MAX1102 Datasheet, PDF (15/16 Pages) Maxim Integrated Products – 8-Bit CODECs

8-Bit CODECs
SYSTEM POWER SUPPLIES
GND
+3V/+5V
1µF
10Ω
0.1µF
GND
V_DD
DGND V_DD
MAX1102
MAX1103
MAX1104
DIGITAL
CIRCUITRY
Figure 10. Power-Supply Connections
Data can be written to the DAC while it is in shutdown.
A control word with A1 = 1 and E0 = 0 disables the
DAC while allowing data to be written to the DAC. The
eight bits following this control word are shifted into the
DAC register. Conversion takes place once the DAC is
enabled.
Two control words are necessary to enable the ADC.
The first control word brings the ADC out of shutdown,
and sets the T/H in acquisition mode. The second con-
trol word initiates the conversion.
Bit 2 (E2) controls the reference. A logic “1” enables
the reference, a logic “0” disables the reference, further
reducing power consumption.
Power Supply Bypassing and Layout
For best performance, use printed circuit boards. Wire-
wrap boards are not recommended. Board layout
should ensure that digital and analog signal lines are
separated from each other. Do not run analog and digi-
tal (especially clock) lines parallel to one another or run
digital lines underneath the device.
Figure 10 shows the recommended system-ground
connections. A single-point analog ground (star-ground
point) should be established at the device ground.
Connect all analog grounds to the star ground. No digi-
tal-system ground should be connected to this point.
The ground return to the power supply for the star
ground should be connected to this point. The ground
return to the power supply for the star ground should
be low impedance and as short as possible for noise-
free operation. High-frequency noise in the VDD power
supply may affect device performance. Bypass the
supply to the star ground with 0.1µF and 1µF capaci-
tors close to the device. Minimize capacitor lead
lengths for best supply-noise rejection. If the power
supply is very noisy, connect a 10Ω resistor in series
with VDD to form a lowpass filter.
Chip Information
TRANSISTOR COUNT: 3226
PROCESS: BiCMOS
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