MAX1407 Datasheet, PDF (46/48 Pages) Maxim Integrated Products – Low-Power, 16-Bit Multichannel DAS with Internal Reference,10-Bit DACs, and RTC

Low-Power, 16-Bit Multichannel DAS with
Internal Reference,10-Bit DACs, and RTC
the placement of the crystal on the PC board layout to
insure that extra clock “ticks” do not couple onto the
crystal pins.
1) It is important to place the crystal as close as possi-
ble to the CLKIN and CLKOUT pins. Keeping the
trace lengths between the crystal and pins as small
as possible reduces the probability of noise cou-
pling by reducing the length of the “antennae”.
Keeping the trace lengths small also decreases the
amount of stray capacitance.
2) Keep the crystal bond pads and trace width to the
CLKIN and CLKOUT pins as small as possible. The
larger these bond pads and traces are, the more
likely it is that noise can couple from adjacent signals.
3) If possible, place a guard ring (connect to ground)
around the crystal. This helps to isolate the crystal
from noise coupled from adjacent signals.
4) Insure that no signals on other PC board layers run
directly below the crystal or below the traces to the
CLKIN and CLKOUT pins. The more the crystal is
isolated from other signals on the board, the less
likely it is that noise will be coupled into the crystal.
There should be a minimum of 0.200 inches
between any digital signal and any trace connected
to CLKIN or CLKOUT.
5) It may also be helpful to place a local ground plane
on the PC board layer immediately below the crystal
guard ring. This helps to isolate the crystal from
noise coupling from signals on other PC board lay-
ers. Note: The ground plane needs to be in the
vicinity of the crystal only and not on the entire
board.
Definitions
Integral Nonlinearity
Integral nonlinearity (INL) is the deviation of the values
on an actual transfer function (with offset and gain error
removed) from a straight line. This straight line can be
either a best straight-line fit or a line drawn between the
endpoints of the transfer function, once offset and gain
errors have been nullified. The static linearity parame-
ters for the MAX1407/MAX1408/MAX1409/MAX1414 are
measured using the endpoint method.
Differential Nonlinearity
Differential nonlinearity (DNL) is the difference between
an actual step width and the ideal value of 1LSB. A
DNL error specification of less than 1LSB guarantees
no missing codes and a monotonic transfer function.
Pin Configurations (continued)
TOP VIEW
IN7 1
DO 2
IN6 3
IN4 4
IN0 5
REF 6
AGND 7
AV_DD 8
CPLL 9
WU1 10
WU2 11
RESET 12
IN1 13
IN2 14
MAX1408
28 IN5
27 IN3
26 DV_DD
25 DGND
24 CS
23 SCLK
22 DIN
21 DOUT
20 INT
19 CLKIN
18 CLKOUT
17 FOUT
16 DRDY
15 SHDN
FB1 1
OUT1 2
IN0 3
REF 4
AGND 5
AV_DD 6
CPLL 7
WU1 8
WU2 9
RESET 10
MAX1409
20 DV_DD
19 DGND
18 CS
17 SCLK
16 DIN
15 DOUT
14 INT
13 CLKIN
12 CLKOUT
11 FOUT
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