Datasheet

8th-Order, Lowpass, Elliptic,
Switched-Capacitor Filters
_______________________________________________________________________________________ 5
Note 1: The maximum f
C
is defined as the clock frequency, f
CLK
= 100 · f
C
, at which the peak SINAD drops to 68dB with a
sinusoidal input at 0.2f
C
.
Note 2: DC insertion gain is defined as ∆V
OUT
/ ∆V
IN
.
Note 3: OS voltages above V
DD
- 1V saturate the input and result in a 75µA typical input leakage current.
Note 4: For MAX7400/MAX7403, f
OSC
(kHz) ≅ 38 · 10
3
/ C
OSC
(pF). For MAX7404/MAX7407, f
OSC
(kHz) ≅ 34 · 10
3
/ C
OSC
(pF).
Note 5: The input frequencies, f
IN
, are selected at the peaks and troughs of the frequency responses.
ELLIPTIC (r = 1.2) FILTER CHARACTERISTICS—MAX7403/MAX7407
(V
DD
= +5V for MAX7403, V
DD
= +3V for MAX7407; filter output measured at OUT; 10kΩ || 50pF load to GND at OUT; SHDN = V
DD
;
V
COM
= V
OS
= V
DD
/ 2; f
CLK
= 100kHz; T
A
= T
MIN
to T
MAX
; unless otherwise noted. Typical values are at T
A
= +25°C.)
Typical Operating Characteristics
(V
DD
= +5V for MAX7400/MAX7403, V
DD
= +3V for MAX7404/MAX7407; V
COM
= V
OS
= V
DD
/ 2; SHDN = V
DD
; f
CLK
= 100kHz;
T
A
= +25°C; unless otherwise noted.)
-120
-80
-100
-40
-60
0
-20
20
012345
MAX7400/MAX7404 (r = 1.5)
FREQUENCY RESPONSE
MAX7400/03-01
INPUT FREQUENCY (kHz)
GAIN (dB)
f
C
= 1kHz
-0.08
0
-0.04
0.12
0.08
0.04
0.20
0.16
0.24
0 202 404 606 808 1010
MAX7400/MAX7404 (r = 1.5)
PASSBAND FREQUENCY RESPONSE
MAX7400/03-02
INPUT FREQUENCY (Hz)
GAIN (dB)
f
C
= 1kHz
-640
-480
-560
-240
-320
-400
-80
-160
0
0 300 600 900 1200 1500
MAX7400/MAX7404 (r = 1.5)
PHASE RESPONSE
MAX7400/03-03
INPUT FREQUENCY (Hz)
PHASE SHIFT (DEGREES)
f
C
= 1kHz
PARAMETER MIN TYP MAX UNITS
-58 -50
-60 -54
Insertion Gain Relative to DC Gain
(Note 5)
-60 -54
f
IN
= 1.533f
C
dB
f
IN
= 2.875f
C
-59 -54
f
IN
= 1.200f
C
f
IN
= 1.261f
C
-0.20 0.10 0.20
-0.20 0.14 0.30
CONDITIONS
-0.20 0.09 0.30
f
IN
= 0.992f
C
f
IN
= 1.000f
C
-0.20 0.02 0.20
f
IN
= 0.902f
C
f
IN
= 0.956f
C
-0.20 0.02 0.20
-0.20 -0.06 0.20
f
IN
= 0.640f
C
f
IN
= 0.784f
C
-0.20 -0.11 0.20f
IN
= 0.408f
C
MAX7400/MAX7403/MAX7404/MAX7407