LDO
TPS7A4501
6V Input
5V
LDO
TPS79633
CDCE72010
DC/DC
TPS62291
3.3V
LDO
TPS79518
1.8V
6V
JP10
JP19
JP11
JP12
JP18
JP20
JP14
JP13
JP4
DC/DC
TPS62231
TRF3703
I/Q Mod
VCXO
AFE722x
AFE7225
TSW3100
Pattern Generator
Serialized LVDS
6x DAC Rate
Synchronous Clock
@ 1/8 DAC Rate
Power Supply Options
5
Power Supply Options
The AFE722x EVM is designed to operate from an external 6 V wall wart supply. A LDO generates a 5V
rail for the TRF3703 IQ modulator as well as for the low noise LDOs which are generating a 3.3 V and 1.8
V rail for the AFE722x and the CDCE72010. Alternatively the 3.3 V and 1.8 V rails can be generated using
DC/DC converters which operate directly from the 6 V input for maximum power efficiency.
The EVM provides options to disable unused circuits by means of pin headers. These headers can also
be used for accurate power measurements where external power supplies can be directly connected to
them.
Three pin headers allow a convenient change between powering the AFE722x and CDCE72010 either
from DC/DC converter or low noise LDO.
6
Clocking Configuration
The AFE722x EVM offers 3 different options for
providing the clock to the AFE722x as well as the
supporting circuitry. The biggest challenge arises
when using the DAC with the TSW3100 because
the TSW3100 expects an input clock at 1/8 of the
DAC input data rate. However since the AFE722x
is designed for the serial LVDS interface, the DAC
data rate is 6x the actual AFE722x clock frequency.
Hence the clock to the TSW3100 needs to 6/8 =
3/4x the AFE722x clock frequency.
9
SLOU330
–
December 2011
EVM Description
Copyright
©
2011, Texas Instruments Incorporated