Rainbow Electronics MAX105 - Manual (Page 17)

plies to the appropriate ground with a 10µF tantalum
capacitor, to filter power supply noise, in parallel with a
0.1µF capacitor. A combination of 0.01µF in parallel
with high quality 47pF ceramic chip capacitor located
very close to the MAX105 device filters high frequency
noise. A properly designed PC board (see MAX105EV
Kit data sheet) allows the user to connect all analog
supplies and all digital supplies together thereby
requiring only two separate power sources. Decoupling AV
CC
, AV
CC
I, AV
CC
Q and AV
CC
R with ferrite-bead
suppressors prevents further crosstalk between the
individual analog supply pins
Thermal Management
The MAX105 is designed for a thermally enhanced 80-
pin TQFP package, providing greater design flexibility,
increased thermal efficiency and a low thermal junc-
tion-case (
θjc) resistance of ≈1.26°C/W. In this pack-
MAX105
Dual, 6-Bit, 800Msps ADC with On-Chip,
Wideband Input Amplifier
______________________________________________________________________________________ 17
AV
CC
Q
AV CC
AGNDR
AGND
AGNDI
AGNDQ
AV
CC
Q
AV CC
AGND
AGNDQ
AGNDI
AGNDR
AV
CC
I
PC BOARD AV
CC
PC BOARD OV CC
PC BOARD AGND FERRITE-BEAD
SUPPRESSORS
PC BOARD OGND
AV CC R AV CC R
AV CC I
OV
CC
Q
OV CC Q
OGNDQ
OGNDQ
OGNDI
OGNDI
OV CC I
OV CC I, OV CC Q
OV CC I
OV
CC
Q
OV CC Q
OGNDQ
OGNDQ
OGNDI
OGNDI
OV CC I
OV CC I
NOTE:
LOCATE ALL 47pF AND 10nF CAPACITORS, WHICH DECOUPLE AV
CC I, AV CC Q, AV CC R, OV CC I, AND OV CC Q AS CLOSE
AS POSSIBLE TO THE CHIP. IT IS ALSO RECOMMENDED TO CONNECT ALL ANALOG GROUND CONNECTIONS TO A COMMON ANALOG
GROUND PLANE AND ALL DIGITAL GROUND CONNECTIONS TO ONE COMMON DIGITAL GROUND PLANE ON THE PC BOARD. A SIMILAR
TECHNIQUE CAN BE USED FOR ALL ANALOG AND DIGITAL POWER SUPPLIES.
AV CC = AV CC I = AV CC Q = AV CC R = +5V ±5%
OV CC I = OV CC Q = +3.3V ±10%
10nF 47pF
4 x 10nF
10nF 47pF
10 µF 10nF
10 µF 10nF
10nF 47pF
10nF
10nF
10nF
10nF
10nF 47pF
47pF
47pF
47pF
47pF
MAX105
Figure 9. MAX105 Decoupling, Bypassing and Grounding