typ
0.5
10
60
18
10
1
7
7
1
1
2
120-035X-000G
Max
11
Unit
mW
mA
µW
pF
pF
pF
pF
Ω
Ω
Unit
kHz
kHz
%
%