a
FEATURES
Single +5 V Supply
On-Chip /4 DQPSK Modulator
Modulator Bypass Analog Mode
Root-Raised Cosine Tx Filters, = 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 A
On-Chip Voltage Reference
24-Pin SSOP
APPLICATIONS
American Digital Cellular Telephony
American Analog Cellular Telephony
CMOS, ADC /4 DQPSK
Baseband Transmit Port
AD7011
GENERAL DESCRIPTION
The AD7011 is a complete low power, CMOS,
π/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
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. 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
π/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
DGND
MCLK
I
BIN (Q DATA)
ANALOG MODE
SERIAL
Q
INTERFACE
MODULATOR
BYPASS
I
Tx DATA (I DATA)
Tx CLK (FRAME)
π
/4 DQPSK
DIGITAL
MODULATOR
10-BIT
Q-DAC
10-BIT
I-DAC
RECONSTRUCTION
FILTERS
ITx
ITx
V
DD
V
AA
AGND
CALIBRATION CIRCUITRY
Q
RECONSTRUCTION
FILTERS
QTx
QTx
READY
AD7011
POWER
2.46V
REFERENCE
BOUT
BYPASS
MODE1
MODE2
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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