Chip information, Table 2. power-supply-voltage combinations – Rainbow Electronics MAX1201 User Manual

Page 13

M
A

X12

+5V Single-Supply, 2.2Msps, 14-Bit

Self-Calibrating ADC

______________________________________________________________________________________

The MAX1201 has three power-supply inputs: analog
V

(AV

), digital V

(DV

), and drive V

(DRV

). Each AV

input should be decoupled with

parallel ceramic chip capacitors of values 0.1µF and
0.001µF, with these capacitors as close to the pin as
possible and with the shortest possible connection to
the ground plane. The DV

pins should also have

separate 0.1µF capacitors again adjacent to their
respective pins, as should the DRV

pin. Minimize the

digital load capacitance. However, if the total load
capacitance on each digital output exceeds 20pF, the
DRV

decoupling capacitor should be increased or,

preferably, digital buffers should be added.

The power-supply voltages should also be decoupled
with large tantalum or electrolytic capacitors at the
point the voltages enter the PCB. Ferrite beads with
additional decoupling capacitors forming a pi network
could also improve performance.

The analog power-supply input (AV

) for the

MAX1201 is typically +5V, while the digital supplies
can vary from +5V to +3V. Usually, DV

and DRV

pins are connected to the same power supply. Note
that the DV

supply voltage must be greater than or

equal to the DRV

voltage. For example, a digital

+3.3V supply could be connected to DRV

while a

cleaner +5V supply is connected to DV

resulting in

slightly improved performance. Alternatively, the +3.3V
supply could be connected to both DRV

and DV

However, the +3.3V supply should

not

be connected to

while the +5V supply is connected to DRV

(Table 2).

Table 2. Power-Supply-Voltage
Combinations

Chip Information

TRANSISTOR COUNT: 56,577

SUBSTRATE CONNECTED TO AGND

(V)

DRV

(V)

ALLOWED/

NOT ALLOWED

Allowed

3.3

Allowed

3.3

Allowed

3.3

Not

Allowed