EM357-RTR Ember, EM357-RTR Datasheet - Page 27

• 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

EM351 / EM357
3 Top-Level Functional Description
Figure 3-1 shows a detailed block diagram of the EM35x.
Figure 3-1. EM35x Block Diagram
The EM35x radio receiver is a low-IF, super-heterodyne receiver. The architecture has been chosen to
optimize co-existence with other devices in the 2.4 GHz band (namely Wi-Fi and Bluetooth), and to minimize
power consumption. The receiver uses differential signal paths to reduce sensitivity to noise interference.
Following RF amplification, the signal is downconverted by an image-rejecting mixer, filtered, and then
digitized by an ADC.
The digital section of the receiver uses a coherent demodulator to generate symbols for the hardware-based
MAC. The digital receiver also contains the analog radio calibration routines, and controls the gain within the
receiver path.
The radio transmitter uses an efficient architecture in which the data stream directly modulates the VCO
frequency. An integrated PA provides the output power. Digital logic controls Tx path and output power
calibration. If the EM35x is to be used with an external PA, use the TX_ACTIVE or nTX_ACTIVE signal to control
the timing of the external switching logic.
The integrated 4.8 GHz VCO and loop filter minimize off-chip circuitry. Only a 24 MHz crystal with its loading
capacitors is required to establish the PLL local oscillator signal.
The MAC interfaces the on-chip RAM to the Rx and Tx baseband modules. The MAC provides hardware-based
IEEE 802.15.4-2003 packet-level filtering. It supplies an accurate symbol time base that minimizes the
synchronization effort of the Ember software and meets the protocol timing requirements. In addition, it
provides timer and synchronization assistance for the IEEE 802.15.4-2003 CSMA-CA algorithm.
The EM35x integrates hardware support for a packet trace module, which allows robust packet-based debug.
This element is a critical component of InSight Desktop, the Ember software IDE, and provides advanced
network debug capability when used with Ember’s InSight Adapter.
3-1
120-035X-000G
Final