MAX1196ECM+TD Maxim Integrated Products, MAX1196ECM+TD Datasheet - Page 19

• Manufacturer Part Number: MAX1196ECM+TD
• Description: IC ADC 8BIT 40MSPS DL 48-TQFP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1196ECM+TD

• Number Of Bits: 8
• Sampling Rate (per Second): 40M
• Data Interface: Parallel
• Number Of Converters: 2
• Power Dissipation (max): 108mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A frequently used modulation technique in digital com-
munications applications is quadrature amplitude mod-
ulation (QAM). Typically found in spread- spectrum-
based systems, a QAM signal represents a carrier fre-
quency modulated in both amplitude and phase. At the
transmitter, modulating the baseband signal with quad-
rature outputs, a local oscillator followed by subse-
quent up-conversion can generate the QAM signal. The
result is an in-phase (I) and a quadrature (Q) carrier
Figure 9. External Unbuffered Reference Drive With MAX4252 and MAX6066
Internal Reference and Multiplexed Parallel Outputs
NOTE: ONE FRONT-END REFERENCE CIRCUIT DESIGN CAN BE USED WITH UP TO 32 ADCs.
MAX4254 POWER-SUPPLY
BYPASSING. PLACE CAPACITOR
AS CLOSE AS POSSIBLE TO
THE OP AMP.
3.3V
MAX6066
Typical QAM Demodulation Application
Dual 8-Bit, 40Msps, 3V, Low-Power ADC with
1
3
0.1µF
3.3V
2
21.5kΩ
0.1µF
______________________________________________________________________________________
1µF
21.5kΩ
21.5kΩ
21.5kΩ
21.5kΩ
2.0V
1.5V
1.0V
10
3
2
5
6
9
4
4
4
11
11
11
1/4 MAX4252
1/4 MAX4252
1/4 MAX4252
3.3V
3.3V
3.3V
1
7
8
10µF
6V
10µF
6V
10µF
6V
1.47kΩ
1.47kΩ
1.47kΩ
47kΩ
47kΩ
47kΩ
1.0V AT -8mA
2.0V AT 8mA
1.5V AT 0mA
component, where the Q component is 90 degrees
phase-shifted with respect to the in-phase component.
At the receiver, the QAM signal is divided down into its
I and Q components, essentially representing the mod-
ulation process reversed. Figure 10 displays the
demodulation process performed in the analog domain,
using the dual matched 3V, 8-bit ADC MAX1196, and
the MAX2451 quadrature demodulator to recover and
digitize the I and Q baseband signals. Before being
digitized by the MAX1196, the mixed-down signal com-
ponents can be filtered by matched analog filters, such
330µF
6V
330µF
330µF
6V
6V
0.1µF
0.1µF
N.C.
N.C.
0.1µF
0.1µF
0.1µF
0.1µF
29
31
32
29
31
32
1
2
1
2
REFOUT
REFIN
REFP
REFN
COM
REFOUT
REFIN
REFP
REFN
COM
MAX1196
MAX1196
N = 1
N = 32
0.1µF
2.2µF
10V
19