REV. B
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a
CMOS, ADC p/4 DQPSK
Baseband Transmit Port
AD7011
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
Single +5 V Supply
On-Chip p/4 DQPSK Modulator
Modulator Bypass Analog Mode
Root-Raised Cosine Tx Filters, a = 0.35
Two 10-Bit D/A Converters
4th Order Reconstruction Filters
Differential Analog Outputs
On-Chip Ramp Up/Down Power Control
On-Chip Tx Offset Calibration
Dual Mode Operation, Analog and Digital
Very Low Power Dissipation, 30 mW typical
Power Down Mode < 10 mA
On-Chip Voltage Reference
24-Pin SSOP
APPLICATIONS
American Digital Cellular Telephony
American Analog Cellular Telephony
GENERAL DESCRIPTION
The AD7011 is a complete low power, CMOS, pi/4 DQPSK
modulator with single +5 V power supply. The part is designed
to perform the baseband conversion of I and Q transmit wave-
forms in accordance with the American Digital Cellular Tele-
phone system (TIA IS-54).
The on-chip pi/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. The 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 pi/4 DQPSK
modulation, the part also provides reconstruction filters to
smooth the DAC outputs, providing continuous time analog
outputs. The AD7011 generates differential analog outputs for
both the I and Q signals.
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. The AD7011 is housed in a space efficient 24-pin
SSOP (Shrink Small Outline Package).
FUNCTIONAL BLOCK DIAGRAM
Tx CLK (FRAME)
BOUT
QTx
V
AA
MODE1
AD7011
ITx
ITx
10-BIT
I-DAC
RECONSTRUCTION
FILTERS
2.46V
REFERENCE
POWER
QTx
CALIBRATION CIRCUITRY
MODULATOR
BYPASS
10-BIT
Q-DAC
Tx DATA (I DATA)
DGND
V
DD
MODE2
AGND
BYPASS
BIN (Q DATA)
RECONSTRUCTION
FILTERS
READY
ANALOG MODE
SERIAL
INTERFACE
pi /4 DQPSK
DIGITAL
MODULATOR
MCLK
I
Q
I
Q