CMOS, ADC /4 DQPSK
Baseband Transmit Port
a
AD7011
GENERAL D ESCRIP TIO N
FEATURES
T he AD7011 is a complete low power, CMOS, π/4 DQPSK
modulator with single +5 V power supply. T he part is designed
to perform the baseband conversion of I and Q transmit wave-
forms in accordance with the American Digital Cellular T ele-
phone system (T IA IS-54).
Single +5 V Supply
On-Chip / 4 DQPSK Modulator
Modulator Bypass Analog Mode
Root-Raised Cosine Tx Filters, ␣ = 0.35
Tw o 10-Bit D/ A Converters
4th Order Reconstruction Filters
Differential Analog Outputs
On-Chip Ram p Up/ Dow n Pow er Control
On-Chip Tx Offset Calibration
Dual Mode Operation, Analog and Digital
Very Low Pow er Dissipation, 30 m W typical
Pow er Dow n Mode < 10 A
On-Chip Voltage Reference
24-Pin SSOP
T he on-chip π/4 Differential Quadrature Phase Shift Keying
(DQPSK) digital modulator, which includes the root raised
cosine filters, generates I and Q data in response to the transmit
data stream. T he AD7011 also contains ramp control envelope
logic to shape the I and Q output waveforms when ramping up
or down at the beginning or end of a transmit burst.
Besides providing all the necessary logic to perform π/4 DQPSK
modulation, the part also provides reconstruction filters to
smooth the DAC outputs, providing continuous time analog
outputs. T he AD7011 generates differential analog outputs for
both the I and Q signals.
APPLICATIONS
Am erican Digital Cellular Telephony
Am erican Analog Cellular Telephony
As it is a necessity for all digital mobile systems to use the lowest
possible power, the device has transmit and receive power-down
options. T he AD7011 is housed in a space efficient 24-pin
SSOP (Shrink Small Outline Package).
FUNCTIO NAL BLO CK D IAGRAM
V
V
AGND
DGND
DD
AA
MCLK
I
Q
I
ITx
ITx
10-BIT
I-DAC
RECONSTRUCTION
FILTERS
BIN (Q DATA)
ANALOG MODE
SERIAL
INTERFACE
MODULATOR
BYPASS
CALIBRATION CIRCUITRY
Tx DATA (I DATA)
Tx CLK (FRAME)
π /4 DQPSK
DIGITAL
MODULATOR
QTx
QTx
10-BIT
Q-DAC
RECONSTRUCTION
FILTERS
Q
READY
POWER
BOUT
2.46V
REFERENCE
AD7011
BYPASS
MODE1 MODE2
REV. B
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use, nor for any infringem ents of patents or other rights of third parties
which m ay result from its use. No license is granted by im plication or
otherwise under any patent or patent rights of Analog Devices.
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