MRF24WB0MA/RM Microchip Technology, MRF24WB0MA/RM Datasheet - Page 14

• Manufacturer Part Number: MRF24WB0MA/RM
• Description: TXRX RF 2.4GHZ PCB ANT 802.11B
• Manufacturer: Microchip Technology

Specifications of MRF24WB0MA/RM

• Frequency: 2.4GHz
• Data Rate - Maximum: 1Mbps
• Modulation Or Protocol: 802.11 b
• Applications: ISM
• Power - Output: 10dBm
• Sensitivity: -91dBm
• Voltage - Supply: 2.7 V ~ 3.6 V
• Current - Receiving: 85mA
• Current - Transmitting: 154mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: On-Board, Trace
• Operating Temperature: 0°C ~ 70°C
• Package / Case: Module
• Wireless Frequency: 2.4 GHz
• Interface Type: SPI, JTAG
• Board Size: 21 mm x 31 mm
• Modulation: DSSS
• Security: WEP, WPA-PSK, WPA-2-PSK
• Operating Voltage: 2.7 V to 3.6 V
• Antenna: PCB Meander
• Operating Temperature Range: 0 C to + 70 C
• Frequency Rf: 2.4GHz
• Transmit Power: 9mW
• Module Interface: SPI, 4-Wire
• Modulation Type: DSSS
• Data Rate Max: 2Mbps
• Supply Current: 154mA
• Supply Voltage Range: 2.7V To 3.6V
• Frequency Range: 2.4GHz
• Leaded Process Compatible: Yes
• Rohs Compliant: Yes
• For Use With/related Products: PIC18, PIC24, dsPIC33, PIC32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MRF24WB0MA/MRF24WB0MB
2.2
The internal regulators for the digital and analog core
power supplies are enabled by driving the HIBERNATE
pin high. Figure 2-2 shows the waveforms for the core
supplies when powering up the MRF24WB0MA/
MRF24WB0MB with a nominal 3.3V applied to VDD.
FIGURE 2-2:
2.3
The
power states. These are Hibernate, Sleep and Active
(two sub-states), as shown in Figure 2-3. The selection
of power state directly affects system behavior, as well
as overall power consumption or battery life. There is
also a “Standby” state that is not user-controlled.
2.3.1
An “Off” state is defined as no power applied to the
device. The Hibernate mode is the closest to controlled
off that the module can approach. It is controlled via the
HIBERNATE pin (high input puts the module into Hiber-
nate). When in Hibernate, the module only consumes
leakage current, but does not maintain state. Hibernate
has to be fully controlled by the PIC MCU and requires
the TCP/IP stack to restart on an awake. This state pro-
vides the best battery life for embedded products. Note
that entering Hibernate for intervals of less than 30 sec-
onds is not likely to save power. Battery life expectation
can be more than a year for devices operating on AA
cells that would be in Hibernate except to wake up
every hour for a small data transfer (<500 Bytes).
DS70632A-page 14
MRF24WB0MA/MRF24WB0MB
Power-On Sequence
Power States
HIBERNATE STATE
2.7 V
(System Dependent)
MRF24WB0MA/MRF24WB0MB POWER-ON SEQUENCE TIMING
Power On Ramp
V
DD
<5 ms
has
several
300 ms minimum
MRF24WB0MA
Preliminary
Internal Boot
There is an internal Power-on-Reset (POR) detect
which starts the boot sequence from the internal ROM
when the core is powered. After approximately 300 ms
from when the VDD supply is within specification, the
MRF24WB0MA/MRF24WB0MB is ready for operation.
2.3.2
The Sleep state is a low power dynamic state that auto-
matically implements the 802.11 Power Save feature.
In this mode, if enabled, the module will enter power
save mode when all activity is complete.
The module will wake autonomously to any PIC inter-
vention so it can check DTIM beacons from the Access
Point. If any traffic is listed as queued for the module,
then it will awaken and get the data from the Access
Point on the next possible opportunity. When data is
acquired, the module will interrupt the PIC microcon-
troller on a normal “data available” indication. If no data
is available on a DTIM check, the module reenters the
Power Save state until the next DTIM. The DTIM inter-
val is programmed at the Access Point. This state can
provide “as if on” behavior of the radio with a significant
power savings versus “always on”. The battery life
expectation of this mode is several days to several
weeks. This mode is characterized by a very low
latency (as low as 200 mS) to transfer data from the low
power state.
2.3.3
The Active state is identified as one of two states where
the radio circuitry is fully on. There is the Receive state
(RX ON) and the Transmit state (TX ON).
SLEEP STATE
ACTIVE STATE
Ready for
Operation
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