Rainbow Electronics MAX7415 - Manual (Page 10)

MAX7408/MAX7411/MAX7412/MAX7415
5th-Order, Lowpass, Elliptic,
Switched-Capacitor Filters
10 ______________________________________________________________________________________
Characteristics table for the input voltage range of COM
and OS. Changing the voltage on COM or OS signifi-
cantly from mid-supply reduces the dynamic range.
Power Supplies
The MAX7408/MAX7411 operate from a single +5V
supply and the MAX7412/MAX7415 operate from a sin-
gle +3V supply. Bypass V
DD to GND with a 0.1µF
capacitor. If dual supplies are required, connect COM
to the system ground and GND to the negative supply.
Figure 4 shows an example of dual-supply operation.
Single-supply and dual-supply performance are equiv-
alent. For either single-supply or dual-supply operation,
drive CLK and SHDN from GND (V- in dual supply
operation) to V
DD . Use the MAX7408/MAX7411 for
±2.5, and use the MAX7412/MAX7415 for ±1.5V. For
±5V dual-supply applications, see the MAX291/
MAX292/MAX295/MAX296 and MAX293/MAX294/
MAX297 data sheets.
Input Signal Amplitude Range
The optimal input signal range is determined by observ-
ing the voltage level at which the signal-to-noise plus
distortion (SINAD) ratio is maximized for a given corner
frequency. The
Typical Operating Characteristics show
the THD+Noise response as the input signal’s peak-to-
peak amplitude is varied.
Anti-Aliasing and Post-DAC Filtering
When using the MAX7408/MAX7411/MAX7412/
MAX7415 for anti-aliasing or post-DAC filtering, syn-
chronize the DAC (or ADC) and the filter clocks. If the
clocks are not synchronized, beat frequencies may
alias into the desired passband.
Harmonic Distortion
Harmonic distortion arises from nonlinearities within the
filter. These nonlinearities generate harmonics when a
pure sine wave is applied to the filter input. Table 1 lists
typical harmonic distortion values with a 10k
Ω
load at
T A = +25°C.
V DD
V+
V-
IN
CLK
GND
INPUT
OUTPUT OUT
0.1 µ F
CLOCK
*CONNECT SHDN TO V- FOR LOW-POWER SHUTDOWN MODE.
SHDN
COM
OS
0.1 µ F
MAX7408
MAX7411
MAX7412
MAX7415
*
V+
V-
Figure 4. Dual-Supply Operation
Table 1. Typical Harmonic Distortion
FILTER
f IN
(Hz)
V IN
(Vp-p)
MAX7408
1k
200
4
2nd 4th
f CLK
(kHz)
500
100
-78.4 -85.5
-88.2
TYPICAL HARMONIC DISTORTION (dB)
-92.8
-93
-86.9
-83.1 -89.5
3rd 5th
MAX7411
1k
200
4
500
100
-80 -90
-88
1k
-92
-92
MAX7415
200
2
500
100
-87
-90
-90
-90
-88
-86
-86
-87
-88
-90
-90
MAX7412
1k
200
2
500
100
-93.1 -86.6
-88.2
-90
-88.9
-85.6
-85.1 -85.7